ABSTRACTS

OF LECTURES AND SCIENTIFIC POSTERS

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EUROPEAN ORTHODONTIC SOCIETY 90th Congress Warsaw, Poland, 2014 18-22 June

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The authors of abstracts marked *** have indicated, or have failed to indicate, that they have a financial interest.

Oral Presentations

1 COMPARISON OF PULPAL IMMNUHISTOPATHOLOGIC CHANGE DUE TO ADHESIVE CLEAN-UP AFTER DEBRACKETING BY LOW-SPEED HANDPIECE WITH AND WITHOUT WATER COOLANT E Afsarierdchi1, A M Kalantar Motamed2, 1International Department, Guilan University of Medical Sciences, Rasht and 2Azad University, Kkhorasgan Branch, Isfahan, Iran

AIM: The heat generated during clean-up procedures after debonding might transmit to the pulp and cause histological changes. Concerns exist regarding pulpal damage caused by the heat generated. The present study Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 investigated the pulpal inflammatory response after debonding with a low-speed handpiece with and without water coolant and the subsequent histological changes. MATERIALS AND METHOD: In this controlled clinical trial 40 premolars, requiring extraction for orthodontic purposes, were obtained from 10 patients. The randomly assigned teeth in the first group were not etched and bonded; in the second group teeth were etched, brackets were bonded and extracted without debonding; in the third group resin removal was undertaken with water coolant and the teeth were extracted 24 hours after debonding. In the fourth group resin removal was undertaken without water coolant and the teeth were extracted 24 hours after debonding and in the fifth group resin removal was undertaken without water coolant and the teeth were extracted 20 days after debonding (n = 8 for each group). The teeth were prepared for histologic examinations for scores of odontoblastic layer disruption, cell-free layer, inflammatory cell infiltration, extravasation of red blood cells, vascular congestion, number of vessels and vessel areas. The data were subjected to Kruskal-Wallis and Mann-Whitney U tests. RESULTS: Tooth pulps where the resin was removed with water coolant (group 3) showed similar results to the other groups without any significant differences. Clean-up technique without water coolant in the teeth extracted 24 hours after debonding resulted in significant histological changes of the pulp; however, these changes reversed to some degree in teeth extracted 20 days after debonding. No significant differences were noted between these specimens and control groups regarding the number and vessel areas, vascular congestion and cell-free layer existence, suggesting healing of the previous pulpal damage. CONCLUSION: Although some pathologic damage to the pulp tissue was reversible and well-tolerated through time; it was concluded that using a water coolant system is necessary to achieve temperature stability and to prevent possible physiologic damages of the pulp tissues during resin removal.

2 ORTHODONTIC TREATMENT PLANNING FOR IMPACTED MAXILLARY CANINES USING CONVENTIONAL RECORDS VERSUS THREE-DIMENSIONAL CONE BEAM COMPUTED TOMOGRAPHICS A Alqerban1, G Willems1, S Fieuws2, R Jacobs1, 1Department of Oral Health Sciences, KU Leuven and 2Departments of Public Health, KU Leuven and Universiteit Hasselt, Belgium

AIM: To compare the orthodontic treatment planning for impacted maxillary canines based on conventional orthodontic treatment records versus three-dimensional (3D) information taken from single cone beam computed tomographic (CBCT) scans. SUBJECTS AND METHOD: Forty individuals with impacted maxillary canines. The patients were identified from among those referred for orthodontic treatment (26 females, 14 males) with a mean age of 12.5 years (± SD 3). In total, 64 impacted canines were referred for CBCT scans. Two sets of information were obtained. The first set consisted of conventional planning records (2D panoramic, 2D lateral cephalograms, and dental casts) and the second set of 3D volumetric images obtained from a single CBCT scan (3D panoramic, 3D lateral cephalograms, 3D virtual study model). For both sets, intra- and extraoral images were included. The e2

radiographic diagnostic features, treatment planning, orthodontists' opinions, and case classifications of both sets were produced and subsequently analyzed by four orthodontists. RESULTS: There was no statistically significant difference in treatment planning between the use of both sets, in terms of either orthopaedic growth modification or orthodontic compensation. Also anticipated complications during treatment and expected treatment duration did not differ significantly. Orthodontists found the conventional set to be insufficient for treatment planning in 22.5 per cent and requested additional radiographs in 63 per cent of cases, compared with 1.3 and 0.5 per cent, respectively (P < 0.001). The observers' confidence level was higher for therapy based on the 3D set compared with the conventional set (96.3% versus 61.9%, P < 0.001). CONCLUSION: There was no statistically significant difference in treatment planning between the use of conventional radiographs and CBCT images. CBCT images have been shown to offer useful orthodontic treatment planning information, similar to that of conventional planning with a high confidence level. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021

3 MASTICATORY MUSCLE CHARACTERISTICS: NEW CLINICAL DIAGNOSTIC ADVANCES PREDICTING ACTIVATOR TREATMENT OUTCOMES. A PROSPECTIVE CONTROLLED STUDY G Antonarakis, S Kiliaridis, Department of , University of Geneva, Switzerland

AIM: To investigate the role of masseter muscle thickness and maximal molar bite force as possible predictors of Class II division 1 functional appliance treatment outcomes in growing children, using a prospective study design. SUBJECTS AND METHOD: Twenty children with a Class II/1 were treated with an activator during a 12-month period. Standard diagnostic orthodontic records (photographs, study casts, lateral cephalograms) were taken before and after this 12-month period, as were maximal molar bite force and ultrasonographic masseter muscle thickness measurements. An age- and gender-matched control group (n = 20) was also included and these children had only maximal molar bite force and masseter muscle thickness measurements before and after a 12-month observation period. RESULTS: Maximal molar bite force showed a significantly greater (P = 0.049) mean increase during the experimental period for the control (x = 63 N; sd = 85 N) than for the treatment group (x = 3 N; sd = 100 N). Masseter muscle thickness also showed a greater mean increase (P = 0.028) for the control (X = 0.6 mm; sd = 0.5 mm) than for the treatment group (x = 0 mm; sd = 1.1 mm). In the experimental group, lower pre-treatment maximal molar bite force was significantly correlated with greater anterior sagittal movement of the mandibular first molars (r = –0.455; P = 0.044) and maxillary molar distalisation (r = –0.487; P = 0.029). Thinner masseter muscles were also correlated with a greater anterior sagittal movement of the mandibular first molars (r = – 0.452; P = 0.045), as well as more mandibular incisor proclination (r = –0.485; P = 0.030). CONCLUSION: Lower maximal molar bite force or masseter muscle thickness favours more mandibular anterior dental movement during activator treatment in Class II/1 malocclusion children.

4 WHY THE LONG FACE? A GENETIC PERSPECTIVE J Antoun, T Merriman, W M Thomson, M Farella, University of Otago, Dunedin, New Zealand

AIM: Long face morphology is a fairly common clinical presentation in orthodontic patient populations, although its exact aetiology is still unclear. Recent data suggests that the growth hormone receptor may play a role in vertical facial development. The aim of this study was to investigate the association between vertical craniofacial form and single nucleotide polymorphisms (SNPs) of the growth hormone receptor (GHR) gene. SUBJECTS AND METHOD: Eighty patients with a distinctively long face (mandibular plane angle greater than two standard deviations, or 42°) and 80 controls were matched for age, gender, and ethnicity. Subgroups of the long face phenotype were also constructed based on the samples’ cephalometric data. Genomic DNA was extracted

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from blood and saliva samples. Cases and controls were genotyped for the rs6180 and rs6873545 polymorphisms using a TaqMan assay. RESULTS: The sample had a mean age of 13.8 years (SD = 4.1), with the majority of participants being female (65%), and of New Zealand European origin (91.3%). Using multiple logistic regression analyses, cases with the CC genotype for rs6873545 were 5.9 times more likely to have a long face than the controls (CI = 1.02-33.80; P < 0.05). In addition, specific clusters of the long face group, as well as the presence of an anterior open bite, a severely short ramus and an obtuse gonial angle were associated with rs6873545 (P < 0.05). CONCLUSION: There is some evidence that polymorphisms of the GHR gene are associated with specific subgroups of the long face morphology. However, larger samples are needed to investigate this further and to confirm genetic variants associated with the long face phenotype.

5 QUANTITATIVE AND VISUAL EVALUATION OF ENAMEL DECALCIFICATION THROUGHOUT FIXED Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 ORTHODONTIC TREATMENT Ö Batmaz, M B Özel, Department of Orthodontics, Faculty of Dentistry, Karadeniz Technical University, Trabzon, Turkey

AIM: To evaluate in the in vivo efficiency of a non- inhibited layer forming, low viscosity liquid polish (Biscover™ LV) in terms of prevention of enamel demineralization by visual inspection and laser fluorescence method (DIAGNOdent). SUBJECTS AND METHOD: Forty five consecutive patients consented to participate in this investigation. Standardised photographic records for visual evaluation and DIAGNOdent measurements at the beginning and end of treatment were taken from 30 subjects who received fixed appliance treatment. Visual inspection was undertaken using Ogaard's modified white spot lesion index. Orthodontic attachments were bonded following a randomized split mouth design using Transbond™XT primer and Biscover™ LV surface protection agent on the same number of contralateral jaws in 30 randomly selected patients. Fifteen patients who did not receive any orthodontic treatment during the follow-up period served as the controls and only DIAGNOdent measurements were taken from this group. The pre-treatment-post-treatment DIAGNOdent and visual inspection score changes were compared by Mann Whitney U test in dichotomous groups and Kruskal Wallis test in multiple groups. Further pairwise comparison of subgroups was carried out according to Conover’s multiple comparisons. Pre-treatment/post-treatment changes were compared using Wilcoxon’s signed rank test. The consistency of DIAGNOdent and visual inspection evaluations were appraised by the Spearman correlation. RESULTS: Mean pre-treatment/post-treatment DIAGNOdent scores were 2.03 ± 1.93 and 3.36 ± 4.14 in the Transbond™ XT group, 1.84 ± 1.46 and 2.87 ± 3.42 for the Biscover™ group and 1.96 ± 1.26 and 2.65 ± 2.13 for the control group. The change in pre-treatment-post-treatment scores were found to be higher in the Transbond™ XT group (P < 0.05). The Pearson correlation coefficient of visual inspection and DIAGNOdent measurements for Transbond™ XT group was r = 0.073 (P = 0.339) and r = 0.194 (P = 0.012) for the Biscover™ LV group. CONCLUSION: Biscover™ was found to be effective in avoiding white spot lesions especially on the distal tooth surfaces according to DIAGNOdent measurements. Both the visual inspection and DIAGNOdent measurement methods were inconsistent in detecting white spot lesions.

6 FACTORS ASSOCIATED WITH ORTHODONTIC PAIN V Beck1, W M Thomson2, N Chandler3, J Kieser4, M Farella1, 1Discipline of Orthodontics, 3Department of Oral Rehabilitation, 3Department of Oral Sciences and 4Sir John Walsh Research Institute, University of Otago, Dunedin, New Zealand

AIM: Up to 95 per cent of orthodontic patients report pain during orthodontic treatment, with some interrupting their treatment due to the pain experienced. Pain is highly subjective: there is a range of pain e4

response among individuals undergoing orthodontic treatment, with some patients feeling high levels of pain and others just mild discomfort. The reasons for this variability are largely unknown. The aim of this study was to investigate factors that may be associated with orthodontic pain experience. SUBJECTS AND METHOD: First, 107 participants were screened for pain response over 48 hours following placement of orthodontic elastomeric separators. Second, the highest (n = 10) and lowest (n = 10) pain responders were identified and data collected on age, anxiety, dental anxiety and fear, catastrophising, cold sensitivity and tooth sensitivity. They also provided a saliva sample for COMT gene sequencing. RESULTS: Statistically significant differences between high and low pain responders were identified with the Pain Catastrophising Scale (PCS), Dental Anxiety Scale (DAS) and Cold Pressor Tests. Multivariate analysis was carried out using a generalised linear model. The empty model showed that 39.3 per cent of pain response type (high or low) was explained by the magnification subcategory of the PCS; once all other variables were controlled for, the adjusted model explained 80 per cent of the variance in the magnification subscale of the Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 PCS. Of the three SNPs of the COMT gene analysed, only rs6269 showed a marginal association with pain responders' haplotypes. CONCLUSION: Pain catastrophising, dental anxiety and cold sensitivity appear to modify orthodontic pain experience. A few simple screening questions may help to identify patients at risk prior to commencing orthodontic treatment, so that patient-specific management strategies can minimise orthodontic discomfort.

7 A RETROSPECTIVE STUDY ON THE INFLUENCE OF MAXILLARY CANINE IMPACTION ON PREMOLAR ROOT MORPHOLOGY K Bertl1, G Benkö2, M Bertl2, A Gahleitner3, C Ulm1, Divisions of 1Oral Surgery and 2Orthodontics, 3Bernhard Gottlieb School of Dentistry, Medical University of Vienna, Austria

AIM: The root morphology of the maxillary first premolar differs from the other premolars by presenting a high incidence of separated roots. This study addressed the spatial conditions during root development as a possible influencing factor. Therefore, maxillary computed tomographic (CT) scans of patients with regularly erupted or impacted permanent canines were evaluated on the root morphology of the premolars. MATERIALS AND METHOD: The following parameters were retrospectively analysed in 250 maxillary CT scans (100 patients with regular erupted permanent canines, 150 patients with at least one impacted permanent canine): gender, status of the canines (erupted/impacted), position of the impacted canines (buccal/palatal; vertically inclined inside/outside the dental arch/horizontally inclined) and root morphology of the premolars. RESULTS: Sixty eight per cent of the patients with at least one impacted canine were female; the canine was impacted palatally in 75.6 per cent and in a horizontally inclined position in 58.4 per cent. In patients with an impacted canine, the number of first and second premolars with separated roots was significantly reduced on the ipsilateral as well as on the contralateral side (all P values < 0.01). CONCLUSION: The present study detected an influence of maxillary canine impaction on the root morphology of all premolars, in that impaction and the associated surplus of space resulted in decreased root separation. This supports the hypothesis that root development is at least partly influenced by increased spatial conditions of the dental arch. However, root development can be regarded as a multifactorial event, influenced by space, direct mechanical interferences, as well as genetic predetermination. The retrospective nature of this observational study did not allow for conclusive differentiation between these factors. Alternatively, root separation and the mesial concavity of the first premolar may represent a path for canine eruption similar to the lateral incisor.

8 WOUND HEALING CAPACITY OF CELLS DERIVED FROM HUMANS WITH CLEFT LIP/PALATE J Beyeler1, S Ruggiero1, I Schnyder2, C Katsaros1, M Chiquet1, 1Department of Orthodontics, School of Dental Medicine and 2Department of Pediatric Surgery, Inselspital, University of Bern, Switzerland

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AIM: A cleft lip/palate (CLP) is the most common congenital facial malformation. Surgically treated patients can be subject to excessive scarring, which later impedes maxillary growth and dentoalveolar development. Since certain growth factors are involved in both craniofacial morphogenesis and regeneration, a primary defect causing CLP could later in life lead to altered wound repair. The aim is therefore to find a functional link between CLP and wound healing in humans. MATERIALS AND METHOD: In a first attempt towards identifying patients at risk, in vitro wound healing assays were performed with primary dermal fibroblasts isolated from excess lip tissue of 16 CLP patients. Human foreskin fibroblasts from nine individuals (6 healthy, 3 phimosis) were used as control strains. Fibroblast monolayers were grown to confluence on culture dishes and scratch wounds 1 mm in width were applied with pipet tips; wound closure was monitored morphometrically over time. Statistical significances were determined by Kruskal-Wallis/multiple comparisons test. The expression of genes involved in wound repair was determined by qRT-PCR, and statistically evaluated by one-way ANOVA and Tukey’s post-hoc test. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 RESULTS: The mean ranks of wound closure rate in vitro showed highly significant differences between individual fibroblast strains (P < 2.2e-16). After performing multiple comparisons test, cells from different individuals could be divided into three migratory groups, namely ‘fast’ (5 CLP, 3 phimosis), ‘intermediate’ (10 CLP, 3 healthy foreskin) and ‘slow’ (1 CLP, 3 healthy foreskin). These phenotypes were stable when assays were repeated with different cell passages from the same patients. Compared with the intermediate and slow migratory groups, TGFA mRNA was significantly (> 2-fold) up-regulated and PDGFC mRNA down-regulated in the fast migratory group. CONCLUSION: Of the CLP fibroblast strains, about one-third exhibited significantly faster wound closure in vitro. Increased cell migration correlated with changed expressions of TGFA and PDGFC. Both growth factors are known to regulate wound repair by affecting cell migration and proliferation. Interestingly, non-syndromic CLP has been linked to polymorphisms in both of these genes. A causal relationship between in vitro wound healing behaviour and growth factor expression still needs to be established.

9 INDIRECT VERSUS DIRECT BONDING OF LOWER FIXED RETAINERS: A RANDOMIZED CLINICAL TRIAL COMPARING PLACEMENT TIME AND FAILURE RATE OVER A 6 MONTH PERIOD E Bovali, S Kiliaridis, M A Cornelis, Department of Orthodontics, University of Geneva, Switzerland

AIM: To compare placement time and failure rate of mandibular lingual retainers bonded with an indirect versus a direct bonding procedure. The hypotheses were that indirect bonding would require less time than direct bonding and that the failure rate would not be affected. SUBJECTS AND METHOD: Sixty consecutive patients having undergone orthodontic treatment were randomly allocated to either an indirect bonding procedure (silicone transfer tray where the composite pads are already prepared on the by the laboratory technician) or a traditional direct bonding procedure (retention wire is prepared by the laboratory technician and composite pads are added intra-orally). Eligibility criteria included presence of the six lower anterior teeth from canine to canine, no active caries, restorations or fractures and no periodontal problems on these teeth. Randomization was accomplished with random permuted blocks of 4 patients. Blinding was not applicable. Bonding time was measured for each procedure. Patients were recalled at 1, 2, 4 and 6 months after placement of the . After assessing normality of the data, an unpaired t-test was used to detect differences in time of intervention. The log-rank test was used to compare survival curves. Lower fixed retainers having at least one composite pad debonded were further considered as failures. RESULTS: Bonding time was statistically significantly shorter for the indirect (353 ± 31 seconds) (m ± sd) versus the direct procedure (400 ± 35 seconds) (P < 0.001). The overall 6 month success rate was similar between the two groups (P = 0.952). CONCLUSION: The initial hypotheses were confirmed. Indirect bonding was statistically less time consuming than direct bonding. The overall 6 month failure rate was similar between the two groups (74.2% versus 75.9%). e6

10 CLASS II ORTHOPAEDIC TREATMENT: A SYSTEMATIC REVIEW OF SYSTEMATIC REVIEWS R Bucci1, L Franchi2, R Rongo1, R Martina1, V D'Antò1, 1Section of Orthodontics, University of Naples 'Federico II' and 2Department of Oral Sciences, Università degli Studi di Firenze, Italy

AIM: To assess the quality of systematic reviews (SR) on functional-orthopaedic treatment of Class II malocclusion and to evaluate the reported skeletal, dental and soft tissue effects of treatment. MATERIALS AND METHOD: A Systematic literature search was conducted using Medline, Latin American and Caribbean Health Sciences, Scientific Electronic Library Online, and the Cochrane Library. The survey covered the period from the beginning of the databases up to September 2013. A further hand-search of the major orthodontic impacted journals and of conference abstracts was performed. No language restrictions were set. The inclusion criteria were the following: to be a SR, focus on the effects of functional/orthopaedic appliances Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 on Class II , and focus on growing patients. The methodological quality was assessed for each paper using two scores: Assessment of Multiple Systematic Reviews (AMSTAR) and Level of Research Design scoring (LRD). Two independent investigators conducted the search and performed the quality assessment. The inter-observer agreement was calculated with Cohen’s κ coefficient. Disagreements between the two examiners were discussed to reach a unanimous score. RESULTS: The search strategy resulted in 161 references. After reading titles and abstracts, 125 references were excluded. After the full-text reading, 12 articles fulfilled the inclusion criteria. Cohen’s κ coefficient measured 0.91. The average AMSTAR score was 5.9 (range from 2 to 9). Four papers were LRD III, five were LRD II-III, two were LRD II and one was LRD V. Most SRs had mandibular growth as an outcome variable, while few considered maxillary control, tooth position and soft tissue changes. CONCLUSION: An average methodological quality of the SRs was found. The primary studies included in the SRs were mainly studies without randomization. Therefore, it seems necessary to improve the quality level of the primary studies on functional treatment of Class II malocclusions. Clinical recommendations can be made only in the broadest sense, due to the limits of the SRs analyzed. Despite the type of appliance, functional treatment of Class II malocclusions was found to have several advantages and benefits, but the clinical significance of the treatment is still questionable.

11 TREATMENT AND POST-TREATMENT EFFECTS INDUCED BY THE FORSUS APPLIANCE: A CONTROLLED CLINICAL STUDY G Cacciatore1, L T Huanca Ghislanzoni1, V Giuntini2, A Vangelisti2, L Franchi2, 1University of Milan and 2University of Florence, Italy

AIM: To evaluate, in a retrospective controlled clinical study, treatment and post-treatment dentoskeletal effects induced by the Forsus device (FRD) in growing patients with a Class II malocclusion. SUBJECTS AND METHOD: Thirty-six Class II patients (mean age 12.3 ± 1.2 years) were treated consecutively with the FRD protocol and compared with a sample of 20 subjects with an untreated Class II malocclusion (mean age 12.2 ± 0.9 years). Lateral cephalograms were taken at the beginning of treatment, at the end of comprehensive treatment (after 2.3 ± 0.4 years), and at a post-retention period (after 2.3 ± 1.1 years from the end of comprehensive treatment). Statistical comparisons were carried out with the unpaired t-test and Benjamini- Hocberg correction (P < 0.05). RESULTS: During the treatment, the maxilla exhibited a significantly greater decrease in the sagittal skeletal position (SNA: –1.7°) in the FRD group versus the controls. All the interdental measurements showed statistically significant corrections in the FRD group versus controls (overjet: –5.1 mm; : –3.1 mm; molar relationship: +3.5 mm). The upper incisors exhibited a significant retrusion (U1 horizontal –1.6 mm) in the FRD group versus the controls. On the contrary, the lower incisors showed a significant proclination (L1 to MPA: +5.°) associated with a significant protrusion (L1 horizontal: +1.5 mm), and (L1 vertical: –1.6 mm). No e7

significant changes were detected in the horizontal or vertical position of the upper molars in the FRD group versus the controls while the lower first molars showed a significant extrusion (L6 vertical: +1.3 mm). At the end of the comprehensive observation interval, no significant sagittal skeletal changes were detected. With regard to the interdental changes, the FRD group showed significantly greater decreases in both overjet (– 3.8 mm) and overbite (–1.5 mm), as well as a significant improvement in molar relationship (+3.7 mm). The upper incisors exhibited a significantly greater retrusion (U1 horizontal: –1.1 mm) in the FRD group. The lower incisors demonstrated a significant intrusion (L1 vertical: –1.2 mm). CONCLUSION: The FRD protocol was effective in correcting a Class II malocclusion mainly at the dentoalveolar level when evaluated 2.3 years after the end of comprehensive treatment.

12 A PRELIMINARY INVESTIGATION OF CYTOKINE EXPRESSION IN GINGIVAL CREVICULAR FLUID FOLLOWING ORTHODONTIC FORCES AND ASSOCIATED ROOT RESORPTION Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 J Chiu1, R Ahuja1, A Khan2, O Dalci1, M A Darendeliler1, 1Department of Orthodontics, University of Sydney, Surry Hills and 2Australian Proteome Analysis Facility, Macquarie University, Sydney, Australia

AIMS: The variability in the amount of orthodontically induced inflammatory root resorption (OIIRR) may result from differences in the levels of anti- and pro-resorptive cytokines in the periodontal ligament (PDL) micro- environment. The aims of this study were to investigate the changes in the cytokine profile in the gingival crevicular fluid (GCF) after applying heavy orthodontic forces and to compare cytokine expression between patients showing high and low volumes of OIIRR. SUBJECTS AND METHOD: A split mouth study comprising eight patients requiring maxillary first premolar extractions. The test teeth had a controlled buccal tipping force of 225 g for 28 days. GCF was collected from both test and control teeth at six time points and analysed with multiplex bead immunoassay to determine the cytokine levels. RESULTS: Statistically significant temporal increases were found for IL-7 at 3 hours and 28 days (P = 0.02) and for TNF-α at 0 hour and 28 days (P = 0.04), 3 hours and 28 days (P = 0.01) and 1 day and 28 days (P = 0.02). IL- 1ß, IL-4, IFN-γ peaked during the 7 days, IL-6, IL-7, TNF-α and GM-CSF peaked at the 28 days period while IL-8 showed no significant fluctuations. Comparing the cytokine profile for three patients with a high OIIRR (> 0.35 mm3) and three patients with a low OIIRR (< 0.15 mm3) the levels of anti-resorptive cytokines IL-4 (P = 0.07) and GM-CSF (P = 0.03) were higher in low root resorption cases. CONCLUSION: The tendency of higher levels of anti-resorptive cytokines IL-4 and GM-CSF in low root resorption cases may indicate their role in reducing the level of OIIRR although clinical significance of this observation needs to be tested in a larger sample.

13 ASSOCIATION BETWEEN NASOLABIAL SYMMETRY AND AESTHETICS IN CLEFT LIP AND PALATE BASED ON THREE-DIMENSIONAL ANALYSIS OF FACIAL IMAGES D Desmedt1, P Fudalej2, M Kuijpers1, A M Kuijpers-Jagtman1, T Maal3, 1Department of Orthodontics and Craniofacial Biology and 3Mond-Kaak-Aangezichtschirurgie, Radboud UMC, Nijmegen, Netherlands and 2Klinik für Kieferorthopädie, Universitat Bern, Switzerland

AIM: To determine a relationship between nasolabial symmetry and aesthetics in subjects with orofacial clefts SUBJECTS AND METHOD: Eighty four subjects at mean age of 10 years (SD = 1.5) with various types of non- syndromic cleft deformity: 11 had a unilateral cleft lip (UCL), 30 a unilateral cleft lip and alveolus (UCLA) and 43 a unilateral cleft lip, alveolus and palate (UCLAP). Each subject had a three-dimensional (3D) stereophotogrammetric image of the face. Symmetry and aesthetics of the nasolabial area were evaluated on cropped 3D facial images. The symmetry of the nasolabial area was calculated based on all 3D data points using a surface registration algorithm (so called `distance maps`). Aesthetic rating of four nasolabial elements (i.e. nose shape, nose deviation, vermillion border and nose profile) was performed according to the modified Asher- e8

McDade index by eight lay raters on a 100-mm visual analogue scale. Statistical analysis included ANOVA tests and regression models. RESULTS: Nasolabial asymmetry increased with increasing severity of the cleft (UCL = UCLA < UCLAP; P = 0.029). Overall, nasolabial appearance was affected by nasolabial asymmetry, subjects with more nasolabial asymmetry were judged as having a less aesthetic nasolabial area (P < 0.001). However, the relationship between nasolabial symmetry and aesthetics was relatively weak in subjects with a UCLAP in whom only vermillion border aesthetics was associated with asymmetry. CONCLUSION: Nasolabial symmetry assessed with 3D facial imaging can be used as an objective measure of treatment outcome in subjects with a cleft deformity.

14 HOW DO WE PERCEIVE CLEFT FACES? AN EYE-TRACKING STUDY S Dogan1, E Dogan1, S Amado2, F Dindaroglu1, 1Department of Orthodontics, School of Dentistry and Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 2Department of Experimental Psychology, Ege University, Izmir, Turkey

AIM: To examine how the faces of subjects with a unilateral (UCLP) or bilateral cleft lip and palate (BCLP) are perceived by laypersons, orthodontists and individuals with a UCLP or BCLP in comparison with non-affected controls. SUBJECTS AND METHOD: Eighty participants (44 females, 36 males) aged between 25 and 35 (mean age; 29.7 years) years. Sixty photographs (smiling frontal view, non-smiling frontal view) of 30 patients (15 females and 15 males; mean age; 28,5 years) (unaffected, UCLP and BCLP) were viewed for 4 seconds by the participants. Unaffected faces were used as a control group. Eye movements of the participants were analyzed using an eye- tracking method while the participants were looking at the photographs. Eye fixations in four areas of interest (AOI) were quantified; eyes, nose, mouth and chin. The location of the first fixation, the duration of fixation and the number of fixations in all AOI were measured for all images. The duration of the first fixation was also measured. RESULTS: All three participant groups focussed on the eyes more often than the other parts, in non-smiling frontal control photographs but just orthodontists stared at the mouth in smiling frontal photographs longer. All three participant groups looked generally at the nose and mouth areas in non-smiling frontal photographs of UCLP. Even though both orthodontists and CLP patients looked at the mouth area, CLP patients stared at the mouth area longer than the orthodontists. All participant groups looked at the nose and mouth areas of the BCLP patients longer in non-smiling and smiling photographs. CLP patients looked on the mouth and nose areas much more than the other groups, in non-smiling frontal photographs. There was no statistically significant difference between males and females when viewing CLP and control faces. CONCLUSION: Participants with a CLP, focused on the mouth and nose areas as much as orthodontists which means psychological examination of CLP patients is essential in a multidisciplinary approach. Dynamic relationships (smiling) draw much more attention than static relationships (non-smiling) in CLP patients.

15 IS THE CERVICAL VERTEBRAL MATURATION METHOD SUITABLE FOR PREDICTION OF FACIAL GROWTH SPURT IN CLASS II SUBJECTS? T Engel¹, A M Renkema², P Pazera¹, C Katsaros¹, P Fudalej¹, ¹Department of Orthodontics and Dentofacial Orthopaedics, University of Bern, Switzerland and ²Department of Orthodontics and Craniofacial Biology, Radboud University Nijmegen, Netherlands

AIM: To evaluate if the cervical vertebral maturation (CVM) method is suitable for prediction of the facial growth spurt in Class II subjects. SUBJECTS AND METHOD: Twenty nine females with a Class II malocclusion born between 1970 and 1983 were selected from the Nijmegen Growth Study. The sample was untreated orthodontically and had cephalograms taken semi-annually from 9 to 14 years of age. The CVM stage was determined twice on cropped cephalograms e9

taken at 9 years by five orthodontists calibrated and experienced in the use of the CVM method. Facial growth was determined based on semi-annual changes of the following distances: Condylion-Gnathion, Condylion-point B, Articulare-Gnathion, Articulare-point B, Nasion-Spina nasalis anterior, and Spina nasalis anterior-Menton. The distances were remeasured after 30 days by two investigators to determine method error. Intra- and inter-rater agreement in CVM staging was established with kappa statistics. A linear mixed effects model was fitted to determine associations between the individual measurements (Cd-Gn, Cd-B, Ar-Gn, Ar-B, N-Spa Spa-Me,) and mean CVM scores after adjusting for time and accounting for the within-patient correlations. RESULTS: Overall, the intra- and inter-rater agreement in the CVM staging was from slight to moderate (kappa ranged from 0.118 to 0.536). The error of cephalometric evaluation was small. The mean CVM score was not associated with any of the six cephalometric measurements after adjusting for age. The only predictor of facial growth was patient age. CONCLUSION: The CVM method is not effective in prediction of the facial growth spurt in Class II females. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021

16 ORAL HEALTH RELATED QUALITY OF LIFE ACROSS THREE DIFFERENT ORTHODONTIC PATIENT GROUPS P Fowler1, H Jack2, J Antoun2, M Farella2, Orthodontic Departments, 1Christchurch Hospital, Christchurch and 2University of Otago, Dunedin, New Zealand

AIM: To investigate the changes between baseline and post-orthodontic treatment oral health related quality of life (OHRQoL) scores in a group of standard adolescent, cleft lip and/or palate (CL/P) adolescent and adult orthognathic surgery patients. SUBJECTS AND METHOD: Eighty three consecutive patients undertook treatment at Christchurch Hospital, New Zealand. This sample consisted of three groups; 30 adolescents (age 14.5 ± 1.9) with severe malocclusions (DAI 45.5 ± –9.0); 24 adolescents (age 12.6 ± 2.8) with CL/P requiring orthodontic treatment as part of their multidisciplinary management (DAI 45.4 ± 13.4); 29 adult (age 19.0 ± 4.3) with severe skeletal discrepancies requiring both orthognathic surgery and orthodontic treatment (DAI 56.6 ± 12.8). Each patient completed the short form Oral Health Impact Profile (OHIP14) questionnaire before and after treatment. One author treated all the study participants with either single or double arch fixed appliances. RESULTS: The baseline OHIP-14 sub-scale scores among the three study groups were significantly different with surgery patients reporting nearly twice the baseline OHIP-14 scores of the other two groups for most of the items (P < 0.05). Post treatment OHIP scores were significantly different among the three groups with CL/P patients reporting higher scores for several items (P < 0.05). Surgery patients experienced significant improvements in all of the seven OHIP-14 sub-scales The effective size (ES) in each of the seven domains ranged from +0.85 and +1.93. Standard patients also experienced significant OHIP-14 improvements in four OHIP 14 sub scales. The highest ES were noted in the psychological discomfort (+0.91) and disability (+0.82) domains. The CL/P group experienced no significant changes between baseline and post-treatment OHIP-14 scores in any of the seven sub-scales; in fact, deteriorated scores were noted in the physical pain domain. The ES for cleft patients ranged from –0.42 to +0.37. After adjusting for age and gender, surgical patients had a significantly greater improvement in pre-treatment OHIP-14 scores than standard and CL/P patients (P < 0.01) CONCLUSION: The effects of orthodontic treatment on OHRQoL differ for distinctly different patient groups even after adjusting for age and gender. The greatest OHRQoL improvement occurs in adults with a need for orthognathic surgery. Limited OHRQoL improvements or negative impacts seem to occur in adolescents with CL/P.

17 ALVEOLAR BONE REMODELLING DURING ORTHODONTIC RELAPSE T J Franzen1, M Monjo2, M Rubert2, P Brudvik3, V V Vandevska-Radunovic1, 1Department of Orthodontics, University of Oslo, Norway, 2Department of Fundamental Biology and Health Sciences, University of the Balearic Islands, Palma de Mallorca, Spain, 3Department of Clinical Dentistry, University of Bergen, Norway

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AIM: To examine the biological changes occurring in alveolar bone during orthodontic relapse. MATERIALS AND METHOD: Maxillary first rat molars were moved mesially for ten days, appliances were removed, and the molars allowed to relapse for 1, 3, 5, 7, 14 or 21 days. Maxillae of 35 rats were sectioned and stained with H&E and TRAP, whilst in 37 rats 3D morphometric parameters of bone sited mesial to the first molars were assessed by micro-CT, subsequently total RNA was isolated and real-time RT-PCR used to measure the expression of bone formation and resorption markers. Comparison among groups was assessed by t-tests or ANOVA, and correlations by Spearman's rank correlation coefficient. RESULTS: One day after appliance removal, the molars relapsed to 68.5% of the achieved OTM, and progressively relapsed to 90.6% at 21 days. Osteoclasts located along the alveolar bone of the first molars peaked at the end of active orthodontic tooth movement (OTM) and were most abundant in the pressure side of the PDL. Osteoclast numbers decreased significantly during relapse and their distribution shifted; after 7 days of relapse TRAP-positive cells were registered in previous pressure and tension sides of the first molars. After 21 Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 days, these cells were concentrated in the distal sides of the PDL. In the bone mesial to the first molars, tissue mineral density and percent bone volume increased whilst total porosity decreased over the experimental period. Gene expression of OCN, Coll-I and ALP decreased during OTM, and tended to increase as the molars relapsed. Gene expression of RANKL and TRAP increased during OTM. Changes in mRNA expression of H+- ATPase were minor. By 21 days the remodelling process appeared to have returned to control levels. CONCLUSION: The findings of this investigation indicate that orthodontic relapse in the rat model occurs rapidly and remodelling of the alveolar bone plays a central role in the relapse processes of actively moved teeth. Bone tissue reactions on a molecular level are similar during OTM and orthodontic relapse.

18 TEMPOROMANDIBULAR JOINT SYMPTOMS BEFORE AND AFTER ORTHOGNATHIC SURGERY U Garagiola, E del Rosso, G Farronato, Department of Biomedical, Surgical, Dental Sciences and Orthodontics, IRCCS Fondazione Ospedale Maggiore Policlinico, University of Milan, Italy

AIM: To evaluate temporomandibular joint (TMJ) symptoms and functional and neuromuscular changes after surgical-orthodontic treatment of orofacial deformities with temporomandibular dysfunction (TMD). SUBJECTS AND METHOD: Four hundred and twenty orthognathic patients their skeletal and dental malocclusion type, TMJ symptoms, headache, cervical and neck pain, otovestibular symptoms were evaluated. Electromyography and kinesiography were used to assess muscular activity and mandibular movements. RESULTS: TMJ symptoms in low and normal angle mandibular retrognathic patients improved (P < 0.01). Almost all craniomandibular symptoms were significantly reduced post-operatively; above all muscular spasms (96%) and headache (61%), (P < 0.01); mandibular kinesology (81%) was improved (P < 0.01). Cervical pain, otovestibular and postural symptoms also seemed to improve after surgery. Post-operative TMD occurred in 8.8 per cent of patients even if they were previously asymptomatic (P < 0.1). A new occurrence of TMD was highest for high angle patients with severe mandibular , treated by bimaxillary surgery. CONCLUSION: Combined surgical-orthodontic treatment may be of a great benefit for correction of discrepancies of the occlusion and maxillo-mandibular relationships, particularly in patients with TMD. Conversely orthognathic surgery can produce TMJ symptoms by changing the position of the mandible and the maxilla and thus the position of the condyle in the glenoid fossa. Mandibular ramus osteotomies have a direct influence on this position, whilst in maxillary osteotomies the influence is indirect because of autorotation.

19 ASYMMETRIC MANDIBULAR : OUTCOME, STABILITY AND PATIENT SATISFACTION AFTER BILATERAL SAGITTAL SPLIT OSTEOTOMY N Hågensli, A Stenvik, L Espeland, Department of Orthodontics, University of Oslo, Norway

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AIMS: To investigate surgical outcome, long-term stability and timing of relapse. Additional objectives were to examine whether osteotomies for horizontal rotation of the proximal segment represent increased risk for nerve injury, and if the patients are satisfied with the overall result. MATERIALS AND METHOD: Lateral and postero-anterior cephalograms, information from patient files, and questionnaires were analysed for 38 patients having more than 4 mm asymmetry at the chin pre-treatment. The radiographs were analysed pre-operatively, post-operatively, after 6 months and 3 years. RESULTS: Asymmetry of the chin and the midline between the lower incisors improved on average by 60 and 71 per cent during surgery. Skeletal relapse was the same for transverse and antero-posterior surgical changes (about 15%), and 50 per cent of the patients still had a significant asymmetry (> 3 mm) at menton 3 years post- surgery. Normal or near normal sensation to the lower lip/chin was reported by about 50 per cent of the patients which is similar to sensory disturbances after bilateral sagittal split osteotomy straight set-backs. Satisfaction with the treatment result was reported by all patients, except for one. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 CONCLUSION: Correction of mandibular asymmetry by BSSO was fairly stable even if a moderate relapse occurred during the first 6 months post-operatively. Rotation of the distal segment during surgery did not represent an increased risk for sensory impairment, and patients were generally satisfied even if more than 3 mm of asymmetry was present in many of them. The findings have implications for treatment planning and the decision to elect one-jaw or bimaxillary surgery.

20 ORAL IMPACT ON DAILY PERFORMANCE IN CHILDREN AND ADOLESCENTS WITH AND WITHOUT HYPODONTIA*** C Hvaring1, A N Åtrøm2, K Birkeland1, 1Department of Orthodontics, University of Oslo and 2Department of Clinical Dentistry, University of Bergen and, Norway

AIM: To assess (1) to what extent the generic and condition specific (CS) forms of the oral impact of daily performance (OIDP) inventory discriminate between patients with and without hypodontia, (2) the association of generic and CS-OIDP with severity and localisation of hypodontia, whilst adjusting for patients' age and gender. SUBJECTS AND METHOD: One hundred and sixty three patients (80 boys, 83 girls), aged 10-17 years were included in a cross-sectional study. Two groups were investigated: 62 patients with non-syndromic hypodontia and 101 non-hypodontia patients. Both groups had a malocclusion of similar treatment need as classified by the Index of Orthodontic Treatment Need, dental health component 4 or 5. All patients underwent a clinical and radiographic examination and completed a Norwegian version of the generic and the CS-OIDP inventory. CS- OIDP scores were established for impacts attributed to hypodontia. RESULTS: The mean number of missing teeth in the hypodontia group was 6.2. Using the generic OIDP instrument, 27.9 per cent of the patients with hypodontia versus 14.0 per cent (P < 0.05) of the patients without hypodontia reported problems with emotional status. The generic OIDP instrument did not discriminate between the two groups with respect to overall and specific oral impact scores. The CS-OIDP discriminated strongly between patients with and without hypodontia regarding problems with emotional status, showing teeth, social contact, speaking and carrying out work. Totals of 30.6 and 9.9 per cent of the patients with and without hypodontia reported at least one oral impact. Compared with the non-hypodontia group, patients with hypodontia, with severe hypodontia ((≥6 missing teeth) and upper anterior localisation of hypodontia were respectively 3.4, 2.5 and 7.0 times more likely to report any oral impact attributed to small teeth, gaps between teeth and missing teeth. A positive correlation was found between upper anterior hypodontia and impacts related to speaking and eating. CONCLUSION: Hypodontia patients report a considerable burden of oral impacts. The generic OIDP inventory did not discriminate between patients with and without hypodontia. In contrast, the CS-OIDP measure attributed to hypodontia discriminated effectively between patients with and without hypodontia and was related to severity and upper anterior localisation of hypodontia. e12

21 ROOT RESORPTION, TREATMENT TIME AND EXTRACTION RATE DURING ORTHODONTIC TREATMENT WITH SELF-LIGATING AND CONVENTIONAL BRACKETS C Jacobs1, P Gebhardt1, V Jacobs1, D Meila2, H Wehrbein1, 1Department of Orthodontics, University of Mainz and 2Department of Neuroradiology, Medical School Hannover, Germany

AIM: To determine the amount and severity of external apical root resorption (EARR) after orthodontic treatment with self-ligating (SL) and conventional (non-SL) brackets. Differences regarding the rate of extraction cases, appointments and treatment time were evaluated. SUBJECTS AND METHOD: Two hundred and thirteen patients with a mean age of 12.4 ± 2.2 years were evaluated retrospectively. Treatments were performed with SL brackets (n = 139, Smartclip, 3M Unitek, USA) or non-SL brackets (n = 74, Victory Series, 3M Unitek). Measurements of crown and root length of the incisors Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 were taken using panoramic radiographs. Three-factor analysis of variance (ANOVA) was performed for an appliance effect. RESULTS: There was no difference between patients treated with non-SL or SL brackets regarding the amount (percentage) of EARR (non-SL: 4.5 ± 6.6 versus SL: 3.0 ± 5.6). Occurrence of severe EARR also did not differ between the two groups (non-SL 0.5 versus SL: 0.3). The percentage of patients with a need for tooth extraction for treatment (non-SL: 8.1 versus SL: 6.9) and the number of appointments (non-SL: 12.4 ± 3.4 versus SL: 13.9 ± 3.3) did not show any differences. Treatment time was shorter with non-SL brackets (non-SL: 18.1 ± 5.3 versus SL: 20.7 ± 4.9 months). CONCLUSION: This is the largest study showing that there is no difference in the amount of EARR, number of appointments and extraction rate between SL and non-SL brackets. For the first time it can be demonstrated that the occurrence of severe EARR does not differ between the two types of brackets.

22 SALIVA PROTEOME ANALYSIS AS THE BEST EVIDENCE FOR CLINICAL DECISIONS TO MINIMIZE THE RISK OF ORTHODONTICALLY INDUCED INFLAMMATORY ROOT RESORPTION K Kaczor-Urbanowicz1, O Deutsch2, A Palmon2, S Chaushu1, 1Department of Orthodontics and 2Institute of Dental Sciences, Hadassah Dental School of Medicine, The Hebrew University of Jerusalem, Israel

AIM: Orthodontically induced inflammatory root resorption (OIIRR) is a common iatrogenic consequence of orthodontic treatment. Nowadays, available methods of clinical evaluation are mostly radiographic and limited. Proteomic analysis of whole saliva (WS) has been suggested as an alternative, non-invasive method. The main goal of this study was to define a panel of potential diagnostic protein biomarkers for OIIRR in WS of orthodontic patients utilizing different proteomic strategies. MATERIALS AND METHOD: Unstimulated WS flow was collected from patients undergoing orthodontic treatment, and age and gender matched controls. Radiographic assessment of periapical radiographs of four upper incisors taken before and 6 months after bonding was done to screen for OIIRR. The patients were divided in six groups according to age (young: aged 10-20 years and adults: aged 21-30 years) and the degree of root resorption (RR) of upper incisors [moderate-to-severe: RR apically, ≥2 mm; mild: RR apically, <2 mm and control]. There were six groups: I-moderate-to-severe, young; II-moderate-to-severe, adults; III-mild, young; IV- mild, adults; V-control, young and VI-control adults. Saliva proteome analysis was performed with the application of both two-dimensional gel-based and label free MS analysis. Obtained data was searched against human section of the Uniprot database and quantified by label free analysis using the MaxQuant 1.2.2.5. software. RESULTS: Overall, 772 proteins were revealed by quantitative MS. A significant increase of 244 proteins was seen in the moderate-to-severe-young group in comparison to the control-young group. Of these, 96 proteins were expressed only in the moderate-to-severe group and 92 were up-regulated by more than threefold. Furthermore, 97 proteins were found with significant decrease in the moderate-to-severe-young group. e13

Comparison with the adults groups revealed similar trend, however with different protein components. In addition, bioinformatics analysis of proteins with significant increase in the young group with moderate-to- severe root resorption revealed: endopeptidase inhibitor activity, cell projection, proteins related to cytoskeleton, regulation of actin cytoskeleton and defence response. CONCLUSION: This investigation showed a WS unique protein expression profile in OIIRR patients, which might indicate a pathogenesis mechanism characterizing root resorption. This research appears to be the first that utilized quantitative MS identification to discover potential diagnostic protein biomarkers for OIIRR.

23 THE IMPACT OF TOOTH AGENESIS ON ORAL HEALTH-RELATED QUALITY OF LIFE IN CHILDREN S Kotecha1, P J Turner1, A Dhopatkar1, T Dietrich2, 1Department of Orthodontics, Birmingham Dental Hospital and 2Department of Oral Surgery, University of Birmingham, U.K. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 AIM: To evaluate, in a cross-sectional survey, the psychosocial impact of tooth agenesis in children, and to investigate the potential influence of gender, socioeconomic status, severity of tooth absence and the number of retained primary teeth on their quality of life (QoL). SUBJECTS AND METHOD: A total of 86 children (36 males, 50 females) with tooth agenesis, aged 11-14 years were recruited. Thirty subjects with a complete dentition, and having a low treatment need, acted as controls. Children completed the validated Child Perceptions Questionnaire (CPQ) and their parents completed the Parental-Caregiver Perceptions Questionnaire. RESULTS: The median number of missing teeth in the sample population was six. There were significant differences in the oral symptoms, functional limitations and the social and emotional well-being reported between the agenesis and control groups. The overall CPQ scores were significantly higher in children with tooth agenesis (P < 0.001). No significant correlation was detected between the number of missing teeth and the QoL score. There was no influence on the CPQ score from gender, socioeconomic status, the site of agenesis or the presence of retained primary teeth. There was moderate correlation between parental and child reported QoL. CONCLUSION: Tooth agenesis may have a significant impact on the QoL of children, resulting in oral symptoms, functional limitation and also affecting emotional and social well-being. This does not appear to be related to the number of missing teeth. This study has implications for our understanding of the effect of tooth absence on the QoL of children and their parents and addressing these reported impacts may help to improve patient satisfaction.

24 VALIDATION OF A SHORT-FORM VERSION OF THE CHILD ORAL HEALTH IMPACT PROFILE TO ASSESS ORAL HEALTH RELATED QUALITY OF LIFE IN ORTHODONTICS L Kragt1,3, H W Tiemeier2, E B Wolvius1, E M Ongkosuwito1, Departments of 1Oral & Maxillofacial Surgery, Special Dental Care and Orthodontics, 2Child and Adolescent Psychiatry and Psychology, and 3The Generation R Study Group, Erasmus University Medical Centre, Rotterdam, Netherlands

AIM: Although measurement of a patient’s perspective becomes more important, it is still not current practice in orthodontics. This study presents the evaluation of a short and practical form to measure oral health related quality of life (OHRQoL) as patient reported outcome measures (PROM) in orthodontic practice and research. MATERIALS AND METHOD: The validated Dutch version of the Child Oral Health Impact Profile (COHIP)-34 was distributed in an orthodontic practice and completed by the parents of 160 children (50% girls, mean age of 11.99 years (1.47 SD)) prior to the start of orthodontic treatment. Additionally, perception of general health and orthodontic treatment need was assessed. Selection of 11 questions for the short form version was expert- (EMO, HT) and response-based. Performance of the reduced questionnaire (COHIP-11) was assessed with Spearmen's correlation and Cronbach’s alpha. Construct validity was assessed by comparing the associations

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between OHRQoL scores from the short form and COHIP-34 with perceived orthodontic treatment need, objective orthodontic treatment need as well as general health perception. RESULTS: Internal consistency of the short form for the orthodontic sample was adequate (Cronbach’s ± >0.70). The OHRQoL score of the short form correlated with the OHRQoL overall (r = 0.932) and subscale scores (r = 0.638-0.802) of the COHIP-34 (P < 0.01), indicating excellent criterion validity. The associations between the OHRQoL scores and subjective as well as objective orthodontic treatment need were not different between the COHIP-34 and the short form. CONCLUSION: The COHIP-11 measures OHRQoL as reliably and with as much validity as the COHIP-34. However, the COHIP-11 is more practical and simpler to administer. Therefore, the results of this study facilitate the use of PROMs in orthodontics and can subsequently contribute to enhance patient satisfaction.

25 COMPUTATIONAL FLUID DYNAMIC ANALYSIS FOR THE ASSESSMENT OF UPPER AIRWAY RESPONSE TO Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 SURGICAL MAXILLOMANDIBULAR ADVANCEMENT J Kurimo1, J Jarnstedt2, T Peltomäki1, S-L Himanen3, 1Oral and Maxillofacial Unit, Department of Otorhinolaryngology, 2Medical Imaging Center, Department of Radiology and 3Department of Clinical Neurophysiology, Tampere University Hospital, Finland

AIMS: To evaluate the change in upper airway airflow resistance after maxillomandibular advancement (MMA), and to examine the effect of MMA on upper airway dimensions and polysomnography in obstructive sleep apnoea (OSA) patients. SUBJECTS AND METHOD: Thirteen patients with OSA were treated by MMA. A cone beam computed tomograph was taken in the natural head position prior to and surgery. A three-dimensional model of the upper airway extending from the level of the lower margin of the third cervical vertebrae to the level of the highest point of the nasopharyngeal cavity was created. The pre- and post-operative airflow resistance in the upper airway area was evaluated with computational fluid dynamics (CFD). OSA symptoms were evaluated by polysomnography and the Epworth sleepiness scale (ESS). RESULTS: Variable improvement of the upper airway dimensions was noted at each horizontal level. The cross- sectional area of the upper airway at all horizontal levels was enlarged. The minimum sagittal dimension increased in every patient. Airflow resistance in the upper airway was smaller post-operatively in 12 cases out of 13 according to CFD. In some cases the influence of MMA was weak to ESS and blood oxygen saturation although the reduction in upper airway airflow resistance was significant. CONCLUSION: MMA of the upper airway reduces upper airway airflow resistance and may offer an effective method to treat OSA. MMA increases the cross sectional area in the most constricted area of the pharynx by expanding the facial skeletal structure to which the soft tissues and tongue are fixed, with a consequent reduction of collapsibility in the presence of negative pressure during inspiration. This reduced possibility of upper airway collapse may contribute to the reduction of obstructive events.

26 VOLUMETRIC OUTCOME ASSESSMENT OF MANDIBULAR SYMPHYSEAL BONE GRAFT MATERIAL IN UNILATERAL CLEFT LIP PALATE PATIENTS USING CONE BEAM COMPUTED TOMOGRAPHY B W Linderup1, P M Cattaneo1, J Jensen2, A Küseler1,2,3, 1Department of Orthodontics, Aarhus University, 2Department of Oral and Maxillofacial Surgery, Aarhus University Hospital and 3Cleft Lip Palate Center, Denmark

AIMS: Volume determination using cone beam computed tomography (CBCT), a medical image processing software, and defined anatomical boundaries has recently been proved to be a reproducible, valid, and practical method for assessing the volumetric outcome of secondary alveolar bone grafting (SABG) in patients with a cleft lip and palate (CLP). Based on these premises, the objectives of this study were to evaluate the bone fill (BF) 1- year post-operatively and relate it to 1) size of the cleft, 2) presence/absence of the cleft-side lateral incisor and 3) developmental stage of root development of the cleft-side canine. e15

MATERIALS AND METHOD: This prospective study included a sample of CBCT scans of 30 consecutive patients with unilateral CLP (UCLP) with a mean age of 9 years 10 months (7 years 1 month to 12 years 7 months) received SABG with mandibular symphyseal bone. The volume of the alveolar bone cleft (VOLpre) and the volume of any residual cleft 1-year post-operatively (VOLpost) were determined by a novel defined semi- automatic method using the medical software Mimics®. The radiographic outcome of the SABG was calculated as a percentage of BF using the formula: (VOLpre-VOLpost)/VOLpre) × 100. The size of cleft was classified as ‘large’ if with a volume larger than 1.000 mm3, ‘medium’ clefts were between 750 and 1.000 mm3 and ;small’ clefts below 750 mm3. Root development of the canine was assessed as either one-third (stage 1), two-thirds (stage 2) or complete (stage 3). RESULTS: Preliminary results from 25 patients, who have completed the protocol before December 2013 showed that mean VOLpre was 887 mm3, mean VOLpost was 107 cm3 and mean BF was 88 per cent. Mean BF was 87 per cent in large clefts, 90 per cent in medium clefts and 86 per cent in small clefts. BF was not Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 statistically significant different neither in patients with presence/absence of cleft-side lateral incisor (present: 88%/absent: 87%) nor in relation to the stage of root development of the cleft-side canine (stage 1: 76%, stage 2: 97% stage 3: 82%). CONCLUSION: BF 1-year after SABG with mandibular symphyseal bone was 88 per cent. The size of the cleft, presence/absence of cleft-side lateral incisor or the root developmental stages of the cleft-side canine did not have statistically significant influence on BF in this present study.

27 ACCURACY AND RELIABILITY OF CONE BEAM COMPUTED TOMOGRAPHIC IMAGING FOR ASSESSING ADENOID HYPERTROPHY M Major1, M Witmans2, H El-Hakim3, P W Major1, C Flores-Mir1, Departments of 1Dentistry, 2Pediatric Pulmonology and 3Pediatric Otolaryngology, University of Alberta, Edmonton, Canada

AIMS: Adenoid hypertrophy is one of the most common aetiologies of nasopharyngeal obstruction. Nasopharyngeal obstruction has been associated with and sleep disordered breathing (SDB). Both are significant conditions the orthodontist should be prepared to identify. Mouth breathing has been proposed as a significant factor for altered craniofacial growth. SDB may cause systemic problems. The aim of this study was to evaluate 1) reliability and accuracy of cone-beam computed tomography (CBCT) for assessing adenoid size compared to nasoendoscopy (NE), 2) influence of clinical experience on the related CBCT diagnosis. SUBJECTS AND METHOD: A prospective/retrospective, cross-sectional agreement study was conducted. Protocol approval was granted by the appropriate ethics committee. Thirty-nine consecutively assessed participants (11.5 ± 2.8 years) were evaluated. Those children and adolescents were referred to the Interdisciplinary Upper Airway Clinic at the University of Alberta. NE was performed in the upright position using a flexible tube endoscope allowing the otolaryngologist to view all the way to the epiglottis. Topical decongestion and anaesthesia were applied. The examinations were prospectively recorded on a digital image- capturing unit, and electronically archived. The otolaryngologist documented the size of the adenoids and other findings using an individual patient information sheet. CBCT images were taken in the upright position with a 12 inch field of view, 300 μm voxel, and 8.9 second scan time. Adenoid size was graded on a four-point scale from CBCT images (by the dental specialists) and clinically from NE (by a paediatric otolaryngologist ( standard). Reliability was assessed with intra- and inter-observer agreement. Accuracy was assessed with agreement between CBCT and NE, plus sensitivity/specificity analysis. RESULTS: CBCT demonstrated excellent sensitivity (88%) and specificity (93%), strong accuracy (ICC = 0.80, 95% CI ± 0.15), and very good reliability, both within observers (ICC = 0.85, 95% CI ± 0.08) and between observers (ICC = 0.84 ± 0.08). Clinical experience of the CBCT evaluators did not have an effect. CONCLUSION: CBCT, when available, is a reliable and accurate tool for identifying adenoid hypertrophy. Caution should be exercised as assessment of adenoids alone is not a proper justification for CBCT imaging.

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28 THE EFFECT OF RETINOIC ACID ON DIFFERENTIATION OF CLEFT AND NON-CLEFT PALATAL KERATINOCYTES A Mammadova1, J Von den Hoff1, H Zhou2, C Carels1, 1Department of Orthodontics and Craniofacial Biology, Radboud university medical center, Nijmegen and 2Department of Molecular Developmental Biology. Nijmegen Centre for Molecular Life Sciences, Netherlands

AIM: Impaired epithelial fusion appears to be the major factor in retinoic acid-induced cleft lip and palate (CLP). Vitamin A, and more specifically its derivate retinoic acid, is an important regulator of epithelial differentiation that could be involved in the development of CLP. In this study, the effects of retinoic acid on the differentiation of palatal keratinocytes were investigated. MATERIALS AND METHOD: Palatal keratinocytes were derived from biopsy specimens from the palatal mucosa of four children with CLP (age 19 ± 1 months) and four control children (age 26 ± 1 months) who had Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 tonsillectomy. Keratinocytes were cultured twofold in 6-well culture plates in keratinocyte growth medium (KGM) until 100 per cent confluence. Then, the cells were switched to differentiation medium containing 2 µM all-trans-retinoic acid (atRA). After 0, 2, 4, and 7 days, mRNA was collected, and the expression of differentiation genes (K1, K10, K14, K16, p63, Involucrin, Cystatin M/E) was analyzed with quantitative real-time polymerase chain reaction using the SYBR green method. The expression data were analyzed by two-way ANOVA at all time points. RESULTS: The expression of the majority of the genes was strongly decreased in both cleft and non-cleft cells treated with atRA, without a significant difference in response between cleft and non-cleft cells. CONCLUSION: Retinoic acid seems to reduce the differentiation of palatal keratinocytes. However, there is no difference in response to the atRA between the cells from the CLP patients and non-cleft subjects. This might be due to the low number of donors. Further research is necessary to understand the effect of the retinoic acid on the differentiation of palatal keratinocytes.

29 UNEXPECTED COMPLICATIONS ASSOCIATED WITH FIXED RETAINERS I Marek, J Kucera, Department of Orthodontics, Dental Clinic of Medical Faculty, Palacký University, Olomouc, Czech Republic

AIM: Fixed retainers are one of the most popular methods of prevention of orthodontic relapse in the anterior region. However, in some cases one can observe malalignment of the teeth such as torque problems or inclination changes. These complications appear despite that the fact that all the teeth are still bonded to the fixed retainer and no history of retainer fracture or debonding has been found. The aim of this presentation is to describe the types of complications related to fixed retainers and identify factors associated this phenomenon. SUBJECTS AND METHOD: Three thousand five hundred consecutive patients (1423 males, 2077 females) with various malocclusions treated orthodontically with fixed appliances followed by fixed retention were recalled 1.5 to 10 years post-treatment (mean = 4.32, SD = 2.66). Each patient had a complete set of documentation i.e. study models, panoramic and cephalometric radiographs, intra- and extra-oral photographs. Based on the documentation, prevalence and type of relapse (complications) were determined. Furthermore, the relationship between complications and the end-of-treatment position of the third molars, intercanine width change during treatment, proclination of incisors during treatment, and symphysis morphology was assessed. RESULTS: Complications were present in 63 (1.8%) patients (25 in the maxilla and 38 in the mandible). Two basic types of complications were found: (1) X-effect, i.e. two adjacent teeth with opposite root/crown torque, and (2) Twist effect, i.e. twisting of the whole anterior segment with opposite torque of contralateral canines). Non-specific complications, e.g. extrusion and/or intrusion were observed. In the mandible 21 subjects had a twist-effect, 12 had an X-effect, and five non-specific complications. In the maxilla, 15 subjects had an X-effect (11 with a broken retainer), seven had a twist-effect and three non-specific complications. Most complications e17

were found after > 2 years in retention. No association between the position of the third molars, intercanine width change, incisor proclination, symphysis width or type of retainer wire and occurrence of complications was found. CONCLUSION: Complications related to fixed retainers were relatively rare in this sample. No predictors of complications were identified.

30 THE USE OF GEOMETRIC MORPHOMETRICS IN ASSESSING SKELETAL CLASS II CLASSIFICATION L Marinaki, E Akli, D Halazonetis, National and Kapodistrian University of Athens, Greece

AIM: Inclusion criteria for Class II treatment randomised controlled studies (RCT) studies are usually limited to a single, or very few cephalometric measurements. The aim of this research was to assess the appropriateness of cephalometric criteria used in such studies for selecting candidate subjects. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 MATERIALS AND METHOD: Cephalometric radiographs of 170 patients were analysed using Procrustes alignment and Principal Component Analysis on 16 skeletal and four dental landmarks. The first three Principal Components (PC) described 60 per cent of skeletal shape variability and were considered to reflect the spectrum of skeletal discrepancy on which patient selection should be based. Random sampling from the normal distribution was used to bootstrap the sample to 1000 virtual ‘patients’, densely covering the shape space. Four Class II inclusion criteria (C1-C4) were extracted from the high-impact Class II RCT literature and applied to this sample, dividing it into selected and non-selected subjects. The criteria were: C1: Overjet > 6, C2: Overjet > = 7, C3: ANB > 5 and overjet > 6, C4: Overjet > = 5 and ANB >4 and SNB <78 and Sn-GoGn = 32 ± 6. The appropriateness of each criterion was evaluated a) by computing the convex hull that enclosed the selected patients and assessing its volume and position relative to the whole shape space (Convex hull is the volume of shape space enclosed by the patients who fulfilled criteria C1 to C4, which ranged from 26 to 67%), b) by computing the relative number of subjects that were selected by the criterion as skeletal Class II, but should be considered skeletally normal, based on their central position in shape space. RESULTS: The percentage of normal patients that were nevertheless selected as suitable for Class II treatment were 19.3, 14.6, 16.5 and 27.3, for C1 to C4, respectively. The convex hull volumes extended from 26 to 67 per cent of the total shape space, for C4 to C1, respectively. Selected patients were widely spread-out in shape space showing poor clustering and covering the whole spectrum of variability in vertical skeletal discrepancies as well as a wide spectrum of anteroposterior discrepancies. CONCLUSION: Presently used cephalometric criteria for Class II RCT studies do not show sufficient precision in patient selection. There is significant concern that selected subjects may differ substantially in skeletal pattern, and may even be skeletally normal, thus rendering the results of such studies questionable. Geometric morphometric methods are recommended as a valid alternative.

31 EFFECTS PRODUCED BY A MODIFIED ALTERNATE RAPID MAXILLARY EXPANSION AND CONSTRICTION PROTOCOL FOR THE EARLY TREATMENT OF CLASS III MALOCCLUSION: A CONTROLLED STUDYɫ ɫ C Masucci, V Giuntini, A Vangelisti, N Defraia, L Franchi, Department of Oral Sciences, Università degli Studi di Firenze, Italy

AIM: To assess the effects of a modified alternate rapid maxillary expansion and constriction (Alt-RAMEC) protocol in combination with the facemask (FM) in Class III growing patients. SUBJECTS AND METHODS: Thirty one Class III patients (17 males, 14 females) were treated with a modified Alt- RAMEC/FM protocol. All patients were evaluated at the beginning (T1, mean age 6.4 ± 0.8 years) and at the end of orthopaedic therapy (T2, mean age 8.1 ± 0.9 years) and compared to a matched sample of 31 Class III patients (16 males, 15 females) treated with rapid maxillary expansion and facemask (RME/FM) and to a matched control group of 21 subjects (9 males, 12 females) with untreated Class III malocclusions. The three groups were compared with ANOVA with Benjamini-Hochberg correction for multiple tests. e18

RESULTS: Both Alt-RAMEC/FM and RME/FM protocols showed significantly favourable effects leading to the correction of the Class III malocclusion. The Alt-RAMEC/FM protocol produced a more effective advancement of the maxilla (SNA: +1.2°) and greater intermaxillary changes (ANB:+1.7°) versus the RME/FM protocol. No significant differences were recorded for mandibular skeletal changes and vertical skeletal relationships. CONCLUSION: The Alt-RAMEC/FM protocol induced more favourable skeletal effects versus RME/FM therapy in Class III growing patients.

ɫɫ Winner of the W J B Houston Oral Research Award.

32 QUALITY OF LIFE IN ORTHODONTIC ONCOLOGY PATIENTS – A CASE CONTROL STUDY M Mitus-Kenig1, M Durka-Zajac2, E Pawlowska3, 1Department of Stomatological Prevention and Hygiene, Jagiellonian University Collegium Medicum, Krakow and Departments of Orthodoncy, 2Pomeranian University, Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 Szczecin and 3Medical University, Lodz, Poland

AIM: Huge advances in cancer treatment have resulted in an overall survival of childhood cancers as high as 80 per cent. The result is increasingly frequent orthodontic treatment of the survivors. Quality of life (QoL) during orthodontic treatment in this group of patients is poorly covered in the literature. The aim of this study was to compare the results of treatment of cancer survivors with a control group of healthy subjects with a particular focus on QoL during treatment both within and between these groups. SUBJECTS AND METHOD: Forty survivors (26 males, 14 females, median age 19.4 years) and 25 patients on maintenance therapy. These were matched with 40 healthy control subjects (for age ±4 years, gender and malocclusion). The 14-item version of the Oral Health Impact Profile was used to assess the effect of orthodontic treatment on QoL in the study sample. A score of occasionally, often and very often was used for identify patients who had experienced at least some oral health impact. The questionnaire was repeated pre-, during (after two weeks and three months) and after orthodontic treatment. The Chi-square test was used to analyse the qualitative data. RESULTS: The average treatment time in the study group was significantly shorter (12.5 versus 18 months; P < 0.01). Orthodontic treatment had an impact on oral health QoL with no significant difference between cancer survivors and healthy subjects before, at 3-months and after treatment. Surprisingly, male oncology patients reported significantly lower QoL during the treatment period than the male control group (38 versus 23% P < 0.05). Taking into account the patients in maintenance therapy, the QoL during the adaptation period was significantly higher than in the control group. CONCLUSION: Orthodontic treatment has an impact on oral health QoL both in cancer survivors and the control group with a significantly higher impact in male oncology patients and those in maintenance therapy.

33 DO PERSONALITY TRAITS AFFECT THE RELATIONSHIP BETWEEN MALOCCLUSION AND THE PSYCHOSOCIAL IMPACT OF DENTAL AESTHETICS? M Mlacovic Zrinski, A Pavlic, V Katic, S Spalj, Department of Pediatric Dentistry and Orthodontics, School of Medicine, University of Rijeka, Croatia

AIM: Malocclusion is often associated with compromised aesthetics and could thus affect the psychosocial status of the individual, but personality traits might modify this relationship. The aim of this study was to explore to what extent the degree of malocclusion and personality traits can predict the psychosocial impact of dental aesthetics. SUBJECTS AND METHOD: The study was cross-sectional on a convenient sample that included 160 university students and orthodontic patients (61.3% female) aged 8-39 years (median 21, interquartile range 19-23 years). The self-administered questionnaire included the Rosenberg Self-esteem Scale, the Big Five Inventory, and the Psychosocial Impact of Dental Aesthetics Questionnaire consisting of the following dimensions: dental self- e19

confidence (DSC), social impact (SI), psychological impact (PI) and aesthetic concern (AC). The self-perception of smile aesthetics was assessed by the Aesthetic Component of the Index of Orthodontic Treatment Need, while the severity of malocclusion was determined professionally with the Index of Complexity, Outcome and Need. Multiple linear regression was used for statistical analysis. RESULTS: A higher degree of neuroticism and self-esteem, a lower degree of malocclusion and better self- perceived aesthetics were significant predictors of a higher degree of DSC, accounting for 1.4, 7.2, 2.7 and 8.9 per cent of variability, respectively. Significant predictors of a higher SI were a lower degree of neuroticism, poorer self-perceived aesthetics and lower self-esteem, accounting for 4.4, 5.3 and 17.1 per cent of variability, respectively. More compromised self-perceived aesthetics and lower self-esteem were significant predictors of a higher PI, accounting for 10 and 5.6 per cent of variability. Lower self-esteem and poorer self-perceived aesthetics were significant predictors of a higher AC, accounting for 10.4 and 4.8 per cent of variability, respectively. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 CONCLUSION: Personality traits and degree of malocclusion are poor predictors of the PI of dental aesthetics.

34 EFFECTS OF PLATELET RICH PLASMA ON BONE FORMATION IN THE EXPANDING MIDPALATAL SUTURE IN RABBITS H İ Mutaf1, A A Biçakçi2, Departments of Orthodontics, Faculties of Dentistry, 1Cumhuriyet University, Sivas and 2Gaziosmanpaşa University, Tokat, Turkey

AIM: To evaluate the effects of a platelet rich plasma (PRP) injection on bone formation in the midpalatal suture during and after orthopaedic maxillary expansion in rabbits. MATERIALS AND METHOD: Twenty four New Zealand rabbits were divided into three groups. All groups were subjected to 7 days expansion and 14 days retention therapy. The control group received a saline solution and the two experimental groups (groups 1 group 2) were treated with a PRP injection. Group 1 received a PRP injection into the midpalatal suture at the beginning of the retention period, while group 2 received repeated PRP administration on two occasions, the first injection was performed 24 hours after the beginning of expansion and the second at the beginning of the retention period. Bone formation in the midpalatal suture was evaluated by radiologically and histologically. Radiographic imaging was performed using multi-slice computed tomography at the beginning of the experiment, at the end of expansion and at the end of the retention period. RESULTS: The quality and quantity of new bone in the midpalatal suture was significantly higher for group 2 than the control group in histological evaluation (P < 0.05). The increase in new bone formation was supported by radiographic evaluation; however the highest density was determined for group 2. CONCLUSION: Local injection of PRP into the midpalatal suture during and after orthopaedic maxillary expansion may increase bone formation and shorten the retention period in rabbits.

35 MSX1 AND PAX9 GENE MUTATIONS AND POLYMORPHISMS IN HYPODONTIA O Ozkepir1, A T Altug1, H Dogan2, S Ceylaner2, G Ceylaner2, 1Department of Orthodontics, Faculty of Dentistry, Ankara University and 2Department of Clinical and Molecular Genetics, Education and Research Center, Intergen Genetics, Ankara, Turkey

AIM: Muscle segment homeobox 1 (MSX1) is well known for its role in craniofacial and dentoalveolar bone development. Paired box 9 (PAX9) is responsible for tooth development and known for its role in the absence of third molars. Therefore, the objective of this study was to investigate if there is a specific pathogenic mutation and/or polymorphism of MSX1 and PAX9 variants in non-syndromic tooth agenesis in the Turkish population. SUBJECTS AND METHOD: One hundred and ten individuals with hypodontia (78 females, 32 males) with any type of congenitally missing teeth. Blood samples were collected from each patient. Sequence analysis of entire coding regions of MSX1 and PAX9 genes were done by a capillary electrophoresis system. Primers were e20

designed and all exons of the genes were amplified. Sequence analyses with both forward and reverse primers were undertaken. Chi-squared test and Kappa analysis were used for statistical evaluation. RESULTS: The total number of missing teeth was 236 amongst all subjects. The incidence of bilateral absence was higher than unilateral; maxillary teeth involvement was higher than mandibular and maxillary; lateral incisors were more frequently missing (right side more frequently than the left side), followed by mandibular and maxillary second molars, respectively. Two variants of MSX1-exon 1 and one variant of MSX1-exon 2 (c.119C>G; c.348C>T and c.*6C>T, respectively) and two variants of PAX9-exon 3 (c.717C>T and c.718G>C, respectively) presented polymorphism. However, the most important finding was the mutation in the PAX9- exon 4 variant (c.857A>G ) which was observed in a male subject who had congenitally missing maxillary lateral incisors. Additionally, a statistically significant difference in allele frequency for MSX1 (c.*6C>T) polymorphism for congenitally missing lateral incisors (P < 0.05). MSX1 (c.*6C>T) polymorphism was previously described as being related to cleft lip and palate. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 CONCLUSION: These findings strongly suggest that hypodontia is under the influence of both MSX1 and PAX9 genes separately and also with the interaction between these two genes. Although there still remains as a question for future studies, the absence of maxillary lateral incisors could be a very mild rebound of a recovered cleft lip and palate deformity.

36 NETWORK META-ANALYSIS: A NEW APPROACH TO RESEARCH SYNTHESIS WITH A POTENTIAL VALUE IN ORTHODONTICS N Pandis1,3,4, P Fleming2, L Spineli3, G Salanti3 , 1University of Bern, Switzerland, 3School of Medicine, University of Ioannina, Greece, 4Private Practice, Corfu, Greece, 2Queen Mary University of London, U.K.

AIM: Network meta-analysis (NMA) is a new statistical approach allowing comparison and grading of interventions, which have not previously been directly compared in clinical trials. This approach has not yet been applied to orthodontics. The aim of this study was to highlight the value of NMA in orthodontic research. MATERIALS AND METHOD: NMA was applied to the existing evidence on initial orthodontic alignment with conventional and self-ligating appliances (SLB) for illustrative purposes. Randomized clinical trials (RCTs), controlled clinical trials (CCTs), and split-mouth designs were included. Patients with full-arch self-ligating and conventional brackets were included and crowding (mm) alleviated during the initial alignment stage per unit of time was recorded. Electronic database searches were supplemented with searches for unpublished literature as standard. Language restrictions were not applied. Data extraction was done in duplicate and independently. RESULTS: Ten trials were included (6 RCTs, 4 CCTs) in the NMA. Conventional brackets were ranked as the most effective system in terms of alignment, followed by In-Ovation-R, Damon and Smart-Clip. The rankograms indicated that conventional brackets and In-Ovation-R are more likely to be the two best options, since they have higher rank probabilities of occupying the first two ranks. Damon and Smart-Clip are more likely to be the least good options, since they have higher rank probabilities of falling within the last two ranks. Conventional brackets appear to lead to the most effective alignment with a Surface Under Cumulative Ranking (SUCRA) value of 68 per cent. In-Ovation-R, Damon and Smart-Clip had SUCRA values of 56, 43 and 32 per cent, respectively. The NMA results indicate that the conventional appliances produce more efficient alignment than the alternatives with a greater mean improvement of 0.03, 0.08 and 0.17 mm/month compared to In-Ovation-R, Damon and Smart-Clip, respectively. However, the estimated differences were not statistically significant and the effect estimates of little clinical importance. CONCLUSION: NMA is a useful technique permitting comparison of interventions which have not previously been compared and allowing interventions to be ranked in order of relative effectiveness. It is likely to meet wider application in orthodontic research.

37 IS MODIFICATION OF THE MINIMAL INCISION TECHNIQUE REPAIR OF ISOLATED CLEFTS OF THE HARD AND SOFT PALATE BENEFICIAL? – A CAST AND RECORD ANALYSIS AT 5 YEARS e21

K Parikakis1, O Larson2, A L-A Karsten1, 1Department of Orthodontics, Karolinska Institutet and 2Department of Plastic Surgery, Karolinska Hospital, Stockholm, Sweden

AIM: To compare the minimal incision (MI) technique with the minimal incision with muscle reconstruction (MMI) technique repair of isolated clefts of the hard and soft palate regarding surgical complications and dentoalveolar status at 5 years of age. SUBJECTS AND METHOD: A consecutive series of 138 Caucasian children born with an isolated cleft palate between 1990 and 2007. Individuals with other craniofacial malformations, apart from Pierre Robin Sequence, were excluded. The patients were treated surgically using MI (N = 30) or MMI (N = 108) palatoplasty at a mean age of 13 months, and divided further into two subgroups: clefts within the soft palate only and a notch less than 3 mm in the posterior border of the hard palate (small cleft, N = 35) and clefts within the hard and soft palate (big cleft, N = 103). A retrospective evaluation of sagittal, transversal, and vertical relationships, structure Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 of the palatal mucosa, and height of the palatal vault at 5 years of age (mean age 5.3) was performed using plaster models. From medical records, the variables of time for surgery, blood loss, complications in the immediate post-operative period, frequency of fistulas and additional pharyngeal flap surgery were evaluated. The Student’s t-test was used for calculating statistical significance and 95 per cent confidence intervals were calculated. RESULTS: Time for surgery was almost double, but post-operative complications were less with the MMI technique. An increased need for pharyngeal flap surgery was found in the big cleft group. The relationship of the first and second primary molars according to the modified Huddart and Bodenham scoring system deviated significantly, showing narrowing of the maxilla in the molar area in the MI and big cleft groups. No other statistically significant difference was found concerning sagittal, transversal or vertical relationships on plaster models at 5 years of age. CONCLUSION: The MMI paltoplasty resulted in better dental occlusion in the molar area, with fewer post- operative complications but almost doubled surgical time.

38 LONG-TERM STABILITY OF MANDIBULAR CHANGES PRODUCED BY EARLY TREATMENT OF CLASS III MALOCCLUSIONS C Pavoni1, R Lione1, L Franchi2, P Cozza1, Departments of Orthodontics, 1University of Rome Tor Vergata and 2University of Florence, Italy

AIM: To evaluate the long-term stability of mandibular changes produced by early treatment of a Class III malocclusion with rapid maxillary expansion (RME) and a facemask (FM) by means of morphometric analysis [Thin-Plate Spline (TPS) analysis]. SUBJECTS AND METHOD: Twenty-five subjects (10 boys, 15 girls; mean age at the start of treatment (T1) 9.3 ± 1.6 years with Class III disharmony were treated with RME and FM therapy followed by fixed appliances. The patients were re-evaluated in the long-term (T2), about 8.5 years after the end of the treatment (mean age, 18.6 ± 2.0 years). Sixteen subjects with an untreated Class III malocclusion comprised the control group. Mandibular shape changes were analyzed on the lateral cephalograms of the subjects by means of TPS analysis. Procrustes average mandibular configurations were subjected to TPS analysis by means of both cross-sectional between- group comparisons at T1 and at T2 and longitudinal within-group comparisons. Statistical analysis of shape differences was performed using a generalized Goodall F test. RESULTS: In the long-term, the treated group exhibited a significant upward and forward direction of condylar growth. On the contrary, untreated Class III subjects showed an upward and backward direction of condylar growth associated with a downward and forward deformation of the mandibular symphysis. CONCLUSION: The analysis of relapse of Class III malocclusion treated with RME and FM showed that early treatment is able to produce significant and favourable long-term mandibular shape changes characterized by an anterior morphogenetic rotation. e22

39 THREE-DIMENSIONAL EVALUATION OF PALATAL VAULT CHANGES IN ASSESSING SUCCESSFUL TREATMENT OF A CONSTRICTED MAXILLA IN GROWING SUBJECTS G Perinetti1, J Primožič2,•L Contardo1, M Ovsenik2, 1Department of Medical, Surgical and Health Sciences, University of Trieste, Italy and 2Department of Orthodontics and Jaw Orthopaedics, University of Ljubljana, Slovenia

AIM: The success of maxillary expansion should not be assessed solely by the elimination of the teeth in ; it should also be defined as the re-establishment of normal maxillary growth. The aim of this research was to quantify the longitudinal palatal changes in children treated for maxillary constriction associated with a functional crossbite (TG) and normal controls (CG). MATERIALS AND METHOD: Study casts of 48 Caucasian subjects (23 TG, 25 CG; mean age, 5.2 ± 0.6 years) were Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 collected at baseline and at 6, 12, 18, 30, 42 and 54 months follow-up. The TG was treated using a cemented acrylic splint expander. Casts were scanned using a laser scanner and palatal surface area and volume, and their increments over time, were calculated. Non-parametric tests were used for the data analysis. The diagnostic performance in assessing successful treatment of palatal constriction was evaluated by the receiver operating characteristic (ROC) curves. RESULTS: Significantly greater increments in palatal surface area and volume were seen for the TG group up to 30 months (P < 0.05, at least). According to the ROC curves the best overall diagnostic performance in terms of accuracy was for the palatal volume at 18 months reaching up to a value of 0.85, by using a cut-off value of increments of 13.5 per cent. CONCLUSION: An increase in palatal volume of at least 13.5 per cent after 18 months out of treatment is a good indicator for the assessment of re-establishment of normal growth in subjects treated for maxillary constriction in the primary dentition.

40 LONG-TERM EVALUATION OF GINGIVAL RECESSIONS AFTER ORTHODONTIC TREATMENT F Pernet, S Kiliaridis, Department of Orthodontics, University of Geneva, Switzerland

AIM: The development of gingival recession after orthodontic treatment is controversial and there are few data on the prevalence, extent, and risk factors for their development. The aim of the present study was to investigate the prevalence and severity of gingival recession (buccal and lingual) after orthodontic treatment and at 5 and 10 years post-treatment in association with the degree of proclination of the lower incisors during orthodontic treatment, the vertical facial morphology of the individuals as well as the width and height of their symphysis. MATERIALS AND METHOD: Good quality study models and lateral cephalograms of 133 patients treated with fixed orthodontic appliances that had been taken before treatment, after treatment and long-term at 5 or 10 years follow-up were analysed by the same investigator. RESULTS: Seven patients (5.2%) and 10 (5.5%) teeth had developed new recession at the end of orthodontic treatment and a total of 13 patients (27.7%) and 22 teeth (11.8%) had recessions at 10 years follow-up. No significant differences were found between the group with small/moderate proclination of the lower incisors (≤10°) and the group with significant proclination (>10°). The present sample did not include extreme proclination of the lower incisors (>15°) and thus the influence of this extreme proclination on the development of gingival recessions could not be assessed. The appearance of new recession seems to be linked to the age of the patient. The development of recessions in the present sample was not related to the facial characteristics. CONCLUSION: Orthodontic treatment and, more specifically, reasonable proclination of the lower incisors may not be considered as risk factors for the immediate or the long-term development of gingival recession.

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41 MANDIBULAR DEVELOPMENT IN GROWING RABBITS WITH TEMPOROMANDIBULAR JOINT ARTHRITIS AND THE EFFECT OF ANTI-TNF-α TREATMENT T Präger1, S Rafayelyan1, K Minden2, P-G Jost-Brinkmann1, A Mußler3, Departments of 1Orthodontics and 3Radiology, Charité - Universitätsmedizin Berlin and 2Department of Paediatric Rheumatology, Deutsches Rheumaforschungszentrum, Berlin, Germany

AIM: Antigen induced arthritis (AIA) in the growing rabbit represents an established model for juvenile idiopathic arthritis (JIA). The aim of this study was to investigate the development of the mandible in growing rabbits suffering from bilateral arthritis of the temporomandibular joint (TMJ). In addition, the therapeutic effect of the TNF-α antagonist etanercept should be investigated. MATERIALS AND METHOD: Eighteen New Zealand White rabbits (8 weeks old) were randomized and allocated to three groups with six animals in each group. In 12 animals a sensitization on ovalbumin (OA) was performed Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 at the age of 10 weeks and followed by the induction of a bilateral arthritis of the TMJ by intra-articular injections of OA. The intra articular injections were repeated every three weeks with the purpose of maintaining the inflammation. In six out of the 12 animals weekly subcutaneous injections of etanercept were given. The remaining six animals served as controls without any intervention. All animals received computed tomographs of the maxillofacial region every three weeks, beginning from week 10 through to week 22, the end of the study. Following segmentation, the development of the mandible was analyzed. RESULTS: Mandibular development was not continuous but, growth decreased from week 10 to week 22. In all groups the highest rate of growth was seen between weeks 10 and 13. Arthritis caused severe disturbances of growth, especially in the condylar process. In the etanercept group a better but not a totally normal mandibular development compared with the control group could be observed. CONCLUSION: AIA of the TMJ causes severe disturbances of growth, which resemble those in JIA in growing rabbits. Under therapy with etanercept improved but not completely normal growth seems to be achievable.

42 EFFECTIVENESS OF ANTIMICROBIAL PHOTODYNAMIC THERAPY OF GINGIVAL HYPERTROPHY IN ORTHODONTIC PATIENTS J Primožič1, R Ovsenik2, M Pirc2, B Gaspirc3, M Ovsenik1, Departments of 1Orthodontics and Jaw Orthopaedics and 3Periodontology, 3University of Ljubljana, Slovenia

AIM: To compare the effectiveness of gingival hypertrophy (GHy) treatment using an ultrasonic cleaner (USc) only or in combination with antimicrobial photodynamic therapy (aPDT) among subjects undergoing fixed orthodontic treatment. SUBJECTS AND METHOD: Twenty one subjects (12 females, 9 males) aged 16.1 ± 3.5 years undergoing at least two years fixed orthodontic treatment with a clinically detectable GHy were included. A split-mouth• design was used, in which one side of the upper dental arch was treated with USc only, while a combination of USc and aPDT was used on the other side. The aPDT consisted of Indocyanine Green as a photosensitizer and laser light (wavelength 808 nm) as its activator. Probing pocket depth was assessed around each tooth at baseline and at one week, one month and three months follow-up. The interdental papilla surface area change was evaluated using a three-dimensional laser scanning system at the one and three months follow-ups. Furthermore, the microbiological composition of gingival crevicular fluid (GFC) was determined by real-time polymerase chain reaction at each time point. Non-parametric tests were used to assess the differences between treatment sides with statistical significance set at P < 0.05. RESULTS: A significant reduction in periodontal pocket depth (–0.74 mm; P < 0.05) was seen at all follow-ups on both treated sides, with no significant differences between sides (P > 0.05). However, no significant changes of the interdental papilla surface area were observed, regardless of the treatment performed. Although not significant, a reduction of periodontal pathogens was observed after one week on both sides, followed by an

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increase to almost initial values. Of note, more pathogenic microbial composition was observed on the side where only USc was used. CONCLUSION: Treatment of GHy with USc only or in combination with aPDT reduces the periodontal pocket depth. However, both treatments have only a short-term effect on the microbial composition of GFC as periodontal pathogens in the periodontal pockets had a tendency to increase to initial values at the three month follow-up. Therefore, it would be clinically advisable to perform at least treatment with USc every month among subjects with GHy undergoing fixed orthodontic treatment.

43 ORTHODONTIC RETREATMENT: A COHORT STUDY A-M Renkema1, R Kiekens2, F Klein Meulekamp3, J Padmos3, Departments of 1Orthodontics and Craniofacial Biology and 3Dentistry, Radboud University Nijmegen, Netherlands and 2Department of Orthodontics, Ghent University, Belgium Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021

AIM: To investigate orthodontic treatment need and to determine the involved causative factors in a sample of consecutive patients undergoing retreatment. SUBJECTS AND METHOD: Fifty-three subjects (18 males, 35 females) undergoing orthodontic treatment for the second time were identified from the files of 1014 patients in orthodontic treatment. The following aspects were determined: (1) malocclusion before initial treatment, (2) retention method after initial treatment, (3) malocclusion before retreatment, (4) planned retreatment method; (5) planned retention after retreatment, (6) expected duration of retreatment, (7) possible cause(s) of the need for retreatment. The aesthetic (AC) and dental health (DHC) component of Index of Orthodontic Treatment Need (IOTN), Peer Assessment Rating (PAR) index and Irregularity Index were scored before (T1) and after initial treatment (T2), and before retreatment (T3). Differences between the three assessment times were analysed using t- and Kruskal-Wallis tests. RESULTS: During initial treatment, considerable improvement was observed. From T2 to T3, an increase in scores of IOTN and PAR (suggesting worsening of occlusion) was observed. However, changes were minor: DHC, AC and PAR increased by 0.5, 0.6 and 4.5 points respectively; thus no objective treatment need was found. Patients were in retreatment mainly due to (i) tooth irregularity and/or spacing or (ii) torqued teeth. The most probable causative factors for orthodontic retreatment need were mainly associated with failed bonded retainers, non-compliance with removable retainers and discontinuation of retention. The expected mean retreatment time was 9.6 months (SD 7.2). CONCLUSION: Patients in this study group had no objective treatment need based on IOTN and PAR score, suggesting that these indices are not suitable to determine orthodontic treatment need in retreatment patients. Attention should be paid to the bonding procedure of fixed retainers to minimize failure rate because failures are associated with an increased need for orthodontic retreatment. Also regular check-ups of bonded retainers are necessary to detect bond failures, post-treatment changes, or complications as early as possible.

44 SKELETAL AND DENTAL EFFECTS OF CLASS III ORTHOPAEDIC TREATMENT: A SYSTEMATIC REVIEW R Rongo, I Polito, R Bucci, R Martina, V D'Antó, Section of Orthodontics, University of Naples ‘Federico II’, Italy

AIM: To review the contemporary high-quality literature, investigating the effects of orthopaedic therapy on the sagittal and vertical planes to evaluate if early treatment is a good option for Class III treatment. MATERIALS AND METHOD: A literature research was performed up to May 2013 using the following research engines: PubMed, Literature in the Health Sciences in Latin America and the Caribbean (LILACS), Scientific Electronic Library Online (SciELO), Cochrane Central Register of Controlled Trials, Scopus and Web of Knowledge. No restriction was applied concerning language or appliances. The eligible papers were identified through database searching, hand-search and analysis of reference list by two authors independently. Records were assessed for eligibility by means of inclusion and exclusion criteria. Disagreements on the selection were resolved through discussion and if necessary consulting a third-reviewer. Only randomised clinical trials and e25

prospective and retrospective controlled clinical trials, with or without follow-up, were included. Once selected the pool of papers to be reviewed, a methodological and quality score process was independently applied by two authors. Data were extracted through a customized form. RESULTS: The search strategy resulted in 1984 records; after the selection process 20 papers were quality assessed by a customizing score. Two studies out of 20 were judged of high-quality, four of medium/high quality, eight of medium-quality and six of low-quality. All the selected studies reported a skeletal improvement; 15 studies out of the 20 reported a significant increase in lower face height with clockwise rotation of the mandible. Overjet correction was accompanied by retroclination of the lower incisors and proclination of the upper incisors. Data on soft tissue profile and on follow-up are currently still insufficient with a low level of bias; however the follow up data of three studies, showed a slight relapse in 15-20 per cent of the patients. CONCLUSION: Class III early functional treatment is efficient in correction of the sagittal relationship between Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 the upper and lower jaw and it may cause a clockwise rotation of the lower jaw. The quality of the studies in this field is improving, but there are still few high quality studies.

45 A COMPARISON OF THE EFFECTIVENESS OF THREE METHODS OF REINFORCEMENT IN THE TREATMENT OF MAXIMUM ANCHORAGE PATIENTS J Sandler, Department of Orthodontics, Chesterfield Royal Hospital, Chesterfield, U.K.

AIM: To compare, in a parallel group randomized clinical trial, the effectiveness of temporary anchorage devices (TADs), Nance button palatal arches and headgear for anchorage supplementation in the treatment of malocclusions that required maximum anchorage. SUBJECTS AND METHOD: Seventy eight patients aged between 12 and 18 years randomly allocated, was based on a computer generated pseudo-random code using random permuted blocks of randomly varying size, to receive anchorage supplementation with either TADs, a Nance button on a palatal arch or headgear. The primary outcome was mesial molar movement. The secondary outcomes were duration of anchorage reinforcement, number of treatment visits, number of casual and failed appointments, total treatment time, dento-occlusal change and the patients perception of the treatment process as far as comfort of placement and removal of the anchorage method measured on 5-point Likert scales. A research assistant who was blinded to the group allocation recorded all the data. Analysis of covariance was carried out thus allowing the fitting of gender as a covariate and adjustment for the baseline scores. RESULTS: At the end of the study 71 patients completed orthodontic treatment. Data analysis showed there was no difference in the effectiveness of anchorage methods therefore patient preference was extremely important. Peer Assessment Rating scores were significantly better with TADs than in the headgear group. The patient questionnaires revealed that comfort levels on placement of TADs and Nance were very similar but more problems arose with the Nance. Headgear was most troublesome and the least popular technique. CONCLUSION: There is no difference in effectiveness between the three groups in terms of anchorage support. TADs and Nance were preferred by the patients, and there were more problems recorded with headgear and Nance buttons. The quality of treatment was also significantly better with TADs. As a result, TADS may be the preferred method of choice for reinforcing orthodontic anchorage in maximum anchorage cases.

46 CHANGE IN QUALITY OF LIFE AFTER TREATMENT OF SEVERE MALOCCLUSION AND ITS ASSOCIATIONS WITH FACIAL PAIN AND TEMPOROMANDIBULAR DISORDERS A-S Silvola1, M Tolvanen2, K Sipilä3, S Lahti2, P Pirttiniemi1, Departments of 1Oral Development and Orthodontics and 2Community Dentistry, Institute of Dentistry, University of Oulu and 3Department of Prosthetic Dentistry and Stomatognathic Physiology, Institute of Dentistry, University of Eastern Finland, Kuopio, Finland

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AIM: To evaluate, in a longitudinal study, the changes in and the relationship between facial pain and temporomandibular disorders (TMDs), and oral health-related quality of life (OHRQoL) in adults who underwent orthodontic or orthodontic/surgical treatment. SUBJECTS AND METHOD: Sixty-four patients (46 females, 18 males, mean age 37.5 years, range 18-64 years) with severe malocclusions. Of these, 44 underwent orthodontic-surgical and 20 orthodontic treatment. Data on OHRQoL, facial pain and Helkimo’s anamnestic dysfunction index (Ai) was collected with a questionnaires before and an average of 3.1 years after treatment. The 14-item Oral Health Impact Profile (OHIP-14 ) was used to measure OHRQoL, the Visual Analogue Scale to measure the intensity of facial pain and Helkimo’s Ai to measure the severity of TMD symptoms. Clinical examinations were performed before and, on average, 3 years after treatment in association with Helkimo’s clinical dysfunction index (Di). Statistical significance of the changes between the two study points were evaluated using Wilcoxon signed-rank test for OHIP-14 severity, facial pain, Di and Ai scores. Associations between changes in OHIP-14 severity, facial pain, Di and Ai scores were evaluated Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 with Spearman correlation coefficient. RESULTS: A statistically significant improvement was found in OHIP scores, facial pain and Di and Ai during the treatment among all patients (P < 0.05). The correlations between changes of OHIP-14 severity, facial pain, Di and Ai were not statistically significant. CONCLUSION: The treatment of a severe malocclusion improved not only OHRQoL but also the signs and symptoms of TMD, as well as decreased facial pain among orthognathic and orthodontic patients. The changes between variables did not correlate, which may be explained by the multifactorial nature of measured variables.

47 IMPACTED CANINE TREATMENT PLAN ASSESSMENT USING MEASUREMENTS AND THREE-DIMENSIONAL ANGLE P Sosars, G Jakobsone, Department of Orthodontics, Riga Stradins University, Riga, Latvia

AIM: Although cone beam computed tomography (CBCT) provides information about the canine position in space [three-dimensional (3D)], usually only measurements in the axial, coronal and sagittal planes are used to assess the impacted canine's 3D position. In the 3D coordinate system a 3D angle was created and it association with 1) treatment choice (traction, extraction, eruption after extraction of the primary canine, in situ) and 2) length of time needed to move the impacted canine into the dental arch was assessed. MATERIALS AND METHOD: The database (interval from 2008-2012) of CBCT scans of a multidisciplinary clinic was checked on the subject of impacted canines. One hundred two impacted canines (83 patients) were retrieved from the database. The patient's records were revised and those who came for the second consultation were included in the study (83 canines, 68 patients). The scans were uploaded in the freeware program, Osirix, allowing assessment of the canine in the coordinate system. A formula to calculate the 3D angle between the occlusal plane and the impacted canine was created. Linear and angular measurements were assessed in the axial, sagittal and coronal planes (resorption of adjacent teeth was also taken into account). RESULTS: The distance and angle in the sagittal plane (P < 0.05), 3D angle (P < 0.05) and age (P < 0.05) determined 36 per cent of the association with the choice of the treatment plan. In the group of traction, distances from impacted canine to the occlusal plane (P < 0.05) and midline (P < 0.05) determined 71 per cent of the association with the length of treatment. CONCLUSION: The 3D angle between the occlusal plane and impacted canine axis determined the treatment choice but it was not associated with the length of treatment.

48 EFFECT OF HEAD POSITIONING IN A CONE BEAM COMPUTED TOMOGRAPHIC UNIT ON THE ACCURACY OF THE SEGMENTED THREE-DIMENSIONAL SURFACE RENDERED VOLUMETRIC MODEL H C Stamatakis, J Dusseldorp, Y Ren, Department of Orthodontics, University Medical Centre Groningen, Netherlands

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AIM: During cone-beam computed tomography (CBCT) examination, the patient’s head position might deviate from the ideal. Since treatment planning for skeletal deformities may be based on the three-dimensional (3D) model of the jaws, the accuracy of the rendered volume is important. The aim of this study was to investigate the effect of head positioning on the accuracy of the segmented surface model using CBCT. MATERIALS AND METHOD: A dry skull of an adult male with a complete dentition was positioned at pre- determined orientations in a Kavo 3D CBCT unit and was scanned at 0.4 and 0.3 mm voxel sizes using fixed exposure and field of view settings. A specially manufactured inclination platform was used for the precise positioning. In total, 25 different orientations were tested in the range of –20 to +20 degrees pitching and –15 to +15 degrees rolling, related to the Frankfort horizontal plane. The segmentation procedure was performed by a user with extended experience in segmenting, employing the same thresholding method. Comparison of the 3D models was carried out by volumetrically comparing them to the ideally centred, non-rotated position. Following intra-observer reliability tests, colour-mapping of volume discrepancies and recording of the sample Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 standard deviation of the differences were performed. RESULTS: The mean differences and sample standard deviations between each positioning and the centred position for the mandible varied from –0.08 mm (SD = 0.11) to –0.13 mm (SD = 0.25) for the negative differences and from 0.08 mm (SD = 0.11) to 0.15 mm (SD = 0.25) for the positive differences. For the maxilla, the mean negative differences varied from –0.22 mm (SD = 0.41) to –0.78 mm (SD = 0.89), while the mean positive differences ranged from 0.19 mm (SD = 0.27 mm) to 0.23 mm (SD = 0.41). CONCLUSION: While some effect of head positioning on the accuracy of the segmented 3D surface rendered hard tissue model may be present, the differences do not exceed clinically relevant levels. However, such an effect tends to be larger in the maxilla than in the mandible. Although variations in head positioning in the CBCT unit are clinically acceptable for the accuracy of segmentation of the hard tissue model, caution has to be taken in surgical planning especially for the maxilla when high precision is required.

49 COMPARISONS OF THE CHONDROITIN SULPHATE LEVELS IN ORTHODONTICALLY MOVED CANINES AND THE CLINICAL OUTCOMES BETWEEN TWO DIFFERENT FORCE PATTERNS R Threesuttacheep1, P Pothacharoen2, P Kongtawelert2, D Jotikasthira1, S Krisanaprakornkit3, Departments of 1Orthodontics, 2Biochemistry and 3Oral Biology and Diagnostic Sciences, Chiang Mai University, Thailand

AIMS: To monitor the remaining interrupted force magnitudes, and to compare the chondroitin sulphate (CS) levels in gingival crevicular fluid (GFC) of moved mandibular canines, the rates of canine movement and the patients' pain and discomfort between interrupted and continuous orthodontic force patterns. SUBJECTS AND METHOD: Fifteen Class I malocclusion patients (5 males, 10 females; aged 17.00 ± 3.18 years) who required orthodontic treatment with first premolar extractions. The interrupted force pattern was generated by elastomeric chains, and the continuous force pattern by - closed coil springs. The initial force magnitude was 120 g. The elastomeric chains were replaced by new ones at the end of the fourth week during the loaded period. During the unloaded and the loaded periods, the remaining interrupted force magnitudes were measured, and those of continuous force pattern were calibrated and controlled. GCF samples were collected with Periopaper® strips. The CS levels were measured by competitive ELISA with monoclonal antibody, and compared by Wilcoxon signed-rank test. The rates of mandibular canine movement were measured, and the amount of pain was assessed by visual analogue scale scores. RESULTS: The medians of remaining interrupted force magnitudes were 120.0, 60.0, 50.0, 37.5 and 25.0 g, and after elastomeric chain replacement 120.0, 62.5, 37.5, 25.0 and 25.0 g, respectively. The medians of CS levels during the loaded period, both interrupted and continuous force patterns, were significantly greater than those during the unloaded period (P = 0.008 and P = 0.027, respectively). The differences between the medians of CS levels of interrupted and continuous force patterns during each 1 week period were not significant. There was no significant difference in the rates of mandibular canine movement, or the patients' pain and discomfort between interrupted and continuous force patterns. e28

CONCLUSION: Both interrupted and continuous force patterns, with 120 g initial force magnitude, caused no difference in biochemically-assessed bone remodelling activity, same rate of mandibular canine movement or the same patients' pain and discomfort. The ‘initial’ orthodontic force magnitude of both interrupted and continuous force patterns may play an important role in alveolar bone remodelling and clinical outcomes.

50 EXAMINATION OF CHANGES IN UPPER CANINE DISTALIZATION USING FINITE ELEMENT ANALYSIS İ Veli, T Özer2, Departments of Orthodontics, 1Izmir Katip Celebi University, 1Izmir and 2Adnan Menderes University, Aydin, Turkey

AIM: Anchorage control is an important factor in the success of orthodontic treatment and various anchorage techniques have been designed for canine distalization. The purpose of this study was to evaluate the initial changes following force application during canine distalization with two different anchorage units using three- Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 dimensional (3D) finite element (FE) analysis. MATERIALS AND METHOD: Two 3D FE models were generated to simulate the distalization of maxillary canine by sliding mechanics and any associated movement of the anchor teeth and anchorage units. In the first model consisting of 111141 elements with 22549 nodes, mini-screws were used as skeletal anchorage units and a force of 150 g was applied distally from a vertical hook placed in the middle of the canine bracket to the miniscrew. In the second model consisting of 109320 elements with 23400 nodes, two transpalatal arches (TPA) were used as anchorage units and a force of 150 g was applied distally from a vertical hook placed in the middle of the canine bracket to a vertical hook placed in the middle of the first molar tube. 3D features of displacement and stress distribution were analyzed following application of orthodontic force. RESULTS: The miniscrews displaced towards the direction of force and the highest stress areas in the loaded miniscrews appeared around the neck. The presence of a TPA did not prevent the initial molar movement. In the first model, the crowns of the posterior teeth displaced distally. Also while intrusion was observed in the mesio-incisal aspects of central and lateral incisors, extrusion was observed in the disto-incisal aspects of the canines and laterals. In the second model, the crowns of the posterior teeth displaced mesially and intrusion was observed in all anterior teeth mostly at the central and lateral incisors. In both models, the canines rotated distopalatally. CONCLUSION: Initial changes at the time of force application during canine distalization with two different anchorage systems were determined using FE analysis.

51 MORPHOLOGIC EFFECTS OF MANDIBULAR PROTRUSION SPLINTS IN ANTIGEN-INDUCED J von Bremen1, K Köhler2, D Zahner3, S Ruf1, Departments of 1Orthodontics, 2Veterinary Pathology and 3Animal Laboratories, University of Giessen, Germany

AIM: Although functional appliances are recommended for patients with juvenile idiopathic arthritis with temporomandibular joint (TMJ) involvement, very little is known concerning the morphologic TMJ reactions. It was the aim to study the histologic effects of mandibular protrusion splints in antigen induced TMJ arthritis in rabbits. MATERIALS AND METHOD: Twenty eight 10-week old male New Zealand white rabbits were randomly divided into four groups: group AO (TMJ arthritis, no splint), group AS (TMJ arthritis, mandibular splint advancement), group OS (no arthritis, mandibular splint advancement), and group OO (control group: no arthritis, no splint). According to the method described by Kapila et al. (1995) all animals were presensitized and sensitized with ovalbumin. After confirmation of sensitization, the animals of groups AO and AS received a bilateral intra- articular ovalbumin-injection to induce TMJ arthritis. One week later mandibular protrusion splints were placed on the upper incisors (AS and OS animals). After 60 days the animals were sacrificed and a semi-quantitative histologic evaluation of each TMJ was carried out. The relationship of the amount of bone apposition (+) to

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resorption (-) was analyzed, with a score of 0• indicating a balance of apposition and resorption. Furthermore, an inflammatory score ranging from 0 (none) to 4 (very high amount of inflammatory reaction) was evaluated. RESULTS: Whereas in group OO the amount of apposition and resorption was almost in balance (-1), OS animals displayed significantly more apposition (+9) and AO animals significantly more resorption (-3) than the untreated control. Arthritis animals with protrusion appliances (AS), however, had remarkably more bone apposition (+4) than resorption, indicating a similar bony reaction as in healthy animals, although reduced in extent. All groups showed certain amounts of inflammatory cells in the TMJ with AO and AS animals having a higher inflammation score (AO = 1.3; AS = 1.8) than the non-arthritis groups (OO v = 0.6; OS = 0.4). CONCLUSION: Mandibular advancement in rabbits with antigen-induced TMJ arthritis is possible without detrimental histologic reactions and appears to partially compensate for the bone loss seen in rabbits with arthritis but without mandibular protrusion splint treatment. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 52 MINI-IMPLANTS USED AS TEMPORARY PONTICS: TECHNIQUE AND SUCCESS RATES*** B Wilmes, M Nienkemper, D Drescher, Department of Orthodontics, University of Düsseldorf, Germany

AIM: Agenesis of the upper lateral incisors is a common finding. If the space is not to be closed by canine substitution, the gap between the end of orthodontic treatment and installation of a definite dental implant must be bridged. To achieve an acceptable aesthetic solution, mini-implants can be inserted as a temporary replacement. The aim of this study was to standardize the clinical protocol and to evaluate the long-term success rate of mini-implants used as temporary pontics. MATERIALS AND METHOD: Over a period of five years 21 mini-implants (2 x 13 mm) were inserted as anchors for temporary pontics in the area of missing teeth in adolescents (aged 11 to 15 years, mean age 13.1 years). Subsequently, laboratory manufactured crowns were fixed on top of the mini-implants. Follow up controls were scheduled every year to evaluate mini-implant stability, the position of the pontic and the condition of the surrounding bone. RESULTS: Twenty out of 21 mini-implants remained stable during the observation period resulting in a success rate of 95.2 per cent. Evaluation of the surrounding tissues revealed continuous bony structures and a healthy soft tissue situation. An infraposition of the mini-implants and attached pontics was detected rarely even after a 5 year observation period. CONCLUSION: Mini-implant borne pontics are a suitable alternative to a bridge or a removable prosthesis in cases of missing laterals. The use of mini-implants with sufficient dimensions results in a high success rate of 95.2 per cent. It appears that the local bone can be preserved and the degree of atrophy reduced. Three- dimensional studies should be performed to quantitatively evaluate the long-term effects on the local bone.

Scientific Poster Presentations

53 DENTOALVEOLAR AND SKELETAL EFFECTS OF MANDIBULAR ANTERIOR REPOSITIONING APPLIANCE A M Aajaji1, U Gönner2, V Gönner-Özkan2, C Palot1, S Barthelemi3, 1Reims, France, 2Kronberg im Taurus, Germany and 3Compiègne, France

AIM: To assess the Class II correction on growing adolescents with the association of fixed appliance and the mandibular anterior repositioning appliance (MARA) system. SUBJECTS AND METHOD: Thirty adolescents with a Class II malocclusion treated by the same practitioner with a combination of the MARA and fixed appliances were compared with a sample of 30 untreated adolescents with a Class II malocclusion. The modifications were analyzed by the cephalometric structural LDV analysis and with structural general and mandibular superimpositions. RESULTS: Skeletal correction of a Class II was highly significant for patients treated with the MARA in compared with the non-treated sample. Condylar growth was also highly significant as well as the increase of mandibular e30

diagonal length. The counterbalancing proportion was 70.77 per cent revealing that two-thirds of condylar growth participated in the increase of mandibular diagonal length. CONCLUSION: The MARA associated with a fixed appliance resulted in a significant increase of diagonal mandibular length. Overjet correction was obtained with 63.3 per cent of skeletal participation and 36.7 per cent of dentoalveolar participation. The Angle Class II correction was due to 46.2 per cent of skeletal component and 53.8% of dentoalveolar component. The MARA leads to a minimal effect on mandibular incisors when class II is corrected.

54 INFLUENCE OF BRACKET-SLOT DESIGN ON THE FORCES RELEASED BY SUPERELASTIC NICKEL-TITANIUM ALIGNMENT IN DIFFERENT DEFLECTION CONFIGURATIONS P Aceto1, R Nucera2, A Laiola1, G Matarese2, L Perillo1, Departments of Orthodontics, 1Second University of Naples and 2University of Messina, Italy Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021

AIM: To evaluate how different bracket-slot design characteristics affect the forces released by superelastic nickel-titanium (NiTi) alignment wires at different amounts of wire deflection. MATERIALS AND METHOD: Three-bracket bending and a classic three-point bending test were used to investigate the load-deflection properties of one superelastic 0.014 inch NiTi alignment wire in different experimental conditions. The selected NiTi archwire was tested in association with three bracket systems: (1) conventional twin brackets with a 0.018 inch slot, (2) a self-ligating bracket with a 0.018 inch slot, and (3) a self- ligating bracket with a 0.022 inch slot. The interbracket distance, considered from the midpoint of every mounted bracket, was set at 7.5 mm. Tests were performed at two different maximum deflections (MD): 2 and 4 mm. Loading and unloading phases were carried out under the same conditions at a constant temperature of 36°C. During testing, temperature was monitored by a thermocouple connected to the bending apparatus. For every test, a new segment wire and new brackets were used. RESULTS: During the unloading phase at 2 mm MD, the average forces at 1.5 mm were higher than those registered at 1.0 mm. The bracket system with the 0.022 inch slot exhibited less force than the bracket system with a 0.018 inch slot. During the unloading phase at 4 mm MD, the average forces at 3.5 mm were less than at 1.5 mm. CONCLUSION: The design of the bracket significantly affects the amount of force released by superelastic NiTi alignment wires. The use of a self-ligating bracket system increases the force released by superelastic wire compared with the conventional ligated bracket system. The type of experimental procedure affects the wire force release. NiTi wires, at different maximum deflection (2 and 4 mm), release significantly different forces at the same unloading data point (1.5 mm). This allows clinicians to manage the NiTi wire force release during alignment.

55 METHODOLOGY FOR THREE-DIMENSIONAL EVALUATION OF SOFT TISSUE CHANGES AFTER CLEFT ORTHOGNATHIC SURGERY. A TECHNICAL NOTE N Adali1, T Coward2, P Haers3, 1Department of Orthodontics and Maxillofacial Surgery, Luton and Dunstable University Hospital NHS Foundation Trust, Luton, 2Department of Facial Rehabilitation, King's College London, and 3Department of Maxillofacial Surgery, South Thames Cleft Services, Guy's and St Thomas' Hospitals NHS Foundation Trust, London, U.K.

AIM: To illustrate a method of superimposition of three-dimensional (3D) stereophotogrammetric images in order to demonstrate and quantify facial change after cleft orthognathic surgery. MATERIALS AND METHOD: Current area and landmark superimposition techniques of 3D stereophotogrammetric images were reviewed. A repeatability study of superimposition was carried out. With ethical approval, two patients with a unilateral cleft lip and palate, right and left, aged 18 years, underwent

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bimaxillary osteotomies with differential impactions of the maxillae by the same surgeon. The two case histories are presented. Pre- (at 1 and 4 months before surgery) and post- (at 14 and 4 months) operatively, 3D stereophotogrammetric images were collected and analysed for changes in facial proportion, volume, convexity and contour. The surgical movements were compared with colour maps and two-dimensional (2D) cephalometric changes correlated to 2D midline contour changes of the 3D images. RESULTS: The repeatability of superimposition was high. The maxillary advancements of 10 mm and 8 mm for each patient correlated with the colour maps and the 2D cephalometric changes correlated with the 2D midline contour changes on the 3D images. This was illustrated with images. CONCLUSION: The results support the use of this method in 3D assessment of cleft orthognathic surgery outcome. The timing of the post-operative images varied considerably which limited the validity of a comparison. The method needs to be applied to a larger patient cohort. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 56 THREE-DIMENSIONAL ANALYSIS OF FACIAL MORPHOLOGY BY CONSTRUCTING AVERAGE FACES OF 10 YEAR-OLD TURKISH CHILDREN H Ademoglu1, H Turkkahraman1, A Yazici2, M Ersöz3, Departments of Orthodontics, Faculties of Dentistry, 1Suleyman Demirel University, Isparta and 3Inonu University, Malatya and 2Department of Computer Engineering, Bogazici University, Istanbul, Turkey

AIM: Advancements in imaging technology brought a new concept to ‘facial average’ in three-dimensional (3D) surface imaging systems that helps eliminate data loss that occurred in two-dimensional (2D) imaging modalities. The aim of this report is to present the 3D analysis of 10 year old Turkish children’s facial surface morphology by constructing average faces. SUBJECTS AND METHOD: The subjects were white children selected from two comprehensive schools in the East Anatolian area of Turkey. Thirty seven male and 42 female images were obtained with a 3D imaging device, 3dMD Face• (3dMD Ltd., London, UK). Those who had undergone previous orthodontic treatment or had craniofacial anomalies were excluded from the study. Body mass index (BMI) was calculated according to gender and age; only subjects with a normal BMI were included. The images were prepared to construct average faces with the help of the Rapidform XOV (3D systems, Seoul, Korea) and gender and age specific average faces were constructed with the specific algorithm. Age and gender specific average faces were superimposed using the best fit method, and differences between male and female average faces were analysed. Surface area and shape differences between gender groups were shown by colour histograms. RESULTS: Facial differences were observed between gender groups. Of the superimposed faces, 47 per cent were at the tolerance level and did not show more than 0.425 mm differences. Of the superimposed faces 52 per cent showed more than 0.425 mm differences as colour deviations. Significant differences were observed for the medial parts of the supraorbital ridge, glabella, superior part of the nasal bone, medial parts of orbital regions, middle parts of infraorbital regions, right and left ala of the nose, columella, nasal tip, tubercule of the superior lip, superiomedial part of the buccal regions, and a part of forehead. These parts were more prominent in females than males. CONCLUSION: Facial averages are useful templates to analyse facial morphology and show 3D facial differences of group of subjects. 3D imaging allows measurement of morphological differences in 3D space which is not possible in 2D imaging.

57 A COMPARISON OF LONG-TERM STABILITY OF INCISOR CROWDING CORRECTION BETWEEN CLASS I AND CLASS II MALOCCLUSIONS M H AhangarAtashi, Department of Orthodontics, University of Tabriz Medical Sciences, Iran

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AIM: The skeletal pattern of the patient might have an important role in the relapse of incisor crowding. The aim of this study was to compare post-retention stability of incisor irregularity correction between skeletal Class I and Class II patients. SUBJECTS AND METHOD: From a large group of recalled skeletal Class I and Class II non-growing patients, whose lower crowding had been relieved over the past 10 years, 28 Class I and 28 Class II patients were randomly selected based on initial cephalometric findings. Mandibular dental casts were obtained and measured for the irregularity index pre-treatment (T1), post-treatment (T2) and at least 10-year post-retention (T3). Repeated measure analysis was used to compare differences between data obtained at T1, T2 and T3. An independent t- test was applied to compare the differences between the skeletal Class I and Class II groups. RESULTS: In Class I and Class II crowded patients, the mean irregularity index for T1, T2 and T3 was 6.31 mm (±0.74), 0.08 mm (±0.004) and 2.13 mm (±0.04), respectively, with an increase of 2.13 mm (±0.04) in the irregularity index from T2 to T3 (P = 0.001). The long-term follow-up of the incisor irregularity index in the two Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 groups showed that the stability of lower incisor alignment over 10 years was higher in the Class II than in the Class I patients (P = 0.001). There were also a positive and direct correlation between the degree of T1 and T3 irregularity index (Pearson’s correlation test = +0.42). CONCLUSION: The long-term stability for treatment of crowding in Class II skeletal patients is higher than in Class I skeletal patients.

58 THE EFFECTS OF MALOCCLUSIONS ON FACIAL ATTRACTIVENESS AND ITS CORRELATION WITH DIVINE PROPORTIONS S Akan, A G Torgut, H Oktay, Department of Orthodontics, Istanbul Medipol University, Turkey

AIM: To evaluate the effects of malocclusion on facial attractiveness and to determine if it is affected by divine proportions. MATERIALS AND METHOD: Standard frontal facial photographs were taken of 174 Class I, 125 Class II, and 36 Class III subjects (mean age: 15.72 ± 4.03 years) in the natural head position. Facial attractiveness of the subjects was evaluated by 10 first year dental students using a 10-point visual analogue scale (VAS). All evaluations were arranged in order, and 30 attractive subjects with the highest score and 30 unattractive subjects having the lowest score were chosen for further analyses. On the photographs of these subjects, 16 landmarks were determined and 12 ratios were measured by means of ImageJ software. A Kruskal Wallis test was used to determine the effects of malocclusion on facial attractiveness, a Student’s t-test to compare the facial proportions of the attractive and unattractive subjects, and one sample t-test to define the relationships between divine proportions and facial ratios. RESULTS: No statistically significant difference was found between malocclusions in terms of facial attractiveness (P = 0.074). Of 12 vertical and horizontal ratios, trichion-menton/nasion-menton (P < 0.001), subnasale-menton/stomion-menton (P < 0.05), nasion-subnasale/stomion-menton (P < 0.05), nasion- subnasale/nasal width (P < 0.005), and trichion-menton/right-left lateral canthus (P < 0.05) ratios showed statistically significant differences between attractive and unattractive subjects. All the ratios except nasion- subnasale/stomion-menton in the attractive subjects and subnasale-menton/stomion-menton and menton- lateral canthus/ lateral canthus-trichion in the unattractive subjects were found to be different from the divine proportions. CONCLUSION: Malocclusions have no effect on facial attractiveness. Facial ratios used in this study have little effect on attractiveness and were different from divine proportions.

59 THE EFFECTS OF A FACEMASK ON PERMANENT CANINE POSITION Y E Akgül, F İ Uçar, Z M Baka, Z İleri, F A Basciftci, Department of Orthodontics, Faculty of Dentistry, Selcuk University, Konya, Turkey

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AIM: To evaluate the position and aspect of the maxillary canine after facemask therapy. MATERIALS AND METHOD: Thirty two maxillary canine teeth from 16 patients. Panoramic radiographs were taken twice, pre- (T1) and post- (T2) facemask therapy. Canine angulation was evaluated according to the bicondylar line (Warford et al., 2003) and mesiodistal evaluation was established according to lateral incisor direction (suggested by Lindauer et al., 1992). Radiographic measurements were performed by the same investigator. Data were analysed employing SPSS Windows version 12.0 software. The Kolmogorov Smirnov test was used to assure homogenous distribution between groups. Differences between T1 and T2 values were analyzed with paired t-tests. RESULTS: The mean ages were 11.28 (T1) and 11.97 (T2)years. There were no significant differences between gender, right or left canine position and the T1 and T2 position of the canines. CONCLUSION: There is no significant side-effect on canine position during facemask treatment. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021

60 EVALUATION OF ALVEOLAR BONE CHANGES AFTER ASYMMETRIC RAPID MAXILLARY EXPANSION M Akin, Z M Baka, Z Ileri, F A Basciftci, Department of Orthodontics, Selcuk University, Konya, Turkey

AIMS: To quantitatively evaluate the effects of asymmetric rapid maxillary expansion (ARME) on cortical bone thickness, alveolar bone height, and to determine the formation of dehiscence and fenestration in surrounding alveolar bone around posterior teeth, using cone-beam computed tomography (CBCT). MATERIALS AND METHOD: The CBCT records of 23 patients with a unilateral skeletal crossbite (10 boys, 14.06 ±1.08 years, 13 girls, 13.64 ± 1.32 years) who underwent ARME were selected from the clinic archives. The bonded acrylic RME appliance, including an occlusal stop, was used in all patients. CBCT records had been taken before ARME and after a 3 months’ retention period. Axial slices of the CBCT images at three vertical levels were used to evaluate the buccal and palatal aspects of the canines, first and second premolars, and first molars. Paired and independent sample t-tests were used for statistical comparison. RESULTS: Buccal cortical bone thickness on the crossbite side was significantly more affected by expansion than that on the non-crossbite side (P < 0.05). ARME significantly reduced the buccal alveolar bone height of the canine (P < 0.01) and first and second premolar (P < 0.05) on the crossbite side. ARME also increased the incidence of dehiscence and fenestration on the crossbite side. CONCLUSION: ARME may quantitatively decrease buccal cortical bone thickness and height on the crossbite side.

61 ACCURACY AND RELIABILITY OF LONGITUDINAL CEPHALOMETRIC MEASUREMENTS USING MANUAL AND DIGITAL METHODS M Akin1, I Veli2, S Aksakalli3, Z Ileri1, Departments of Orthodontics, 1Selcuk University, Konya, 2Izmir Katip Çelebi University, Izmir and 3Bezmialem University, Istanbul, Turkey

AIM: To compare the accuracy and reliability of longitudinal cephalometric measurements using manual and different digital tracing methods, and to determine whether different tracing methods affect the measurement of changes in the treatment results. MATERIALS AND METHOD: Thirty pre- and post-treatment cephalometric radiographs. Seventeen angular and five linear measurements were determined by one operator both manually and using five different software programs (Dolphin Imaging Version 10.5, Quick Ceph Studio, Nemoceph NX 2006, and Vistadent AT 3.1). Intraclass correlation coefficient was used to assess intraobserver reliability. A paired t-test and one-way analysis of variance were used to detect differences between the manual and digital methods at a significance level of 0.05.

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RESULTS: Intraobserver reliability demonstrated excellent agreement between initial tracings. Correlation coefficients values of all measurements were found to be above 0.85. The same pre- and post-treatment measurements changed significantly in all methods. The most significant changes were observed for ANB and SNA angles. CONCLUSION: All digital cephalometric tracing methods were reliable and acceptable as manual tracing methods and neither manual nor digital tracing methods affected the measurement of changes in the treatment results.

62 SALIVARY CORTISOL RESPONSE TO FIXED ORTHODONTIC TREATMENT IN ADOLESCENTS A Aksoy1, F Gültekin1, Y Alpağan Özkaynak1, G Karacin1, B Dağdeviren2, 1Department of Orthodontics, Faculty of Dentistry and 2Department of Medical Biochemistry, Faculty of Medicine, University of Suleyman Demirel, Isparta, Turkey Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021

AIM: To determine the salivary cortisol levels as a determinant of pain during fixed orthodontic treatment after insertion of two initial wires of different sizes. SUBJECTS AND METHOD: Twenty patients (10 boys, 10 girls) aged between 12-17 years. The saliva samples were collected between 09:00 and 09:15 on the first day before treatment (T0), after banding on the same day (T1), again at 09:00 and 09:15 on the next day before placement of the brackets and archwire (T2), and after placement of the archwire (T3). The saliva samples collected were analysed for the level of cortisol. RESULTS: The mean level of salivary cortisol for girls was 0.59 µg dl-1 and for boys 0.52 µg dl-1 at T0. T0 was used as the control group for this study. The cortisol level for girls then dropped to 0.34 µg dl-1 at T1, 0.44 µg dl-1 at T2 and 0.40 µg dl-1 at T3 day. It also dropped to 0.34 µg dl-1 at T1, 0.40 µg dl-1 at T2 and 0.41 µg dl-1 at T3 for boys. There was no significant difference between boys and girls before treatment at T0 (P > 0.05). Regarding 0.014 and 0.016 inch initial wire diameters; there was no significant difference of cortisol levels for these two thicknesses of initial wires at T0 (0.66-0.45 µg dl-1) and T1 (0.38-0.30 µg dl-1). The cortisol level showed no significant difference either at T2 (0.46-0.38 µg dl-1) or T3 (0.46-0.35 µg dl-1). CONCLUSION: No significant differences in cortisol levels were found in terms of gender and initial wire thickness (0.014 and 0.016 inch wire) during fixed orthodontic treatment after banding or before or after initial archwire insertion.

63 DENTOALVEOLAR CHANGES IN PATIENTS WITH TOOTH AGENESIS M Alexandrova1, G Alexandrova1,2, S Dianiskova1,2, 1Department of Orthodontics, Slovak Medical University and 2Private Orthodontic Practice, Bratislava, Slovakia

AIM: To determine whether the number and location of missing teeth has an influence on dentoalveolar development. SUBJECTS AND METHOD: One hundred orthodontic patients aged between 11 and 38 years with at least one missing tooth (excluding third molars) and prior to any orthodontic treatment divided into two groups. Patients in the first group had fewer than four missing teeth and in the second group were patients with oligodontia (4 or more congenitally missing teeth). According to the location, they were assigned to two subgroups. In the first group were those with tooth agenesis in the maxilla and in the second patients with tooth agenesis in the mandible. Skeletal and dentoalveolar characteristics were evaluated according to measurements on lateral cephalograms using Jedlickova’s analysis of the computer program KefaloView (Version 4.07). UI:NS angle, LI:ML angle, UI:NPo distance and LI:APo distance were compared with standard norms published by Jedlickova and evaluated using a one sample t-test (SPSS 19).

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RESULTS: Statistically significant reductions were found in UI:NS angle, UI:NPo and LI:APo distances in all groups. The decrease in UI:NPo (P < 0.001) and LI:APo (P < 0.001) distances was greater in severe cases (patients with oligodontia). Other values were within normal ranges. CONCLUSION: There are differences between subjects with a full dentition and those with hypodontia. Tooth agenesis may have negative influence on the development of the dental arch and inclination of the upper incisors. Location and severity have a significant effect.

64 PREDICTORS OF ROOT RESORPTION ASSOCIATED WITH MAXILLARY CANINE IMPACTION IN PANORAMIC IMAGES A Alqerban1, R Jacobs1, S Fieuws2, G Willems1, 1Department of Oral Health Sciences, KU Leuven and 2Departments of Public Health, KU Leuven and Universiteit Hasselt, Belgium Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 AIM: To develop a prediction model for root resorption caused by impacted canines based on radiographic variables assessed on two-dimensional (2D) panoramic radiographs with the intention to reduce the need for additional cone beam computed tomographic (CBCT) imaging. SUBJECTS AND METHOD: Three hundred and six patients (188 females, 118 males; mean age, 14.7 years; SD, 5.6; range, 8.4-47.2 years). In total, 406 impacted maxillary canines were studied, from 206 patients with unilateral impaction and from 100 patients with bilateral impaction. Initial 2D panoramic radiography was available, and three-dimensional CBCT imaging was obtained upon clinical indication. The generated radiographic variables and specific features investigated were collected on 2D panoramic imaging and were correlated to the presence/absence of root resorption detected on CBCT. RESULTS: The incidence of root resorption of the adjacent teeth was 33.8 per cent. A prediction model using panoramic images for the possible presence of root resorption was established (AUC = 0.74, 95% CI: 0.69; 0.79) and validated by applying leave-one-out cross-validation (AUC = 0.71, 95% CI: 0.66; 0.77). For the subgroup of presence of severe root resorption, the discriminative ability increased to 0.80. In this prediction model, patient gender, canine apex, vertical canine crown position, and canine magnification were the strongest predictors for root resorption. CONCLUSION: The final prediction model for root resorption based on available panoramic radiographs could help justify the need for additional CBCT examination.

65 IN VITRO COMPARISON OF CONTEMPORARY RADIOGRAPHIC IMAGING TECHNIQUES FOR THE MEASUREMENT OF INTER-RADICULAR WIDTH IN A SIMULATED HYPODONTIA CASE B Al-Tamimi, D Bister, Department of Orthodontics, King’s College London Dental Institute, Guy's Hospital, London, U.K.

AIM: To assess the reliability of measurements of inter-radicular spaces using dental pantomograms (DPT), long cone periapical (LCPA) views and cone beam computed tomography (CBCT) in an in vitro study. MATERIALS AND METHOD: A set-up containing human teeth simulating a hypodontia patient undergoing fixed appliance treatment was used. LCPAs were taken at standardized horizontal angulations to the occlusal plane. DPT, I-CAT and Accuitomo CBCT images were also taken. The distances between the roots were measured at the midpoint of the roots and the cemento-enamel Junctions (CEJ) of adjacent teeth. The measurements were repeated five times. The results of each modality were compared with each other and to the gold standard, which was the actual interdental space as measured on the set-up, using a digital calliper to the nearest 0.5 mm. Analysis of variance was used to test differences between the means for each modality. Method error was calculated by subtracting the gold standard from the measurements. Bland-Altman plots were used to look for agreement between measurements. Pairwise comparisons for the radiographic methods were performed and associated 95 per cent confidence limits are given.

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RESULTS: Coefficient of variance for intra-examiner reliability was 0.022 for DPT, 0.009 for ICAT, 0.012 for Accuitomo, and 0.005 for LCPA taken at 0 degrees. Inter-radicular widths obtained by DPT consistently overestimated real inter-radicular widths by 2.48 mm [95 per cent confidence interval (CI):-1.09-6.05 mm]. The LCPA taken at 0 degrees to the occlusal plane performed better but overestimated the inter-radicular width by 1.5 mm (CI:–0.095-4.03 mm); the reliability deteriorated as tube angulation increased. Accuitomo and ICAT CBCTs performed similarly: they overestimated the root to root width by 0.50 mm and the CEJ by 0.22 mm. CONCLUSION: The CEJ was unreliable for all radiographic techniques, whilst the midpoint of the roots was a better landmark. Care needs to be taken as to which radiographic method is used for assessing inter-radicular spaces when planning implants.

66 THE ‘RETRACTION AND TORQUE’ ARCH COMBINED WITH USE OF MINI-IMPLANT SUPPORTED ANCHORAGE: A CEPHALOMETRIC STUDY Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 M Amasyalı1, Ş Karaçay2, H Karaçay3, M Doğru4, Dental Service, 1Kütahya Military Hospital, Kütahya and 2Gulhane Military Medical Academy Haydarpasa Training Hospital, Istanbul, 3Department of Orthodontics, GATA, Ankara and 4Department of Orthodontics, Faculty of Dentistry, Dicle University, Diyarbakır, Turkey

AIM: To introduce the retraction and torque (R&T) arch to the orthodontic literature and to show the use of this archwire together with miniscrews in patients requiring maximum anchorage. SUBJECTS AND METHOD: Twelve patients (mean age 21.2 years) who required camouflage treatment. Following canine distalization, miniscrews were placed between the maxillary first molars and second premolars, and the R&T arch was applied for the retraction of incisors. The vertical retraction arms of the arch were adjusted between the apex of the lateral incisor and the alveolar bone so that the retraction force passed through the centre of resistance of the four incisors and forced the incisors to bodily retract. Closed coil-springs applying a force of 150 g were used to retract the incisors. The retraction period lasted for 217 days. RESULTS: SNA and NV-A decreased (P < 0.05) indicating alveolar bone re-remodelling around point A. The reduction in SNA caused a statistically significant decrease in ANB (P < 0.01). SN/1, NA/1, NA-1, and overjet decreased significantly (P < 0.01) depending on the retrusion of the incisors. The distances from the apex and incisal point of the central incisor to the SV reference plane also decreased significantly (P < 0.01) revealing nearly parallel movement of the incisors. Anchorage loss of the molars and a decrease in nasolabial angle were not significant (P > 0.05). CONCLUSION: Combined use of the R&T arch with miniscrews is an effective method to retract the incisors without anchorage loss. Tooth movement was nearly parallel.

67 DETERMINATION OF OCCLUSAL CONTACTS IN THE FINISHING PHASE OF ORTHODONTIC TREATMENT USING THE T-SCAN SYSTEM® L Andreeva, I Djorova, Orthodontic Department, Medical University, Sofia, Bulgaria

AIM: To establish a method of application of the T-Scan® system (Tekscan, Inc., South Boston, Massachusetts, USA) for investigation of correct occlusal contacts in the finishing phase of the orthodontic treatment. SUBJECTS AND METHOD: Thirty two patients at the end of the active part of orthodontic treatment or at the retention phase. To determine the cusp-fossae relationships, these contacts in different positions of the lower jaw including centric occlusion bite, right lateral excursion bite, left lateral excursion bite, protrusive bite and centric relation were explored. Five movies were made to illustrate the different ways patients bite and the changes in occlusal relationships. Three records of each patient were made for better accuracy. The methodology has five important steps and they should be performed for accurate registration of the bite. 1. Allow the patient to become accustomed to closing comfortably and repeatedly on the sensor. Adjust the sensitivity to match the sensor sensitivity to the patient’s bite force. 2. Intraoral placement of the appropriate

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sensor of the T-Scan system in the mouth of the patient. 3. Instruct the patient to bite firmly on their distal teeth and hold in this position for 1.5 seconds before opening. For better authenticity the patient should repeated this action 3-5 times. The record may be acceptable when 1-3 red/pink occlusal contacts appear. 4. Recording data. Five recordings for each patient were obtained in the following order: 1. centric occlusion; 2. left lateral excursive bite; 3. right lateral excursive bite; 4. protrusive bite; 5. centric relation. This method was used on 32 patients and five movies were made of each patient in different bite positions and the movements were recorded in graphs and tables. RESULTS: Using these data the difference in transverse occlusal contacts can be determined and compared with the anatomical norm in orthodontic treatment.

68 ORTHODONTIC MANAGEMENT OF TRAUMATIZED TEETH: A REVIEW S Andrés, J Mendes, J Durán, J M Ustrell, University of Barcelona, Spain Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021

AIM: To offer an updated vision of the action plan dentists should follow when dental trauma occurs, and its clinical management prior to and during orthodontic treatment. MATERIALS AND METHOD: Data collection was by consulting databases. The chosen articles were retrospective and prospective studies, clinical reports and literature reviews. In total, 14 sources were considered, including two textbooks. RESULTS: Following trauma, there must be a preventive waiting time before beginning orthodontic treatment. In concussions, subluxations and crown/crown-root fractures without pulp damage the waiting period is three months. For complicated fractures, a wait of three months after endodontic treatment will be required. With severe luxation, such as intrusion, extrusion or lateral luxation, a six month period of observation is recommended. The advice for avulsions and root fractures is to postpone orthodontic treatment one year. CONCLUSION: It is still unclear how to successfully move a traumatized tooth. To achieve a successful treatment result an adequate waiting time between the trauma and treatment onset must be considered. Apart from using mild and intermittent forces, any cortical contact or long-term orthodontic treatment should be avoided.

69 CORRELATION OF TEMPOROMANDIBULAR AND MAXILLOFACIAL MORPHOLOGY IN PATIENTS WITH MALOCCLUSIONS A Aoki, T Kageyama, M Hoshino, D Koide, K Yamada, Matsumoto Dental University, Nagano, Japan

AIM: Since patients with malocclusion show various kinds of occlusal interference, the load to the temporomandibular joint (TMJ) might be different due to the kind of malocclusion. The aim of the present study was to investigate the relationship between the TMJ and maxillofacial morphology in patients with malocclusion using TMJ sagittal arthrotomograms. SUBJECTS AND METHOD: Thirty adult patients (6 men, 24 women) with Angle Class I and II malocclusions were randomly selected. TMJ morphology before orthodontic treatment was measured using longitudinal TMJ sagittal arthrotomograms obtained with a cephalometric laminograph. RESULTS: Condylar pass angle showed a significant positive correlation to SNA, the antero-posterior width of the fossa showed a significant positive correlation with SNA and SNB, and condylar height showed a significant positive correlation to the Go-Me length. CONCLUSION: The antero-posterior position of the maxilla and mandible are related to the morphology of the glenoid fossa and condyle, and the length of the mandibular body.

70 A COMPARISON OF THE RESISTANCE TO RELAPSE OF COAXIAL AND RECTANGULAR RETENTION WIRES

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D Arnold1, M Dalstra2, C Verna1, 1Department of Orthodontics and Pediatric Dentistry, University of Basel, Switzerland and 2Department of Orthodontics, University of Aarhus, Denmark

AIM: To determine the forces delivered by coaxial and rectangular wires used for fixed retainers in different displacement modes associated with simulated relapse in a three-tooth set-up. MATERIALS AND METHOD: The following commercially available wires were chosen: 0.016• × 0.022 inch• braided, rectangular dead soft 8-braided, 0.014 inch coaxial, and 0.016• × 0.016 inch• plain. The wires were tested in a force system identification (FSI) machine, which enabled measurement of the three force components and the three moment components, while performing incremental movements of either of the six degrees of freedom (3 translations and 3 rotations). For the FSI machine, a special jig was designed, which allowed a set-up with three neighbouring artificial teeth. The two outer teeth were fully connected to one side of the jig, while the middle tooth was fixed to the other side of the jig, which was freely movable relative to the Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 other side. After the middle tooth was positioned into the 'zero' position, the retention wire was cemented into place. Three movement patterns were then chosen: buccolingual translation (±2 mm), vertical translation (±2 mm) and proclination (±5°). These movements were performed in 10 increments and at each increment the forces and moments at the teeth were measured and plotted into graphs. The slopes of the experimental curves are an expression of the stiffness of the retention wire and thus its efficacy. RESULTS: The braided wire always showed larger stiffness values than the coaxial one. The stiffness of the wires was comparable in both the buccolingual and vertical translations. The transverse forces were negligible for the three different testing modes. The braided wire showed more vertical resistance during buccolingual movement. During proclination the braided wire also offered more resistance to vertical displacement, while the coaxial wire showed relative stiffer values in the buccolingual displacement. CONCLUSION: The wide range of resistance observed in this study seems to be an expression of the combination of the morphology and displacement mode. In case of mandatory need for control of vertical relapse rectangular wire is suggested.

71 THE AUSTRO REPOSITIONER: NEW TRENDS IN FUNCTIONAL ORTHODONTICS M D Austro Martinez1, C Garcia Ballesta1, O Cortes Lillo1, M Lopez Nicolas2, E Osorio Cruz3, 1Odontopediatry- Orthodontic and 2Ergonomics Departments, Murcia University and 3Exclusive Orthodontic, Cordoba, Spain

AIM: To promote the stimulation of the mandibular growth in patients with mandibular hypoplasia, protruding it by using a fixed appliance that keeps the mandible in such a position 24 hours a day. MATERIALS AND METHOD: A fixed appliance that is cemented on the 16 and 26 was designed. The bite registration is taken on the patient repositioning the mandible to an anterior position in order to construct an acrylic wedge that follows a sliding plane. As the patient closes/occludes, the teeth in the lower jaw contact the acrylic wedge forcing the mandible to move forward along the inclined plane reaching a protruded bite while the teeth are together in contact. In dolichofacial patients the mandible slides forward reaching full closure and avoiding extrusion of the molars. In brachyfacial patients, their lower incisors contact the acrylic of the appliance lifting the posterior bite and releasing the back sectors from any contacts causing therefore an extrusion that will improve and solve the anterior overbite. A study was undertaken involving 20 patients aged 9-11 years and a control group where the outcome of wearing the appliance for one year was evaluated by assessing the pre-treatment and the 1 year recall teleradiographs. RESULTS: The Austro Repositioner achieved greater mandibular growth as well as a correct maxillary- mandibular relationship for all treated patients. CONCLUSION: The Austro Repositioner successfully keeps the mandible in a more anterior position. It also has the advantage of being fixed, unlike other appliances such as the Bionator, Fränkel or Klammt which are removable, so it works during the whole day. Moreover it is a comfortable appliance that does not require

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patient cooperation. Full compliance in wearing functional removable devices all the time is difficult to achieve. However the Austro Repositioner works constantly 24 hours a day, showing results in the short term. Furthermore, it resulted in greater mandibular growth for all the subjects compared with the control group.

72 DETERMINATION OF THREE-DIMENSIONAL PHARYNGEAL AIRWAY VOLUME IN INDIVIDUALS WITH DIFFERENT SKELETAL PATTERNS Y Ay Doğan1, Mİ Karadede2, İ Yildiz3, 1Faculty of Dentistry, Adnan Menderes University, Aydin, 2Department of Orthodontics, Faculty of Dentistry and 3Department of Biostatistics, Faculty of Medicine, Dicle University, Diyarbakir, Turkey

AIM: To compare the volume and shape of the airways of patients with different skeletal patterns. MATERIALS AND METHOD: Cone beam computerized tomographs (CBCT) of 235 patients (114 girls, 121 boys). Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 Lateral cephalometric analysis was done on these selected CBCTs and divided into groups to contain a similar number of boys and girls due to their skeletal patterns. After dividing into three groups based on ANB angle as Class I (0 ≤ ANB ≤4), Class II (ANB >4°) and Class III (ANB <0°), each group was further divided into subgroups based on SN-GoGn and the sum of the inner angles (IAT) as low (SN-GoGn <28, IAT<393), medium (28 ≤ SN- GoGn ≤36, 393≤ IAT ≤399) and high (SN-GoGn>36, IAT>399) face pattern. Airway measurements were undertaken using the Dolphin three-dimensional software program on CBCT scans. RESULTS: Oropharyngeal, nasopharyngeal and total airway volumes of Class II patients were smaller than those of Class I and Class III patients. There were no significant differences in oropharyngeal, nasopharyngeal and total airway volumes between Class I and Class III patients. Patients with a high facial pattern showed smaller total airway volumes to those with a low facial pattern. CONCLUSION: Orthodontic treatment of patients should be determined by airway capacity.

73 AESTHETIC IMPACT OF MALOCCLUSION IN DIFFERENT SKELETAL MALOCCLUSION GROUPS C Aydoğan, F Kazancı, Department of Orthodontics, Yüzüncü Yıl University, Van, Turkey

AIM: Orthodontic treatment demand keeps growing. All potential orthodontic patients have a self-perception of malocclusion. Patients mainly seek orthodontic treatment for aesthetic improvement. Several studies have investigated the relationship between treatment need and subjective perception of malocclusion. The aim of this study was to determine the relationship between normative treatment need and the subjective aesthetic impact of malocclusion in patients with different skeletal patterns. SUBJECTS AND METHOD: One hundred and forty eight children between 12-14 years of age (79 girls, 69 boys) seeking orthodontic treatment. The Index of Orthodontic Treatment Need (IOTN) and Oral Aesthetic Subjective Impact Scale (OASIS) were used to determine normative treatment need and subjective impact of malocclusion. Kruskal-Wallis and Mann-Whitney U tests were used to analyze the data in different skeletal patterns. RESULTS: The distribution of patients in skeletal groups were 51 (34.5%) Class I, 52 (35.1%) Class II, and 45 (30.4%) Class III. OASIS scores of Class II patients were significantly higher than Class I and III patients. The aesthetic component of IOTN resulted in 12 per cent no need, 23 per cent slight need, 25 per cent borderline need and 40 per cent great need, while the dental health component resulted in 5.4 per cent slight need, 20.3 per cent borderline need and 74.3 per cent great need. OASIS scores significantly increased in direct proportion with the level of treatment need. CONCLUSION: Quality of life (QoL) assessment in orthodontics has gained more attention in recent years. According to the present results, skeletal Class II patients and those with a great treatment need had a higher aesthetic impact of malocclusion when OASIS was used as a measure of QoL.

74 A PROSPECTIVE CLINICAL EVALUATION OF BONDED LINGUAL RETAINER FAILURE

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Z M Baka, M Akin, Department of Orthodontics, Selcuk University, Konya, Turkey

AIM: To prospectively evaluate the failure rate of bonded lingual retainers, and to determine the distribution of failures over a 6 month period. SUBJECTS AND METHOD: One hundred and fifty consecutively treated patients (92 females, 58 males, mean age: 14.89 ± 1.08 years) who received a canine-to-canine lingual retainer bonded to the lingual surfaces of both maxillary and mandibular anterior teeth after active orthodontic treatment were followed up for 6 months. A 0.0215 inch five-stranded wire (PentaOne, Masel) was bonded to the teeth using Transbond LR. The patients were reviewed at 1, 3, and 6 months after bonding of the retainer. Retainer failure during the 6-month observation period were registered, compared, and statistically analyzed with a Cochran Q test at the P < 0.05 level. RESULTS: Retainer failure was observed in 14 patients. The total failure rate was 9.3 per cent. The highest Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 failure rate was seen in the first month (P < 0.05). Females exhibited higher failure rates than males (P < 0.05). Three patients had repeated failures. The failure rate was higher in the mandible and in the right quadrant for both the maxilla and mandible. The total survival rate was 90.7 per cent. CONCLUSION: The results of this study indicated that higher failure rate is seen in the first month of the retention period. Therefore, regular check-ups are necessary to determine bond failures.

75 CLASS II TREATMENT BY EXTRACTION OF MAXILLARY FIRST PREMOLARS OR A FATIGUE RESISTANT DEVICE: SOFT TISSUE EFFECTS IN COMPARISON Z M Baka, M Akin, M E Yilmaz, F A Basciftci, Department of Orthodontics, Selcuk University, Konya, Turkey

AIM: To the compare dentofacial soft tissue treatment effects of two alternative Class II treatment modalities (Forsus FRD versus maxillary first premolar extractions) in late adolescent patients with Class II malocclusions. SUBJECTS AND METHOD: Sixty two patients with a Class II malocclusion. Among these, 31 subjects (16 girls, 15 boys with a mean age of 14.8 years) were treated with a vForsus FRD and 31 subjects (15 girls, 16 boys with a mean age of 15.1 years) had upper maxillary first premolar extractions. The groups were matched for age and gender. Pre- and post-treatment lateral cephalograms were retrospectively analyzed. Twenty nine cephalometric landmarks were identified on each lateral cephalometric radiograph. The groups were compared with a Mann-Whitney U test at the P < 0.05 level. RESULTS: The aesthetic plane-upper lip distance increased significantly in the extraction group (P < 0.05). Soft tissue profile convexity (when the nose was taken into consideration) (2.92°) and nasolabial angle (1.38°) increased in the extraction group whereas they decreased 1.89 and 1.46 degrees, respectively, in the Forsus FRD group. Overjet decreased, lower alveolabial sulcus thickness (si-B) and mental thickness (pog-pog') increased significantly in both groups P < 0.05). Overbite decreased significantly in the Forsus FRD group; in contrast it increased in the extraction group. CONCLUSION: Both treatment methods corrected the Class II discrepancies through soft tissue changes. However, extraction treatment resulted in upper lip retraction and Forsus FRD treatment showed limited soft tissue profile improvement. So both treatment methods may not compensate the aesthetic facial outcome that can be achieved by orthognathic surgery.

76 THREE-YEAR FOLLOW-UP OF NON-EXTRACTION CROWDED CASES TREATED WITH THE DAMON SYSTEM F A Basciftci, Z M Baka, S Bayram, E A Erdur, Department of Orthodontics, Selcuk University, Konya, Turkey

AIM: To retrospectively investigate treatment efficiency and 3 year follow-up stability of the Damon system by evaluating the Peer Assessment Rating (PAR) index, posteroanterior lateral cephalometric changes, and the intercanine and intermolar widths.

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SUBJECTS AND METHOD: Fifty-five patients treated with a 0.022 inch slot Damon D3 MX bracket system were evaluated. Cephalometric radiographs, dental models, and PAR scores were measured, and evaluated pre- (T1), post- (T2), and 3 years after (T3) treatment. Repeated measure analysis of variance (ANOVA)/paired t-test were performed to evaluate the differences between the periods. RESULTS: The mean PAR score of 34.75 at T1 was reduced to 3.35 and 3.05 at T2 and T3, respectively, resulting in a 90.35 per cent reduction with treatment. At T1-T2 and T1-T3, maxillary intercanine and intermolar width and mandibular intercanine width increased significantly. Although intercanine and intermolar widths decreased in both arches at T2-T3, only maxillary intercanine width showed a small, but statistically significant decrease (0.09 mm, P = 0.001). The value of SNB angle, Md1-NB (mm), Md1-NB (°), and E Plane-Lower Lip increased significantly at T1-T2 and T1-T3. Therefore, treatment resulted in mandibular incisor and lower lip proclination. All of the posteroanterior cephalometric changes were statistically significant except facial width changes at T1-T2. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 CONCLUSION: The findings show satisfactory results and a good follow-up stability with the Damon system. The Damon system can be used for non-extraction treatment in crowded patients.

77 EVALUATION OF THE RELATIONSHIP BETWEEN P561T AND C422F POLYMORPHSIMS IN GROWTH HORMONE RECEPTOR GENE AND MANDIBULAR PROGNATHISM S Bayram1, F A Basciftci1, E Kurar2, Departments of 1Orthodontics and 2Genetics, Selcuk University, Konya, Turkey

AIM: To evaluate the allele and genotype frequencies of P561T and C422F polymorphic sides of the growth hormone receptor (GHR) gene and the relationship between mandibular prognathism (MP) and these two single nucleotide polymorphisms (SNP) in a Caucasian population. SUBJECTS AND METHOD: A total of 99 subjects with severe skeletal Class III MP who planned to undergo or had undergone orthognathic surgery and 99 subjects with normal occlusion were examined to evaluate the relationship between MP and 2 SNPs in exon 10 of GHR gene. Blood samples were used to extract genomic DNA and the polymerase chain reaction-restriction fragment length polymorphism method was used to determine genotypes of P561T and C422F. The Minitab 14.0 packet program was used to perform statistical analysis. RESULTS: Allele frequencies of the C422F and P561T variants were determined. Because of the low allele frequency in the control group, statistical analysis could not be performed to determine the difference between the MP and control groups. Therefore, the data was combined in order to determine the association of P561T mutation and craniofacial measurements. No correlation between body height and P561T polymorphism was found. Effective mandibular length (Co-Gn) and lower face height (ANS-Me) were correlated with the P561T variant. CONCLUSION: GHR might be a candidate gene for mandibular morphogenesis in this population.

78 DENTAL FEAR AND ANXIETY IN RELATION TO MORPHOLOGY OF DRAWING AND HAND-WRITING OF CHILDREN A Beck1, T K Fábián2, P Fejérdy3, P Hermann3, G Fábián1, Departments of 1Paedodontics and Orthodontics and 3Prosthodontics, Semmelweis University, Budapest, Hungary and 2Private Practitioner, Svendborg, Denmark

AIM: Dental fear and anxiety is an increasing problem in dentistry. Therefore, research related to this topic is needed, especially for children and adolescents. It was presumed that morphological analysis of hand-drawings and hand-written free associations with the teeth may be a good tool for the understanding of deeper psychological processes behind the phenomena. SUBJECTS AND METHOD: Hungarian primary and grammar school subjects participated in this study (n = 277, 114 females, 163 males; mean age 13.97 ± 2.77 years). Dental fear was measured by the Hungarian versions of the Dental Anxiety Scale (DAS) and the Dental Fear Survey (DFS). For measuring the subjects’ expectations in

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terms of dental fear of surrounding people, the Expectation Scale (ExP) was used. To measure anxiety level, the Hungarian version of Spielberger’s State and Trait Anxiety Inventory (STAI-S, STAI-T) was used. Following administration of the scales, the subjects were asked to make drawings and free associations with the teeth. In case of hand-drawings 14 (formal, structural or content) parameters were analyzed. Evaluating the written free associations, 14 basic grapho-analytical parameters were administered. Data of the scales have been published previously: dental fear scores (DAS, DFS or ExP) interrelated with six drawing parameters and seven writing parameters and anxiety scores (STAI-S or STAI-T) interrelated with four drawing parameters and five writing parameters (one-way ANOVA P≤ 0.05). For statistical analysis, the Statistica 11• software (Stat Soft) was used; the minimal level of significance was P≤ 0.05. RESULTS: There were numerous morphological parameters of hand-drawings and hand-writings which are interrelated with the dental fear and anxiety scores in this study. There were large differences in relation to that, which particular dental fear related or anxiety related scale was used. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 CONCLUSION: The drawing and writing parameters measured in this study are not suitable for diagnostic or screening purposes neither in relation to dental fear nor in relation to anxiety, because they are somewhat uncertain. However, it may not be excluded that other morphological parameters of hand-drawing/writing may be found, which could be used for such purposes.

79 EXPLORING WHY YOUNG PEOPLE DECIDE TO UNDERGO FIXED APPLIANCE ORTHODONTIC THERAPY AND THEIR ANTICIPATIONS PRIOR TO TREATMENT S Bell1, A James2, P Benson1, 1School of Clinical Dentistry and 2Department of Sociological Studies, University of Sheffield, U.K.

AIMS: To give voice to young people and to explore why they are undergoing fixed appliance treatment and what they anticipate their experiences will be. This will provide the dental community with a greater understanding of young people’s perspectives prior to undergoing orthodontic treatment. The data presented here forms the first stage of a larger study exploring young people’s perspectives of orthodontic treatment. SUBJECTS AND METHOD: Fifteen 10-15 year old participants were recruited from the orthodontic department of a teaching hospital and from an orthodontic practice in Sheffield, UK. All participants had decided to proceed with fixed appliance treatment although they had not had their appliances fitted. Qualitative interviews were carried out with each participant at a location of their choice and were recorded using a dictaphone. The semi- structured interviews explored issues of importance to the young people, including why they were undergoing treatment and what they anticipated their experiences of treatment would be. In addition, a video camera was lent to each participant for them to record video diaries in their own time to describe their thoughts or feelings relating to their planned treatment. The interview and video data were transcribed, coded in NVivo and analysed using a thematic analysis approach. RESULTS: Using video-diaries is an innovative qualitative method and proved to be a successful way of collecting data in this research project. Participants’ primary reason to undergo treatment was to improve the appearance of the teeth although the reason participants wanted straight teeth varied, and gender played a significant role in this. Male participants were more likely to cite functional reasons in addition to appearance as motivating factors for treatment. Most participants were not worried about the appearance of the appliances. For some participants undergoing orthodontic treatment signified a rite of passage through adolescence. Participants’ involvement in the decision for them to undergo treatment varied and was not always welcome. CONCLUSION: Gender played an important part in affecting participants’ motivation for treatment. orthodontic treatment is a widespread and accepted undertaking during adolescence in the UK.

80 QUALITY OF LIFE ASPECTS DURING ORTHODONTIC TREATMENT IN PATIENTS WITH AND WITHOUT TEMPOROMANDIBULAR DISORDERS

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M-A Bencze, E Teodorescu, E Ionescu, O Popoviciu, V Milicescu, Department of Orthodontics and Dentofacial Orthopedics, ‘Carol Davila’ University of Medicine and Pharmacy, Bucharest, Romania

AIM: Facial aesthetics and functionality of the stomatognathic system have a major impact on quality of life (QoL). Orthodontic therapy, including these goals, can improve the perception of QoL, especially among teenagers and young adults, faced with social demands. SUBJECTS AND METHOD: The perception of life quality during orthodontic treatment was evaluated in a group made up of 46 patients between the ages of 12-25 years, with various dento-maxillary anomalies, half of them with temporomandibular dysfunction (TMD) and half were symptom free. The patients were assessed prior to orthodontic therapy and one year after treatment onset, and the data obtained compared with the initial situation. The temporomandibular disorders were classified according to the method of diagnostic criteria (Dworkin-LeResche) and quantified by Helkimo’s Dysfunction Index. The perception of QoL was assessed with a Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 questionnaire, tailored after that proposed by Adlyanon et al. (1996). The questionnaire included questions concerning the impact of oral health status, during the last 6 months, on: 1) masticatory efficiency, 2) speaking and pronouncing clearly, 3) cleaning teeth, 4) sleeping and relaxing, 5) smiling without embarrassment, 6) emotional state, 7) enjoying contact with other people and 8) carrying out current school work/tasks. Data were analyzed using the SPSS statistical package, through descriptive and inferential statistical methods, applying non-parametric tests (Chi-square, Spearman correlation). RESULTS: Sixty three per cent of the subjects (73.9% of those with TMD symptoms and 32.4% of patients without joint pathology) described the existence of at least one sign of the impact of oral health status on QoL over the last 6 months. After a year of orthodontic treatment, the number of patients who reported their oral- dental health status affected adversely the QoL was significantly reduced to 39.1 per cent, particularly in those with TMD (43.4% of those with symptoms, and 34.7% of patients without joint pathology). CONCLUSION: Improving jaw function (the values of Helkimo’s Dysfunction Index reduced) and facial and dental aesthetics contributes to increasing confidence and self-esteem and has a positive impact on QoL.

81 INVESTIGATION OF ROOT DILACERATIONS IN AN ORTHODONTIC PATIENT POPULATION BASED ON CONE-BEAM COMPUTED TOMOGRAPHY Y A Benkli1, S K Buyuk2, A E Sekerci3, A Ekizer2, 1Department of Orthodontics, Faculty of Dentistry, Ordu University and Departments of 2Orthodontics and 3Maxillo-Facial Radiology, Faculty of Dentistry, Ericyes University, Kayseri, Turkey

AIM: To determine the prevalence and distribution of root dilacerations (RD) in a Turkish orthodontic patient population using cone-beam computed tomography (CBCT). SUBJECTS AND METHOD: A retrospective study was conducted of CBCT images of 514 patients (273 boys, 241 girls; mean age 13.7 years; range, 9 to 21 years). The images were examined for the presence of root dilacerations. A chi-square test was used to compare the prevalence of dilacerations between gender and upper and lower jaws. RESULTS: Data showed that 104 (20.2%) of these subjects had one or more teeth that were dilacerated and these were detected in 48 (17.6%) boys and 56 (23.2%) girls. The maxillary first molars were most often dilacerated (3.08%), followed by the maxillary first premolars (2.80%). Anterior teeth were the least affected, exhibiting dilacerations in approximately 1 per cent of cases. Statistical analysis showed no significant differences among the groups with respect to gender, age, and localization (P > 0.05). CONCLUSION: A higher frequency of dilacerations was detected among orthodontic patients in this study when compared with previous investigations based on periapical or panoramic radiographs, most likely because of the use of CBCT. RD was most frequently found to affect the posterior teeth. Early detection could be important in the treatment problems associated with root dilacerations.

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82 A FINITE ELEMENT METHOD FOR ORTHODONTIC BIOMECHANICAL SIMULATION C Bica1, M Suciu2, D Esian1, A Drasoveanu1, Departments of 1Paediatric Dentistry and Orthodontics and 2Prosthetics, University of Medicine and Pharmacy, Tirgu Mures, Romania

AIM: To quantitatively analyse the biomechanical reactions with two components: stress and displacements, after applying horizontal forces on the teeth with different levels of alveolar bone resorption, and to develop the comparative studies. MATERIALS AND METHOD: Three-dimensional models of the upper central incisor were created, two of which corresponded to the two different levels of alveolar bone resorption, and the third model to the upper central incisor without alveolar bone resorption. ALGOR V16 software allowed simulations with horizontal forces of progressively increasing intensity over the middle point of the labial side of the tooth. The effect of the forces Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 was assessed by the values of stress and displacements on the tooth, on the periodontal ligament (PDL), and on the alveolar bone. For correct interpretation of the results, the features of stress on both sides, oral and labial, on the tooth, on the PDL and alveolar bone were traced. RESULTS: The distribution of stress on the tooth, on the PDL, and on the alveolar bone was similar, regardless of the intensity of the force applied, both in the presence and absence of alveolar bone resorption. In all simulations carried out the maximum values of stretching stress type were recorded at the cervical tooth level, on the oral side, and at the apical level on the labial side. The distribution of displacements, depending on the force direction, was similar in all the studied simulation cases; they were highest at the cervical tooth level and decreased progressively towards the apical level, both on the labial and oral sides. CONCLUSION: The values of stress and displacements increase progressively along with the intensity of the applied force and with the degree of alveolar bone resorption. Comparing the biomechanical reactions in the studied simulation cases, intensification of the phenomena that occur in the presence of alveolar bone resorption was observed.

83 CONE BEAM COMPUTED TOMOGRAPHIC EVALUATION OF MIDPALATAL SUTURE BONE DENSITY BEFORE, AFTER AND DURING RETENTION OF RAPID MAXILLARY EXPANSION IN GROWING PATIENTS R Bigliazzi1, A de Oliveira Silva Magalhães1, E Saito Arita2, F A Bertoz3, K Faltin Jr.1, Departments of 1Orthodontics and 2Oral Radiology, School of Dentistry, University Paulista, São Paulo and 3Department of Pediatric and Social Dentistry, Dental School, UNESP Univ Estadual Paulista, Araçatuba, Brazil

AIM: To analyze changes in bone density (BD) of the midpalatal suture after rapid maxillary expansion (RME) with the Hyrax type expander in growing subjects using cone beam computed tomography (CBCT). SUBJECTS AND METHOD: Fourteen patients (9 girls, 5 boys; mean age, 11.7 ± 2.4 years) who required RME as part of their orthodontic treatment and had pre- (T0) and post- (at the end of active expansion (T1), after a retention period of 3 months (T2) and after 6-month (T3) retention period) expansion CBCT scans. On the axial CBCT images four regions of interest (ROIs) in the midpalatal suture were analyzed. BD was measured in voxel grey scale histogram. BD measurements were compared using Friedman analysis of variance (ANOVA) with post hoc tests. A P value less than 0.05 was considered significant. RESULTS: BD values in all ROIs in the midpalatal suture decreased significantly after active expansion (T0-T1) and significantly increased during the retention periods (T1-T2 and T1-T3). According to the density values 3 months after expansion (T0-T2), the remineralization was incomplete. At 6 months of retention non-significant differences in BD were observed in comparison with the pre-treatment values (T0-T3). CONCLUSION: The active phase of RME produced effective opening of the midpalatal suture with significant decreases in BD levels. The results revealed that more than 3 months is necessary for complete sutural recovery

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after RME, thus indicating in prepubertal patients, the recommendation to extend the retention time to 6 months to achieve the midpalatal suture remineralization.

84 COMPARISON OF A FATIGUE RESISTANT DEVICE AND ANDRESEN ACTIVATOR IN THE TREATMENT OF CLASS II DIVISION 1 MALOCCLUSIONS F Bilgic1, G Basaran2, O Hamamci2, 1Department of Orthodontics, Mustafa Kemal University, Hatay and 2Dicle University, Diyarbakır, Turkey

AIM: To evaluate the effects of the Forsus™ FRD EZ (3M Unitek, Monrovia, California, USA) appliance and the Andresen activator in terms of skeletal, dental and soft tissue changes in actively growing patients presenting with a Class II division 1 malocclusion. SUBJECTS AND METHOD: Sixty subjects (study groups, n = 40 and control group, n = 20). Inclusion criteria were: Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 Class II division 1 malocclusion, retrognathic mandible, normal or low angle growth pattern, and peak growth period. The first study group consisted of 20 patients (8 females, 12 males) who were treated with the Forsus appliance, while the second group of 20 patients (9 females, 11 males) received treatment with the Andresen activator. The control group (9 females, 11 males) received no treatment. Lateral cephalometric films were taken before treatment, before installation of the appliance and just after removal of the Forsus appliance in the first group. In the second group, radiographs were obtained before and at the end of 6 months of appliance use. The control group were followed for the same amount of time. Wilcoxon analysis was used to evaluate the differences that occurred in each group. Oneway ANOVA and Bonferroni tests were used for intergroup comparison. RESULTS: Both appliances enhanced mandibular growth, helped increase the length of the mandible and had a restraining growth effect on the maxilla. Posterior face height showed a significant increase in the activator group only. The mandibular incisors were proclined while the maxillary incisors were both retroclined and extruded in both treatment groups. The mandibular incisors were intruded in the Forsus group. Mesial movement and extrusion of the mandibular first molars was observed in both treatment groups, whereas both distalization and intrusion of the maxillary first molars was only observed in the Forsus group. Moreover, the occlusal and palatal planes rotated in a clockwise direction as a result of dentoalveolar changes in the Forsus group. Overbite and overjet were reduced and the soft tissue profile improved in both treatment groups. CONCLUSION: Both appliances proved effective in the treatment of growing individuals with Class II malocclusions with mandibular retrognathia, by a combination of skeletal, dental and soft tissue changes.

85 VALIDATION AND PRECISION OF META-ANALYSIS BASED DENTAL AGE ASSESSMENT IN A SWISS POPULATION F Birchler1, S Kiliaridis1, V Lucas2, C Combescure3, L Vazquez4, Departments of 1Orthodontics and 4Oral surgery and maxillofacial radiology, University of Geneva, Switzerland, 2Department of Paediatric Dentistry, King’s College London Dental Institute, U.K and 3Division of Clinical Epidemiology, Geneva University Hospital, Switzerland

AIM: Demirjian et al. (1973) classified radiological tooth development of the crown and root in eight stages. A dental age database of British Caucasians has been established (Roberts et al., 2008) and predicted dental age had good agreement with chronological age. The aim of this study was to use Demirjian’s tooth developmental stages in combination with the British meta-analysis system and to test the accuracy of age prediction on a Swiss population with developing teeth. MATERIALS AND METHOD: Developing teeth in the left maxilla and mandible and all third permanent molars on 50 panoramic radiographs of Swiss Caucasian healthy children were staged following the method of Demirjian. All radiographs were assessed twice by two observers blinded to gender and chronological age. Meta-analysis

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was used to calculate a dental age for each subject, using a random effect model and a fixed effect model. This dental age was compared with the gold standard of chronological age using Bland and Altman analysis. RESULTS: There was a good intersession agreement for all teeth using Demirjian’s method. The dental age calculated with the fixed effect model overestimated the age of the subjects (average +1.25 months, ranging from –1.94 to + 2.15 years) compared with chronological age, whereas the random effect model underestimated age (average –3.8 months, ranging from –2.23 years to +1.60 years). CONCLUSION: Demirjian’s staging method is precise for teeth in both jaws. The dental age assessment with British standards has to be used with caution on patients of Swiss descent.

Demirjian A, Goldstein H, Tanner J M 1973 A new system of dental age assessment. Human Biology 45: 211-227 Roberts G J, Parekh S, Petrie A, Lucas V S 2008 Dental age assessment (DAA): a simple method for children and emerging adults. British Dental Journal 204: 192-193 Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021

86 STABILITY OF NON-EXTRACTION VERSUS FOUR PREMOLAR EXTRACTION TREATMENT 10 YEARS OUT OF RETENTION R Bjering1, M Midtbø2, K Birkeland2, V Vandevska-Radunovic1, Departments of Orthodontics, 1University of Oslo and 2University of Bergen, Norway

AIM: Long-term stability of the occlusion and incisor alignment between extraction and non-extraction orthodontic treatment has been a much discussed topic. In borderline cases, extraction is often performed in order to secure stability of the treatment result. The purpose of this study was to investigate long-term stability of treatment results between patients treated non-extraction and with extraction of four premolars, 10 years out of retention. MATERIALS AND METHOD: Archived retention dental casts of 44 patients (26 extraction, 18 non-extraction) were analyzed at three stages: pre-treatment (T1), post-treatment (T2) and 10 years out of retention (T3). All patients were treated with full fixed appliances and received a removable retainer in the maxilla and fixed canine-to-canine retainer in the mandible for two years after debonding. The following variables were compared: Peer Assessment Rating (PAR) Index, Little’s Irregularity Index (LII) for the maxilla and the mandible, overjet, overbite, mandibular canine distance and duration of treatment. Differences between the groups were analyzed using unpaired t-tests at all time stages. RESULTS: At T1 mandibular LII score showed a significant difference between the groups, the extraction group having a higher score (3.2 versus 1.8). At T2 the overbite in the extraction group was significantly, but not clinically deeper than in the non-extraction group (2.7 mm versus 2.1 mm). No significant differences were found in PAR index, maxillary LII score, overjet or mandibular canine distance at any of the time stages. However, duration of treatment was significantly longer in the extraction group compared with the non- extraction group (33.3 versus 25.2 months). CONCLUSION: Post-treatment occlusal and incisor stability 10 years out of retention was not significantly different between patients treated with four premolar extractions and those treated non-extraction.

87 INFLUENCE OF OCCLUSAL FACTORS IN THE PRESENCE OF SIGNS AND SYMPTOMS OF TEMPOROMANDIBULAR DISORDERS A Blanco Aguilera1, L González López2, E Blanco Aguilera3, J L De la Hoz Aizpurúa1, A Blanco Hungria4, 1University San Pablo CEU, Madrid, 2Private Practice, Córdoba, 3University of Santiago de Compostela and 4Andalusian Health Service, Córdoba, Spain

AIM: The relationship between occlusion and the presence of temporomandibular disorders (TMD) has been one of the most controversial issues of the last decades. There are many opinions supporting or refuting this

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theory. The aim of this study was to analyze the ‘real’ association between some occlusal features included in the research diagnostic criteria (RDC)/TMD questionnaires and the presence of signs and symptoms of TMD. SUBJECTS AND METHOD: The sample included 1220 patients aged from 18 to 82 years old, from the primary Andalusian Health Service. These patients were referred to the TMD unit for diagnosis according to the RDC/TMD protocol, including both anamnesis and exploration phases. The inclusion and exclusion criteria were those included in the RDC/TMD core tool. The occlusal features included were the Angle molar Class, incisor overjet, and dynamic occlusion. Bivariate descriptive analysis was then performed followed by a binary logistic regression to evaluate the relationship between each occlusal feature and the presence of signs and symptoms of TMD. All statistical data were obtained using the SAS program, version 9.3. RESULTS: No significant association was found between Angle molar Class and the different groups of Axis I (P = 0.517), or between Angle molar Class and pain intensity (P = 0.76). Dynamic occlusion was not associated with Angle molar Class or pain intensity (P = 0.32 and P = 0.79. respectively). Having an overjet greater than 6 mm Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 did not result in higher pain intensity (P = 0.595). CONCLUSION: It can be suggested that the occlusal features studied (the different Angle molar Class, an increased overjet or the dynamic occlusion) did not result in risk factors for the presence of signs and symptoms of TMD.

88 RELATIONSHIP BETWEEN TEMPOROMANDIBULAR DISORDERS AND TENSION-TYPE HEADACHE A Blanco Aguilera1, L González López2, E Blanco Aguilera3, J L De la Hoz Aizpurúa1, A Blanco Hungria4, 1University San Pablo CEU, Madrid, 2Private Practice, Córdoba, 3University of Santiago de Compostela and 4Andalusian Health Service, Córdoba, Spain

AIM: Myofascial pain in temporomandibular disorders (TMD) and tension-type headaches have many similar symptoms. The aim of this study was to analyze the grade of association between both types of pathology in a TMD population. SUBJECTS AND METHOD: For this study, 1616 patients selected from a cohort of the Andalusian Health Service were investigated following the Research Diagnostic Criteria (RDC)/TMD criteria. Inclusion and exclusion criteria were those included in the RDC/TMD consorce. The variable ‘tension-type headache’ was obtained from the 18 questions of the anamnestic part of the RDC/TMD. Then a bivariated analysis was made to study the association between the presence of tension-type headaches and some sociodemographic, psychological and clinical variables related to TMD. Its association with age, gender, Axis I groups, discopathy, arthropathy, myofascial disorders, pain intensity, grade of chronic pain, anxiety, depression, or somatization was measured. All statistical data were analysed using the SAS program, version 9.3. RESULTS: The prevalence of a tension-type headache was 71.53 per cent. Females reported more tension-type headaches than males (P < 0.005). Other sociodemographic variables, such as age, were not statistically significant. There was a statistically significant association between tension-type headache and pain intensity (P < 0.005), and those groups of the Axis I with the higher levels of pain (those with both, myofascial pain and arthropatic pain) (P < 0.005). With respect to Axis II of the RDC/TMD, patients with headaches presented higher levels of anxiety (P < 0.005), but not depression. The R2 of Nalgerkerke obtained was 28 per cent. CONCLUSION: There is a strong association between being a female adult with TMD, higher pain intensity and higher anxiety level, and the presence of tension-type headaches.

89 SKELETAL ANCHORAGE – FREQUENCY OF USE AND INDICATIONS IN DAILY PRACTICE N Bock, S Ruf, Department of Orthodontics, University of Giessen, Germany

AIM: To investigate how often and for which indications skeletal anchorage devices are used in daily orthodontic practice.

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MATERIALS AND METHOD: A questionnaire was sent to all full members of the German Orthodontic Society in 2013 in order to assess the particular experience and satisfaction with miniscrews (temporary anchorage devices) and/or osseointegrated palatal implants. Furthermore, the reasons for usage or non-usage of skeletal anchorage were investigated. RESULTS: The response rate was 49 per cent (n = 1177). Only 2 per cent of the skeletal anchorage devices were inserted by the orthodontists themselves. Thirty eight per cent of the responders stated that they did not to use any skeletal anchorage devices at all. The majority of the users employed skeletal anchorage predominantly seldomly (≤2 new patients/3 months: 63). Seventy seven per cent of all users indicated mainly good experiences while 47 per cent reported simple and trouble-free utilisation in daily clinical practice. Furthermore, 37 per cent of the users believed that skeletal anchorage application usually results in shorter treatment duration. The non-users gave the following reasons for non-usage: individual treatment concept provides no indications (55%), scepticism regarding additional benefit (45%) and success rate (42%), Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 insertion/surgery too complex (43%) and increased costs (28%), doubts concerning complications/injuries (35%) and no appropriate surgeon close by (11%). CONCLUSION: Sixty two per cent of orthodontists in Germany use skeletal anchorage devices. However, most of them indicate a rather low frequency and do not insert the devices themselves. The reasons for non-usage are: missing indications as well as concerns regarding benefit, success rate, surgery and complications.

90 PREVALENCE REDUCTION OF IMPACTED TEETH AS A RESULT OF ORAL HEALTH IMPROVEMENT N Bock, A Ruediger, N Ha-Phuoc, S Ruf, Department of Orthodontics, University of Giessen, Germany

AIM: Current data on the prevalence of tooth impaction (PTI) in developed countries are lacking, the last reports for central Europe date from the 1970s. Since then, general oral health has remarkably improved [i.e. the decayed missing filled (DMFT) index decreased by 89.7% between 1983 and 2005 in former Western Germany]. Thus, the aim of this study was to investigate the current PTI (excluding third molars teeth) in a central European population of orthodontic patients and to compare it to general oral health improvement. MATERIALS AND METHOD: The pre-treatment panoramic films of all patients (n = 8393) from the period 1986- 2011 were screened. For patients with impactions, the pre- and post-treatment panoramic films were assessed for general oral health (MF-index, modified from the DFMT-index). RESULTS: Two hundred and eighty patients (47% male, 53% female) showed at least one impacted tooth and were included in the study. Sixty seven per cent of all impacted teeth were canines and 88 per cent of these were located in the upper jaw. Comparing PTI and oral health (MF-index) development from 1986 until 2011, a slightly higher linear reduction was seen for the MF-index than for the PTI (-4.8% versus 3.7%). Differentiating among teeth, a similar decrease was seen for the MF-index and the PTI in patients with impacted incisors (– 1.2%/–1.0%) and premolars (–0.9%/–0.7%), while for patients with impacted canines the association was less pronounced (–3.3%/–2.4%). CONCLUSION: The prevalence of tooth impaction in a central European population of orthodontic patients decreased by 3.7 per cent over a period of 25 years (1986-2011). The reduction was closely associated with oral health improvement (MF-index reduction –4.8%). The smaller prevalence reduction for tooth impaction confirms the role of intrinsic, genetic factors in the aetiology of tooth impaction.

91 THE LONGEVITY OF PRIMARY SECOND MOLARS WITH AGENESIS OF SUCCEEDING PREMOLARS AND FACTORS ASSOCIATED WITH SURVIVAL: A SYSTEMATIC LITERATURE REVIEW J Bollhalder1, N Pandis2, T Eliades1, P Fleming3, 1Department of Orthodontics and Pediatric Dentistry, Center of Dental Medicine, University of Zurich, 2Department of Orthodontics and Dentofacial Orthopedics, Faculty of Medicine, University of Bern, Switzerland, 3Barts and The London School of Medicine and Dentistry, Institute of Dentistry, Queen Mary University of London, U.K. e49

AIM: To systematically review the literature on the longevity of primary second molars with agenesis of succeeding premolars. MATERIALS AND METHOD: Several electronic databases including Medline and Embase were searched. Unpublished literature was searched on the National Research Register, and Pro-Quest Dissertation Abstracts and Thesis database. In addition, handsearching was performed to identify potentially relevant studies. Eligible studies provided information on chronological age at the time of the investigation, type of teeth assessed, diagnostic tools used and analysis of factors associated with survival of the primary second molars (root resorption, infra-occlusion). Two authors undertook independent data extraction. Methodological quality was assessed using the Newcastle Ottawa assessment scale for observational studies. RESULTS: Up to October 2013, 99 articles were retrieved (94 from electronic searches and 5 from handsearching). After applying selection criteria, 10 studies were eligible for this systematic review. The Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 analysis of the data of the studies showed that in patients with agenesis of the second premolars, the mesial root of the lower second primary molars showed a larger degree of root resorption than the distal root. The maxillary second primary molars were also more affected than in the mandibular arch. The level of root resorption remained unchanged in the long-term for approximately 50 per cent of the retained primary mandibular second molars. Infra-occlusion of the retained primary molars was shown to occur more frequently and severely during the time of maximum growth velocity in adolescents. If infra-occlusion had not manifested by the pubertal growth spurt, it may be expected to progress slowly. Neither infra-occlusion, tipping of adjacent teeth, nor root resorption increased significantly beyond the age of 20 years. CONCLUSION: Based on this systematic review, retention of healthy primary mandibular second molars is a viable treatment alternative. It is, however, not possible to predict the probability of survival for a single primary molar at an early age, but the overall probability for retained primary molars beyond 20 years of age can be estimated, on average, to be more than 90 per cent.

92 THREE-DIMENSIONAL MODEL ANALYSIS OF UPPER TOOTH MOVEMENT AFTER CARRIÈRE-DISTALIZER TREATMENT U U Botzenhart, D Klein, T Gedrange, Department of Orthodontics, University Medical Center, Technical University Dresden, Germany

AIM: The Carrière-distalizer is a simple, economic but compliance-dependent orthodontic device primarily for upper molar distalisation which, on account of its incorporated joint, also allows a derotation of the first molar at the same time. Although it is frequently clinically used, nevertheless, up to now no investigations about the movement magnitude or the clinical effectiveness of this appliance are available. The objective of this study was a three-dimensional metric evaluation of positional dental changes of upper molars, canines and incisors after therapy with Carrière distalizer and a possible assessment of the clinical success rate of this appliance. SUBJECTS AND METHOD: Patients (n = 30) with an adolescent permanent set of teeth and dental Angle Class II, who had been treated with the Carrière-distlizer, on one or both sides of the jaw, and also model casts at the beginning of therapy (T0) as well as after Carrière-distalizer treatment (T1), were included in the study. Model cast were three-dimensionally scanned (D250 scanner, 3Shape® dental system, Copenhagen, Denmark, scan exactness 20 µm) and also three-dimensionally measured (Ortho-Analyzer™, 3Shape®) so that every patient served as their own control. Furthermore, clinical outcomes were related to therapy time, measured by the time from the insertion of the Carrière (T0) up to its removal (T1). Statistical evaluation was performed by means of Wilcoxon and Duncan tests (software IBM SPSS®, version 20, ± =.05). RESULTS: After double-sided Carrière treatment statistically significant post-therapeutic positional changes could be ascertained for all examined dental groups. A statistically significant dependence of these positional changes on therapy time could not be ascertained.

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CONCLUSION: The Carrière-distalizer is favourable for clinical space acquisition by distalisation and derotation of molars. By installation of the joint at the molar pad, molar derotation outweighs distalisation. Further studies are necessary to assess dental tooth movement in the lower jaw linked with this appliance.

93 EVALUATION OF OFFICE RECONDITIONING OF STAINLESS STEEL SELF-LIGATING BRACKETS AFTER SANDBLASTING M Boukili1, O Sorel1, F Chagneau2 , 1Department of Orthodontics, University of Rennes and 2Genie Mécanique, IUT de Rennes, France

AIM: To evaluate office reconditioning of stainless steel self-ligating brackets after sandblasting. MATERIALS AND METHOD: This in-vitro study was performed on 52 human premolar teeth extracted for orthodontic reasons and randomly divided into two groups. Two types of stainless steel self-ligating brackets Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 were tested, one with a metal mesh base (Empower®, American Orthodontics) and one with a three- dimensional laser structured base (Discovery® sl 2.0, Dentaurum). Bond strength was assessed after performing three orthogonal traction tests. For the first test, new brackets were bonded using Transbond® XT (3M Unitek) onto the surfaces of the premolars of group A. For the second test, the debonded brackets were sandblasted with 110-micron aluminium oxide granules then rebonded following the same protocol onto the premolars of group B. For the third test, the attachments were sandblasted and rebonded onto the premolars of group A after removing the residual composite with a tungsten carbide bur. RESULTS: The difference in the bond strength between the new and sandblasted brackets was statistically insignificant, regardless of the type of bracket. However, removing the remaining composite with a bur significantly increased the adhesion strength for the two types of attachments. CONCLUSION: Office reconditioning of stainless steel self-ligating brackets is a simple and effective method that encourages re-positioning the brackets when a positional error is detected at the end of the aligning phase or during the finishing phase. Nevertheless, removing the remnant composite after debonding must be meticulous and minimal as the bond strength significantly increases.

94 INFLUENCE OF THE HYDROSPLINT ON POSTUROSTABILOMETRIC BALANCE AND MASTICATORY MUSCLE TONUS IN PATIENTS WITH DISTAL OCCLUSION V Brishten, I Rubleva, M Dushenkova, Z Shaipova, L Persin, Department of Orthodontics, MSUMD, Moscow, Russia

AIM: To determine the level of hydrosplintinfluence on posturostabilometric balance and masseter tonus in patients with distal occlusion SUBJECTS AND METHOD: Thirty subjects, aged 15-35 years, 15 of whom had a physiological occlusion and 15 a distal occlusion. Stabilometric balance and masseter tonus were examined with a stabilometric platform (BioPostural System, Galbiati, Italy) and a miotonometer (Miotonus 3c, (Russia) while wearing the hydrosplint before adjustment and 15-20 minutes after wear. RESULTS: In patients with distal occlusion, the crossed distance before hydrosplint therapy was 18.432 ± 8.7, after 18,1395 ± 5.7 mm, sway area before 2244.9 ± 423.9 after 2121.7 ± 460.2 mm², ellipse surface before 4.135 ± 1.4, and after 4.8315 ± 2.3 mm². Myotonometry showed no significant changes, as in the case of subjects with normal occlusion. CONCLUSION: Wear of an hydrosplint does not lead to a clinically significant improvement of stabilometry and myotonometry parameters in patients with a physiological or distal occlusion.

95 ORTHOGNATHIC SURGERY OF CLEFT RELATED DENTOFACIAL DEFORMITIES

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A Brudnicki, W Piwowar, E Sawicka, Department of Pediatric Surgery, Institute of Mother and Child, Warsaw, Poland

AIM: Orthognathic surgery is often the only option to successfully finish the multidisciplinary treatment of different types of clefts. At the same time of surgery cleft related deformities usually become a great challenge to the maxillofacial surgeon. The purpose of this presentation is to point out the main stages and the most important aspects of such treatment from the surgical point of view to improve and coordinate the therapeutic efforts of the orthodontist. MATERIALS AND METHOD: At the Institute of Mother and Child 550 surgical interventions related to the treatment of cleft patients are performed every year; 300 of them were primary operations and 250 secondary surgery, among them orthognathic procedures which constituted 20-30 cases a year. RESULTS: On the basis of personal experience in the field of orthognathic surgery of cleft cases the main Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 principles as well as the most difficult obstacles connected to that kind of treatment were established and presented. CONCLUSION: Understanding of both the possibilities and limitations of surgical treatment of cleft related occlusal and facial deformities is important to any orthodontist involved in the treatment of such cases.

96 IN VIVO METAL ION RELEASE FROM ORTHODONTIC APPLIANCES: A SYSTEMATIC REVIEW OF THE LITERATURE R Bucci, F Pianese, R Rongo, R Valletta, V D'Antò, Section of Orthodontics, University of Naples ‘Federico II’, Italy

AIM: To perform a systematic review (SR) of the literature on in vivo metal ion release from fixed orthodontic appliances, evaluating their concentration in biological fluids and oral mucosa cells. MATERIALS AND METHOD: A literature search was conducted through different databases (PubMed, Scielo, Lilacs, Web of Knowledge, Scopus). An additional hand-search was performed on several orthodontic journals (European Journal of Orthodontics, Angle Orthodontist, American Journal of Orthodontics and Dentofacial Orthopedics, Korean Journal of Orthodontics) with impact factor. The research was independently conducted by two authors, from the beginning of each database or digital orthodontic journal, up to September 2013. All the in vivo studies performed on humans, focusing on metal ion release from orthodontic fixed appliances, were included. The methodological quality of each paper was assessed by means of a customised checklist. RESULTS: An initial search resulted in 652 papers. Reading all titles and abstracts 30 references were selected. After full-text reading, 24 papers fulfilled all the inclusion criteria. The most frequently measured ion was nickel (24 references), followed by (15 references). The most studied sample was saliva. The results on the statistical significance of increase ion levels in biological fluids and oral mucosa cells were controversial. The majority of the studies analysed ion concentration in the short-term (within one or two months from the beginning of orthodontic treatment). CONCLUSION: The results make it impossible to provide a definite conclusion on the significance of an increase in ion level in biological fluids and oral mucosa cells. Even when a statistically significant increase was reported, the concentrations were always lower than the average daily dietary intake and did not reach toxic levels. Nevertheless, these findings do not preclude that even low concentrations could induce acute hypersensitivity or chronic sub-toxic disease, increasing the inflammation caused by plaque.

97 COMPARISON BETWEEN DIRECT AND INDIRECT BONDING TECHNIQUES: BONDING TIME AND FAILURE RATE J V Bozelli1, R Bigliazzi1, C L F Ortolani2, F A Bertoz3, K Faltin Jr.1, Departments of Orthodontics, Schools of Dentistry, 1University Paulista, Sao Paulo, 2University of São Paulo and 3Pediatric and Social Dentistry, Dental School, UNESP Univ Estadual Paulista, Araçatuba, Brazil

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AIM: To evaluate the time taken in bonding of bracket using the direct (DBB) and indirect (IBB) bonding techniques, the length of time for laboratory (IBB) and clinical steps (DBB and IBB) as well as the prevalence of bracket detachment after a 24 week follow-up. SUBJECTS AND METHOD: Seventeen patients (7 males, 10 females) aged about 21 years and requiring orthodontic treatment. Among a total of 304 brackets, 151 were bonded following the DBB approach and 153 according to the IBB procedure. The same bracket type and bonding material were used in both groups. Data were submitted to statistical analysis by Wilcoxon non-parametric test at the 5 per cent level of significance. RESULTS: Considering the total time, the IBB technique was more time-consuming than the DBB (P < 0.001). However, considering only the clinical phase, the IBB took less time than the DBB (P < 0.001). There was no significant difference (P = 0.910) for the time spent during laboratory positioning of the brackets and clinical session for IBB in comparison with the clinical procedure for DBB. There was also no difference for the Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 prevalence of bracket detachment between either group. CONCLUSION: IBB can be suggested as a valid clinical procedure since the clinical session was faster and the total time spent in laboratory positioning of the brackets and clinical procedure was similar to that of DBB. In addition, both approaches resulted in a similar frequency of bracket detachment.

98 DENTAL COMPUTED TOMOGRAPHIC IMAGING FOR AGE ESTIMATION: MORPHOLOGICAL ANALYSIS OF THE THIRD MOLAR IN A TURKISH POPULATION K Cantekin1, A E Sekerci2, S K Buyuk3, Departments of 1Pediatric Dentistry, 2Maxillo-Facial Radiology and 3Orthodontics, Faculty of Dentistry, Erciyes University, Kayseri, Turkey

AIMS: Computed tomography (CT) is capable of providing accurate and measurable three-dimensional images of the third molar. The aims of this study were to analyze the development of the mandibular third molar and its relation to chronological age and to create new reference data for a group of Turkish participants aged 9 to 25 years on the basis of cone-beam CT images. MATERIALS AND METHOD: All data were obtained from the patients’ records, including medical, social, and dental anamnesis and cone-beam CT images of 752 patients. Linear regression analysis was performed to obtain regression formulas for dental age calculation with chronological age and to determine the coefficient of determination (r) for each gender. RESULTS: Statistical analysis showed a strong correlation between age and third-molar development for males (r = 0.80) and females (r = 0.78). CONCLUSION: A database of developmental stages of the third molars in a population of Turkish children and young adults was established according to the Demirjian classification system on CT images. For dental age estimation of these subjects, four regression formulas were obtained for both females and males. CT images are clinically useful for the accurate and reliable estimation of dental ages of children and young adults.

99 A REVIEW OF SURGICAL TECHNIQUES TO MODIFY ORTHODONTIC TOOTH MOVEMENT M Cadenas de Llano1, A Iglesias-Linares2, E Solano-Reina1, 1Department of Estomatology, University of Sevilla and 2Complutense University of Madrid, Spain

AIM: To analyze articles discussing surgically assisted orthodontic tooth movement (OTM), summing up the data and comparing them, in order to obtain a clear idea of the existing methods and their effectiveness. MATERIALS AND METHOD: A literature review was performed on databases (MedLine and Scopus) including studies with human/animals with at least one experimental group and a control group, a minimum of five samples per group, and focused on surgically-based methods to modify tooth movement with application of force by orthodontic or orthopaedic devices. Case reports/series, descriptive studies, review/opinion articles,

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letters, and papers that did not match the objectives of this review or with no adequate description of technique or administration dose were excluded. RESULTS: Of the 65 articles finally included in the general review about methods to modify OTM, 16 were classified as surgical techniques, 10 of which proposed corticotomy (perforations or longitudinal incisions on the alveolar cortical bone) as a viable method to enhance OTM, based on the regional acceleratory phenomena. Osteotomy or bone distraction were also considered methods to surgically speed up OTM. CONCLUSION: Scientific innovation in this field needs to standardize procedures described, in order to clarify the results and optimize the efficiency in the advancements. Methods based on higher scientific consistency need to generalize their designs to be able to compare the results.

100 GENETICALLY-BASED METHODS TO MODIFY ORTHODONTIC TOOTH MOVEMENT: A LITERATURE REVIEW M Cadenas de Llano1, E Iglesias-Linares1, A Iglesias-Linares2, 1Department of Estomatology, University of Sevilla Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 and 2Complutense University of Madrid, Spain

AIM: To review articles that describe genetic modification of orthodontic tooth movement (OTM), summing up the results and making it possible to properly compare them, in order to obtain a clear idea of existing methods. MATERIALS AND METHOD: A review on MedLine and Scopus databases was performed, and any experimental study, clinical or in vitro investigation about accelerating or decelerating orthodontic tooth movement based on genetic modification that included at least one experimental group and a control group was included. The exclusion criteria were case reports, and articles that did not correspond with the objectives of this review or with no adequate description of the technique, administration dose or regimen. RESULTS: Four studies were classified as gene therapy based-methods, all using animal models. An inhibitory effect on OTM was found when osteoprotegerin was overexpressed locally in the periodontal region while an increase in OTM occurred when the RANKL gene was overexpressed, and when compared with surgical methods, gene transfer of RANKL was proven to be more effective. CONCLUSION: Scientific innovation in this field requires better standardization of the procedures used in order to clarify findings and describe better the efficiency of the advancements obtained. Human-based studies are lacking.

101 ROOT RESORPTION OF UPPER AND LOWER PREMOLARS FOLLOWING 4 WEEKS OF OCCLUSAL TRAUMA AND AN 8 WEEKS HEALING PERIOD: A MICROCOMPUTED TOMOGRAPHIC STUDY F Cakmak1, E I Karadeniz2, S Elekdag-Turk3, T Turk3, M A Darendeliler4, Departments of Orthodontics, Faculties of Dentistry, 1University of Bulent Ecevit, Zonguldak, 2Karadeniz Technical University, Trabzon and 3University of Ondokuz Mayis, Samsun, Turkey and 4Discipline of Orthodontics, Faculty of Dentistry, University of Sydney, Australia

AIM: In orthodontics, temporary use of a mini bite-plane is a common method to increase the vertical dimension in patients in order to facilitate several treatment procedures. However, this method transmits excessive occlusal forces through the periodontal ligament and causes trauma. The aim this study was to evaluate the amount of root resorption in humans following 4 weeks of occlusal trauma and 8 weeks of retention. SUBJECTS AND METHOD: Twelve patients (6 girls, 6 boys) who required bilateral maxillary and mandibular first premolar extractions as a part of their orthodontic treatment. One side of each patient was randomly selected as the control. On the contralateral side, a light-cure glass ionomer cement was bonded onto the occlusal surface of the lower first premolar in such a way that the cement was in contact with the upper first premolar and increased the patient’s vertical dimension 2 mm. The bite raisers were removed after 4 weeks and the upper and lower premolars were extracted after 8 weeks. Each sample was imaged using a microcomputed

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tomographic scan system and analyzed with specially designed software for volumetric measurements of resorption craters. RESULTS: There was a significant difference in the amount of root resorption between the control and experimentally traumatized teeth in the maxilla and mandible with P values of 0.04 and 0.007, respectively. CONCLUSION: Restorative build ups that increase the vertical dimension 2 mm could have a detrimental effect on tooth supporting structures even after a healing period of 8 weeks.

102 DO ORTHODONTIC MALOCCLUSIONS AFFECT THE DIETARY INTAKE OF ADOLESCENTS? N Canigur Bavbek1, E Koksal2, B Balos Tuncer1, C Tuncer1, N Sanlier2, 1Department of Orthodontics, Faculty of Dentistry and 2Department of Nutrition and Dietetics, Faculty of Health Sciences, Gazi University, Ankara, Turkey

AIM: Orthodontic anomalies may lead to a number of consequences on patients’ quality of life which are Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 generally expressed by aesthetic concerns and effects on self-esteem. However, these orthodontic problems may be essential for patients’ dietary intake or what they choose to consume; thus altering adolescents’ eating behaviour. Therefore the aim of this study was to evaluate how orthodontic problems contribute to dietary intake, body mass index (BMI) and total energy income of adolescents. MATERIALS AND METHOD: Demographic and dietary data of 76 patients (30 boys, 46 girls, mean age 11.4 ±2.4 years), possessing good oral and systemic health were obtained by questionnaires. The patients were grouped according to malocclusion (Class I: 10; Class II: 40; Class III: 26), skeletal discrepancy (Class 1:27; Class 2:28; Class 3:21), overjet and overbite. Overjet and overbite were grouped as decreased (<0 mm); normal (0-4 mm); and increased (>4 mm). BMI (kg/m2) was calculated from weight and height measurements and evaluated according to the World Growth Reference Data for children aged 5-19 years. Dietary intake was measured by the 24-hour dietary recall method and dietary quality (DQ) was assessed by the Healthy Eating Index-2010 (HEI-2010). Then energy and nutrient intake was calculated using the Nutrition Information System (BeBiS) program. Statistical analysis for intergroup comparisons were made by Kruskal-Wallis test. Correlations between HEI-2010 scores, BMI with skeletal, dental relationship, overjet and overbite were evaluated with Spearman correlation coefficienct. P < 0.05 was assigned as statistically significant. RESULTS: The prevalence of underweight and overweight adolescents according to BMI was 18.4 and 28.6 per cent, respectively. HEI-2010 revealed that the DQ of 36.8 per cent of adolescents was poor, whereas it was average for 63.2 per cent. Correlation between energy and protein intake and dental classification, demonstrated an increase towards Class II (r = 0.237) and Class III (r = 0.228) malocclusions from Class I (P < 0.05). Total fruit score was the lowest in skeletal Class III adolescents (r = 0.253; P < 0.05). As overbite increased; energy (r = 0.297), carbohydrate (r=0.238) and protein (r = 0.305) intake also increased (P < 0.05). CONCLUSION: Changes in overbite and presence of a dental or skeletal anomaly may alter the DQ of adolescents with respect to HEI-2010 scores.

103 FACIAL ASYMMETRY: A RETROSPECTIVE STUDY V Caridi, M Bartolomucci, G Galluccio, Department of Oral and Maxillo-Facial Sciences, ‘Sapienza’ University of Rome, Italy

AIM: The point at which ‘normal’• asymmetry becomes ‘abnormal’ can be defined by an aesthetic limit and a functional limit. When a patient complains of facial asymmetry, the underlying cause should be studied; the aetiology includes congenital disorders, acquired diseases, and traumatic and developmental deformities. The aim of this investigation was to investigate a possible genetic liability in the transmissibility of asymmetric traits, through an initial analysis developed using twofold approach: (1) exploring family history by questionnaire and (2) examining differences in laterality between the patient and their corresponding parent by aesthetic analysis.

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SUBJECTS AND METHOD: A total of 52 Italian subjects (57% females, 43% males; mean age 11 years 7 months). Individuals in the sample were categorized according to diagnosis of facial asymmetry, non-syndromic patients, participation by informed consent and negative medical history of the maxillo-facial complex. Differences in length between the distance from the anthropometric points to the facial midline and to the horizontal reference were measured on a frontal facial photograph. Subjects were categorized as having left- or right-sided laterality. RESULTS: Analyzing the questionnaire’s answers, 65 per cent of parents with correspondence of laterality reported a positive family history. For each linear measurement, there was a high percentage of parent-child pairs with correspondence of laterality of asymmetry traits. CONCLUSION: Data analysis showed that the mother is the parent most involved in the correspondence of laterality. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 104 FIBROSIS IMPAIRS MUSCLE REGENERATION OF THE SOFT PALATE AFTER EXCISIONAL INJURY ɫɫ P L Carvajal Monroy, A M Kuijpers-Jagtman, F Wagener, J Von den Hoff, Department of Orthodontics and Craniofacial Biology, Radboud University Nijmegen Medical Centre, Netherlands

AIM: Scar formation and defective regeneration may hamper the functional recovery of the soft palate muscles after cleft palate repair. This causes problems in speech and swallowing. The aim of this study was to investigate the regeneration of the soft plate after excisional injury in a rat model. MATERIALS AND METHOD: One-millimetre excisional defects were made in the soft palate of 32 male adult Sprague Dawley rats. The wound area was evaluated after 3, 7, 28 and 56 days using AZAN staining for collagen and immunohistochemistry for muscle markers. One-way ANOVA with Holm-Sidak post-hoc analysis was used for statistical analysis. RESULTS: An increase in activated satellite cells was indentified adjacent to the wound at day 3, while proliferating and differentiating myoblasts were identified within the wound only at day 7. A significant amount of collagen-rich fibrotic tissue was evident at day 28 and persisted over time. Only few myofibres were identified within the wound area at 56 days. CONCLUSION: Muscle regeneration in the soft palate begins with the activation and proliferation of satellite cells from the wound margins. Proliferating and differentiating myoblasts failed to form new myofibres within the fibrotic wound area. New therapies based on regenerative medicine might improve regeneration of the soft palate muscles after injury and thus improve the functional outcome.

ɫɫ Winner of an EOS poster award

105 INFLUENCE OF DENTAL MIDLINE DEVIATIONS IN THE PERCEPTION OF FACIAL AESTHETICS F Cascales-Moya, L López-Ruiz, B Izquierdo-Gómez, A Vicente, L A Bravo-González, Orthodontic Unit, Faculty of Dentistry, University of Murcia, Spain

AIM: To analyze how dental midline deviation influences perceptions of facial aesthetics amongst three groups: orthodontists, general dentists and laypersons. MATERIALS AND METHOD: A frontal facial photograph of an individual was digitally manipulated using Adobe Photoshop C3 (Adobe Systems Inc., San Jose, California, USA) to produce varying degrees of dental midline deviation (0, 2 and 4 mm). The images were assessed by orthodontists (n = 50), general dentists (n = 50) and laypersons (n = 50). The average age of the three groups was 40-50 years. The proportion of male-female subjects was 25:25 in each group. Each image was awarded a mark between 1 and 5 depending on aesthetic preference, 1 being the lowest value and 5 the highest. Data were analysed using the Kruskal-Wallis (P < 0.05) and Mann-Whitney tests, applying Bonferroni correction (P < 0.016)

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RESULTS: No significant (P > 0.05) differences were detected between the three groups of smile assessors in their responses to the non-dental midline deviation smile (0 mm). However, aesthetic perception of the 2 and 4 mm dental midline deviation smile showed significant difference between dental professionals (orthodontists and general dentists) and laypersons (P < 0.016). CONCLUSION: Laypersons found a dental midline deviation more acceptable than orthodontists and general dentists. In this way, the profession of the evaluators affected the evaluation of smile aesthetics when a dental midline deviation was present.

106 RELATIONSHIP BETWEEN MALOCCLUSION, JOINT LAXITY AND POSTURE: A CLINICAL EVALUATION M Castellano, M Bartolomucci, E Barbato, A Silvestri, G Galluccio, Department of Oral and Maxillo-Facial Sciences, ‘Sapienza’ University of Rome, Italy Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 AIM: Significant correlations have been reported between joint laxity and temporomandibular Joint disorders but no data are available on the relationship between malocclusion, joint laxity and posture. The aim of this research was to investigate this correlation in orthodontic patients. SUBJECTS AND METHOD: One hundred and seven patients with a symmetrical malocclusion and malocclusion and mild to moderate non-syndromic craniofacial asymmetry. The patients had undergone clinical and radiographic evaluation. All the measurements were also carried out in a homogeneous control group. The criteria for the assessment of joint laxity were revised by Beighton et al. (1973). In the present study, those with a Beighton score of 4 or greater were considered positive to the test and entered in the statistical analysis. The data of 61 patients (Class II = 60.6% of subjects, Class III = 14.8% of subjects, Class I = 24.6% of subjects) were analysed using the t-test. The Shapiro-Wilk test was used to verify the normality of the data. RESULTS: In the present sample, 73.8 per cent (n = 45) presented a positive Beighton test for joint laxity. Two interesting results were found: 1) A high percentage of joint laxity in males, while laxity was most frequently observed in females; moreover, joint laxity was represented in all subgroup of studied populations; 2) Alteration of the pelvic torsion postural parameter. In a symmetric pelvis without torsion of the iliac bones, pelvic torsion angle is 0 degrees (according to Harzmann). In the subgroup of patients with Class II malocclusion (n = 37), the angle was 1.09 ± 2.96 degrees. The parameter was statistically significant (P = 0.0118) in relation to the presence of joint laxity. CONCLUSION: Data in the literature suggest an association between systemic joint laxity, joint hypermobility and the presence of musculoskeletal symptoms. In addition, significant correlations have been reported between joint laxity and TMJ disorders. The present findings suggest a relationship between malocclusion and joint laxity.

107 RETROSPECTIVE STUDY OF DEBONDED BRACKETS IN ORTHODONTICALLY TREATED PATIENTS S Ceh Smigoc, A Fekonja, Department of Orthodontics, Health Center Maribor, Slovenia

AIM: To determine differences in debonding brackets considering age, gender and location of the tooth. SUBJECTS AND METHOD: One hundred and eighty patients (95 females, 85 males) with fixed appliance in both jaws. Patients with prematurely debonded appliances and those who had previous prosthetic replacement of one or more teeth were excluded. The brackets were placed from the second left to the second right premolar in the upper and lower jaws. The patients were divided into three groups according to age at debonding of fixed appliance. The first group included patients up to the age of 14 years, the second group patients aged 15 to 17 years, and the third group patients aged 18 years and above at debonding of the fixed appliance. RESULTS: Considering age, there were no statistically significant differences between any group for bond failure brackets. There were also no statistically significant differences between debonding brackets in the lower jaw

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compared with the upper jaw. Male patients had a higher failure rate than females. Most debonded brackets were found on the upper left second premolar followed by the lower left second premolar. CONCLUSION: In all three groups investigated there was almost equal affinity for debonding brackets in both jaws, but male patients had greater affinity for debonding brackets than females.

108 EVALUATION OF NASOALVEOLAR MOULDING TREATMENT EFFECTS ON CLEFT LIP AND PALATE INFANTS R M Çelık, Z Ileri, M Akin, Department of Orthodontics, Selcuk University, Konya, Turkey

AIM: To evaluate, retrospectively, the effects of nasoalveolar moulding (NAM) used for infants with a cleft lip and palate (CLP) on the cleft segments and posterior and medial alveolar widths. MATERIALS AND METHOD: The records of 55 CLP patients were examined (20 unilateral CLP, 15 bilateral CLP, 20 hard palate cleft). The NAM treatment suggested by Grayson was used in all patients. The registrations were Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 recorded at the beginning of treatment (T1) and before lip surgery (T2). The average treatment duration was determined as 5 months. Three measurements [posterior maxillary arch width (T-T'), middle maxillary arch width (M-M') and alveolar cleft width (C-L)] were determined to evaluate the cleft segments and alveolar widths on the intraoral models. For statistical analysis, Shapiro Wilks, paired simple t, Kruskal Wallis and Mann Whitney U-tests were used. RESULTS: Cleft width showed statistically significant changes, and the cleft segments closed during treatment (P < 0.01). Maxillary posterior and middle width measurements were increased during treatment (P < 0.01). Between group comparisons showed that all values were statistically significant (P = 0.000 for C-L, P = 0.023 for M-M', P = 0.000 for T-T'). The maximum increase of T-T' values was found in the hard palate cleft patients (2.50 mm) and the maximum decrease of C-L values in the unilateral CLP patients (–7.33 mm). CONCLUSION: NAM in infants with a unilateral CLP, a bilateral CLP or a hard plate cleft produces positive effects on the cleft segments, posterior and medial alveolar widths.

109 COMPARISON OF THE MORPHOLOGY OF THE PALATE BETWEEN SKELETAL CLASS III AND CLASS I MALOCCLUSION SUBJECTS B-K Cha, K-H Lee, G-S Song, I Jang, D-S Choi, College of Dentistry, Gangneung-Wonju National University , Gangneung, South Korea

AIM: Many previous studies have investigated the difference between skeletal Class III and Class I malocclusion subjects. However, no study has focused on the morphology of the palate. The purpose of this research was to introduce a quantitative method using a three-dimensional (3D) digital model to measure the morphology of the palate, and to compare the morphology of the palate between Class III and Class I patients. MATERIALS AND METHOD: Twenty 3D digital models of skeletal Class III (ANB ≤ 0°) patients and 20 3D digital models of skeletal Class I (0° < ANB < 4°) patients. 3D scanning of the plaster models was performed using the Orapix 3D scanner (KOD300, accuracy ±50 µm, Orapix Co., Ltd., Seoul, South Korea) with a point spacing of 0.15 mm. 3D reverse remodelling software (Rapidfrom XOR/Redesign 3, Inus Technology Inc., Seoul, South Korea) was used for 3D reconstruction of digital models and 3D measurements. The palate was sectioned on the second premolar and first molar area of the 3D digital maxillary model. By forming a circle which is most similar to the shape of the sectioned palate at each site and measuring the radius, the morphology of the palate was examined. RESULTS: At the second premolar area, the convex palate was the most frequent (50.0%), followed by flat (45.0%), and concave (5.0%) palates in the Class III group. In the Class I group, however, the flat palate was the most frequent (70.0%), followed by convex (17.5%) and concave (12.5%) palates. These frequencies showed significant differences between both groups. However, there was no difference in the frequencies of the morphology of the palate at the first molar area between the groups.

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CONCLUSION: The morphology of the palate is different in Class III subjects compared with Class I subjects.

110 COMPARISON OF CLOSURE OF THE SPHENO-OCCIPITAL SYNCHONDROSIS IN PATIENTS WITH SKELETAL CLASS I AND CLASS III MALOCCLUSION B-K Cha, H-R Choi, J H Yang, I Jang, D S Choi, College of Dentistry, Gangneung-Wonju National University, Gangneung, South Korea

AIM: To compare the time and pattern of ossification of the spheno-occipital synchondrosis in patients with skeletal Class I and Class III malocclusions using cone beam computed tomography (CBCT). MATERIALS AND METHOD: CBCT images were chosen from 186 Korean patients (93 males, 93 female) who were enrolled consecutively for orthodontic treatment. The patients were divided into four groups according to ANB and gender. The degree of ossification of the spheno-occipital synchondrosis was classified into four Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 stages: 1, the synchondrosis is completely open; 2, the radiopaque ossification centres appear within the synchondrosis; 3, the synchondrosis is partially ossified but still visible as mixed radiopaque and radiolucent vestige; 4, the synchondrosis has been completely ossified. In stage 2, the location and appearance of the ossification centres in the synchondrosis were displayed in 3-by-3 boxes in order to determine where the ossification centres were frequently observed and how they were fused. RESULTS: There was no difference in the time and pattern of ossification of the spheno-occipital synchondrosis between patients with skeletal Class I and Class III malocclusions. The ossification centres appeared most frequently in the superior parts but no apparent pattern of closure, such as from above to downward, was observed, in any groups. CONCLUSION: Although skeletal Class III patients have anteroposterior skeletal discrepancy, the time and pattern of closure of the spheno-occipital synchondrosis were not different compared with subjects without a malocclusion. At the beginning of closure of the synchondrosis, the ossification centre appears in variable patterns and seems to become larger and more complex in the progress of closure.

111 EFFECTS OF FORCE APPLIED FOR MAXILLARY : A STUDY USING FINITE ELEMENT ANALYSIS H Chalermwong1, B Suzuki1, E Y Suzuki1, T Fongsamootr2, Departments of 1Orthodontics and Pediatric Dentistry and 2Mechanical Engineering, Chiang Mai University, Thailand

AIM: To investigate the effects of buccal force for maxillary molar distalization, using finite element (FE) analysis. MATERIALS AND METHOD: Using FE models, molar distalization with buccal force using the miniscrew- supported sliding jig technique was simulated. FE models, including the maxillary molar teeth, the periodontal ligament, and the maxillary bone were constructed using a three-dimensional computer-aided design program. FE model 1 with only the first molar included and FE model 2 with both the first and second molars were generated. To distalize the maxillary molar using the miniscrew implant for indirect anchorage, a force of 200 g was applied at the jig’s vertical leg to transfer the distalizing forces to the first molar tube. Stress distributions along the root surface, as well as initial tooth displacement, were analyzed. RESULTS: The stress distribution pattern was similar in both FE models. Stress values on the distal root surface were greater than those on the mesial root surface. The highest Von Mises stress value was found on the cervical third of the root surface and the stress values decreased towards to the apex. The tooth displacement in both FE models showed distal tipping, extrusion, and mesial out-rotation of the maxillary molars, but the greater amount of tooth displacement was observed in FE model 1.

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CONCLUSION: Initial tooth displacement from maxillary molar distalization with the miniscrew-supported sliding jig showed distal tipping, extrusion, and mesial out-rotation. The FE model with the second molar not included showed greater tipping, extrusion, and mesial out-rotation than the FE model with the second molar included.

112 ORTHOGNATHIC SURGERY IN AN ASIAN POPULATION – PATIENTS’ MOTIVATION FOR TREATMENT AND SATISFACTION WITH OUTCOME M T Chew1, H B Wong2, 1Department of Orthodontics, National Dental Centre Singapore and 2Health Services Research Branch, Ministry of Health, Singapore, Singapore

AIMS: To evaluate patients’ motivation for orthodontic-surgical treatment and to investigate their satisfaction with the outcome. SUBJECTS AND METHOD: A consecutive series of 120 patients who underwent orthognathic surgery from May Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 2008 to July 2009 in a single institution. Motivation for treatment and satisfaction with treatment outcome were assessed through analysis of data gathered from a questionnaire administered during the 1-year post- surgery review. The logistic regression model was used to examine the association between factors and the motivation for treatment. The analyses were performed using STATA version 10 and a P value of 0.05 was used to determine statistical significance. RESULTS: Out of the 103 patients who responded to the questionnaire (86% response rate), there were 59 males and 44 females. The mean age at the time of surgery was 22.2 years (SD 5.6). The majority had Skeletal III problems (86%) and underwent two-jaw surgery (89%). The most common reason for seeking surgery was dissatisfaction with facial appearance (65%), followed by chewing difficulties (51%) and professional recommendation (48%). Temporomandibular joint symptoms (6%) and facial pain/headache (5%) were not major reasons for seeking treatment. No significant association was found between gender and seeking treatment due to dissatisfaction with facial appearance or chewing difficulties. However, patients who were younger were found to be more likely to seek treatment due to chewing difficulties (OR: 1.10, 95% CI: 1.01 to 1.22, P = 0.039). Ninety-five per cent of patients gave a favourable score when asked how satisfied they were with the results of surgery. Eighty-five per cent would undergo the same surgery again and 83 per cent would recommend the same surgery to others. CONCLUSION: Dissatisfaction with facial appearance was the most common reason for seeking orthognathic surgical treatment. Orthognathic surgery was carried out with a high level of patient satisfaction.

113 THE LINGUAL ORTHODONTIC TECHNIQUE: PREDICTABILITY OF THE RESULTS B P Chiodo, V Paoloni, P Cozza, Department of Orthodontics, University of Rome Tor Vergata, Italy

AIM: To evaluate the high level of congruence reached with the Incognito lingual orthodontic technique, between the fabricated set-ups and the final clinical result by model scan. SUBJECTS AND METHOD: Fifteen patients (5 males, 10 females, mean age 31.7 years) all treated by the same operator with the Incognito lingual technique in both dental arches (including second molars) and debonded between January 2012 and December 2012. None of the patients had rebonded brackets. They all had a Class I, II or III malocclusion and the initial crowding was more than 4 mm. For each patient the following records were obtained: pre-treatment dental casts, pre-treatment set-up, post-treatment dental casts, pre- and post- treatment cephalograms and panoramic radiographs, and pre-, interim- and post-treatment photographs. Pre- treatment set-ups and post-treatment dental casts were scanned with an ATOS optical scanner (GOM, Braunschweig, Germany) at a spacial resolution of 20 µm. Digital models were loaded into Geomagic Studio software (Geomagic U.S., Research Triangle Park, North Carolina, USA) and the surfaces corresponding to the gingival tissue were removed to prevent any influence of soft tissue changes on registration. The remaining

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surfaces corresponding to the dental arches were simplified and then superimposed using emodel software (version 8.05; Geodigm, Chanhassen, Minnesota, USA) to combine both models in the same coordinate system. RESULTS: Discrepancies in the transverse position between the set-up and outcome were small for all teeth (±0.4 mm) except for the second molars (±1 mm). CONCLUSION: The advantage of an individual lingual appliance is in the accuracy of tooth positioning. The Incognito technique was accurate in achieving the tooth movements planned in the set-up. The greatest discrepancies in position were within ±0.4 mm.

114 THREE-DIMENSIONAL COMPUTED TOMOGRAPHIC EVALUATION OF COMPENSATIONAL CHANGES OF DENTOALVEOLAR PATTERNS IN PATIENTS WITH FACIAL ASYMMETRY H-J Chong1, S-C Kim2, 1Graduate School of Dentistry, Wonkwang University, Iksan and 2Department of Orthodontics, Wonkwang University Daejeon Dental Hospital, Daejeon, Korea South Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021

AIM: To evaluate compensational changes of dentoalveolar patterns in patients with facial asymmetry using three-dimensional computerized tomography. SUBJECTS AND METHOD: The asymmetry group included 30 adults (17 male, 13 females; mean age, 20.6 years) with menton deviation of at least 3 mm from the facial midline. The control group consisted of 10 adults (6 men, 4 women; mean age, 24.7 years) without any severe skeletal deformities. Nine measurements were used to analyze the differences between the deviated side and non-deviated side. The correlation between menton deviation and asymmetry were evaluated. RESULTS: In the asymmetry group, the parameters that were smaller on the deviated side were buccal width ratio at the middle (P < 0.01) and apex (P < 0.01), lingual width ratio at apex (P < 0.001). Parameters that were larger on the deviated side were lingual width ratio at the middle (P < 0.01) and lingual area of alveolar bone (P < 0.01). Menton deviation was negatively correlated with differences in the inclination angle of tooth axis between deviated side and non-deviated side (r = -0.148, P < 0.05). CONCLUSION: Compensational changes of tooth inclination angle, alveolar bone width, and alveolar bone area were obvious in asymmetric patient with significant menton deviation.

115 LONG-TERM CHANGES OF THE PHARYNGEAL AIRWAY AFTER TREATMENT WITH A BIONATOR IN SKELETAL CLASS II ADOLESCENTS C Chung, C h Shin, E s Baek, K-H Kim, Y J Choi, Department of Orthodontics, Gangnam Severance Dental Hospital, Seoul, Korea South

AIM: To evaluate the long-term changes in pharyngeal airway dimensions after functional appliance treatment in skeletal Class II adolescents. SUBJECTS AND METHOD: Pharyngeal airway dimensions were compared between skeletal Class II adolescent subjects (N = 24, mean age: 11.6 ± 1.29 years) who were treated with Class II bionators and age-matched skeletal Class I control subjects (N = 24, mean age: 11.0 ± 1.21 years) using a series of lateral cephalograms from the initial visit (T0), after treatment (T1) and termination of growth (T2). RESULTS: The length of the nasopharyngeal region was similar between the skeletal Class I and Class II adolescents at all time points, while the lengths of the upper and lower oropharyngeal regions and the area of the pharyngeal airway were significantly smaller in the skeletal Class II adolescents compared with the Class I control adolescents at T0 (P < 0.05). However, at T1, the pharyngeal airway dimensions of skeletal Class II adolescents increased and became similar to those of the controls. CONCLUSION: Functional appliance therapy can increase the pharyngeal airway dimensions in growing Class II adolescents and this effect is maintained until the termination of growth.

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116 LONG-TERM EFFECTS OF VACUUM FORMED RETAINERS ON PERIODONTAL HEALTH M Çifter, A Çekici, A D Çelikel, Department of Orthodontics, Faculty of Dentistry, Istanbul University, Turkey

AIM: Success of orthodontic treatment should not be evaluated just by perfectly aligned teeth and occlusion. Relapse in the long-term can be associated both with changes related to growth and orthodontic treatment. Therefore attention should be paid to prevention of relapse utilising appropriate retention procedures. To date a large number of retention regimens have been introduced to prevent relapse after orthodontic treatment. The most commonly prescribed retainer types are Hawley retainers, bonded canine-to-canine retainers and vacuum formed retainers (VFRs). Despite some disadvantages of VFRs such as reduced vertical settling and occlusal wear, they have become increasingly popular due to their improved aesthetics, ease of application, reduced cost and ease of fabrication. The influence of retention regimens on periodontal and dental status, in the long term, is as important as their effectiveness in preventing relapse. The aim of this research was to Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 evaluate the long-term effects of VFRs on periodontal health. SUBJECTS AND METHOD: Patients who had completed active orthodontic treatment. On the same day the fixed appliance was removed, VFRs were applied to both jaws. Clinical periodontal measurements were recorded as plaque index (PI), bleeding on probing (BOP), calculus index (CI), periodontal pocket depth (PD), gingival recession (GR) and clinical attachment level (CAL) on the day of bracket removal and 1, 6 and 12 months following active orthodontic treatment. The changes between the time points were evaluated using Wilcoxon’s signed rank test. RESULTS: PI was significantly decreased in first month and did not significantly increase until 12 months. There was a significant increase in BOP and PD at 6 months when compared with baseline. In terms of GR, no significant change was observed. CAL was increased at 6 and 12 months. CI was significantly increased at all times when compared with baseline. CONCLUSION: There is a need for more frequent periodontal recalls for maintaining oral hygiene and the health of periodontal tissues of patients using VFRs.

117 REPRODUCIBILITY OF THE FRÄNKEL MANOEUVRE FOR EVALUATION OF SAGITTAL SKELETAL DISCREPANCIES IN CLASS II INDIVIDUALS I Cioffi1, V d'Antó1, M Casillo1, P Chiodini2, R Martina1, Departments of 1Orthodontics and 2Biostatistics, University of Naples Federico II, Italy

AIM: Cephalometric criteria for the evaluation of sagittal skeletal discrepancies in Class II individuals are highly questionable. The Fränkel manoeuvre allows easy evaluation of the sagittal relationship of the upper and lower jaw. Nonetheless its reproducibility has not been investigated. SUBJECTS AND METHOD: One hundred individuals aged between 10 and 13 years with an Angle Class II malocclusion. Two photographs, one of the facial profile at rest, and the other with the mandible postured forward until a Class I molar relationship was achieved (i.e. Fränkel manoeuvre) were collected (T0). The records were evaluated by six orthodontists, divided into two groups according to their clinical experience. The outcome measure was dichotomous, i.e. facial profile with the Fränkel manoeuvre was worse or not. The evaluation was repeated after a two week interval (T1). Inter- and intraobserver agreement were evaluated by computing Cohen’s κ. RESULTS: The agreement (κ values) between T0 versus T1 for each examiner ranged from 0.38 to 0.72. The overall agreement between the two observations was κ= 0.62 ± 0.05 (95% CI = 0.52-0.73). The agreement in the group with <5 years of clinical experience was 0.61 ± 0.07 (95% CI = 0.46-0.75), while in the group >10 years it was 0.64 ± 0.07 (95% CI = 0.49-0.79). The overall agreement between groups (experience <5 years versus experience>10 years) was κ = 0.59 ± 0.06 (95% CI = 0.47-0.70)

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CONCLUSION: The Fränkel manoeuvre is reproducible since substantial inter- and intraobserver agreement were found. It is not influenced by the level of clinical experience.

118 MAXILLOFACIAL FEATURES AND SYSTEMIC DYSMORPHISMS IN HEMIFACIAL MICROSOMIA (GOLDENHAR SYNDROME) E Cohen, N Cohen, F Cipriani Noce, J F Giordanetto, A Cohen, Pediatric Department, Inter-Regional Center for Rare Diseases, San Paolo Hospital, Savona, Italy

AIM: Hemifacial microsomia (HFM) is a multisystemic congenital rare disease with an estimated frequency of 1/3000-5000. Most cases of HFM are sporadic and are caused by a unilateral abnormal morphogenesis of the first and second branchial arches. The aim of this study was to define the frequency of maxillofacial and systemic malformations in a cohort of HFM patients. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 SUBJECTS AND METHOD: The data of 41 patients (19 females; 22 males) were analyzed. Five patients were excluded due to insufficient information. Data achieved through history, physical examination, photographs, diagnostic radiology and laboratory examinations were introduced and analyzed in a computerized database (FileMaker Pro). Maxillofacial deformities were graded according to OMENS plus classification (Orbital asymmetry, Mandibular hypoplasia, E auricular deformity, Nerve involvement and Soft tissue deficiency; plus for cardiac abnormalities). All evaluations were made prior to orthodontic or surgical therapy. RESULTS: Mandibular hypoplasia was observed in 35 out of 36 patients with a preponderance of the right side (23/35). No bilateral mandibular hypoplasia was observed. Thirty four out of 36 patients had external ear anomalies (anotia or microtia). Three cases had bilateral malformed ears. Hearing impairment, associated with stenosis or atresia of the external ear canal, was found in 28 patients; three of them had bilateral ear canal disorders. Ocular anomalies were seen in 17 patients (11 with dermoid cyst). Twenty one patients had orbital malformations. Facial nerve paralysis was observed in 16 subjects. Cleft palate, macrostomia and preauricular tags were also described. Thirty one out of 36 patients had systemic malformations. The most frequent malformations were: vertebral anomalies (26/36), genitourinary (13/36) and cardio-vascular disease (13/36). Eleven patients had cerebral anomalies, two of which had intellectual disability. CONCLUSION: No correlation was observed between the severity of the systemic abnormalities and the severity of the maxillofacial deformities suggesting that the OMENS plus score is clinically insufficient in terms of prognostic aspects, morbidity and quality of life of this group of patients. A new and more complete classification is needed. All patients suspected of HFM should undergo a complete systematic clinical and instrumental investigation and should be followed by specialized multidisciplinary team centres.

119 TIMING OF ORTHODONTIC TREATMENT AND SURGICAL CORRECTION IN PATIENTS WITH HEMIFACIAL MICROSOMIA: PERSONAL EXPERIENCE AND REVIEW OF THE LITERATURE N Cohen, E Cohen, F Cipriani Noce, J F Giordanetto, A Cohen, Pediatric Department, Inter-Regional Center for Rare Diseases, San Paolo Hospital, Savona, Italy

AIM: According to personal experience and a review of the literature, this study suggests the timing and type of orthodontic and surgical treatment in hemifacial microsomia (HFM) based on the severity of craniofacial deformities. MATERIALS AND METHOD: An extensive review of the literature using PubMed was carried-out. One thousand two hundred and sixty two articles were analyzed and after careful review, 91 were found to be relevant and were examined. Forty one patients with HFM (19 females; 22 males) were analyzed and divided into three groups, based on the phase of surgical-orthodontic treatment performed. RESULTS: Group 1 (20; 3 months to 9 years) patients too young for ear and mandibular surgical correction. For 5 out of 20 patients soft tissue and/or cleft palate surgery was performed. Group 2 (14; 9-18 years) still had

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ongoing orthodontic and surgical treatment. Group 3 (7; 15-29 years) patients that have concluded their orthodontic and surgical treatment. CONCLUSION: Removal of prearicular tags and correction of macrostomia are preferably performed during the second year of life in order to reduce general anaesthesia related complications. In severe macrostomia and/or extensive cleft palate, earlier surgery might be necessary. The type and timing of mandibular correction depends on the severity of the mandibular hypoplasia. Patients with type I mandibular hypoplasia should receive functional orthopaedic treatment during the early mixed dentition phase utilizing an asymmetrical functional activator. Functional therapy in the majority of these patients is sufficient for the reestablishment of structural and functional harmony of the entire stomatognatic system. Type IIa, IIb and III mandibular hypoplasia will need combined orthodontic and surgical correction. A functional orthodontic appliance during the mixed dentition phase should generally precede surgical correction. Surgery is usually performed during pre-puberty (9-11 years old). Surgery should be followed by orthodontic treatment in order to get the Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 maximum benefit of the procedure. External ear reconstruction is better performed at age 9 to 10 years, preferably after mandibular correction, in order to achieve a near-normal physical appearance during adolescence providing a significant psychological impact and improvement of the quality of life.

120 THE UTILITY OF CONE BEAM COMPUTED TOMOGRAPHY IN THE DIAGNOSIS OF MAXILLOFACIAL ABNORMALITIES IN PATIENTS WITH HEMIFACIAL MICROSOMIA N Cohen, E Cohen, F Cipriani Noce, J F Giordanetto, A Cohen, Pediatric Department, Inter-Regional Center for Rare Diseases, San Paolo Hospital, Savona, Italy

AIM: Hemifacial microsomia (HFM) is a rare congenital disease characterized by a unilateral asymmetric craniofacial malformation. HFM affects skeletal structures (orbit, mandible and ear), soft tissue and nerves. The aim of this study is to underline the importance of cone beam computed tomography (CBCT) in the diagnosis and treatment planning of skeletal malformations in HFM patients. MATERIALS AND METHOD: CBCT was carried out in 24 HFM patients (9 females; 15 males) and data on the mandible, condyle, glenoid fossa, zygomatic bone, orbit, auditory canal and ear malformations were analyzed. All DICOM images, acquired by an ICAT scanner, were studied through Osirix, Dolphin and ExamVision software and compared with the information obtained from clinical evaluation and traditional radiographic images. RESULTS: CBCT allowed the visualization of skeletal abnormalities not detectable by physical examination or by standard two-dimensional images. A CBCT scan offered three-dimensional high quality and high definition images of the mandibular condyle and glenoid fossa providing significant benefits in the planning phase of orthodontic and maxillofacial surgical correction. CONCLUSION: Given the wide variety of malformations and deformities associated with HFM, cranial CBCT scan is to be considered a prerequisite to the planning phase of orthodontic and surgical treatment. Considering the young age of HFM patients at the diagnostic and planning phase, the use of CBCT technology, that applies a low- dose X-ray, reduces the radiation - related biological risk. A CBCT scan can also be helpful to other specialists (audiologist, opthalmologist, ENT, plastic surgeon, etc) that make part of the multidisciplinary team during the diagnostic phase, reducing the need for other radiographic examinations.

121 TMA SPRING EXPANDER IN EARLY CLASS III TREATMENT C Colasante, M Greco, A Giancotti, University of Rome Tor Vergata Fatebenefratelli Hospital, Italy

AIM: To test the efficacy of modified acrylic expander with two TMA springs bonded to the palatal surface of the upper central incisors in patients with an anterior crossbite and hyperdivergent growth pattern. SUBJECTS AND METHOD: Thirteen patients (8 females, 5 males, mean age 8 years) presenting a dental Class I occlusion, maxillary constriction and moderate crowding in the upper and lower arches. Radiographic analysis

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showed a normal growth pattern with a hyperdivergent tendency, a skeletal Class III malocclusion associated with lingual inclination of the upper incisors and slight vestibular inclination of the lower incisors. The treatment plan was to correct the maxillary constriction by means of a bonded acrylic expander with two TMA springs in order to prevent mandibular clockwise rotation and facilitate crossbite resolution. The expander activation (6 mm) was performed by the patients’ parents and lasted 10 days. RESULTS: For all patients the anterior crossbite was completely corrected with good vertical control. CONCLUSION: The modified TMA spring expander proved to be efficient in patients with a Pseudo Class III malocclusion.

122 COMPARATIVE EVALUATION OF DIFFERENT TECHNIQUES USED IN ORTHODONTICALLY ASSISTED ERUPTION OF IMPACTED SECOND MOLARS G Colicchia, F Carpenteri, G Vizzielli, S Di Benedetto, G Galluccio, Post-Graduate School in Orthognatodontics - Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 Sapienza University of Rome, Italy

AIM: To compare the orthodontic techniques mostly used to aid impacted second molar eruption to underline biomechanical properties, technique advantages and disadvantages, therapeutic effectiveness and treatment time. MATERIALS AND METHOD: A systematic review of the scientific literature from 1972 to 2013 was carried out regarding impacted second molar uprighting. Data from 38 articles was compared. Eighteen patients were selected (mean age 14.3 ± 2.3 years). Twenty seven impacted second molars were described; 23 mandibular and four maxillary. The techniques used were: surgical dislocation with brass lace, transpalatal appliance/lower lingual holding arch with distal uprighting arm, cantilever, intermaxillary , open-coil springs and miniscrews. RESULTS: Treatment times were evaluated. Average time (in months): surgical dislocation with brass lace 7.3; transpalatal appliance/lower lingual holding arch with distal uprighting arm 7.9; cantilever 12; intermaxillary elastics 10; coil springs 1 and miniscrews 5.5. CONCLUSION: The present literature does not discriminate the superiority of one technique. This is due to the depth of the inclusion, mesio-or disto-version, complications such as bracket debonding, traction devices or miniscrew posting and patient cooperation.

123 TEMPOROMANDIBULAR PATHOLOGY AFTER ORTHOGNATHIC SURGERY B Crovato, F Paiocchi, F Savoldi, C Tian, L Visconti, Department of Orthodontics, University of Brescia, Italy

AIM: Orthognathic surgery is used routinely to correct serious malocclusions and the number of patients treated with orthognathic surgery is rapidly increasing; it is also widely utilised for the correction of aesthetic problems. The purpose of this study was to investigate the effects of orthognathic surgery on condylar reremodelling through the evaluation of cone-beam computed tomography (CBCT) images. MATERIALS AND METHOD: Twenty CBCT images obtained from consecutive patients, aged between 20 and 40 years, were considered as the control group, and five CBCT scans of patients, who had orthognathic surgery, were selected to assess morphological condylar changes between pre- and post-surgery. Condylar measurements were performed in the sagittal, frontal and transverse planes. The condylar dimensions were evaluated using CBCT scans obtained about 1 month pre-surgery, and then repeated about 1 year post-surgery. RESULTS: There was no significant difference between pre- and post-surgical condylar dimensions either in the test or control group patients. The paired-samples t-test, with a significance level α = 0.05, was used to statistically analyze pre- and post-surgery measurements. However in some cases a change in the mandibular posterior ramus height (measured on Ar-Go) and of the PFH/AFH ratio, was appreciated. There was an increase

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of 7 mm in one patient and a decrease of 9.3 mm in another, with mandibular post-rotation and a decrease of the PFH/AFH value. CONCLUSION: The onset of dysfunctional re-remodelling of the condyle following orthognathic surgery could not be demonstrated. There was instead the constant presence of a functional condylar re-remodelling, allowing the adjustment necessary to maintain a normal function of the temporomandibular joint in the new skeletal pattern. However it cannot be completely dismissed that orthognathic treatment could be a co-factor for condylar resorption in predisposed patients, such as in a case of oestrogenic imbalance, as reported in literature.

124 VARIOUS DOCUMENTATION ROUTINES AMONG SWEDISH ORTHODONTISTS E Dahl1, L-I Norevall1, A Marcusson2, 1Department of Orthodontics, Centre for Orthodontics and Paediatric Dentistry and 2Department of Dentofacial Orthopaedics, Maxillofacial Unit, University Hospital, Linköping, Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 Sweden

AIM: To investigate what recordings are used by Swedish orthodontists before, during, and after orthodontic treatment. MATERIALS AND METHOD: In October 2012 a survey was sent by e-mail to 215 orthodontists in Sweden. E-mail addresses for active members were obtained from the Swedish Orthodontic Society. A survey software, Publech® Survey 5.7, was used for constructing a questionnaire of 11 questions. There were 139 respondents (64.7%). Data was analysed by descriptive statistics (Microsoft® Excel® 2010). RESULTS: Registrations before, during, and after orthodontic treatment varied. The most common recordings before treatment were intra- (96%) and extra-oral photographs (95%). This was followed in descending order by panoramic radiographs (90%), study casts (82%), cephalometric radiographs (52%) and intraoral radiographs (51%). During treatment periapical radiographs were most frequently registered (80%) followed by intraoral photographs (27%). At debond intra- (87%) and extra- (62%) oral photographs were more used than study casts (47%). Follow-up appointments three months or less after debond was reported by 90 per cent and reported one year after debond by 46 per cent. One year after debond 53 per cent discharged their patients. CONCLUSION: Registrations among Swedish orthodontists vary with the most frequent recordings done before treatment. The most common documentation is intra- and extra-oral photographs. This is followed by panoramic radiographs and study casts.

125 ‘SURGERY FIRST’ APPROACH FOR ORTHODONTIC FORCED ERUPTION OF IMPACTED MAXILLARY CANINES D Dalessandri1, M Migliorati2, Departments of Orthodontics, 1University of Brescia and 2University of Genova, Italy

AIM: One of the most common protocols for treating impacted maxillary canines is to place an orthodontic appliance, to align teeth and to open the space for a canine crown, and to apply orthodontic traction in order to force eruption of the canine. Sometimes, especially in adult patients, the canine could be ankylosed and it must be extracted. Unfortunately, it is hard to diagnose canine ankylosis before starting active orthodontic traction. The aim of this study was to test a ‘surgery first’ approach and to evaluate the efficacy of miniscrew anchored traction in forcing canine eruption, before placing any other orthodontic appliance. SUBJECTS AND METHOD: Twenty adult patients with one palatally impacted upper canine (8 males, 12 females) aged between 28 and 73 years, were randomly divided into two groups of 10. Group A patients, test group, were treated placing a miniscrew in the mandibular jaw and applying an elastic force of between 100 and 150 g, until canine eruption, following which they were treated with a multibracket fixed appliance. Group B patients, control group, received orthodontic brackets to align the dental arches and to open the space for the canine crown. Forced eruption of the impacted canine was then achieved by means of a stainless steel ligature secured

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to a 0.012 inch nitinol auxiliary orthodontic archwire. Total treatment time, complications and incidence of failures were recorded and statistically analyzed with descriptive statistics and differences between groups were analyzed with the Mann-Whitney U-test. RESULTS: Seven canines (3 in group A and 4 in group B), were diagnosed as ankylosed after six months of treatment without any visible movement on the radiograph, and were extracted. The treatment time of group A patients was significantly longer compared with group B patients (4 months ± 13 days). There was no statistically significant difference regarding the incidence of complications. CONCLUSION: Orthodontic forced eruption of palatally impacted maxillary canines in adult patients could fail in the case of canine ankylosis. The use of the surgery first approach, compared with the classic approach, allows the orthodontist to detect canine ankylosis earlier and to adapt the treatment plan, before placing any other orthodontic appliance. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 126 THE USEFULNESS OF CONE BEAM COMPUTED TOMOGRAPHY IN INVESTIGATING ROOT RESORPTION CAUSED BY ORTHODONTICS D Dalessandri1, M G Piancino2,.L Svanetti1, L Contardo2, C Paganelli1, 1Departments of Orthodontic, University of Brescia, 2Department of Orthodontics and Gnatology - Masticatory Function, Dental School, University of Turin and 3Department of Orthodontics, University of Trieste, Italy

AIM: To investigate the reasons for apical root resorption of anterior teeth in patients undergoing multibracket orthodontic treatment. MATERIALS AND METHOD: Post-treatment cone beam computed tomographic (CBCT) images of 114 patients, treated during the same period of time in the same orthodontic department, 38 with radiological signs of apical root resorption of the six anterior teeth that appeared during orthodontic treatment (group A) and 76 without any sign of root resorption at the end of the treatment (group B), were compared on pre-treatment CBCT images. The amount of resorption and localization, tooth movement direction and the relationship with surrounding anatomical structures were recorded. Direction of movement was obtained by comparison of the final and initial tooth position. Descriptive statistics were applied to these data. Differences in the relationship with surrounding anatomical structures between the two groups were statistically analyzed, using the Mann- Whitney U-test, considering each tooth and orthodontic movement separately. RESULTS: The incidence of root resorption was significantly higher for the lower incisors, followed by the lateral upper incisors, central upper incisors, and canines. In both groups no root resorption was found when teeth underwent only extrusive movement. When teeth underwent mesial, distal, buccal, lingual, or combined movements, spatial proximity with anatomical boundaries was significantly higher in group A compared with group B, whereas there was no significant difference when teeth underwent only intrusive movement. CONCLUSION: A CBCT examination could be useful in treatment planning to evaluate the spatial relationship between teeth and surrounding anatomical structures and boundaries, allowing identification of teeth with an increased risk of root resorption caused by the vicinity of the teeth to the structures during orthodontic movement. Accurate control of movement is essential when moving the tooth in the proximity of anatomical boundaries, in order to minimize the risk of root resorption during mesial, distal, buccal, lingual, or combinations of these movements.

127 VIRTUAL MAXILLOFACIAL SURGERY PLANNING AS A TOOL FOR QUALITY CONTROL M Dalstra, T K Pedersen, B Melsen, Department of Orthodontics, Aarhus University, Denmark

AIM: Since traditional plaster surgery can be prone to orientation errors of the occlusal plane, virtual maxillofacial surgery planning is used to compare the actual outcome of virtual surgery planning and plaster surgery.

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MATERIALS AND METHOD: During the last two years, for over 100 surgery patients, the planning and production of the surgical splint was performed both with traditional plaster surgery and virtual surgery planning. The latter made use of pre-surgical cone beam computer tomography (CBCT) data merged with digital study models. The fit of both splints was checked prior to surgery and the actual splint used at surgery was the traditionally produced one if the operation was scheduled for an even week and the virtually produced one for an uneven week. Only when the intended splint did not fit, was the alternative splint used. The majority of surgeries included in this study were double procedures (60%) and LeFort I (30%). Six to eight weeks post- surgery, a new set of CBCT scans were taken as well as a digital model made. These were then merged together as a post-surgery model of the patient. Thus three models for each patient, the pre-surgical model, the model with the planned outcome and the actual post-surgical model, were then available for comparison and evaluation. Using the planning software tools for linear and angular measurements, the planned and actual movements of the teeth could then be determined. Furthermore, a built-in articulator allowed for visualization Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 of the occlusion and contact points through a distance plot with a colour scale in each of the three models. RESULTS: The study is still ongoing, but preliminary results indicate that discrepancies between the planned and actual outcome do occur. In a number of cases, where the traditionally produced splint was used at surgery, the planned occlusion was not achieved and a less optimal occlusion with either frontal or one-sided contacts was obtained. CONCLUSION: Virtual maxillofacial surgery planning not only provides a better understanding of the individual patient’s anatomy than traditional plaster surgery, but allows post-surgery quality control by enabling comparison between the achieved and planned outcome.

128 RELIABILITY AND VALIDITY OF THE ITALIAN VERSION OF THE PSYCHOSOCIAL IMPACT OF DENTAL AESTHETICS QUESTIONNAIRE V D'Antò, R Rongo, C Levatè, R Bucci, R Valletta, Section of Orthodontics, University of Naples ‘Federico II’, Italy

AIM: The Psychosocial Impact of Dental Aesthetics Questionnaire (PIDAQ) is a valid tool to assess the influence of dental aesthetics on Oral Health Related Quality of Life (OHRQoL) in young adults. In particular, it focuses on some dental aspects specifically related to orthodontics. An Italian version of PIDAQ is still not available. The aim of this study was to assess the validity and reliability of the Italian version of PIDAQ for its application among young Italian adults. MATERIALS AND METHOD: The questionnaire was translated into Italian, back translated and cross-culturally adapted. Later, it was pre-tested on a convenience sample of 75 subjects. Afterwards, the Italian version of PIDAQ was administered to 598 subjects, randomly selected in the city of Naples (Italy), aged 18-30 years, along with two other instruments, the Aesthetic Component of Index of Orthodontic Treatment Need (AC-IOTN) and the Perception of Occlusion Scale (POS), which identified the self-rated malocclusion. Validity was assessed by evaluation of the criterion validity, determined with an ANOVA test, and the internal consistency, measured using Cronbach’s alpha coefficient for the subscales. Finally, test-retest reliability was assessed, on 75 subjects, by means of Intraclass correlation coefficient. RESULTS: The four domains of the PIDAQ significantly differed when compared with the self-rated level of malocclusion, measured with both AC-IOTN and POS. The internal consistency of the subscales ranged between 0.79 and 0.92. Test-retest reliability for domains ranged from 0.81 to 0.90. CONCLUSION: The Italian version of PIDAQ showed good reliability and validity. It highlighted the satisfactory discriminative and evaluative psychometric properties. Hence, it can be suggested for future studies on orthodontic-specific OHRQoL in Italian young adults.

129 VIRTUAL TISSUE ALIGNMENT AND CUTTING PLANE DEFINITION – A NEW METHOD TO OBTAIN OPTIMAL LONGITUDINAL HISTOLOGICAL SECTIONS

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J Danz1,2, M Habegger1, D Bosshardt3, C Katsaros1, A Stavropoulos4, 1Department of Orthodontics and Dentofacial Orthopaedics, University of Bern, Switzerland and 2Section of Periodontology, University of Aarhus, Denmark, 3Robert K Schenk Laboratory of Oral Histology, University of Bern, Switzerland, 4Department of Periodontology, Faculty of Odontology, Malmö University, Sweden

AIM: When investigating periodontal tissues in small experimental animals, the histomorphometric evaluation requires reproducible alignment of maxillae and highly precise central sections of buccal roots; this is a cumbersome and technically sensitive process due to the small specimen size. The present report describes and analyzes a method to transfer virtual sections of micro-computer tomographic (µCT) generated image stacks to the microtome for undecalcified histologic processing. MATERIALS AND METHOD: A total of 84 undecalcified sections at all buccal roots of seven untreated rats were evaluated with three methods: µCT data median cut level, histologic processing with individual section level and Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 µCT processing with individual section level. The accuracy of individual section co-ordinate transfer from virtual slice to the histologic slice, right-left side differences and the measurement error for linear and angular measurements on µCT and on histological micrographs were calculated using the Bland-Altman method, interclass correlation coefficient and the method of moments estimator. Moreover, manual alignment of rat maxilla was compared with multiplanar computer-reconstructed alignment. RESULTS: Insufficient processing quality led to a 2.4 per cent histomicrograph drop-out for geometric constructions (2 out of 84). Median RP-root distance method led to a 67.9 per cent drop-out rate whereas individual definition of the section level was successful in all 84 slices for the SH-aligned and MPR-aligned virtual µCT sections. A median difference of –148 μm was found between the virtual section level and the obtained histological section. Comparisons of differences between the left and right hemi-maxillae showed a similar deviation in the MPR-aligned µCTsections and the histographs (–19.5 and –20 μm. respectively). The error between the two methods of alignment was 20.5 μm for tooth position and –0.5 for inclination. When comparing the variances of the differences between duplicate measurements for the same parameters, no significant differences were observed regarding RC-MPS (P = 0.0613); however, significant differences were found regarding inclination (P = 0.0401). CONCLUSION: The high methodolocical standardization presented ensures retrieval of histological slices with an excellent display of anatomical microstructures in a reproducible manner, minimizes random errors, and thereby may contribute to the reduction in the number of animals needed.

130 CHANGES IN THE PERIODONTAL LIGAMENT BY ORTHODONTIC FORCES: A MICRO-RAMAN ANALYSIS OF AMIDE I AND LIPID CONTRIBUTIONS F d'Apuzzo1, M Lepore2, G Raucci1, C Camerlingo3, L Perillo1, Departments of 1Orthodontics and 2Experimental Medicine, Second University of Naples, and 3Institute of Cybernetics, CNR, Pozzuoli, Italy

AIM: micro-Raman spectroscopy (μ-RS) was performed to evaluate structural changes in periodontal ligaments (PDL) after orthodontic tooth movement. SUBJECTS AND METHOD: Orthodontic patients between 13 and 21 years of age (mean 17.5 years) treated between November 2012 and June 2013 with extraction of premolars. Before extractions, a 50 g closed coil spring (Sentalloy®) was attached between bands and brackets with a power pin on the first molars and premolars, respectively, after unilateral of the premolar with a diamond bur, using the other side as the control. The patients were randomly assigned to three groups whose extractions were performed after 2, 7 or 14 days of force application. A PDL scarification of the extracted teeth was performed. Each sample was fixed in 4 per cent paraformaldehyde, stored in 100 per cent alcohol and examined by a micro- Raman spectrometer equipped with a confocal inverted microscope, a liquid nitrogen cooled CCD detector and a 633 nm helium-neon laser. Spectra were preliminarily analyzed using the application routines provided by the software package (SpectraMax™ Software) and a baseline correction program for the data acquisition software e69

was used. For signal interpretation, the complex spectra were also analyzed by convoluted Gaussian and Lorentzian shaped vibration modes to determine convolution peaks with optimized intensity, position and width. RESULTS: Comparative analysis of PDL Raman spectra revealed significant molecular bond changes at protein Amide I (1550-1750 cm-1) and lipid CH2 (2800-3000 cm-1) wave number regions. In Amide I range, the intensity changes occurred mainly after 2 days of force application; after 7 days, a little readjustment of the protein structure was still present for relocation and bond formation of hydrogen atoms; after 2 weeks the mode assigned to α-helix structure decreased by about 75 per cent of the control value, due to a partial transition from α- to β-shape, promoted by hydrogen bonding and increased disorder. The methyl groups were wider after stress indicating tissue relaxation. CONCLUSION: Raman measures are useful to match the macromechanical behaviour of PDL samples after orthodontic force application. Therefore, μ-RS is a promising tool for orthodontic applications due to its Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 sensitivity to even subtle chemical and structural changes of the analyzed tissue.

131 NON-SYNDROMIC CLEFT LIP WITH OR WITHOUT A CLEFT PALATE IN ARAB POPULATIONS: GENETIC ANALYSIS OF 15 RISK LOCI IN A NOVEL CASE-CONTROL SAMPLE FROM YEMEN N Daratsianos1, K A Aldhorae2, A Böhmer3 K Ludwig3 E Mangold3, 1Department of Orthodontics and 3Department of Genomics, Life and Brain Center, Institute of Human Genetics, University of Bonn, Germany and 2Orthodontic Department, College of Dentistry, Thamar University, Yemen

AIM: Non-syndromic orofacial clefting (nsOFC) is among the most common of all congenital disorders and has a genetically complex aetiology. Based on embryological and epidemiological data, the phenotype can be differentiated into non-syndromic cleft lip with or without cleft palate (nsCL/P) and non-syndromic cleft palate only (nsCPO), with nsCL/P being the most frequent form. Recent genetic research, predominantly performed in populations from Europe and Asia, has identified numerous genetic susceptibility loci for nsCL/P. As only few data are available concerning genetic susceptibility to nsCL/P in Arab populations, a large, newly recruited nsOFC sample from Yemen was investigated. SUBJECTS AND METHOD: Patients were recruited within the context of surgical outreach programmes that took place in Yemen between 2010 and 2012. Controls were recruited from blood donors of the same ethnic origin in the same area. Blood samples of patients/controls were transferred to the Institute of Human Genetics, Bonn where DNA was extracted. For each of the 15 currently known nsCL/P risk loci, the top single-nucleotide polymorphism (SNP, plus nine back-up variants) were genotyped in 242 nsCL/P cases and 420 healthy controls. Although patients with nsCPO were also recruited, they were not included in the present analysis due to insufficient sample size (n = 49). RESULTS: Single-marker association analysis revealed significant associations for four loci (8q24, 9q22, 10q25, 13q31). The strongest association was for the European high risk locus at 8q24 (P corrected = 5.09×10-4; heterozygous odds ratio = 1.74 (1.22-2.47), homozygous odds ratio = 2.47 (1.55-3.93). Five additional loci (1q32.2, 3q12, 8q21, 17q22, 20q12) showed nominal significance that did not withstand correction for multiple testing. Although the six remaining loci (1p22, 1p36, 2p21, 3p11, 15q22, 17p13) failed to reach nominal significance, the risk alleles were in the same direction as in the discovery studies. CONCLUSION: This study represents the first investigation of currently known nsCL/P genetic risk factors in a large Arab case-control sample from Yemen. The results suggest that the majority of the 15 known nsCL/P risk loci identified in European and Asian ethnicities also confer risk for nsCL/P in Arab populations.

132 DIAGNOSTIC CAPABILITY OF QUESTIONNAIRES AND/OR CLINICAL EXAMINATION FOR THE ASSESSMENT OF PAEDIATRIC SLEEP DISORDERED BREATHING

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G de Luca Canto, V Singh, M P Major, P W Major, C Flores Mir, Department of Dentistry, University of Alberta, Edmonton, Canada

AIM: The gold standard for the diagnosis of sleep disorder breathing is a full overnight polysomnography (PSG). Dentists/prosthodontists do not have access to PSG, therefore the diagnostic value of alternative paediatric sleep disordered breathing (PSDB) diagnostic methods (clinical history and/or physical examination) were evaluated to determine their diagnostic value. MATERIALS AND METHOD: A systematic review/meta-analysis was conducted following acceptable guidelines. Only articles whose primary objective was to evaluate the diagnostic capability of clinical evaluation (i.e., clinical history and/or physical examination) and/or questionnaires to diagnose PSDB were selected. Full overnight PSG had to be used as 'the gold standard'• reference test. The evaluated population should be of individuals from 0 to 18 years of age. Studies from any language were considered. Medline, PubMed, Embase, Cochrane Library Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 and Lilacs were searched. The methodology of selected studies was evaluated using the 14-item Quality Assessment Tool for Diagnostic Accuracy Studies. Sensitivity and specificity of the diagnostic tests were the main outcome evaluated. Review Manager 5.2 (RevMan) was used to construct Receiver Operator Characteristics graphs and Forest plots. Some of the required data was not specifically specified in the articles so data had to be calculated or obtained from the authors. To decrease heterogeneity, the studies were separated into four groups to provide the meta-analysis according with the index test (questionnaires, questionnaire and physical examination, questionnaire or physical examination and/or other test and physical examination and another test). Additional analysis was carried out using diagnostic odds ratio and Youden’s Index. RESULTS: Finally 24 articles were selected. Only 11 of those were included in the meta-analysis. Only the paediatric sleep questionnaire (PSQ) had diagnostic accuracy good enough to be used as a screening method for SDB. However, PSQ reported diagnostic values (specificity, net present value, and Younden’s Index values), which were not sufficient to be considered a true diagnostic tool for PSDB. CONCLUSION: Use of the identified questionnaire could be considered an acceptable screening test before referring the positive cases to the sleep medicine specialist. Involvement of orthodontists in the PSDB identification process could potentially contribute significantly to the children’s health.

133 EVALUATION OF A RESEARCH PROTOCOL FOR MONITORING ORTHODONTIC TOOTH MOVEMENT S Del Prete, A Dichicco, M Castellano, A Putrino, G Galluccio, Department of Oral and Maxillo Facial Sciences, Post-Graduate School in Orthognatodontics - Sapienza University of Rome, Italy

AIM: Evaluation of an experimental sampling protocol to study mediators of orthodontic tooth movement. MATERIALS AND METHOD: A literature review was made on tooth movement mediators, possible sources and methods of sampling, to draft the best protocol for an optimal study on orthodontic movement efficiency. Subsequently the gold standard of each area was selected. IL-1β and osteoprotegerin (OPG) were chosen as mediators, gingival crevicular fluid as the source and paperstrips as the method. Samplings were made on upper canines, one banded (test tooth, in an ectopic vestibular position), and the contralateral unbanded (control tooth). Samples were obtained six times. Analysis was performed with an ELISA test. Plotting absorbance values, in duplicate, the intra-assay variation coefficient was calculated, to provide information on protocol reproducibility and result accuracy. The findings were positive if the coefficient was <10 per cent. The chosen protocol was tested on two female patients, treated with self-ligating brackets. RESULTS: Positive values were obtained for both mediators (slight superiority for OPG). CONCLUSION: The positive values achieved demonstrate protocol validity. For a better protocol evaluation, studies in triplicate on a wider sample population are necessary.

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134 COMPARATIVE EXAMINATION OF ARCHWIRES BY THREE-DIMENSIONAL SURFACE TOPOGRAPHY AFTER CLINICAL USE K Déri1, E Varga1, G Fábián1, G Varga2, 1Department of Paedodontics and Orthodontics, Semmelweis University, Budapest and 2Institute of Manufacturing Science, University of Miskolc, Hungary

AIM: To determine the changes of surface roughness of commercially available orthodontic nickel titanium (NiTi) archwires on the basis of different time of clinical use. MATERIALS AND METHOD: The surface roughness measurements were undertaken using the CL2 optical sensor of the Altisurf 520 type three-dimensional (3D) surface roughness measuring equipment. The featuring data of the confocal chromatic probes are: axial resolution 0.012 µm and axial accuracy 0.06 µm. The frontal region of two different types of NiTi archwires (sizes: 0.016 × 0.016 and 0.016 × 0.022 inches) was examined in five different places on a 100 × 100 µm surface. The applied time intervals of the archwires were: 1.5, 3 and 5 Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 months and the comparative base was the surface roughness of the new, commercially available archwires. From the different standardized (ISO 25178) 3D parameters, detailed examination was carried out measuring the changes of arithmetic mean height (Sa). RESULTS: The average measured values were Sa = 0.739 µm after 1.5 months of use and 0.589 µm after 3 months. The Sa values relating to the arch used for 5 months were almost the same as at 3 months; their decline was less than 1 per cent. For the 0.016 × 0.016 arches a regressive tendency was observed but to a lesser extent. The average surface roughness of the new archwires was Sa = 0.626 µm. The decrease was 35 per cent for the 0.016 × 0.022 inch and 21 per cent for the 0.016 × 0.016 inch archwire. CONCLUSION: By increasing the period of clinical use, the surface roughness of the archwires reduced as the wire became smoother over time. However, progress of orthodontic treatment is determined by factors other than the length of time an archwire is in use.

135 INDICES OF ORBICULARIS ORIS MUSCLE ACTIVITY IN PATIENTS WITH MALOCCLUSION, COMPLICATED BY DENTAL CROWDING M Dmitrenko, Postgraduate Department of Orthodontics, Higher Medical Educational Institution of Ukraine 'Ukrainian Medical Stomatological Academy', Poltava, Ukraine

AIM: To study indices of orbicularis oris activity in patients with malocclusion, complicated by dental crowding. SUBJECTS AND METHOD: Thirty four patients with malocclusion and a severe degree of severity of dental crowding (15 males, 19 females, aged 16-29 years) who underwent orthodontic treatment. The treatment group was divided into three: Group Ia comprised 11 subjects with mandibular crowding (mean age 19.27 ± 1.08 years); group Ib, 10 patients with maxillary dental crowding (mean age 20.10 ± 1.60 years) and group Ic, 13 subjects with both maxillary and mandibular crowding (mean age 20.15 ± 1.45 years). The control group consisted of 10 patients with malocclusions but without dental crowding (mean age 20.70 ± 1.32 years). The findings were compared with similar indices in subjects with normal occlusion (mean age 21.3 ± 1.25 years). The index of orbicularis oris activity (ACTIV,%) was determined for each patient. A Student’s t-test was used to analyze statistical difference between different groups. RESULTS: Comparative analysis did not show significant differences between groups according to age, gender, type of malocclusion or the severity of dental crowding (P > 0.05).It was determined that the activity of the orbicularis oris before treatment varied depending on the clinical form of dental crowding. Patients with maxillary crowding showed greater activity of muscles of the upper lip during maximum voluntary clenching (ACTIV = –0.99 ± 7.44%)(P < 0.05). Activity of the muscles of the lower lip in patients with mandibular crowding (ACTIV = 20.52 ± 4.22%) and crowding of both maxillary and mandibular teeth (ACTIV = 17.93 ± 4.33%) prevailed. After complex treatment of dental crowding, the ACTIV indices were not significantly different in groups Ia, Ib, Ic and from controls with normal occlusion (P > 0.05).

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CONCLUSION: Activity of the orbicularis oris in patients with malocclusion, complicated by dental crowding depend on clinical form of crowding. The results show that orthodontic appliance therapy accompanied by massage and physiotherapy improve the activity of the orbicularis oris.

136 DURATION OF ORTHODONTIC TREATMENT FOR MALOCCLUSIONS WITH DENTAL CROWDING M Dmitrenko, Postgraduate Department of Orthodontics, Higher Medical Educational Institution of Ukraine ‘Ukrainian Medical Stomatological Academy’, Poltava, Ukraine

AIM: To compare the treatment duration of a malocclusion with dental crowding in two groups of subjects. SUBJECTS AND METHOD: Ninety two patients with a severe degree of dental crowding (29 males, 63 females; mean age 16 years 6 months) were divided into two groups. Group 1 comprised 51 subjects (16 males, 35 females; mean age 16.51 ± 0.43 years) treated with fixed edgewise appliances. In addition they carried out Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 recommended massage and physiotherapy to improve the functional state of the masseter, temporal and orbicularis oris muscles. Group 2 comprised 41 subjects (13 males, 28 females; mean age 16.78 ± 0.53 years) treated with fixed edgewise appliances. The treatment time for the groups was compared with a t-test RESULTS: Comparative statistics did not show any difference between the groups according to age, gender, malocclusion or the severity of dental crowding. There were no significant differences between the groups according to treatment with extractions or orthodontic stripping (P < 0.05). The average treatment duration for maxillary anterior crowding for groups 1 and 2 was 13.29 ± 0.70 and 18.49 ± 0.90 months, respectively, which were statistically different (P < 0.05). The average treatment duration for mandibular anterior crowding for groups 1 and 2 was 11.80 ± 0.38 and 17.86 ± 1.81 months, respectively, which was statistically different (P < 0.05). CONCLUSION: The duration of orthodontic treatment for malocclusions with dental crowding is shorter with additional administration of massage and physiotherapy for improvement of the functional state of the masseter, temporal and orbicularis oris muscles.

137 THE CRANIOFACIAL STRUCTURE AS A RISK FACTOR IN OBSTRUCTIVE SLEEP APNOEA M Dobrowolska-Zarzycka, J Szymańska, I Dunin-Wilczyńska, M Kosecka, M Smyl-Golianek, Department of Jaw Orthopedics, Medical University of Lublin, Poland

AIMS: Comparison of the craniofacial pattern of patients with obstructive sleep apnoea (OSA) with cephalometric norms according to Hasund and Segner, and to determine the relationship between the severity of the disease expressed by the apnoea-hypopnoea index (AHI) and the position of maxilla and mandible. MATERIALS AND METHOD: Medical records of 41 patients diagnosed with OSA. The collected data included: age and gender, AHI, body mass index and lateral radiographs together with measurements of upper and lower pharyngeal depth. RESULTS: Comparison of patients with OSA with cephalometric norms by Segner and Hasund revealed that the craniofacial structure of OSA patients differed significantly only in SNB angle. Other angles: SNA, ANB, NL/NSL, NL/ML and NSL/ML did not differ significantly from accepted standards. The upper measurement of the nasopharynx was decreased in 97.6 per cent of patients and the lower measurement in 75.6 per cent. Analysis of the impact of the craniofacial pattern on the severity of OSA showed a significant impact of the position of the mandible (SNB), skeletal Class (ANB) and rotation of the mandible (NSL/ML). CONCLUSION: A decreased SNB angle is a risk factor of OSA. Patients with a skeletal Class II malocclusion, retro positioned and clockwise rotated mandible show higher levels of AHI.

138 FACEMASK VERSUS BONE-ANCHORED MAXILLARY PROTRACTION FOR THE CORRECTION OF CLASS III IN PATIENTS WITH . A SYSTEMATIC REVIEW

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I Doulis1, I Toulia1, D Kloukos2, A Souliotis1, Departments of Orthodontics and Dentofacial Orthopedics, 1251 Hellenic Air Force V.A. General Hospital, Athens, Greece and 2University of Bern, Switzerland

AIM: To systematically search the literature and compare the dentofacial effects of maxillary protraction therapy by means of facemask versus bone-anchored appliances in patients with Class III malocclusions due to upper jaw retrusion. MATERIALS AND METHOD: Electronic database searches of published and unpublished literature were performed. The following electronic databases with no language and publication date restrictions were searched: Medline (via Ovid and PubMed), Embase (via Ovid), the Cochrane Oral Health Group’s Trials Register and Central. Unpublished literature was searched on ClinicalTrials.gov, the National Research Register, and Pro- Quest Dissertation Abstracts and Thesis database. The reference lists of all eligible studies were hand-searched for additional studies. Two review authors performed data extraction independently and in duplicate using Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 individualised data collection forms. Disagreements on data extraction and quality assessment were resolved by discussion or the involvement of an arbiter. RESULTS: From the 725 articles identified by the search, after application of the specific inclusion and exclusion criteria and removal of the duplicates, 40 papers were considered eligible for inclusion in the review. After further selection following the full text reading stage, five studies qualified for the final review analysis. Among them no randomised clinical trial was identified. All studies were assessed for their quality and graded eventually from low to moderate level of evidence. Common result across the included studies was that bone- anchored maxillary protraction might have greater effect on maxillary advancement than a facemask. Moreover, some side-effects, such as mandibular rotation, extrusion of maxillary molars, and proclination of maxillary incisors, might be reduced by bone-anchored maxillary protraction. CONCLUSION: Both treatment options improve the skeletal relationship and the patient’s profile. However, bone-anchored maxillary protraction is associated with greater dentofacial changes and a lower incidence of adverse dentoalveolar effects.

139 EFFECT OF CHLORHEXIDINE VARNISH APPLICATION ON BACTERIA COLONIZATION AND GINGIVAL HEALTH IN ORTHODONTIC PATIENTS. A SYSTEMATIC REVIEW I Doulis1, I Toulia1, D Kloukos2 A Souliotis1, Departments of Orthodontics and Dentofacial Orthopedics, 1251 Hellenic Air Force V.A. General Hospital, Athens, Greece and 2University of Bern, Switzerland

AIM: To systematically search the literature and assess the efficacy of differently concentrated chlorhexidine varnishes on bacteria colonization and gingival health in orthodontic patients. MATERIALS AND METHOD: Electronic database searches of published and unpublished literature were performed. The following electronic databases with no language and publication date restrictions were searched: Medline (via Ovid and PubMed), Embase (via Ovid), the Cochrane Oral Health Group’s Trials Register and Central. Unpublished literature was searched on ClinicalTrials.gov, the National Research Register, and Pro- Quest Dissertation Abstracts and Thesis database. The reference lists of all eligible studies were hand-searched for additional studies. Two review authors performed data extraction independently and in duplicate using individualised data collection forms. Disagreements on data extraction and quality assessment were resolved by discussion or the involvement of an arbiter. RESULTS: From the 155 articles identified by the search, after application of the specific inclusion and exclusion criteria and removal of the duplicates, 30 papers were considered eligible for inclusion in the review. After further selection following the full text reading stage, 16 studies qualified for the final review analysis. Among them 12 randomised clinical trials were identified. All studies were assessed for their quality and graded eventually from low to high level of risk of bias. Common results across the included studies were that bacteria counts were reduced as compared to baseline values, after chlorhexidine application. Moreover, the results

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suggest that treatment with an antibacterial varnish decreases the levels of inflammatory mediators in gingival crevicular fluid, thus being beneficial in patients with chronic gingival inflammation. CONCLUSION: Repeated application of chlorhexidine varnish in patients with high bacteria levels may be beneficial throughout orthodontic treatment with fixed appliances, as far as it concerns bacteria colonization and maintenance of gingival health.

140 MALOCCLUSION AND POSTURAL BODY ADAPTATION M Drohomyretska, M Bilous, Department of Orthodontics, National Academy of Post-Graduate Education, Kyiv, Ukraine

AIM: To determine correlations between the parameters of body posture adaptation patterns and malocclusion. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 SUBJECTS AND METHOD: Eighty five adolescents with occlusal pathology and scoliotic posture (mean age 15.7 years, 38 males and 47 females). The subjects underwent an orthodontic examination as well as posturometric three-dimensional assessment of the sagittal and frontal planes of the back, electromyography, dynamometry, plantography and plantometry. RESULTS: According to posturometric analysis, deviations were found in the frontal plane: 25.5 per cent scoliotic posture, 53.3 per cent scoliosis 1 gr. and 10.7 per cent scoliosis 2 gr. In the horizontal plane there were 2.9 per cent spinal rotations and 7.6 per cent postural rotations. These spinal changes had interrelations to different patterns of malocclusion. CONCLUSION: Orthodontic treatment can be significantly improved by involving osteopathic correction to the treatment plan.

141 RADIOGRAPHIC PREDICTION OF THE DURATION OF TREATMENT OF PALATALLY IMPACTED CANINES I Dubovska1, M Kotas1, P Krejci2, M Spidlen1, P Borbely3, Departments of 1Orthodontics and 2Pedostomatology. Clinic of Dental Medicine, Medical Faculty of Palacky University, Olomouc, Czech Republic and 3Hansa - Dont Fogszabalyozasi Studio, Budapest , Hungary

AIM: To find determine the diagnostic value of the position of palatally impacted canines on dental pantomograms (DPTs) and lateral cephalograms for predicting treatment duration. SUBJECTS AND METHOD: Fifty four patients who successfully underwent orthodontic treatment for palatally impacted canines. Forty one subjects had only one canine impacted, and 13 both canines, i.e. 67 palatally impacted canines were evaluated regarding treatment time, inclination of canine long axis, and the vertical distance between the canine crown tip and occlusal plane on the DPT and cephalogram. Pearson’s correlation was used for statistical analysis. RESULTS: A moderate positive correlation (r = 0.487) was found between the duration of treatment and the degree of canine inclination to a vertical reference line on the DPT. There was a low negative correlation (r = – 0.359) between the duration of treatment and the vertical position of an impacted canine on the cephalogram. Correlation of the duration of treatment and canine inclination to the vertical reference line on the DPT, as well as of the duration of treatment and canine inclination to an occlusal line on the cephalogram was negligible (r = 0.164 and r = 0.196) CONCLUSION: There are only poor associations between orthodontic treatment duration for a palatally impacted canine and the position of an impacted canines on a DPT and lateral cephalogram regarding their inclination or vertical distance to the occlusal plane. For predicting treatment duration other radiographic predictors can be recommended, e.g. horizontal anteroposterior position of the canines in the so-called zones according to McSherry.

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142 INFLUENCE OF PATIENT AGE ON THE CHANGES OF ENAMEL CRACK CHARACTERISTICS AFTER REMOVAL OF METAL BRACKETS I Dumbryte1, L Linkeviciene2, M Malinauskas3, T Linkevicius2, T Jonavicius3, 1Vilnius Research Group, 2Institute of Odontology, Faculty of Medicine, Vilnius University, 3Department of Quantum Electronics, Physics Faculty, Vilnius University, Lithuania

AIM: To determine the influence of age on enamel crack characteristics before and after removal of metal brackets. MATERIALS AND METHOD: This in vitro study was carried out on 90 premolars extracted from two groups of patients. The mean age of the younger group (n = 45) was 25 years (range 18 to 34 years); the mean age of the older group (n = 45) was 43 years (range 35 to 54 years). All the selected teeth satisfied the inclusion criteria (intact buccal enamel with no white spots, no pre-treatment with chemical agents, no previous orthodontic Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 treatment, no damage caused by the extraction procedure). Following scanning electron microscopy (SEM) examination, teeth from both age groups were divided into three subgroups of 15: subgroup 1, teeth with enamel cracks, subgroup 2, the teeth without initial cracks, and subgroup 3, a control group to study the effect of dehydration on existing cracks or formation of new ones. For all the teeth from subgroups 1 and 2, the same bonding and debonding procedures of metal brackets were conducted. The width, length, and location of the longest enamel crack were evaluated with SEM before and after removal of the brackets. In subgroup 3, the teeth were subjected to the same analysis only without bonding. Statistical analyses were carried out using the Statistical Package SPSS 17.0. RESULTS: After removal of metal brackets the increase in the mean overall width of the cracks was 0.9 µm (P < 0.05) in the younger group and 3.84 µm (P < 0.05) in the older group. For both groups the widest enamel cracks were located in the cervical third of the tooth following debonding, with the higher width values in the older group. There was no increase in the mean overall length for either age group. New enamel cracks were recorded in 5 of 15 (33.3%) samples from the younger group, and 6 of 15 (40%) samples from the older group. Higher width and length values of new cracks were observed in the older group. CONCLUSION: Removal of metal brackets leads to greater risk of enamel surface damage in older patients.

143 PRONOUNCED ENAMEL CRACKS – GREATER RISK OF ENAMEL SURFACE DAMAGE FOLLOWING DEBONDING OF METAL BRACKETS? I Dumbryte1, L Linkeviciene2, M Malinauskas3, T Linkevicius2, T Jonavicius3, 1Vilnius Research Group, 2Institute of Odontology, Faculty of Medicine, Vilnius University, 3Department of Quantum Electronics, Physics Faculty, Vilnius University, Vilnius, Lithuania

AIMS: To compare characteristics of pronounced and weak enamel cracks, and to determine whether teeth having pronounced cracks show greater risk of enamel surface damage after removal of metal brackets. MATERIALS AND METHOD: In this in vitro study, following examination with scanning electron microscopy (SEM), 60 extracted human premolars that satisfied the inclusion criteria (intact buccal enamel with no white spots, no pre-treatment with chemical agents, no previous orthodontic treatment, teeth extracted from patients aged between 18 and 34 years) were divided into two groups of 30: group 1, teeth having pronounced enamel cracks (visible with a naked eye under normal room illumination) and group 2, teeth showing weak cracks [not apparent under normal room illumination but could be visualized with use of scanning electron microscopy (SEM)]. Fifteen teeth from each group were bonded with metal brackets and the rest served as a control to study the effect of dehydration on existing cracks. Debonding was performed with the use of appropriate pliers by hand. The width, length, location, and direction of the longest pronounced or weak enamel crack were evaluated with SEM before and after bracket removal. The control group teeth were subjected to the same analysis only without bonding. Statistical analyses were carried out using the Statistical Package, SPSS 17.0.

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RESULTS: After removal of the metal brackets an increase was noted in the mean overall width of pronounced (0.85 µm, P < 0.05) and weak (1.03 µm, P > 0.05) enamel cracks. The greatest changes in width appeared in the middle third of the tooth in group 1 (0.96 µm, P < 0.05) and in the occlusal third of the tooth in group 2 (1.68 µm, P > 0.05). There was no increase in the mean overall length for either group. Horizontal cracks were recorded in group 1. The changes in other directions were characteristic for both groups. CONCLUSION: Teeth having pronounced cracks do not show a greater risk of enamel surface damage after removal of metal brackets. Thus, visibility of a crack before bonding cannot be regarded as a diagnostic characteristic for prediction of possible enamel surface damage following debonding.

144 PERCEPTION OF DISCOMFORT AND PAIN AS A RESULT OF ORTHODONTIC TREATMENT M Durka-Zajac1, M Mitus-Kenig2, K Wozniak1, E Pawlowska3, 1Department of Orthodontics, Pomeranian Medical University, Szczecin, 2Department of Stomatological Prevention and Hygiene, Jagiellonian University Collegium Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 Medicum, Krakow and 3Department of Orthodontics, Medical University, Lodz, Poland

AIMS: To follow the progress of adaptation after insertion of new appliances and to study the relationship between the type of appliance worn (separators, fixed appliance after the initial archwire, fixed appliance after archwire activation, fixed appliances with elastics, functional appliance, removable upper and/or lower appliance, Haas, facemask) and pain or discomfort experienced, between pain sensations and attitude toward treatment and their effects on patients’ compliance. SUBJECTS AND METHOD: Two hundred and seventy patients (148 girls, 122 boys) with a mean chronological age of 13.8 years for girls and 14.7 years for boys. Pain response was assessed for each category using the visual analogue scales (VAS), a questionnaire and an analgesic consumption record. The Kolmogorov-Smirnov test of normality was used for VAS scores. For assessment of the relationship between VAS scores and consumption of pain relief, Spearman rank correlation analysis was utilized. The level of significance was set at P < 0.05. RESULTS: A statistically significant association was found between age and pain experienced. No gender discrimination was found for perception of pain. The placement of orthodontic separators resulted in a painful experience for 78 per cent of patients. Although not statistically significant, the most highly affected daily living activity was observed after placement of the initial archwire (93%) and 65 per cent after archwire activation. Fixed appliances produced more pain than removable or functional appliances. Patients wearing fixed appliances reported higher values for intensities of pressure, tension, pain and sensitivity to teeth. Approximately 24 per cent of patients reported pain as the factor which prevented them from wearing elastics. Almost all patients undergoing orthodontic treatment had moderate difficulty in chewing and biting foods of firm to hard consistency, which caused them to change the consistency of their food. CONCLUSION: Pain symptoms are common and the prevalence of such experiences varies with different types of appliance during orthodontic treatment, insertion of the initial archwire being the most painful stage.

145 TREATMENT EFFECTS OF FUNCTIONAL APPLIANCES IN PATIENTS WITH CLASS II SKELETAL MALOCCLUSIONS M Durka-Zajac1, M Mitus-Kenig2, K Wozniak1, 1Department of Orthodontics, Pomeranian Medical University, Szczecin and 2Department of Stomatological Prevention and Hygiene, Jagiellonian University Collegium Medicum, Krakow, Poland

AIM: To determine the skeletal and dentoalveolar effects produced by the Twin Block and the AdvanSync functional appliance in the treatment of growing patients with Class II malocclusions. MATERIALS AND METHOD: A retrospective study was conducted using lateral cephalograms of patients consecutively treated with the Twin Block (n = 30) and AdvanSync (n = 30) during their skeletal growth spurt as evaluated by the improved cervical vertebral maturation method. Cephalograms were taken at two time points:

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pre-treatment and post-functional appliance treatment. Treatment changes were evaluated between the time points using 35 variables. Repeated measures analysis of variance (ANOVA) was used to assess if the samples were morphologically comparable at the outset and to determine if there were significant differences between the groups for the various increments of change. Given a significant ANOVA, the source of the difference was explored via Tukey-Kramer tests. RESULTS: At the post-functional appliance phase, both appliances showed significant increases in total mandibular length, ramus height, and anterior/posterior face height. The AdvanSync resulted in significant restriction of maxillary growth; more than Twin Block. The changes revealed significant mandibular growth enhancement with Twin Block and a significant headgear effect with the AdvanSync. The Twin Block group expressed better control of the vertical dimension. Overbite, overjet, and Wits appraisal decreased significantly with both appliances. The Twin Block group had significant flaring of the lower incisors at the end of treatment. Over the long-term, there were no significant soft tissue changes among treated and untreated subjects. The Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 treatment time for AdvanSync was six months less than the Twin Block. CONCLUSION: The Twin Block and AdvanSync resulted in normalization of the Class II malocclusion. The AdvanSync showed more headgear effect but less mandibular length enhancement than the Twin Block. Both appliances resulted in similar dentoalveolar changes.

146 CORRELATION BETWEEN CHRONOLOGICAL AGE, MANDIBULAR CANINE MINERALIZATION STAGES AND CERVICAL VERTEBRAL MATURATION V Dzemidzic, A Tiro, L Redzepagic Vrazalica, E Nakas, Department of Orthodontics, School of Dental Medicine, University of Sarajevo, Bosnia and Herzegovina

AIM: Optimal treatment time is a fundamental concept of orthodontic treatment of skeletal disharmonies. Successful correction of skeletal disharmonies can be achieved by growth modification in patients who have a certain amount of growth remaining. The most favourable time for treatment of skeletal disharmonies is before and/or during the pubertal growth spurt. There are wide individual variations in the timing of start, amount and duration of pubertal growth acceleration and thus assessment of individual development stages is required. Individual skeletal maturity can be assessed by means of several more or less reliable parameters. The aims of this study were to investigate the relationship between chronological age, mandibular canine mineralization stages and maturation of the cervical vertebrae and to determine which of these parameters is the best first level diagnostic tool for estimating the time of the pubertal growth spurt. SUBJECTS AND METHOD: Forty male and 40 female subjects aged from 9 to 15 years. Chronological age was obtained on the basis of their date of birth. Panoramic radiographs were studied to determine the mineralization stage of the permanent left mandibular canine according to the method of Demirjian. Cervical vertebral maturation (CVM) indices were determined on lateral cephalometric radiographs, according to the method described by Hassel and Farman. Pearson’s correlation coefficient was estimated separately for males and females to measure the relationships among chronological age, mandibular canine mineralization stages and CVM. RESULTS: A significant correlation was observed between chronological age and CVM (r = 0.911, P < 0.01 for females and r = 0.908, P < 0.01 for males), and between chronological age and mandibular canine mineralization stages (r = 0.753, P < 0.01 for females and r = 0.846, P < 0.01 for males). The correlation coefficient between mandibular canine mineralization stages and CVM was r = 0.728, P < 0.01 for females and r = 0.917, P < 0.01 for males. CONCLUSION: There is a significant correlation between chronological age, mandibular canine mineralization stages and CVM. Chronological age can be the first level diagnostic tool for estimating the timing of the pubertal growth spurt.

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147 HEAT TREATING NICKEL TITANIUM ARCHWIRES B Egloff, C Rapin, M P Filleul, Université de Lorraine, Nancy, France

AIM: Preformed copper Ni-Ti 35°C® orthodontic archwires are commercially available. Whilst they are popular with orthodontists due to their elastic properties, they also have limits since their shapes cannot be changed and a very small range of different preformed archwires are offered. The aim of this study was to determine whether heat treatment of the archwires could be the answer. MATERIALS AND METHOD: Thirty Copper Ni-Ti 35°C® preformed orthodontic archwires from the same manufacturer were tested. For each individual archwire one of the straight lateral segments of each archwire was bent to a 95 degree angle. This bend was maintained throughout heat treatment by three alumina posts. Torsion behaviour was evaluated with a test-bench (French Patent n° 089/06480) and the mean results were plotted to obtain a reference stress-strain curve of the degree of elasticity of the sample. Ten minute heat Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 treatment in an oven at 450°C was individually applied to each archwire. Each archwire was then allowed to cool, freed from the three retaining posts and submitted to two tests. The ‘permanent’ bend in the lateral segment was measured. The elasticity of the metal was evaluated on the test bench used before heat treatment and a new plot was made in the same way as the original one. The before and after plots were compared. RESULTS: The bend of the archwire, originally at 95 degrees, was partially retained; its mean ‘permanent’ angle was measured at 108 degrees with a 3 degree standard deviation. The elastic properties of the archwires were not significantly changed by the 10 minute heat treatment at 450°C. CONCLUSION: A 10 minute heat treatment at 450°C applied to a force-bent copper Ni-Ti® archwire allows its partial deformation without loss of mechanical properties. Further research is required to investigate the effects of longer heat treatment periods.

148 BONE MARROW MESENCHYMAL STEM CELLS ENHANCE BONE FORMATION IN ORTHODONTICALLY EXPANDED MAXILLAE IN RATS A Ekizer1, M E Yalvaç2, T Uysal3, M F Sönmez4, F Sahin5, 1Department of Orthodontics, Faculty of Dentistry, Erciyes University, Kayseri, Turkey, 2Center for Gene Therapy, Nationwide Children's Hospital, Ohio State University, USA, 3Department of Orthodontics, Faculty of Dentistry, Izmir Katip Celebi University, İzmir, Turkey, 4Department of Histology and Embryology, Faculty of Medicine, Erciyes University, Kayseri, Turkey and 5Department of Genetics and Bioengineering, Faculty of Engineering and Architecture, Yeditepe University, Istanbul, Turkey

AIM: In this study, bone marrow derived mesenchymal stem cells (MSCs) were transplanted into the interpremaxillary suture of the rats after rapid maxillary expansion aiming to increase new bone formation in the suture and prevent relapse. MATERIALS AND METHOD: Rat bone marrow MSCs were isolated from six femora of syngeneic male Wistar rats and cultured. The surface antigens of bone marrow MSCs were analyzed using flow-cytometry analysis. Eighteen male Wistar rats were divided into two equal groups. Both groups were subjected to expansion for 5 days, and 50 cN of force was applied to the maxillary incisors with a helical spring. Bone marrow derived MSCs (1.000.000) were applied to the interpremaxillary suture, after force application into the interpremaxillary suture of the experimental group. RESULTS: After 14 days, histomorphometric analysis revealed that a single local injection of MSCs into the midpalatal suture increased new bone formation in the suture, by increasing the number of osteoblasts, new vessel formation, compared with the phosphate buffered saline injected controls. CONCLUSION: This preclinical study might provide the rationale for the underlying potential clinical use of MSCs after maxillary expansion. Given the fact that MSCs are currently under use in clinical trials, this approach might

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be a feasible treatment strategy to accelerate new bone tissue formation in the midpalatal suture and to shorten the treatment period for patients undergoing maxillary expansion reinforcement.

149 IS A 0.018 OR 0.022 INCH BRACKET SLOT SYSTEM MORE EFFECTIVE IN THE ALIGNING STAGE? A MULTI- CENTRE RANDOMISED CLINICAL TRIAL A El-Angbawi, D Bearn, G McIntyre, Department of Orthodontics, Dundee Dental Hospital and School, Scotland, U.K.

AIM: To compare 0.018 inch and 0.022 inch conventional pre-adjusted orthodontic bracket slot systems in terms of the effectiveness of the levelling and alignment stage of orthodontic treatment. SUBJECTS AND METHOD: One hundred and five patients treated in three centres (secondary care hospitals in Scotland) were randomly allocated to treatment with either the 0.018 inch (n = 52) or 0.022 inch bracket slot (n Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 = 53) Victory conventional pre-adjusted bracket systems (3M Unitek). The levelling and alignment stage of treatment was assessed from the start of treatment until the ligation of the working archwire for each bracket slot system (0.016 × 0.022 stainless steel (0.018 inch group) and 0.019 × 0.025 stainless steel (0.022 inch group). Periapical radiographs were taken of the maxillary incisors before and after 9 months of treatment to assess orthodontically-induced inflammatory root resorption (OIIRR). The ‘Smiles better’ questionnaire for patient perception was completed by the participants at 6 months from the start of treatment. The data collected during the levelling and aligning stage of treatment included the duration of treatment and number of appointments, OIIRR and patient perception of wearing appliances. Comparison between the two study groups was conducted using the one-way ANOVA or chi-square test, depending on the nature of the data at 80 per cent power and a significance level of P < 0.05. RESULTS: The data from 92 patients was analysed. No statistically significant difference in the duration or number of scheduled appointments was found between the two bracket slot systems. No statistically significant difference in the severity of root resorption and patient perception of wearing orthodontic appliances between the two study groups was found except for soreness of the teeth where more patients in the 0.022 inch group experienced significant pain. CONCLUSION: There is no difference in the effectiveness of the levelling and alignment stage of orthodontic treatment between the 0.018 or 0.022 inch conventional bracket slot systems except for the soreness of teeth.

150 EFFECT OF FLUORIDE ON ROOT RESORPTION WITH ORTHODONTIC FORCE OF 150 GRAMS FOR 12 WEEKS: A MICROCOMPUTED TOMOGRAPHIC STUDY S Elekdag-Turk1, D Isci2, A Doğan3, T Turk1, M A Darendeliler4, 1Department of Orthodontics, Faculty of Dentistry, University of Ondokuz Mayis, Samsun, 2Oldcitydent Dental Hospital, Eskisehir, 3Department of Orthodontics, Faculty of Dentistry, University of Suleyman Demirel, Isparta, Turkey and 4Discipline of Orthodontics, Faculty of Dentistry, University of Sydney, Australia

AIM: To investigate the effect of high and low amounts of fluoride intake from birth on orthodontically induced inflammatory root resorption under force application of 150 g for 12 weeks. SUBJECTS AND METHOD: Twenty-eight patients who required maxillary premolar extractions as part of their orthodontic treatment were selected from two cities in Turkey with a low fluoride concentration of ≤0.05 ppm (low fluoride intake group-LF) and a naturally occurring high fluoride concentration of ≥2 (high fluoride intake group-HF) in the public water system. The patients in group HF had various degrees of fluorosis. Buccal tipping orthodontic forces were applied to the maxillary first premolars for 12 weeks (84 days). In both groups a buccally directed force of 150 g was produced by a 0.017 × 0.025 inch beta-titanium- cantilever spring (Beta III Titanium; 3M Unitek, Monrovia, California, USA). At day 84, the teeth were extracted, and the samples were analyzed with microcomputed tomography.

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RESULTS: In group HF, a reduced amount of root resorption was measured for all areas, except the distal surface. However, this reduced amount of root resorption was only significantly different for the palatal surface (P = 0.009) and the middle third (P = 0.026). CONCLUSION: Fluoride may reduce the volume of orthodontically induced inflammatory root resorption craters. Nevertheless, further research is required to determine a safe zone of fluoride for the reduction of root resorption as well as the prevention of side-effects, such as fluorosis.

151 RETRIEVAL ANALYSIS OF IN VIVO AGED LINGUAL FIXED RETAINERS: MATERIAL PROPERTIES AND HYPOTHESES ON INTRAORAL PERFORMANCE T Eliades1, N Pandis2. G Eliades3, S Zinelis3, 1University of Zurich, Switzerland, 2Private practice, Corfu and 3University of Athens, Greece Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 AIM: To study the mechanical, physical and chemical properties of orthodontic adhesives and wires used in lingual fixed retainers following long-term intraoral use MATERIALS AND METHOD: Twenty five lingual fixed retainers made of 0.0195 inch multistrand wire and bonded with Realiabond™ adhesive were removed from the mandibular arches of patients following a mean of 6.6 years (range 2.2-17.4 years). Control specimens of identical as-received materials were fabricated by utilizing the same procedures as those performed clinically. The indentation modulus and hardness of wires and adhesives was investigated with instrumental indentation testing; infrared spectroscopy was employed to study their degree of conversion; and scanning electron microscopy/energy-dispersive spectroscopy to characterize their structure and surface precipitations. Data were analyzed a with two-sample t-test (a=0.05). RESULTS: No significant difference was found in the mechanical properties of wires between the control and retrieved groups rejecting the hypothesis that intraoral conditions and loading may result in alteration of their modulus and that this factor may be implicated in unwanted tooth movement; no difference in hardness was shown for the hardness of adhesive specimens. The degree of cure of retrieved adhesives higher (P < 0.05) than their control counterparts was probably due to release of monomers during intraoral service. Retrieved sample surfaces showed precipitations of proteinaceous matter, which were calcified with the adsorption of Ca, Mg, K, and P. CONCLUSION: Changes in some mechanical and physical properties of retainers indicate phenomena occurring during their service life and may provide justification for the formulation of hypotheses.

152 ORTHODONTIC TREATMENT WITH EXTRACTION OF SECOND MOLARS AND ITS INFLUENCE ON DENTOFACIAL STRUCTURES AND THIRD MOLAR ERUPTION*** S Enersen1, L J Gjestrum1, B-E Hjulstad2, K Birkeland1, V Vandevska-Radunovic1, 1Department of Orthodontics, University of Oslo and 2Private Practice, Trondheim, Norway

AIM: To investigate the effect of mandibular second molar extraction on skeletal and dental structures, and to assess the position of the mandibular third molar post-extraction SUBJECTS AND METHOD: Fifty patients treated in a private practice by one authors between 1985 and 2011. All patients had extractions of the mandibular second molar and conventional orthodontic treatment that finished before the eruption of the third molars. Skeletal and dental variables were analyzed on cephalometric radiographs before (T1) and after (T2) treatment. Third molar inclination was evaluated on panoramic radiographs at T1, T2 and on average 3 years after the end of treatment (T3). A paired sample t-test was used to test the differences between the treatment stages. RESULTS: Cephalometric analysis showed a significant reduction in the ANB angle as a result of increased mandibular (SNB) and decreased maxillary prognathism (SNA). The intermaxillary angle (ML/NL) was significantly reduced at T2, but the changes in the mandibular angle (ML/NL), although decreased, were not

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significant. The interincisor angle increased from 131.0 at T1 to 134.0 after treatment; these changes were significant. This was mainly due to the uprighting of the mandibular incisors and their position relative to the mandibular plane. At T1, the mean inclination of the mandibular third molar to the first molar was 31.3 degrees on the left side and 26.9 degrees on the right side. The third molars on both sides showed increased mesial tipping after extraction (T2), but uprighted at T3, demonstrating a significant decrease in inclination. CONCLUSION: The extraction of mandibular second molars led to uprighting of the mandibular incisors and an increase in the interincisor angle. The results further indicate that third molars tip and drift mesially after extraction of the second molars, but upright at eruption.

153 THE EFFECT OF ENAMEL CONDITIONING BY SANDBLASTING AND USE OF ENAMEL SEALANT ON THE BOND STRENGTH OF ORTHODONTIC BRACKETS M Epple1, D Ohlendorf2, S Kopp2, 1Private Practice, Munich and 2Orthodontic Department, JWG University Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 Frankfurt, Germany

AIM: One aim of this in vitro study was to evaluate the effect of enamel conditioning by sandblasting on the bond strength of orthodontic brackets. Furthermore the question should be answered, whether the replacement of the original primer by the enamel sealant Pro Seal™ reduces the bond strength of orthodontic brackets MATERIALS AND METHOD: One hundred extracted human premolars were divided into four groups. Sandblasting was performed using the Microetcher® with 50 µm aluminium oxide. Metal brackets were bonded to all teeth using the Transbond™ XT Light Cure Orthodontic Adhesive System. In one half of the specimens the complete adhesive system was applied. In the second half Pro Seal™ was used. The shear debonding test was performed using a Digital-Push-Pull-Gauge. To evaluate the effect of enamel sandblasting, the debonding forces of the different groups were pooled and compared by the Wilcoxon-Mann-Whitney-U-test. To answer the question, whether the replacement of Transbond™ XT by Pro Seal™ reduces the bond strength of brackets, the debonding forces of the correlating groups were pooled and compared by the Wilcoxon-Mann-Whitney-U-test. RESULTS: Specimens that were conditioned solely by phosphoric acid etching did not a statistically significant higher median bond strength than specimens that were additionally sandblasted (123 N versus 107 N; P = 0.04). Priming using Transbond™ XT resulted in a statistically significant higher median bond strength than using Pro Seal™ (142 N versus 102 N, P < 0.001). CONCLUSION: Enamel sandblasting prior to acid etching does not result in an increase of bond strength. Instead a statistically significant reduction of the bond strength was observed. Although in all groups clinically acceptable bond strength values of 5-10 MPa were reached, enamel conditioning by sandblasting combined with acid etching cannot be recommended for clinical use. Using Pro Seal™ the bond strength of brackets was not reduced by a clinically relevant amount. The original primer solutions can be replaced by Pro Seal™.

154 DEMINERALIZATION AND USE OF SEALER AROUND BRACKETS IN DAILY PRACTICE – A SURVEY C Erbe1, A Alhafne1, A Jahn2, H Wehrbein1, 1Department of Orthodontics and 2Institute of Medical Biostatistics, Epidemiology and Informatics, University of Mainz, Germany

AIM: The development of incipient caries lesions around brackets is a common negative side-effect of orthodontic treatment with fixed appliances, particularly in patients with poor oral hygiene. The objective of this survey study was to develop a questionnaire for evaluating data about frequency, use and control of sealer around brackets and observation of demineralization after treatment with fixed orthodontic appliances in daily practice.

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SUBJECTS AND METHOD: One thousand members of the German Society of Orthodontics (DGKFO) who were randomized, selected by a statistician received the questionnaire via post. The number of selected orthodontists was adjusted to the province size. RESULTS: The response rate was 52.4 per cent. More than half of the chosen orthodontists (n = 282) worked alone in their own office and 242 worked together with others in one office. Most of them (59.1%) had worked as orthodontists >5-25 years, <5 years were 7.1 per cent and >25 years were 33.8 per cent, respectively. Of the participants 89.1 per cent were between 36 and 65 years of age, 7.6 per cent under 36 years and 3.2 per cent above 66 years. After treatment with fixed orthodontic appliances, visible demineralizations were rarely observed by 61.8 per cent of the orthodontists, sometimes by 36.5 per cent and frequently by 1.7 per cent. Almost all participants, 93.7 per cent, used sealer next to brackets in their office. The most frequently used sealer was Pro Seal (38.2%), followed by Fluor Protector (27.5%), Cervitec Plus (25.8%) and Protecto CaF2 Nano (18.9%). The use of other sealers (Maximum Cure, Alpha Glaze, Ortho Solo, Light Bond, Clinpro XT Varnish, Opal Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 Seal and Tiefenfluorid) for preventing white spot lesion during orthodontic treatment ranged between 15.1 and 2.5 per cent. Most orthodontists applied the sealer once per the whole treatment period. Two hundred and eighty orthodontists inspected the sealer layer for defects, 219 reported no need for control and 25 gave no response. Visual inspection of the sealant layer was stated by 56.7 per cent of the orthodontists, 44.3 per cent used a change of the environment and 33.2 per cent used a probe as tactile control. CONCLUSION: Different sealers around brackets were often used as preventive measure in private orthodontic offices in Germany. Most of the orthodontists applied the sealer once per treatment with fixed orthodontic appliances. More than half of the orthodontists (53.4%) inspected the layer for defects. Visual control was preferred.

155 A QUESTIONNAIRE TO ASSESS THE KNOWLEDGE AND WILLINGNESS OF GENERAL DENTAL PRACTITIONERS WITH REGARD TO ORTHODONTIC RETENTION Z Esmail, C Slipper, Department of Orthodontics, Royal Alexandra Children’s Hospital, Brighton, U.K.

AIM: Retention is the phase of orthodontic treatment that attempts to maintain teeth in their corrected positions after active tooth movement. The length of the retention period is still a contentious issue as the evidence is lacking, therefore many clinicians elect for indefinite retention. Patients treated on the National Health Service (NHS) in the United Kingdom are routinely followed up for one year post-debond. Monitoring retention indefinitely is unfeasible in secondary care, therefore the responsibility must lie with the patient and their general dental practitioners (GDPs). This aim of this audit was to assess if local GDPs are able to manage retention and whether further training is recommended. MATERIALS AND METHOD: Dental practices were identified by a 15 mile radial search using the ‘NHS.uk find a dentist’ service, of which, at the time of accessing 74 dental practice were deemed suitable. Each practice was sent a questionnaire, a covering letter and an addressed envelope. Non-responders were sent a reminder letter after 4 weeks. RESULTS: The response rate was 66 per cent. Thirty five per cent of GDPs were not familiar with any type of retainer, and over 50 per cent were uncomfortable with assessing and adjusting a retainer. The possible reason for these low numbers is the assumption of monitoring retention falls with the specialist practice, with only 35 per cent of GDPs feeling the obligation lies with them. This is probably a reflection of the dental school curriculum set out by the General Dental Council. Almost 75 per cent of respondents did not provide replacement retainers, with the most prevalent reason being insufficient training, followed by remuneration. There were also inconsistencies on charging for replacement retainers as some were provided on the NHS and others privately. Seventy five per cent of respondents reported that they would attend a training session in the monitoring of retention.

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CONCLUSION: Secondary care does not have the resources to monitor patients indefinitely; therefore it is essential that patients are discharged to their GDP for further follow-up and maintenance. The knowledge of local GDPs regarding retainers was lower than expected. The perception is that retention supervision lies with the specialist.

156 DENTOSKELETAL FEATURES IN MIXED DENTITION CHILDREN WITH DISPLACED MAXILLARY CANINES G Fabiani, M Vitale, M Iovane, R Cataneo, L Perillo, Department of Orthodontics, Second University of Naples, Italy

AIMS: To analyze the prevalence of displaced, buccal and palatal, maxillary canines (DMC), to investigate the association with sagittal and vertical skeletal relationships and some upper lateral incisor anomalies. SUBJECTS AND METHOD: Consecutive subjects were examined from January 2012 to January 2013. Inclusion Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 criteria were: age between 7 and 12 years, mixed dentition, 1 or 2 cervical vertebral maturation stage, high quality initial dental casts, intraoral photographs, panoramic and latero-lateral radiographs. Subjects with at least one canine in Lindauer II, III or IV sector and/or an α angle >31 degrees were included in the DMC group, whereas those with both canines in sector I and an α angle ≤31 degrees were used as the control group (CTR). According to clinical and radiographic examinations, DMC were then divided into palatally displaced canines (PDC) and buccally displaced canines (BDC). Sagittal and vertical skeletal relationships were evaluated using ANB and SN/GoMe angles, respectively. Diagnosis of aplasia or small-sized maxillary lateral incisors was performed by clinical examination, dental casts and panoramic radiographs. Chi-square tests were used to compare the prevalence rates of skeletal features. P values less than 0.05 were considered significant. RESULTS: The sample had 123 children, 40 (32.52%) DMC and 83 (67.48%) CTR. The DMC group included 11 (27.5%) PDC and 29 (72.5%) BDC subjects. The M:F ratio was 1:3 in PDC and BDC, and 1:1 in the CTR group. The unilateral-to-bilateral ratio was approximately 1:1 and 3:1 in PDC and BDC subjects, respectively. The most common sector combination for unilateral and bilateral displacements was ‘II,I’ and ‘II, II’, respectively. PDC occurred more frequently in Class I and hyperdivergent subjects, and BDC in Class I or II and normodivergent subjects. Only one DMC child had congenital absence of the lateral incisor. No subject showed small-sized lateral incisors. CONCLUSION: DMC occurred more frequently in girls than boys with a M:F ratio of 1:3. Unilateral were more common than bilateral displacements by a factor of 2:1. No statistically significant correlation with skeletal features was observed. No association with lateral incisor anomalies was found. Working in cooperation with other research centres may be useful to extend and support these findings.

157 IMPACT OF EXTRACORPOREAL SHOCKWAVE THERAPY ON ORTHODONTIC TOOTH MOVEMENT – A RANDOMIZED CLINICAL TRIAL F Falkensammer1, C Arnhart2, W Schaden3, J Freudenthaler1, H-P Bantleon1, Departments of 1Orthodontics and 2Oral Surgery, Bernhard-Gottlieb University Clinic of Dentistry, Vienna and 3Department of Surgery, AUVA Trauma Center, Vienna, Austria

AIM: This randomized clinical trial investigated the effect of extracorporeal shock wave therapy (ESWT) on the amount of orthodontic tooth movement and periodontal parameters. SUBJECTS AND METHOD: Twenty-six adult orthodontic patients participated in this clinical trial, all of them receiving lower second molar mesially directed movement. The fixed orthodontic device included superelastic coil springs (200 cN) and miniscrews as temporary anchorage devices. The active treatment group received single shockwave treatment with 1000 impulses in the region of tooth movement. The placebo group was treated with a deactivated shockwave applicator but acoustic sham. The study period was 4 months with monthly data exploration.

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RESULTS: No statistically significant difference in posterior-anterior tooth movement between the treatment and placebo group was seen during the observation period. Gender had no significant influence on tooth movement in either group. No significant difference occurred in mesiodistal tipping and rotation, but a significant difference (P =0.035) in buccolingual tipping of the molars was found. Periodontal status of the patients (sulcus probing depth, gingival index) did not significantly differ in either group. The plaque index showed a significant difference (P = 0.003). CONCLUSION: Single application of ESWT was neither associated with a statistically significant acceleration of tooth movement nor with an altered periodontal status in vivo. Shockwaves showed no harmful effects in the investigated area.

158 THE IMPACT OF EDUCATION ON THE PERCEPTION OF FACIAL PROFILE AESTHETICS AND TREATMENT NEED Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 F Falkensammer1, A Loesch2, C Krall3, F Weiland4, J Freudenthaler1, Departments of 1Orthodontics and 3Medical Statistics, 2Bernhard Gottlieb University Clinic of Dentistry, Vienna and 4Private Practice, Deutschlandsberg, Austria

AIM: To evaluate the influence of education on the perception of various male and female Caucasian profiles regarding attractiveness and treatment need. MATERIALS AND METHOD: Four hundred questionnaires were distributed among six groups of raters (non- academic laymen, academic laymen, preclinical students, clinical students, orthodontists, maxillofacial surgeons). Male and female profile images were altered digitally in the sagittal and vertical dimension resulting in nine different male and female profiles. The raters had to assess the images according to attractiveness and treatment need. RESULTS: Three hundred and four questionnaires were completed. Gender had no significant influence on the perception of profile attractiveness. The different groups of raters considered the Class I normodivergent profiles as most attractive. Significant differences in the perception of attractiveness were seen between laymen, orthodontists and maxillofacial surgeons. The orthodontists and maxillofacial surgeons more often reported a treatment need. The orthodontists discerned profiles more sensitively. CONCLUSION: Attractive male and female profiles are recognizable by any rater. Education seemed to have a significant influence on facial profile perception and recommendation for treatment need of unattractive profiles. Professionals should be aware of their judgment discrepancy compared with laymen.

159 FRACTURE TORQUE OF FOUR DIFFERENT COMMERCIALLY AVAILABLE BRAZILIAN BRANDS OF ORTHODONTIC MINI-IMPLANTS K Faltin Jr.1, R S Ambrosio1, R Bigliazzi2, C L F Ortolani2, J V Bozelli1, Departments of Orthodontics, Schools of Dentistry, 1University Paulista, Sao Paulo and 2University of São Paulo, Brazil

AIM: To assess the fracture torque of four different commercially available Brazilian brands of orthodontic mini- implants. MATERIALS AND METHOD: Fifty two mini-implants, divided into four groups of 13 specimens each, were assessed by manufacturer, namely: Morelli, with a diameter of 1.5 mm, transmucosal section of 2 mm and length of 10 mm; SIN, with a diameter of 1.6 mm, transmucosal section of 2 mm and length of 10 mm; Conexão, with a diameter of 1.5 mm, transmucosal section of 2 mm and length of 9 mm; and DSP, with a diameter of 1.6 mm, transmucosal section of 2 mm and length of 10 mm. The mini-implants were inserted into a device, orientated according to a pre-adjusted, standard fixture method and submitted to increasing torque until fracture. Tests were performed in a universal testing machine in accordance with standard F543/13 of the American Society for Testing and Materials. Bartlett’s test was employed to determine whether groups were

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matched for variability, whereas a single fixed factor analysis of variance (ANOVA) was used to compare means. Finally, differences among groups were assessed using Tukey’s test for multiple comparisons RESULTS: The mini-implants by Morelli exhibited the highest mean fracture torque of 42.4 N.cm, followed by SIN at 38.2 N.cm, DSP at 30.2 N.cm, and Conexãoat 26.3 N.cm. CONCLUSION: Although a significant difference was found among the four groups of specimens, all mini- implants proved fit for use in anchorage systems.

160 EVALUATION OF STABILITY AND POST-TREATMENT BEHAVIOUR OF MANDIBULAR CLASS II SUBJECTS TREATED WITH THE BALTERS BIONATOR K Faltin Jr., N A Ângelo Abatayguara, R Bigliazzi, C L F Ortolani, R S Ambrosio, Department of Orthodontics, School of Dentistry, University of São Paulo, Brazil Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 AIM: To evaluate the behaviour and stability of post-treatment changes obtained with bionator therapy in mandibular Class II patients. SUBJECTS AND METHOD: Thirty three subjects, 13 males and 20 females, with a mean age of 10 years 2 months at the start of treatment with the Balters Bionator (T0), 13 years and 1 month after orthopaedic treatment (T1) and 20 years post-treatment (T2). The treatment effects of the Bionator were evaluated during the interval T1- T2, 2 ± 1 year, which included a phase associated with orthodontic treatment for refining the occlusion. The interval T2-T3, of 6 years 9 months, provided information about changes after treatment. The data was analysed by a t-test for paired samples. RESULTS: Post-treatment there was a decrease in the total face height of 1.48 degrees and face depth of 0.84 degrees. There was noted long-term growth of the maxilla and mandible, 8.54 and 10.02 mm, respectively. ANB angle decreased 1.48 degrees, narrowing the relationship between the maxillomandibular relationship. The angles BaNa-point A and SNA remained stable post-treatment. There was a decrease in the mandibular plane angle with the Frankfort plane at 2.9 degrees. The dental relationships remained stable, with a decrease in interincisal angle of 2.99 degrees. The nasolabial angle also remained stable. CONCLUSION: There was long-term stability of the results as well as improvement of the analyzed values, which favours a balanced dento-facial-skeletal and functional system with no sign of relapse.

161 REGISTRATION OF MANDIBULAR MOVEMENTS USING AN INERTIAL MOVEMENT UNIT SENSOR: THE NEW DIMENSION BEYOND THREE-DIMENSIONS R Fastuca, A Caprioglio, P A Zecca, A Macchi, University of Insubria, Varese, Italy

AIM: Conventional methods employed for the registration of three-dimensional (3D) displacements in the mandible are useful for diagnosis and monitoring active treatment in orthodontics. Nevertheless they have several limitations due to interferences by metals and the fact that rotational movements are not directly registered but derived from only one source point provided by the system. The aim of the present study was therefore to use an inertial movement unit (IMU) sensor to overcome these issues and provide a live registration of jaw movements that can be interfaced with 3D analysis software. MATERIALS AND METHOD: The preliminary reproducibility of the IMU sensor was tested using a rigid trajectory set. Forty two patients were tested during chewing food of different hardness. Exclusion criteria were musculoskeletal disorders or pathologies, presence of dentures. Two IMU sensors were attached to the mandible and head in order to obtain a cranial reference system. The registrations were performed twice by the same trained operator with a one-month interval time. Dahlberg coefficient was used to verify the method error. The Shapiro Wilk test was employed to verify the normal distribution of the data then the paired t-test to compare results between the two time points. The level of significance was set at P < 0.05.

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RESULTS: IMU sensors provided a reliable and reproducible registration of the mandible during chewing in the tested sample (P < 0.05). CONCLUSION: IMU sensors are a reliable and easy to use tool in registering 3D mandibular movements during chewing. Moreover the employed sensors and software allowed the data to be exported and the registered movements applied to computer aided designed models of the archwires in order to have virtual reproduction of the static and dynamic occlusion of the patient.

162 IMPACTED TEETH FROM THE ORTHODONTIC STANDPOINT A Fekonja, Department of Orthodontics, Health Centre Maribor, Slovenia

AIM: To observe the frequency and distribution of impacted teeth in orthodontic patients. MATERIALS AND METHOD: The retrospective study was conducted using panoramic radiographs of patients Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 who had undergone orthodontic therapy from October 2002 to October 2013, both male and female, with mean age of 14 years 2 months. The type of impaction (excluding third molars), the number of impacted teeth in a single patient, the position of the impacted tooth in relation to the adjacent structures, and the treatment carried out, were recorded. RESULTS: Out of 1909 orthodontically treated patients 63 (3.3%) were found to have at least one impacted tooth. The male to female ratio was 1:1.52. The most frequently impacted tooth was the maxillary canines (79.0%), followed by the lower second premolars (9.87%). Single tooth impaction (74.6%) was the most common, followed by two (22.2%) or more (3.2%) impacted teeth in the same patient. Of the impacted teeth, 93.8 per cent were orthodontically treated, while 6.2 per cent were extracted due to their poor position. CONCLUSION: With early detection of impacted teeth, alternative treatment modalities can be planned and performed with a multidisciplinary team approach in order to establish an aesthetic and functional dentition and minimize the complications of impacted teeth.

163 PATIENTS’ SATISFACTION AFTER ORTHODONTIC-ORTHOGNATHIC CORRECTION OF SKELETAL CLASS III MALOCCLUSIONS A Fekonja, Department of Orthodontic, Health Centre Maribor, Slovenia

AIM: To evaluate the relationship between pre-operative psychological status and attitude and post-surgical adjustment and experience of the orthodontic-surgical treatment. SUBJECTS AND METHOD: The sample in this retrospective study consisted of patients with skeletal Class III malocclusions who were treated with combined orthodontic-orthognathic surgery treatment by same orthodontist and surgeon between October 2003 and October 2013. Data on emotional status, psychological changes and surgical experience were collected via a structured questionnaire. RESULTS: The majority (94.4%) of the skeletal Class III patients were satisfied with the overall outcome of the continued orthodontic-surgical treatment. Almost all patients (88.9%) noticed marked changes in their facial appearance after surgery. Chewing ability improved after orthodontic-surgical treatment in all patients. CONCLUSION: The face is the most important individual factor determining the physical appearance of individuals. The smile is rightfully deemed a valuable means of non-verbal social communication and a criterion of facial attractiveness. Orthodontic-surgical treatment is a well-accepted protocol for patients with skeletal discrepancies and sometimes is the only option for achieving an acceptable occlusal, functional and good aesthetic result in patients with a Class III dentofacial deformity.

164 SEXUAL DIMORPHISM IN MESIODISTAL AND BUCCOLINGUAL TOOTH DIMENSIONS IN SERBIAN PEOPLE G Filipovic1, S Filipovic2, J Radojicic1, M Janosevic1, P Janosevic1, 1Faculty of Medicine, University of Nis and 2Institute of Occupational Health, 'Serbian Railways', Nis, Serbia e87

AIM: The presence of sexual dimorphism in the size of the teeth is important in forensic identification of unknown individuals. The use of population-specific data is necessary since sexual dimorphism varies between different populations. Since there are no odontometric standards for determining gender in the Serbian population, the purpose of this study was to analyze the presence of sexual dimorphism in the mesiodistal and buccolingual diameters of permanent teeth in a sample of Serbians. SUBJECTS AND METHOD: Measurements were taken of 200 individuals of both genders, aged between 18 and 25 years, on plaster casts using a digital calliper with precision of 0.01 mm. Percentages of sexual dimorphism were calculated for the mesiodistal and buccolingual dimensions using the formula of Garn et al. Student’s t- and Mann-Whitney U-tests and descriptive statistics were used to analyse the sample. RESULTS: When comparing the pooled dimensions of the teeth from the left side of the dentition with those of the right side, no significant differences were found. Most of the teeth examined were larger in males than in Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 females but most of the differences were not statistically significant. For the mesiodistal dimension, the only significant differences were found for the maxillary and mandibular canines. Measurements of the buccolingual dimensions were significantly higher in males with P values of < 0.05 for mandibular I1, < 0.01 for maxillary I1, mandibular I2 and P2, < 0.001 for maxillary I2, C and M1 and mandibular C, P1 and M1. CONCLUSION: There are significant differences between genders for dimorphism of teeth. Males have larger teeth than females. Maxillary and mandibular canines were the most dismorphic teeth, followed by the maxillary lateral incisor and mandibular first molar. Buccolingual dimensions showed a greater significant difference between genders.

165 PATIENTS’ UNDERSTANDING OF ORTHODONTIC RETENTION: A REGIONAL AUDIT J Flanagan1, S Kotecha1, J Panesar2, Departments of Orthodontics, 1Birmingham Dental Hospital and 2Good Hope Hospital, Birmingham, U.K.

AIM: To assess the understanding of the need for retainers of patients currently undergoing fixed orthodontic treatment and to evaluate patients’ knowledge of the retention phase of treatment. SUBJECTS AND METHOD: Two hundred and fifty patients undergoing fixed appliance treatment at five units in the West Midlands during March 2013 were invited to complete a piloted questionnaire. RESULTS: A 100 per cent response rate was achieved. The majority of patients (82%) were aware of the need to wear retainers following orthodontic treatment. Sixty seven per cent of patients understood why retainers were required but less than half of patients (45%) understood how long they would need to wear the retainers. Two- thirds of patients were given written information on retainers. Thirty per cent of patients thought they would be entitled to retreatment in the event of relapse, although 46 per cent were aware that the National would not cover this. Eighty five per cent of patients reported that wearing retainers was well explained to them. CONCLUSION: Although the majority of patients are aware of the need to wear retainers following active orthodontic treatment, not all patients understand the purpose of retention. The need for retainers should be explained as part of the consent process.

166 THE ROLE OF NK CELLS IN ORTHODONTIC TOOTH MOVEMENT O Fleissig1, A Glassner2, J Enk1, O Mandelboim1, S Chaushu1, 1Orthodontic Department, Faculty of Dental Medicine and 2Lautenberg Center for General and Tumour Immunology, Hebrew University, Jerusalem, Israel

AIM: Orthodontic tooth movement (OTM) is an inflammation (sterile) based process in which immune cells are involved. Surprisingly, very little is known about the type and function of immune cells in this process. NK-cells are major secretors of TNFα and IFNγ cytokines which have been shown to promote differentiation of monocytes into osteoclasts and activation of osteoclasts which enable OTM through bone resorption. The main

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activating regulatory receptor of NK-cells in mice is Ncr1. The aim of this research was to investigate the direct in vivo role of NK-cells, their Ncr1-receptor and their secreted cytokines in OTM. MATERIALS AND METHOD: Nickel titanium closed-coil springs were set between the upper left first molar (M1) and upper-incisors (mesial force) of C57BL/6 mice in wild-type (WT) control group and four experimental groups (n = 10) for 12 days: Ncr1-knockout mice in which the gene encoding for Ncr1-receptor was replaced by GFP (Ncr1gfp/gfp), Ncr1-heterozygote mice (Ncr1gfp/+), TNFα and IFNγ knockout-mice (TNFα-/- and IFNγ-/-). Due to the GFP presence in Ncr1 knockout-mice NK-cells, the in vivo accumulation of NK-cells in the periodontal- ligament (PDL) could be evaluated. A split-mouth technique was used, in which the distance between M1 and M2 was measured using a microcomputed tomographic scanner. The maxillae of the mice were decalcified and frozen sectioned. NK-cells number and location were evaluated using immunofluorecense staining. Osteoclasts number and location were evaluated using tartrate resistant acid phosphotase staining. RESULTS: The number of GFP labelled NK-cells significantly increased in the PDL of orthodontically-moved teeth Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 in comparison to the contralateral side (P < 0.05). OTM was significantly reduced in TNFα-/- and IFNγ-/-(by 2.65 and 2.25 fold on average, respectively, P < 0.05) compared with WT mice, but was not affected by the partial or complete absence of Ncr1-receptor (Ncr1gfp/+ and Ncr1gfp/gfp groups). Osteoclasts number correlated with the M1-M2 distance. CONCLUSION: NK-cells accumulate in the PDL in response to orthodontic forces. TNFα and IFNγ influence the rate of OTM, however, this effect is probably not mediated by the Ncr1-receptor. The specific mechanisms underlying the influence of NK-cells on OTM are being elucidated in ongoing studies. Understanding the immune mechanisms involved in OTM will help find novel therapeutic means for its clinical control.

167 ORTHODONTIC MOVEMENT THROUGH NON-AUTOLOGOUS BONE GRAFTS. A SYSTEMATIC REVIEW E Fleitas, F de la Iglesia, A Puigdollers, Universitat Internacional de Catalunya, Barcelona, Spain

AIM: To conduct a systematic review on orthodontic movements through non-autologous bone grafts and show the results for the teeth involved and the periodontal environment. MATERIALS AND METHOD: A search conducted in Medline-PubMed, Cochrane Central Register and Google Scholar. The key words were ‘orthodontic movement and allograft’, ‘xenograft’, ‘non-autogenous bone graft’. RESULTS: Sixty two journal articles followed the inclusion criteria. Early orthodontic traction is recommended between 6 and 12 weeks post bone graft surgery. Viability and vitality was observed for all displaced teeth and there was a better periodontal condition in the regenerated area. Improvement in aesthetic, avoiding clefts in orthodontic space closure after extraction, also improvement of the newly formed bone as well as the contour of the alveolar ridge was found in every studied case. CONCLUSION: Either orthodontic movement or eruption of teeth through non-autologous bone grafts have are possible and show promising results, but, contrary to previous orthodontic opinion, traction must begin in an early stage.

168 ANALYSIS OF THE EFFECTS OF ACTIVATOR TREATMENT IN GROWING PATIENTS WITH CLASS II MALOCCLUSIONS K Gaidarova, Department of Orthodontics, Faculty of Dental Medicine, Medical University, Sofia, Bulgaria

AIM: To prove the efficiency of activator treatment through an analysis of dental and skeletal changes in lateral cephalometric radiographs taken before and after treatment. SUBJECTS AND METHOD: Twenty patients in the mixed dentition aged 8 to 10 years treated with an activator with expansion screw, Adams’ clasps for the upper first permanent molars and vestibular wire for the upper anterior teeth. The vestibular surface of lower anterior teeth was covered with an acrylic cap in order to avoid tipping of the lower anterior teeth. The construction bite positioned the mandible forward to overcorrection at

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the canines; the distance between the lateral teeth was 4 mm above the physiological rest position. During treatment, contact was maintained between the acrylic and upper lateral teeth, while the lower posterior teeth were encouraged to erupt by trimming the acrylic on the vestibular and lingual aspect. The dental and skeletal changes were compared on lateral cephalometric radiographs taken before and after the treatment. RESULTS: Correction of the Class II malocclusions occurred at the expense of skeletal changes (reduction of ANB, increase of Go-Me) and dental changes (distalization of the upper lateral teeth and mesialization of the lower lateral teeth). CONCLUSION: Correction of a Class II malocclusion with an activator occurs at the expense of dental and skeletal changes and that the orthopaedic effects are more considerable than dental ones.

169 TABLES FOR ESTIMATING THE DENTAL AGE OF CHILDREN FROM THE FORMER YUGOSLAV REPUBLIC OF MACEDONIA Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 I Galić1, V Ambarkova2, E Nakaš3, 1Study of Dental Medicine at School of Medicine, University of Split, Croatia, 2Dental Clinic in Skopje, University of Ss. Cyril and Methodius, Skopje, Former Yugoslav Republic of Macedonia and 3Department for Orthodontics, Faculty of Stomatology, University of Sarajevo, Bosnia and Herzegovina

AIM: Children’s ages can be estimated by evaluating dental maturation of tooth growth and mineralization. Most commonly this is done by evaluating maturation of selected permanent teeth on dental pantomograms (DPTs). The aim of this research was to test the French-Canadian standards of dental maturation developed by Demirjian and Goldstein (1976) on children from Skopje. MATERIALS AND METHOD: Nine hundred and ninety six DPTs collected from healthy children were evaluated (481 boys, 485 girls aged 6.0 to 13.9 years). Mineralization of the crowns and roots of the seven permanent teeth from the left side of mandible were determined and dental age was then calculated the dental age using a maturation score based on the French-Canadian standards. RESULTS: A statistical difference was observed between the evaluated dental age and the chronological age of children (P < 0.001) with determination coefficients (R2) of 0.67 in boys and 0.63 in girls. The mean absolute errors (MAE) were 1.02 ± 0.74 years and 1.10 ± 0.79 years, and root mean squared errors (RMSE) were 1.12 and 1.17 years in boys and girls, respectively. Using a non-linear regression model, function formulae were established for boys [age = (ln (maturation score /(100 - maturation score) ) +4.350)/0.695 ] and girls [age = (ln (maturation score / (100 - maturation score)) +4.786)/0.785 ], which increased R2 up to 0.83 in boys and 0.85 in girls and decreased MAE to 0.62 ± 0.52 and 0.59 ± 0.46 years in boys and girls, respectively. RMSE was decreased to 0.81 and 0.75 years in boys and girls, respectively. CONCLUSION: New function formulae were established and tables were created to predict dental age with more confidence and accuracy for children of the Former Yugoslav Republic of Macedonia.

170 A THREE-DIMENSIONAL ORTHODONTIC AND SURGICAL STUDY OF THIRD MOLARS: MAGNETIC RESONANCE IMAGING VERSUS CONE BEAM COMPUTED TOMOGRAPHY U Garagiola, E del Rosso, P Cressoni, R Soldo, G Farronato, Orthodontics and Pediatric Department, University of Milan, IRCCS Fondazione Ospedale Maggiore Policlinico, Milan, Italy

AIM: To assess three-dimensional (3D) volumetric anatomical reconstruction of the third molars and the relationships with the inferior alveolar nerve canal (IAN) by magnetic resonance imaging (MRI) versus cone beam computed tomography (CBCT). The precise localization of third molars and the study of their relationship with the IAN is a critical for correct surgical approach. MRI is a technique applied in various branches of medicine; it allows tissue images to be obtained using their behaviour in a high intensity magnetic field.

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MATERIALS AND METHOD: Twenty patients underwent CBCT and MRI with a new 3D protocol that provides Dicom data acquisition which can be imported into 3D reconstruction and visualization software. Segmentation of jaw bones and dental elements was performed and the location of the IAN was mapped. RESULTS: Volumetric MRI scans appear ideal for producing virtual models of anatomical structures, especially the third molars and the IAN. The 3D MRI volumetric reconstruction was similar to the 3D CBCT volumes (P < 0.1). In this way the operator can see in the three planes of space, the structures of interest, with a dimensional ratio of 1:1. CONCLUSION: The results confirm the possibility of using this MRI technique for 3D-volumetric investigation of dental and maxillo-mandibular structures. The main advantage in the application of MRI is the total absence of ionizing radiation delivered to the patient; however there is greater execution time of the examination and data review. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 171 CARIES, MALOCCLUSION, ORAL HEALTH AND FOOD: CORRELATION IN 12-YEAR OLD NEAPOLITAN STUDENTS D Giugliano1, A Longobardi1, V Grassia1, A Majorana2, L Perillo1, 1Department of Orthodontics, Second University of Naples and 1Department of Odontostomatology and Pedodontics, University of Brescia, Italy

AIM: To assess the prevalence of caries in association with diet, oral hygiene and malocclusion in a sample of schoolchildren in Naples, Italy. SUBJECTS AND METHOD: The students had to belong to schools in the territory divided into districts to avoid any possible bias the social heterogeneity. From the 79 schools a ‘cluster’, 48 were selected, with one or two classes from each. The number of decayed, missing and filled teeth (DMFT) were obtained from 536 (11-13 year old) children attending the secondary schools. The children completed questionnaires to provide dietary and oral hygiene information and underwent a dental examination for caries and malocclusion following World Health Organisation guidelines. DMFT values for each subject were used for statistical analysis. The association between caries, dietary habits, oral health, and occlusion was assessed with contingency tables, the χ2 test. The significance level was set at 0.05. RESULTS: Caries was found in 284 students (53%), and the mean DMFT value was 1.8 (1.64 for boys, 1.96 for girls) More girls (286) than boys (250) had caries but the difference was not statistically significant. The caries (D) component of DMFT was highest while the M component (lost teeth) was evident only in 21 students (3.92%). Thirty-five students (6.53%) finished orthodontics while 74 (13.8%) were still undergoing treatment. A Class I molar relationship was prevalent in 57.28 per cent of patients, followed by Class II (12.69%) and Class III (3.16%). Overjet and overbite were normal for most students. A deviation from the median was detected in the 32.09 per cent of the sample. Of the students with dental crowding, 51.37 per cent had caries, but the relationship between caries and malocclusion was significant (P = 0.02) only in those with a crossbite (11.7%). There was no significant relationship between food consumption and prevalence of caries. No statistically significant difference was found between children who did not brush and children who did. None of the children had fluoride prophylaxis. CONCLUSION: In agreement with other national findings, the high D number suggests the need for therapy in this age group. The increased risk of caries was confirmed only for crossbite, perhaps due to a dried oral cavity. Decay prevalence was not related to food consumption and tooth brushing in this sample.

172 CLINICAL EFFECTIVENESS OF SURGICAL AND NON-SURGICAL APPROACHES FOR ACCELERATED ORTHODONTIC TOOTH MOVEMENT: A SYSTEMATIC REVIEW AND META-ANALYSIS N Gkantidis1, I Mistakidis2, T Kouskoura1, N Pandis1, 1Department of Orthodontics and Dentofacial Orthopedics, University of Bern, Switzerland and 2Department of Orthodontics, Aristotle University of Thessaloniki, Greece

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AIM: To assess the clinical effectiveness of surgical and non-surgical approaches for accelerated orthodontic tooth movement. MATERIALS AND METHOD: Randomized controlled trials (RCTs), and controlled clinical trials (CCTs) were eligible for inclusion. Electronic search for published and unpublished studies in English, German, French or Italian was conducted in Medline, Embase, Google scholar beta, and all Cochrane Databases, at the end of November 2013 with no time restrictions. Orthognathic surgery and distraction osteogenesis interventions were excluded. Risk of bias was assessed using the Cochrane risk of bias tool for RCTs, and a specifically designed tool for CCTs. Studies with low and unclear risk of bias were mathematically combined using the random effects model. RESULTS: Thirteen trials involving 274 participants were included. Seven trials reported on low-intensity laser (4 split-mouth RCTs, 3 CCTs), one CCT on photobiomodulation, one split-mouth RCT on pulsed electromagnetic fields, and four RCTs on corticotomy (1 parallel; 3 split-mouth). Most studies evaluated only a part of the treatment (11 assessed single tooth retraction in extraction space and 1 alignment). One trial with unclear risk Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 of bias concluded that over the entire treatment duration low-intensity laser was more effective compared with the conventional method (md = –167 days; 95% CI: –215.8, –118.2); average treatment duration for the control was 18.8 months (SD: 4.3). Meta-analysis of two trials indicated, during the first month of therapy, higher canine retraction rate by 0.73 mm/month with corticotomy versus the control (wmd = 0.73; 95% CI: 0.28, 1.19, P = 0.002; I2 = 46.9%, P = 0.17). Meta-analysis of three studies with an evaluation period of more than 3 months showed a higher canine retraction rate with low-intensity laser versus the control (wmd = 0.62 mm/month; 95% CI: 0.16, 1.08, P < 0.001; predictive interval: –5.33, 6.56; I2 = 98.8%, P < 0.001). CONCLUSION: There is some evidence that corticotomy and low laser therapy are effective, whereas the evidence for photobiomodulation or pulsed electromagnetic fields is weaker. Overall, the results should be interpreted with caution given the small number, quality, and heterogeneity of the included trials. Further research is required in this field with additional attention to adverse events and cost-benefit analysis.

173 EFFECTIVENESS OF USING IN THE CORRECTION OF MILD DENTOALVEOLAR MALOCCLUSION*** E Golik1, M Ivanova1, Y Martyts2, 1Kiev State Dental Hospital and 2Ternopil Medical University, Ukraine

AIM: To demonstrate the use of transparent aligners, Easy Align. SUBJECTS AND METHOD: Thirty five patients have been treated with this system since the beginning of 2013. As an example of these appliances, the clinical case of a 28 year old patient is presented. He had a dentoalveolar malocclusion, Class I on the right side, with mild crowding of the anterior maxilla and rotation of teeth 15, 14, 11, 21. The working steps were: 1. Removing impression; 2. Manufacture of high strength plaster models; 3. Scanning of plaster models; 4. Based on digital models, radiographs, photographs and personal data of the patient, analysis and treatment plan of the patient is made. Simulation of the final treatment result is made on the computer with special software; 5. Simulated treatment is partitioned into virtual (computer) set- up models; 6. Models are made of virtual set-up models by a process of computer milling; 7. Easy Align is made on models by forming under pressure from special adapt of certain thickness; 8. Fixation of appliances. The aligner is used 22 hours a day; it can only be removed to undertake oral hygiene and during eating. Each appliance is used consistently. Depending on the clinical situation, different thickness of Easy Align is chosen (from 0.5 to 0.82 mm). RESULTS: The term of treatment was 194 days. The patient did not use the appliance 12 in the maxilla for 2 weeks, but this term was added to the total treatment time. At the end of treatment, there was a slight expansion of the dental arches, which allowed levelling of the teeth in the upper jaw and mandibular premolar adjustment. A correct position of the rotated teeth was achieved. CONCLUSION: This aligner system is a good alternative to the non-removable technique in orthodontic treatment.

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174 POSSIBLE IMPLICATION OF OXIDATIVE STRESS IN THE PERIODONTIUM L Gölz, S Memmert, B Rath-Deschner, S Frede, W Götz, Clinic of Orthodontics, University of Bonn, Germany

AIM: Oxidative stress (OS) is characterized by an accumulation of reactive oxygen species (ROS) and plays a crucial role in hypoxic and inflammatory events. Recent studies have indicated that OS is an important co-factor in the aetiology and pathogenesis of different oral and dental diseases. The periodontal ligament (PDL) is a connector between the tooth and the surrounding alveolar bone, functioning as a shock-reabsorbent barrier to protect these structures. Mechanical forces or periodontal bacteria may induce local hypoxic as well as inflammatory reactions in the periodontium. Therefore, this study focused on OS induced mechanism in periodontal cells and tissues. MATERIALS AND METHOD: Human primary PDL fibroblasts and osteoblasts as well as osteoclasts (THP-1 based) Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 were cultured under hypoxic conditions and/or stimulated with lipopolysaccharide of Porphyromonas gingivalis, a periodontal pathogen bacteria. Another group, without any stimuli, served as control. After varying time points, mRNA expression as well as protein synthesis of proinflammatory cytokines, metalloproteinases (MMPs) and transcription factors were analyzed using RT-PCR, Western blots, immunostaining and specific ROS assays. Furthermore, periodontal human tissues were obtained from healthy and periodontally diseased patients to determine different mediators immunohistochemically. The mean and standard error of the mean (n = 6-9) were calculated and one-way ANOVA and the post-hoc Tukey’s multiple comparison test were applied for statistical analysis. RESULTS: Hypoxic and inflammatory stimuli induced different mRNA as well as protein expression patterns of the proinflammatory cytokine interleukin-1ß, MMP-1 and transcription factors (e.g. hypoxia-inducible factor-1α) in primary human PDL cells, osteoblasts and osteoclasts. This was accompanied by a significant alteration of ROS formation. In addition, redox systems such as catalase or superoxide dismutase were upregulated in the cells and inflamed tissues, which may be attributed to a ROS accumulation in disease processes such as gingivitis and periodontitis. CONCLUSION: Hypoxic and inflammatory stimuli cause OS in periodontal cells and tissues, which seems to play a key role during oral inflammatory diseases.

175 INFLUENCE OF SOCIODEMOGRAPHIC AND PSYCHOLOGICAL FACTORS IN THE REPORTING OF PAIN IN A TEMPOROMANDIBULAR JOINT DYSFUNCTION POPULATION L González López1, A Blanco Aguilera2, E Blanco Aguilera3, A Rodriguez Torronteras4 R Segura Saint-Geróns4, 1Private Practice, Córdoba, 2San Pablo CEU University, Madrid, 3University of Santiago de Compostela and 4Andalusian Health Service, Córdoba, Spain

AIM: Pain has been defined by the International Academy for the Study of Pain as ‘A sensorial and emotional experience associated with a real or potential hurt’. Pain threshold is subjective, and sociodemographic or psychological factors play an important part in pain modulation. The aim of this study was to analyze the relevance of some sociodemographic and psychological factors in the reporting of pain in a temporomandibular joint dysfunction (TMD) population. SUBJECTS AND METHOD: One thousand two hundred and twenty patients who reported pain in the orofacial region, sounds or limitation in mandibular movements; were explored using the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). Inclusion and exclusion criteria were those include in the RDC/TMD consorce. The RDC/TMD questionnaires were used, taking as the dependent variable the ‘intensity of pain’, obtained from: the pain of the patient at that moment, the worst pain in the last six months, and the mean pain of the last six months. All questions were measured on a visual analogue scale (VAS). A bivariate analysis was then made, analyzing its grade of association with some sociodemographic and psychological features, such as

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age, gender, socioeconomic status, marital status, academic level, depression, anxiety or somatization. All statistic dates were obtained using the program, SAS Inc., version 9.3. RESULTS: The main pain intensity was (5.36). With respect to the age and gender, a positive association between both factors and the reporting of pain was found, being more prevalent in females (P < 0.001) between 41 and 60 years of age (P = 0.017). A positive association between academic level and higher pain intensity was also observed (P = 0.001), with higher levels of pain in patients with lower academic abilities. Similar results were found respect to marital status (P = 0.003), with a higher mean of pain in those who were married. No association was observed between salary level (P = 0.262) and the reporting of pain. CONCLUSION: There is a positive association between higher reporting of pain, and being a married female, between 41 and 60 years of age, with a low academic level.

176 IS THERE A POSITIVE ASSOCIATION BETWEEN PARAFUNCTIONAL HABITS AND THE PRESENCE OF SIGNS Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 AND SYMPTOMS OF TEMPOROMANDIBULAR DISORDERS? L González López1, A Blanco Aguilera2, E Blanco Aguilera3, A Rodriguez Torronteras4 R Segura Saint-Geróns4, 1Private Practice, Córdoba, 2San Pablo CEU University, Madrid, 3University of Santiago de Compostela and 4Andalusian Health Service, Córdoba, Spain

AIM: The role of parafunctional activities in the aetiology of temporomandibular disorders (TMD) has increased over the last decades. Nowadays many authors suggest a possible association between both entities. The aim of this investigation was to analyze the real influence of some parafunctional activities on the development of signs and symptoms of TMD. SUBJECTS AND METHOD: One thousand two hundred and twenty patients who reported pain in the orofacial region, sounds or limitation in mandibular movements were examined by an experienced investigator using the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). The RDC/TMD questionnaires were used, taking as the dependent variable the ‘intensity of pain’, obtained from: the pain of the patient at that moment, the worst pain in the last six months, and the mean pain of the last six months; being every question measured by a visual analogue scale. Then, a bivariated analysis was made, analyzing the grade of association between the pain intensity and some parafunctional activities included in the RDC/TMD questionnaire, such as chewing gum, mandibular support, forced mandibular positioning or occupational habits. Differences between Axis I groups were also measured. All statistic dates were obtained using the program, SAS Inc., version 9.3. RESULTS: There was a significant association between increased reporting of pain and chewing-gum (P = 0.007), mandibular support (P < 0.001), and forced mandibular positioning (P = 0.012). No significant association was found between pain and occupational habits (P = 0.43). Regarding the Axis I classification, a significant statistical association was also found between chewing-gum (P = 0.005), mandibular support (P < 0.001), forced mandibular positioning (P = 0.005), and those groups with higher values of pain (myopathic and arthropathic patients). However, there was no statistical association between those groups and the presence of occupational habits (P = 0.45). CONCLUSION: There is a positive association between a higher report of pain and the presence of some parafunctional habits, such as chewing-gum, mandibular support, or forced mandibular positioning in patients with TMD. No association was found between occupational habits and the presence of signs or symptoms of TMD.

177 MESIODISTAL TOOTH WIDTHS IN A SPANISH POPULATION: A COMPARISON STUDY M González Velasco, E Rulli Sabbatini, S García Esteve, Mª J Martinez Lozano, M Romero Maroto, Department of Orthodontics, Rey Juan Carlos University, Madrid, Spain

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AIM: To analyze tooth sizes in a Spanish orthodontic population and validate the universally accepted tables of Garn et al., for predicting mesiodistal widths of teeth in Spanish patients. SUBJECTS AND METHOD: The sample was selected randomly, according to inclusion criteria, among patients who had undergone treatment between 2007 and 2013. A total of 100 patients were included in this study, 50 males and 50 females. Initial study casts for each patient, prior to any orthodontic treatment, were used to measure the mesiodistal widths of all teeth. The measurements were determined by an electronic digital dental gauge. Statistical evaluations were performed using SPSS v20.0 for Windows. RESULTS: Males have greater mesiodistal widths when compared with females. A positive correlation was observed between homologous teeth for both the maxillary and mandibular dentition, and the same positive relationship was observed between the teeth in the first and second quadrants as well as those in the third and fourth quadrants. Tables published by Garn et al. (1968) were analyzed and compared with measurements obtained. It was established that the published data could be used in the Spanish population, with the Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 exception of molar widths, whose mesiodistal values proved to be higher in this population. CONCLUSION: Spanish females present with smaller mesiodistal tooth widths compared with Spanish males. Homologous teeth within the same arch have similar average widths. The tables published by Garn et al. (1968) can be successfully used to estimate the mesiodistal widths of the permanent teeth in Spanish populations.

178 EFFECT OF NdFeB MAGNETS FOR ALIGNING IMPACTED TEETH ON TYPODONT MODELS S Goto, Y Hata, M Hida, K Miyazawa, Department of Orthodontics, Aichi-Gakuin University, Nagoya, Japan

AIM: To develop attraction methods for treatment of an impacted teeth using magnetic force. The attractive forces of various magnets were measured, and the optimal magnet for aligning an impacted tooth was chosen. Further, it was possible to prevent corrosion in the oral cavity by bonding a magnetic plate with high corrosion resistance to an impacted tooth. MATERIALS AND METHOD: Two types of close circuit NdFeB magnets Gigauss D1000, GC Co., Physiomagnet 5531, Morita Co.) and four kinds of open circuit NdFeB magnets (Neomag Co) were used. A 5.5 mm diameter plate with a high content of Cr-Mo ferritic stainless steel with excellent corrosion resistance (SUS447J1) was used as the magnet keeper. The usefulness and safety of the magnetic attraction methods was undertaken using a typodont model. RESULTS: Using the close circuit magnet in a space of 0.5 mm, the attractive force becomes 0 g. On the other hand, an attractive force of about 40 g is exerted in an space of 3.0-4.0 mm with the open circuit magnet. When the flux densities of the magnetic fields were measured, the values at all points were lower than those recommended by the World Health Organisation and the International Commission on Non-Ionizing Radiation Protection. The Impacted teeth with traction force on the model were shown to be vertically extruded. CONCLUSION: Traction of impacted teeth using NdFeB magnets and a high corrosion resistance stainless steel keeper is both useful and safe.

179 CLEAR ALIGNER AND AUXILIARY DEVICES IN EXTRACTION TREATMENT M Greco, A Giancotti, Department of Orthodontics, University of Rome Tor Vergata Fatebenefratelli Hospital, Italy

AIM: To illustrate the use and efficacy of modified clear aligner technology (CAT) to produce translatory tooth movements and radicular control in extraction treatment. SUBJECTS AND METHOD: Twelve adult patients aged 25 to 30 years, with Class II malocclusions, maxillary protrusion, normal skeletal patterns and increased overjet and overbite. All patients had panoramic and lateral radiographs taken at the beginning (T1) and end (T2) of treatment. All were treated by means of CAT and extraction of two maxillary premolars in order to reduce the protrusion. To achieve translation movement of

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the lateral teeth with correct root control, lingual appliances (In-Ovation L) were passively bonded on the upper canines, premolars and first molars. A stainless steel 0.018 inch archwire was inserted in the brackets and the planned aligners were cut to best fit the teeth and the sectional fixed appliance during lateral space closure. The last phase of anterior retraction was undertaken without auxiliary devices. RESULTS: At the end of treatment all patients showed a full molar Class II relationship and a Class I canine relationship with correct root parallelism all the extraction sites. Some small inaccuracies in positioning were detected when mesial root inclination was evident before treatment. CONCLUSION: Modified CAT with lingual sectional appliances proved to be an efficient technique to manage root movements in extraction treatment.

180 ANTERIOR THREE-DIMENSIONAL CONTROL IN BIDIMENSIONAL ORTHODONTICS M Greco, A Giancotti, University of Rome Tor Vergata Fatebenefratelli Hospital, Italy Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021

AIM: To test the efficacy of bidimensional self-ligating brackets in the management of torque control of the anterior teeth. SUBJECTS AND METHOD: Fifteen patients presenting with a Class II division 1 malocclusion with moderate crowding in the lower arch and an increased overjet. All patients had radiographs (lateral cephalogram and panorex) taken before and after treatment. All were treated following the bidimensional technique (SL brackets) with extraction of the previously restored upper first molars. The technique aimed to fill slot of the bracket in the anterior teeth and protract the molars. RESULTS: All patients finished with the upper third molars in the position of the second molars and the second molars in the position of the first molars and a Class I canine relationship and Class II molar relationship with a correct overjet, overbite and incisor inclination. CONCLUSION: Bidimensional orthodontics can be considered an efficient technique in anterior anchorage control and for three-dimensional incisor position.

181 DIAGNOSTIC PERFORMANCE OF COMBINED CANINE AND SECOND MOLAR MATURITY FOR IDENTIFICATION OF THE GROWTH PHASE C Greco1, L Contardo1, R Di Lenarda1, S Salgarello2, G Perinetti1, 1University of Trieste and 2University of Brescia, Italy

AIM: Analysis of the diagnostic performance of the circumpubertal dental maturation stages of the mandibular canine and second molar, as individual teeth and in combination, for identification of the growth phase. SUBJECTS AND METHOD: Three hundred healthy subjects, 192 females and 108 males, (mean age, 11.4 ±2.4 years; range, 6.8-17.1 years). Dental maturity was assessed through the calcification stages from panoramic radiographs of the mandibular canine and second molar. Determination of the growth phase (as pre-pubertal, pubertal and post-pubertal) was according to the cervical vertebral maturation method (CVM). The diagnostic performances of the dental maturation stages, for both individual teeth and in combination, for identification of the growth phase were evaluated using positive likelihood ratios (LHRs), with a threshold of ≥10 for satisfactory performance. RESULTS: For the individual dental maturation stages, most of these positive LHRs were ≤1.6, with values ≥10 seen only for identification of the pre-pubertal growth phase for canine stage F and second molar stages D and E, and for the post-pubertal growth phase for second molar stage H. All of the combined dental maturation stages yielded positive LHRs of up to 2.6. CONCLUSION: Dental maturation of either individual or combined teeth has a minimal role in identification of the pubertal growth spurt and should not be used to assess the timing for treatment that are required to be performed at this growth phase.

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182 DENTAL ARCH FORM IN CLASS II MALOCCLUSION C Grippaudo, S Sferra, A Greco, B Oliva, R Deli, Dental Institute, Catholic University of Sacred Heart, Rome, Italy

AIM: To investigate the relationship between dental arch forms and vertical growth patterns in skeletal Class II malocclusions. Isaacson et al., Nasby et al., and Forster et al., showed that the shape of the dental arch is related to the vertical dimension and that transverse jaw relationships are related to vertical skeletal growth. The hypothesis tested was that in Class II patients, arch form is variable according to mandibular growth direction. SUBJECTS AND METHOD: Seventy three Caucasians with an untreated skeletal Class II malocclusion (ANB average = 6.2°), aged between 11 and 38 years and in the permanent dentition were divided into three groups according to the values of the angle sella-nasion plane/mandibular plane (SN-PM): >35.5 degrees (26 subjects); Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 30.5

183 ATTRITION AS AN INDICATION FOR ORTHODONTIC TREATMENT: THE RELATIONSHIP BETWEEN ATTRITION AND MALOCCLUSION K Grzegocka1, S Williams1, J Loster2, A Wieczorek2, B W Loster1, Departments of 1Orthodontics and 2Prosthodontics, Dental Institute, Faculty of Medicine, Jagiellonian University Medical College, Cracow, Poland

AIM: Over the past 20 years many studies have attempted to define factors which could indicate the necessity for orthodontic treatment for an individual patient. Function, muscular efficiency, the risk of trauma, aesthetic indications and others are often named although the risk of attrition as a risk for tooth loss has seemingly never been stressed. The present study aims to determine the frequency of significant tooth attrition in a young Polish population and to describe the various patterns of wear in relation to the malocclusion observed. It is hoped that malocclusion representing a risk of attrition and thus indicating orthodontic therapy can be defined. MATERIALS AND METHOD: Plaster casts of 59 Polish adolescents (21 males, 38 females, average age 20 years 2 months, maximum 20 years 10 months, minimum 18 years 9 months), all selected for orthodontic therapy. Subjects were included in the study irrespective of the type of malocclusion they exhibited and 32 (54.2%) had already been treated orthodontically. All models were examined by one author and the presence and extent of attrition was recorded using the ‘Simplified Tooth Wear Index’ (TWI) (partial recording system). RESULTS: Twenty two individuals (37.3%) showed occlusal wear facets (10 males, 12 females). The teeth most affected were anterior (TWI simplified: 8.8), upper (95.4%), lower (63,6%) or both (59%) incisors and canines (50%). The mean TWI value was 11.0 (range 2 to 28). No individual tooth with a score of three was recorded.

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Forty one per cent (40.9%) of investigated young adults with dental wear exhibited a Class I malocclusion with crowding, deep bite, open bite or crossbite with a locked bite. Distal malocclusion with retrusion of the upper incisors was present in 31.8 per cent and Class II with protrusion of upper incisors occurred in 22.7 per cent of cases. Mesial malocclusion was relatively uncommon (1 case only). CONCLUSION: There is as a high prevalence of dental attrition in young Polish adults needing orthodontic therapy. The risk of dental attrition should be considered as a valid indication for orthodontic treatment.

184 CEPHALOMETRIC NORMS OF THE UPPER AIRWAY OF CHINESE CHILDREN AND THE ASSOCIATION BETWEEN AIRWAY DIMENSIONS AND CRANIOFACIAL STRUCTURES M Gu1, Y Yang1, R W K Wong1, U Hagg2, C P J McGrath1, 1Faculty of Dentistry, The University of Hong Kong and 2Faculty of Health Sciences, University of Copenhagen, Denmark Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 AIM: To retrospectively establish cephalometric norms of the upper airway for Chinese children, and to determine association between airway dimensions and craniofacial features. SUBJECTS AND METHOD: A random sample of 224 male and 201 female 12-year-old southern Chinese children, for whom lateral cephalograms were available. Statistical analysis was performed to analyze 11 key cephalometric parameters for airway dimensions and 29 parameters for craniofacial features. Gender difference of airway dimensions was analyzed using two-sample t-test. The subjects were further divided into four subgroups according to ANB angle (Class I, mild Class II, severe Class II or Class III) and three subgroups according to the intermaxillary angle (low, normal or high angle), respectively. Association between airway parameters and ANB angle class and intermaxillary angle class was analyzed with analysis of variance. Pearson’s correlation analysis was computed to determine correlations between airway and craniofacial parameters. RESULTS: Significant differences were found in the high angle subgroup in the vertical position of the hyoid bone (P < 0.01), retroglossal pharyngeal depth (P < 0.05) and soft palatal angle (P < 0.001) compared with the other two intermaxillary angle class subgroups. A moderate correlation (r > 0.5) between airway dimensions and craniofacial features was evident in the severe Class II subgroups (ANB >7°). Of note there was a strong correlation (r > 0.7) between mandibular length (Cd-Gn) and the vertical position of hyoid bone and a moderate correlation (r > 0.6) between mandibular length and the sagittal position of hyoid bone. CONCLUSION: Cephalometric norms of the upper airway for Chinese children have been established with gender-specific standards. High angle subjects tend to have a lower positioned hyoid bone and a narrow retroglossal airway. In severe Class II subjects, mandibular length is correlated with the position of hyoid bone in both the vertical and sagittal dimensions.

185 INFLUENCE OF CEMENTUM PRESENCE AND PERIODONTAL LIGAMENT WIDTH ON STRESS DISTRIBUTION: A FINITE ELEMENT ANALYSIS M Guimarães Roscoe, S Delcastanher Karkuszewski, C Baptiston Tanaka, R Yague Ballester, J Barbosa Cruz Meira, University of Sao Paulo, Brazil

AIM: To investigate, by finite element analysis (FEA), the influence of cementum presence and periodontal ligament (LP) width on stress distribution with intrusion loading. MATERIALS AND METHOD: Four axisymmetric FEA models were created using the geometry of a maxillary second premolar: LPU-SC: uniform LP (0.25 mm of width) without cementum, LPU-C: LP uniform LP with cementum, LPNU-SC: non-uniform LP (0.3 mm of width at the cervical and apical third, and 0.2 mm at the middle third) without cementum, LPNU-C: LP non-uniform LP with cementum. The enamel, dentine, pulp, cortical and cancellous bone were included in both models and were considered elastic and isotropic. A total load of 10 N was applied at the occlusal surface, simulating an intrusion movement. The displacement of the

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nodes at the cancellous bone base was restricted. The minimum principal stress (σ3) distribution was analyzed at the radicular dentine, the periodontal ligament and the cortical bone. RESULTS: For the radicular dentine, the peak of σ3 was obtained at the cervical region (–0.57 MPa to LPU-SC, – 0.58 MPa to LPU-C, –0.57 MPa to LPNU-SC, -0.59 MPa to LPNU-C). For the periodontal ligament, the peak of σ3 was obtained at the apical region (–0.34 MPa to LPU-SC, –0.43 MPa to LPU-C, –0.34 MPa to LPNU-SC, –0.34 MPa to LPNU-C). For cortical bone, the peak of σ3 was obtained at the middle third radicular (–0.34 MPa to LPU-SC, – 0.27 MPa to LPU-C, -0.34 MPa to LPNU-SC, –0.34 MPa to LPNU-C). CONCLUSION: FEA demonstrated that the cementum presence and the LP width did not affect the stress distribution at the radicular dentine, periodontal ligament or cortical bone.

186 REMOTE SECOND OPINION ORTHODONTICS BY SMARTPHONE V Gushchin1, B Vande Vannet2, 1Private Practice, St Petersburg, Russia and 2Department of Orthodontics, Vrije Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 Universiteit Brussel, Brussels, Belgium

AIM: In recent years digital technology has been more widely used. Diagnosis and treatment planning of the entire spectrum of orthodontic malocclusions can be done digitally. The aim of this study was to test mobile applications for a second opinion. MATERIALS AND METHOD: Viber and Skype were tested at long distance by Smartphone. Two practitioners (one recently graduated and one experienced clinician) tested the online use of second opinions during a 6 month trial period. Each day a case was transferred for discussion. Only photographs of cast models and intraoral photographs were transferred after written consent of the patient. After transfer and delivery of an opinion the cases were deleted by both clinicians. RESULTS: In total 100 second opinions were delivered. No technical problems were observed during the testing period. Viber was preferred (75%) over Skype (25%) as no special log in is required for the Viber application and transfer of photographs was easier. Towards the end of the trial period more agreement in treatment procedures was achieved between both clinicians. CONCLUSION: Using digital technology allowed the practitioners to adapt more standardized treatment strategies. It strengthens orthodontic specialists in experience and in deciding which treatment to choose. The use of these communication tools could enhance national and international peer review.

187 EFFECTS OF NASOALVEOLAR MOULDING ON SKELETAL DEVELOPMENT OF PATIENTS WITH A UNILATERAL CLEFT LIP AND PALATE AT 5 YEARS OF AGE B A Guven, A Arisan, M Aksu, Department of Orthodontics, Faculty of Dentistry, Hacettepe University, Ankara, Turkey

AIM: To assess the effects of nasoalveolar moulding (NAM) on skeletal development of patients with a unilateral cleft lip and palate (UCLP) at 5 years of age MATERIALS AND METHOD: Sixty six lateral cephalometric radiographs were obtained from 26 UCLP subjects who received NAM prior to surgical repair (NAM group, mean age 5.1 ± 0.8 years), 20 UCLP subjects who did not have any NAM prior to surgery (non-NAM group, mean age 5.1 ± 0.8 years) and 20 non-cleft control subjects (control group, mean age 5.1 ± 0.8 years). The lateral cephalometric radiographs were digitally traced using Quick Ceph Studio software. Seven angular and seven linear measurements were evaluated. Statistical analysis was performed using one-way analysis of variance (ANOVA) and post-hoc Tukey's test. A P value of less than 0.05 was considered to be statistically significant. RESULTS: No statistically significant difference was observed in skeletal development between the NAM and non-NAM groups. Significant differences were observed in the NAM and non-NAM groups when compared with the control group. S-N distance was significantly shorter and SNA angle and Co-A distance were significantly

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smaller in the NAM and non-NAM groups than in the control group (P < 0.001, P < 0.05 and P < 0.001, respectively). SN-PP and maxillary height were significantly larger in the NAM and non-NAM groups than in the control group (P < 0.001 and P < 0.01, respectively). SNB angle and Co-Gn distance were smaller in the NAM and non-NAM groups than in the control group (P < 0.05 and P < 0.001, respectively). Na-Me, ANS-Me and NA-ANS distances were shorter in the NAM and non-NAM groups compared with the control group (P < 0.001). CONCLUSION: NAM treatment did not result in any significant difference in skeletal development when compared with the non-NAM group in early childhood. However, both cleft patients with and without NAM showed reduced sagittal and vertical skeletal development of the face when compared with their healthy peers.

188 INFLUENCE OF THE FORSUS APPLIANCE ON THE ANGULATIONS OF THE THIRD MOLARS IN BOTH JAWS I S Guvenc, C Doruk, S Dursun, B Talay, Department of Orthodontics, Faculty of Dentistry, Cumhuriyet University, Sivas, Turkey Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021

AIM: To assess the angular changes of the long axis of the upper and lower third molars relative to the lower border of the corpus and palatal plane using standardized panoramic radiographs after fixed functional treatment (Forsus, FRD) SUBJECTS AND METHOD: Two groups were formed; 25 patients in the first group were treated with the Forsus appliance and 20 patients in the control group were treated without using the Forsus appliance. The patients in the first group were growing subjects who had normal gonial angles and were skeletal Class II at the beginning of treatment. The control group comprised growing subjects who had minor crowding at the beginning of treatment and required no or minimal anterior tooth movement. Treatment and growth effects on the maxillary and mandibular third molar angulations were evaluated on pre- and post-treatment panoramic radiographs. For the lower molars, the angle between the third molar long axis and the lower border of corpus; and for upper molars, the angle between the long axis of the third molar and the palatal plane were measured. RESULTS: There was a statistically significant difference between the groups (P < 0.05). Inclination of the maxillary and mandibular third molars were affected after fixed functional treatment (Forsus, FRD). Lower third molar uprighting and upper third molar distal tipping were observed. CONCLUSION: Treatment with the Forsus functional appliance has an impact on the inclinations of developing third molars.

189 LOCAL INJECTION OF PULP CELLS ENHANCES WOUND HEALING DURING THE INITIAL PROLIFERATIVE PHASE THROUGH THE STIMULATION OF HOST ANGIOGENESIS Y D Ha, H Kwon, Y J Choi, K-H Kim, C J Chung, Department of Orthodontics, Gangnam Severance Dental Hospital, Seoul, Korea South

AIM: To examine the effect of pulp cell injection on wound healing and soft tissue regeneration. MATERIALS AND METHOD: Pulp cells were isolated from extracted premolars by the outgrowth method. Fluorescently labelled pulp cells were locally injected into a mouse wound healing model. Soft tissue regeneration was evaluated using photographs, histology and RT-PCR, and the injected cells were traced to evaluate host engraftment. Angiogenesis was measured by performing immunohistochemical staining of CD31. The level of secreted vascular endothelial growth factor (VEGF) in the pulp cell’s conditioned medium (CM) was compared with the CM of fibroblasts and keratinocytes. The paracrine effect of pulp CM on angiogenesis was evaluated by tubular network formation using endothelial cells. RESULTS: Local injection of pulp cells enhanced soft tissue regeneration, the amount of extracellular matrix production and the expression of CD31+ cells during the initial stage when compared with phosphate buffered saline injected controls. The fluorescently labelled pulp cells were engrafted into the hair follicles of the adjacent normal dermis but not into the wound site per se. A significantly higher level of VEGF was secreted into

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the CM of pulp cells when compared with dermal fibroblast and keratinocytes. Tubular network formation of endothelial cells and the proliferation of dermal fibroblasts were significantly enhanced by the application of pulp cell CM when compared with control media. CONCLUSION: Local injection of pulp cells is effective in enhancing soft tissue regeneration during the initial proliferative phase, especially through paracrine mechanisms regulating host angiogenesis and proliferation.

190 EXTRACTION VERSUS NON-EXTRACTION: INTRODUCING NEW CEPHALOMETRIC INDICES W Hahn, M Hahn, S Hahn, Private Practice, Hamburg, Germany

AIM: To retrospectively compare, by means of lateral cephalograms (two-dimensional) and digital volume tomography (three-dimensional), the location and inclination of the lower incisor and canine axis to assess stability with and without extractions of four premolars. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 SUBJECTS AND METHOD: Patients with a Class II division 1 malocclusion, meso- to dolichofacial and an initial age from 11.1 to 13.2 years. Fixed appliances, labial as well as lingual (WIN™, 3M-Incognito™, STB™, Begg) were used. Thirty two patients treated without extractions were allocated to group NE (17 females, 15 males). Group E comprised 26 patients (12 females, 14 males) treated with extraction of four premolars. Both groups with labial appliances used additional palatal and or lingual arches and Class II elastics. All individuals had 3-3 fixed retainers immediately after removal of the fixed appliances. Post-treatment cephalograms were compared with pre-treatment set-ups (lingual cases) and post-treatment casts. The t-test was applied for intergroup comparison. RESULTS: 1) Variables SN.PP, SN.Ocl and FMA did not present statistically significant differences between groups. 2) Digital volume tomography revealed the best buccal/labial bone cover of lower canines and incisors with an intercanine distance between 26 and 28 mm. 3) A new index for positioning the lower incisor is proposed: a) incision superius and inferius on a circle around R2-point through the incisors, as well as b) incisor axis perpendicular to the R2-B-Line. CONCLUSION: It is concluded that lateral cephalometric as well as digital volume tomography data analysis (obtained for reasons such as trauma, etc.) showed a significant influence on a clinician’s view on relapse and stability.

191 A THREE-DIMENSIONAL SURVEY OF CLEFTING IN ROMANIAN CHILDREN L-G Halitchi1, D Apostol2, L Pruna3, 1Department of Orthodontics, University of Apollonia, 2Department of Paediatric Surgery, UMF Gr. T. Popa, and 3Department of Geometry, University Gh. Asachi, Iasi, Romania

AIM: In Romania there are only a few studies which document spontaneous and coordinated growth changes in young Romanian children with a cleft palate (CP). The aim of this research was to: 1. identify the functional adaptations of the oral cavity to the disrupted architecture of the palate in children with a cleft lip and palate (CLP); 2. evaluate and measure the opening of the palatal cleft in palate in patients with a CLP; 3. provide dimensional information for orthopaedic-orthodontics in the pre-surgical phases. SUBJECTS AND METHOD: The first group comprised 64 patients with a CP, aged between 2 days and 2 years, operated by the same surgical team and the second group 60 patients with normal development of the face. Maxillary impressions were taken of both groups. The maxillary casts were scanned three-dimensionally using a digitalized device that picks up data from the cast surfaces and processes them into a 3D matrix. Direct measurements were made of the anterior and posterior diameter of the cleft opening. Student’s t-tests, both simple and bivariate, were performed with SPSS 13.0 software. RESULTS: The bivariate Student’s t-test established that there were statistically significant negative differences between the mean values of the anterior and posterior width of the maxillary alveolar arch, positive non- significant differences for the length and positive differences for the depth of the palate in the study group

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compared with the control group children Cleft opening varied between 0.5 to 10 mm and interfered with the orthopaedic prescription. NMA and palatal plates were used in the study group to ensure normal growth and development before surgery CONCLUSION: From the therapeutic point of view surgery in the CP group is undertaken at different ages, from 2 to 4 years old, and do not react like other groups from other European Cleft Centres and may benefit of a good residual growth that had been identified prior to late palatoplasty by Berkovitz. The 3D technique allows graphical representation of normal and cleft palates from 0 to 2 years of age

192 DIMENSIONAL ACCURACY OF RAPID PROTOTYPING MODELS MANUFACTURED FROM CONE BEAM COMPUTED TOMOGRAPHS S H Han1, H R Park2, H R Shin3, H Jin4, H C Song5, Divisions of 1Orthodontics, 3AGD and 5Oral Surgery, Department of Dentistry, The Catholic University of Korea / St. Vincent's Hospital, Suwon and Private Practices, 2Ansan and Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 4Suwon, Korea South

AIM: To analyze the dimensional accuracy of the craniomaxillary complex and mandibular models manufactured from cone beam computed tomography (CBCT) and the rapid prototyping (RP) technique. MATERIALS AND METHOD: After CBCT images were acquired from three human dry skulls, three prototype models were produced by the three-dimensional printing (3DP™) technique. Eleven landmarks were identified and 13 linear measurements were taken on the craniomaxillary complex while four landmarks were identified and nine linear measurements were taken for the mandible. All measurements were repeated 20 times by one examiner with a sufficient time interval between each successive measurement. Each linear measurement was categorized by its dimension: sagittal, vertical, and transverse. After mean absolute differences (MAD) and mean relative difference (MRD) were calculated, the dimensional stability of the RP models was examined by ANOVA. RESULTS: MAD and MRD between the RP models and the human dry skulls were –0.15 ± 0.46 mm (0.98 ± 0.93%) in the craniomaxillary complex, 0.50 ± 0.29 mm (1.36 ± 0.94%) in the mandible, and 0.12 ± 0.52 mm (1.14 ± 0.94%) in the craniomaxillary complex and mandible combined. In the craniomaxillary complex, MAD and MRD were smaller in the vertical plane (0.12 ± 0.35 mm and 0.70 ± 0.69%) than in the transverse plane (–0.16 ± 0.50 mm and 1.10 ± 0.98%). In the mandible, MAD and MRD were 0.56 ± 0.30 mm (0.31 ± 0.25%) in the sagittal plane, 0.56 ± 0.23 mm (1.85 ± 0.82%) in vertical plane and 0.31 ± 0.25 mm (0.33 ± 0.20%) in transverse plane. There was no statistically significant difference in MAD and MRD among three dimensions. CONCLUSION: Though RP models prepared from CBCT were slightly enlarged compared with their dry skull counterparts, their dimensional accuracy was similar to that prepared from multislice CTs. Therefore, RP models based on CBCT may be a valuable aid in orthognathic surgical procedures.

193 OCCLUSAL CHANGES IN 57 CONSECUTIVE INDIVIDUALS WITH BILATERAL COMPLETE CLEFT LIP AND PALATE FROM 8 TO 21 YEARS H Haslerud Høimyr1, E Rønning2, G Semb3, 1Department of Orthodontics, University of Oslo, 2Section of Odontology, Oslo Cleft Team, University Hospital of Oslo, Norway and 3Dental School, University of Manchester, U.K., and University Hospital of Oslo, and Bredtvet Resource Center, Norway

AIM: To describe the occlusal changes (dental occlusion, dental arch relationship and maxillary arch width) from 8 to 21 years in patients with complete bilateral cleft lip and palate (CBCLP). MATERIALS AND METHOD: Study models of 57 consecutive patients with non-syndromic CBCLP obtained at 8, 16 and 21 years. All surgical and orthodontic treatment was carried out by the Oslo Cleft Team, Norway. Maxillary arch width was measured directly on the models, dental occlusion evaluated by the Huddart-

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Bodenham method, and dental arch relationship assessed by the CBCLP yardstick and the modified yardstick for post-orthodontic evaluation RESULTS: Following improvement between 8 and 16 years, there was a slight reduction in upper arch width, and deterioration of the occlusion and in dental arch relationship between 16 and 21 years. The changes were larger in the lateral than in the anterior segment. CONCLUSION: At last in terms of dental arch form and relationships, the protocol described appears to have been compatible with acceptable long-term results. Complete stability of post-orthodontic arch form cannot be assured however and patients should be informed about this.

194 AETIOLOGY OF AGENESIS OF MANDIBULAR SECOND PREMOLARS – A LITERATURE REVIEW S Hassanzadeh, L-I Norevall, Department of Orthodontics, Center for Orthodontics, Linköping, Sweden Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 AIM: Tooth agenesis is one of the most common dental developmental problems. Agenesis is the failure of tooth bud development, causing congenital absence of a single tooth or various combinations of teeth. The prevalence of agenesis varies widely in the literature, affecting from 2.6 per cent up to 11 per cent of the population. In Caucasian samples the mandibular second premolar is the most frequently reported. The aim of this review was to assess the available literature on the aetiology of tooth agenesis of mandibular second premolars. MATERIALS AND METHOD: A literature search was performed in Medline database (Entrez PubMed, http://www.ncbi.nlm.nih.gov/pubmed). The search was limited between 1970 and 2013 and to the English and Swedish languages. A complementary search was performed via reference lists and authors, focusing on the aetiology of agenesis of mandibular second premolars. RESULTS: The literature search resulted in 223 articles, from those 223 articles, six abstracts were not available, and therefore 217 abstracts were screened to determine various aetiological factors of agenesis of mandibular second premolars. Out of the 217 abstracts, 10 articles fulfilled the criteria and were chosen to be studied. The complementary search from reference lists and authors gave eight additional articles and all 18 articles were analyzed in full text. CONCLUSION: The main conclusion of this literature review is that agenesis of mandibular second premolars can be regarded as a multifactorial condition. (1) Ethnic differences are seen and in Caucasian samples the mandibular second premolars the most frequently reported missing tooth. (2) Gender differences are seen: the prevalence of agenesis in females was higher. Agenesis may occur as a part of a syndrome or in isolation. (3) Syndromic: More than 49 syndromes, including Down and Aperts, have been associated with agenesis. (4) Non- syndromic: Is related to abnormal function of specific genes that are responsible for the more severe types of agenesis. Defects in genes such as PAX9, MSX1 and AXIN2 have been associated with agenesis.

195 AN AUDIT OF PATIENT USE OF AND SATISFACTION WITH THEIR MANDIBULAR ADVANCEMENT SPLINT. E Hegarty, R McMullan, Orthodontic Department, Altnagelvin Hospital, Londonderry, U.K.

AIM: To assess all mandibular advancement splint (MAS) recipients referred from a medical specialist, to determine patient satisfaction with their MAS and percentage still using the appliance over a 3 year period and to assess complications associated with MASs and their frequency. MATERIALS AND METHOD: Data for MAS patients for the period was retrieved from the Altnagelvin orthodontic laboratory logs. A questionnaire was designed and used to carry out a telephone survey to assess patient use and satisfaction with their MAS. Participants were guaranteed anonymity by the data collector. The questions consisted of open and closed questions as well patients being allowed to give percentage ratings for satisfaction. Finally patients were allowed to comment on the MAS and service. The data collected was statistically analysed.

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RESULTS: Forty five of the 50 patients were successfully contacted. All patients were referred by a medical specialist. Ninety one per cent described the MAS as successful in treating their symptoms. Eighty two per cent of patients still used their MAS. Eighty per cent experienced at least one complication. Patients commented of not being made aware of all possible complications and of being issued with only verbal instructions CONCLUSION: MASs are an effective treatment option for obstructive sleep apnoea. A patient advice leaflet should be designed and implemented with medical histories thoroughly examined.

196 TWIN ZYGOSITY DETERMINATION USING FACIAL STEREOPHOTOGRAMMETRY COMPARED WITH THE DNA-METHOD AMONG YOUNG ADULTS T Heikkinen1, V Vuollo1, M Sidlauskas2, V Harila3, A Sidlauskas2, 1Department of Oral Development and Orthodontics, University of Oulu, Finland, 2Department of Orthodontics, Lithuanian University of Health, Kaunas, Lithuania and 3Central Hospital Oral Diseases, University of Oulu, Finland Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021

AIM: To compare the three-dimensional (3D) facial stereophotogrammetric method versus DNA analyses in zygosity determination. Twin zygosity determination is important in exploring genetic and environmental influences in different traits can be performed with DNA, serologic and anthropometric comparisons. Facial form has been held as one of the most heritable forms, and usually is the starting point in similarity determination in every age. However, despite the same genes, monozygotic (MZ) twins are not always identical in their appearance due to variability in genetic mechanisms, maternal and environmental influences. SUBJECTS AND METHOD: The faces of 150 pairs of young adult Lithuanian twins were photographed with a stereophotogrammetric device (3dMD Atlanta, Georgia, USA) and zygosity was determined according to the similarity of facial form, calculated from linear and angular measurements after land marking the anthropometric points. RESULTS: Preliminary results showed that zygosity determination using facial 3D scans were almost as successful as the DNA method. Evaluation of the similarities showed that most of the upper facial dimensions and vertical parameters had higher genetic control compared with the lower face and sagittal or horizontal ones. CONCLUSION: Zygosity determination using facial stereophotogrammetry is an effective method and cost friendly per case/pair. From an ethical point of view, stereophotogrammetry of the face does not depend on ionizing radiation compared with radiographic techniques using either two (lateral and anteroposterior) or three dimensional (cone beam or computed tomography) techniques. The equipment for stereophotogrammetry, however, is expensive and requires modern 3D software.

This study was supported by an EOS grant.

197 INVESTIGATION OF ADHESIVE STRENGTH OF BRACKETS ON SURFACES USING VARIOUS METHODS OF SURFACE CONDITIONING T Heinrich, D Ohlendorf, S Kopp, Poliklinik für Kieferorthopädie, Zentrum der Zahn-, Mund- und Kieferheilkunde (Carolinum) der Johann Wolfgang Goethe-Universität Frankfurt am Main. Germany

AIM: During recent years the number of adult patients seeking orthodontic treatment has increased. This implies the need for bonding orthodontic brackets with respect to various dental restorative materials. Therefore the aim of this study was to investigate the adhesive strength of brackets on a ceramic surface dependent on various surface conditioning. MATERIALS AND METHOD: Twenty specimens of feldspatic ceramic (Cerec Vitablocks) were divided into four groups and divided into the following surface treatments: (1) a silica-modified aluminium-trioxide sand (Rocatec-System) and silane were applied to the porcelain surfaces, (2) sandblasting 50 µm aluminium trioxide

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followed by hydrofluoric acid and silane, (3) sandblasting 110 µm aluminium trioxide followed by hydrofluoric acid and silane and (4) hydrofluoric acid followed by silane. After surface treatment, metal brackets (Smartclip 3M Unitek, Monrovia, California, USA) were bonded with Transbond™ XT (3M Unitek) to the specimen. Because of the rectangular form of Cerec Vitablocks it was possible to prepare one specimen with four brackets on each side of the specimen. Therefore 80 shear tests were carried out by a detachment machine, which had an integrated analyzer (Digital Force Gauge, Model SH-500; PCE Group oHG, Meschede, Germany). For statistical analysis, the one-way analysis of variance (ANOVA) and the Scheffé’s test for multiple comparisons were used to analyze group differences. RESULTS: Statistically significant differences were found between groups 1 and 2 (P = 0.001), between group 1 and 3 (P = 0.001) and between group 1 and 4 (P = 0.001). The values for groups 2-4 were all similar and not statistically significant (P value ≥0.05). The mean value and standard deviation of all groups were as follows: group 1: 4,16 ± 0.72 MPa; group 2: 2.96 ± 0.67 MPa; group 3: 2.50 ± 1.03 MPa; group 4: 2.69 ± 0.73 MPa. Using Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 silane resulted in significantly higher bond strength values. CONCLUSION: Silane is a material that is inexpensive, effective and does not have a detrimental effect on health; this technique can be recommended for practice.

198 A RETROSPECTIVE AUDIT TO ASSESS THE QUALITY OF LATERAL CEPHALOGRAMS N Hikmat, C Slipper, Department of Orthodontics, Royal Alexandra Children’s Hospital, Brighton, U.K.

AIM: To assess the quality of lateral cephalograms taken at the Royal Alexandra Children’s Hospital against 15 criteria which need to be met for optimum diagnostic value and t identify common faults and make recommendations to improve the diagnostic quality of the radiographs. Proposed standard: 100% compliant in all categories MATERIALS AND METHOD: A retrospective audit was undertaken of 50 consecutive lateral cephalograms taken between September 2013 and November 2013. The data was recorded on a standardized data collection form. Each of the 15 quality criteria were assessed as either met or not met. RESULTS: Only eight out of 15 of the criteria points were 100 per cent compliant. The following did not meet the criteria: correct head position, occlusion, ear rod position, point A and UIA/LIA visible, ruler for calibration, jewellery present and no appropriate collimation. The standard set was not met. CONCLUSION: Only eight out of 15 points met the standards set. Discussions are taking place with the radiology team about adding collimation and a mirror has been recommended to assist with head position. A checklist has also been provided to ensure jewellery is removed prior to exposure and the use of collimation to reduce the radiation exposure to the skull.

199 A TWO CYCLE RETROSPECTIVE AUDIT OF THE BASIC PERIODONTAL EXAMINATION AS PART OF THE ROUTINE ORTHODONTIC EXAMINATION A Hindocha, N Patel, S Visram, J Turner, Orthodontic Department, Birmingham Dental Hospital, U.K.

AIMS: To identify if 100 per cent of all new adult orthodontic patients have a basic periodontal examination (BPE) carried out as part of their initial consultation in accordance with the British Society of Periodontology (BPE) guidelines and whether appropriate referrals to treat the periodontal condition are being made. The second cycle aimed to investigate whether the implemented changes were effective at demonstrating an improvement. MATERIALS AND METHOD: A retrospective audit of 90 clinical records was carried out with cycle 1 from January to June 2010. Data collected included a record of: age, BPE record, oral hygiene status, grade of the clinician, and whether an appropriate referral was made. Changes were implemented and a second audit cycle was carried out retrospectively collecting data from 90 records between January and October 2013.

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RESULTS: Only five patients had a BPE recorded during cycle 1 (n = 90). Referrals for addressing a periodontal condition were made for eight patients, with five being referred to their general dental practitioner (GDP) and three to the periodontal department. Oral hygiene was recorded for all patients. Changes implemented included the ordering of more probes to ensure their provision in every examination kit, the new patient proforma was altered to include a BPE check box, and the results of this audit were shared. Cycle 2 demonstrated a significant improvement whereby 55 patients had a BPE recorded, of which 43 records contained the updated proforma and 13 records the old proforma. This highlights the effectiveness of the updated proforma sheet. Referrals for addressing a periodontal condition were made for 13 patients, with eight being referred to their GDP and five to the periodontal department. Oral hygiene status was recorded for all patients. CONCLUSION: Whilst significant improvements have been a made, there is a need to educate all staff to use the new proforma, and to remove the old proforma from the clinic. It is believed that further education of the Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 entire department will improve the BPE record keeping in order to meet the gold standard of 100 per cent.

200 CLINICAL COMPARISON OF DIFFERENT SPACE OPENING MECHANICS J Horvath, Department of Community Dentistry, Faculty of Dentistry, Semmelweis University, Budapest, Hungary

AIM: To introduce the ‘simple space opening spring’ (SSOS) and to qualitatively compare the SSOP and other space opening mechanics during clinical use. SUBJECTS AND METHOD: Twenty patients with upper anterior space deficit treated with four different mechanics to open space. The four groups were: A. Expansion loop in the main arch, B. Open coil spring in the main arch, C. Composite stops on a superelastic arch, D. SOPS spring. Each group consisted of five subjects. During space opening treatment the following were compared: handling (simplicity, chair time for inserting and activation), effectiveness, control of arch form, hygiene, patient comfort, costs. RESULTS: In space opening the most effective mechanic is the expansion arch, because it works without friction. However, group A had the lowest level of arch control. The bending of it needs time and also costs, but material costs are low. It usually causes discomfort for the patient, and it is difficult to clean it. Groups B and D had same levels of effectiveness and control on arch form because they work along an ideal arch. Coil spring (group B) insertion and activation need more time and the material costs are higher but it is excellent both with regard to comfort and hygiene. The superelastic wire with stops (group C) was the least effective due to its low level of force, but it can be useful in patients with minimal crowding. However, it is the best in comfort and hygiene. The SOPS (group D) was positioned in the middle of the range with regard to effectiveness but it has good arch form control quick and is a cheap solution. However, there are problems with hygiene and patient comfort. CONCLUSION: For opening spaces various mechanics, which differ from each other in advantages and disadvantages, can be chosen. In an actual case and circumstances a decision has to be made on which to use to achieve the best result.

201 A STUDY OF THE MAIN OCCLUDING AREA IN SUBJECTS WITH MANDIBULAR PROTRACTION M Hoshino, K Takeo, D Koide, A Aoki, K Yamada, Matsumoto Dental University, Nagano, Japan

AIM: To investigate the difference in location of the main occluding area (MOA) between patients with mandibular protrusion (MP) and normal occlusion (NO). SUBJECTS AND METHOD: Eight patients with MP and eight with NO were instructed to clench a piece of temporary material in the particular occluding area that was preferably used during mastication. The MOA was judged by locating the tooth on which the temporary stopping rested. RESULTS: The MOA in the NO and MP groups was located in the upper and lower first molar areas, and the upper first molar and the lower second molar, respectively. The MOA in the MP group was located more

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medially and anteriorly in the upper dental arch and more laterally and posteriorly in the lower dental arch compared with the NO group. CONCLUSION: The location of the MOA in the MP group is related to the antero-posterior position of the maxilla and mandible.

202 EVALUATION OF THE EFFECTS OF DIFFERENT FORCE DIRECTIONS ON DENTOFACIAL STRUCTURES DURING MAXILLARY PROTRACTION E Hudamlı, S Elekdag-Turk, T Turk, Department of Orthodontics, Faculty of Dentistry, University of Ondokuz Mayis, Samsun, Turkey

AIM: To evaluate the dentofacial effects of protraction forces with different directions. SUBJECTS AND METHOD: This study consisted of two groups, each containing 13 patients. The average Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 chronological age was 11.85 ± 0.97 years and 11.86 ± 1.72 years for the first and second groups, respectively. The subjects had an Angle Class III molar relationship with a negative overjet or an edge-to-edge incisor relationship. For both groups, Hyrax appliances were activated every 12 hours during the first week and deactivated every 12 hours during the second week. This activation/deactivation/activation procedure was repeated. For both groups, a protraction force was applied via a modified headgear facebow. The elastics were inserted from the outer bow to the pre-labial arch of a Delaire-type facemask. In the first group the inner bow was inserted from the distal openings of the upper first molar tubes. The direction of force was parallel and 15 mm above the occlusal plane. In the second group the inner bow was inserted from the distal openings of the upper first premolar tubes. The direction of force was 10 mm above and 20 degrees to the occlusal plane. A total force of 700 g was applied in both groups. During the first 3 months the protraction force was applied for 16-18 hours in both groups. For the second 3 months the application time was reduced to 12 hours with the same force level. During the second 6 months the patients were instructed to use nightime only. RESULTS: A significant increase of SNA angle and decrease of SNB angle were observed in both groups. As a result of these changes the increase of ANB angle was found to be significant. In both groups, vertical facial heights showed significant increases. CONCLUSION: The Class III malocclusion was corrected with anterior movement of the maxilla and posterior movement of the mandible in both groups. Although less anterior rotation was observed with anterior movement of the force application point, there was no significant difference between the groups.

203 EFFECTS OF MAXILLARY OR BIMAXILLARY OSTEOTOMY ON TEMPOROMANDIBULAR DISORDERS AND ON SNORING T Hulkko, J Kellokoski, R Myllykangas, R Pahkala, Institute of Dentistry, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland

AIM: To evaluate signs and symptoms of temporomandibular disorders (TMD) and snoring in Finnish adults before and after maxillary or bimaxillary surgical-orthodontic treatment. SUBJECTS AND METHOD: Twenty nine females and 11 males (mean age 31.8 years, SD 13.9) who underwent maxillary (n = 24) or bimaxillary (n = 16) osteotomy between 1999 and 2011. The most common primary diagnoses of the patients were maxillary hypoplasia/retrognathia, mandibular hyperplasia/prognathia, anterior open bite and crossbite. The patients’ TMD signs and symptoms and frequent snoring were recorded before pre-operative orthodontic treatment and about two years after maxillary or bimaxillary surgery. The change in the frequency of headache was tested with the Wilcoxon signed-ranks test. The McNemar test was used to assess the significance of changes in TMD signs before and after treatment. Chi-square statistics and the Fisher exact test were used to analyze the differences in prevalence of TMD and snoring between genders. RESULTS: At the baseline the most common TMD signs were muscle pain (43%), clicking (38%) and deviation on opening (28%). About one-third of the patients suffered from weekly headache (30%) and snoring (38%), and 23 e107

per cent had bruxism. With treatment the improvement was most remarkable in headache and in masticatory muscle pain (P < 0.001 and P = 0.022, respectively). No significant difference between genders was found in TMD signs at the beginning of treatment, only muscle pain tended to be more common among females. At baseline no gender difference was found in the prevalence of snoring, but post-operatively the difference was statistically significant (P = 0.014). With treatment snoring disappeared in more than half of the women but in men snoring seemed to persist. CONCLUSION: Maxillary or bimaxillary surgical-orthodontic therapy is a good choice of treatment to reduce especially myogenous TMD-pain in patients with severe malocclusions. Interestingly, with maxillary/maxillomandibular treatment females seemed to get more relief from snoring compared with males. The improvement in headache highlights the significance of a harmonic and stable occlusion.

204 EVALUATION OF THE INTERFACE BETWEEN SLA TREATED MINI-IMPLANTS AND BONE WITH FOCUSED Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 ION BEAM AND TRANSMISSION ELECTRON MICROSCOPIC TECHNIQUES M Hwang, S-M Kang, Y-J Seo, K-H Park, S-H Kim, Department of Orthodontics, Kyung Hee University, Seoul, Korea South

AIM: To evaluate the implant-bone interface, the orthodontic sand blasted with large grit and acid etched (SLA) surface treated mini-implants removed from patients after treatment were frozen to maintain the natural state. Focused ion beam (FIB) milling and transmission electron microscopic (TEM) were used to investigate chemical osseointegration of the implant-bone interface in nano resolution through electron energy loss spectroscopy (EELS) analysis. MATERIALS AND METHOD: The orthodontic mini-implants used were surface treated C-implants (Ti V Grade Alloy, threaded mini-implants). The selection criteria of the implants were: 1) Used in orthodontic treatment and planned for removal between March 2011 to September 2012, 2) Large resistance on removal with a manual screwdriver, 3) Bone attachment identified with the naked eye on removal of the mini-implants. Among 100 mini-implants removed, total 22 mini-implants (1.8 mm in diameter, 8.5 mm in length C-implant) satisfied above criterion. The removed mini-implants were placed into saline solution and cryopreservation performed within 1 hour. Cryopreservation was adopted to prevent any damage to the sample during the process of the fixation, making a specimen with FIB, and transferring for TEM observation. RESULTS: Observation of bone and implant surface using scanning electron microscopy and the FIB technique showed separation and cracking of the bone-implant interface for most mini-implants. That is, retention of implant is mostly considered as mechanical retention caused by rough surface of SLA surface treated area. In TEM analysis, from some specimens (2 of 22), tight contact was found between bone and Ti. In EELS analysis, chemical bonding of dispersed Ca and Ti on sample #4 could be confirmed. CONCLUSION: SLA surface treated orthodontic implants can provide chemical integration between bone and implant.

205 LATERAL VIEW PHOTOGRAPHS AS A TOOL FOR ASSESSING MORPHOLOGICAL RISK FOR SLEEP DISORDERED BREATHING IN CHILDREN – THE PHYSICAL ACTIVITY AND NUTRITION IN CHILDREN STUDY T Ikävalko1, T Lakka1, H Tuomilehto2, M Närhi1, R Pahkala1, Institute of Dentistry, University of Eastern Finland, Kuopio and 2Oivauni Sleep Clinic, Kuopio, Finland

AIM: To evaluate the lateral view photograph of the face as a tool for assessing morphological risk (i.e. facial convexity) for sleep disordered breathing (SDB) in children and to test how reliably different health care professionals can visually observe the facial profile in the photographs. SUBJECTS AND METHOD: The present study is part of The Physical Activity and Nutrition in Children (PANIC) study, which is an ongoing two-year controlled exercise and diet intervention study in Finnish schoolchildren. In the present sample there were 382 children (47% girls), the mean age of the children was 7.6 (SD 0.4) years. e108

Lateral view photographs were taken to classify the facial profile as convex, normal or concave. The photographs were examined by a reference orthodontist, a dental student, and seven different healthcare professionals who work with children. Furthermore, to analyze the facial morphology more closely the reference orthodontist evaluated four angular measurements based on 13 digitized soft tissue landmarks of the lateral view photographs. Inter- and intra-examiner consistencies were evaluated using kappa statistics and intraclass correlation coefficient (ICC). RESULTS: Kappa values for inter-examiner assessments between the reference orthodontist and seven observers varied from 0.290 to 0.579, agreement varying between 73 and 79 per cent. The corresponding value of the public health nurse was low (agreement 56%). The highest value was achieved between two orthodontists. The intra-examiner kappa value of the reference orthodontist for assessing the profiles twice (two week interval) was 0.920, the agreement percentage being 93.3. The ICC value for the reference orthodontist’s double soft tissue measurements varied from 0.902 to 0.980. The highest value was for the facial Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 convexity angle. CONCLUSION: In order to recognize the morphological risk for SDB a more profound knowledge of the growth and development of the face is needed. In addition to oral health professionals, other health care professionals might also be in a key role to identify the risk features. The lateral facial photograph is a good method to recognize facial convexity, especially if there is a need for a low-cost and non-invasive method for epidemiological purpose.

206 ASSOCIATION BETWEEN THREE-DIMENSIONAL MANDIBULAR MORPHOLOGY AND CONDYLAR MOVEMENT IN FACIAL ASYMMETRY SUBJECTS M Ikeda, J-i Takada, J J Miyamoto, K Moriyama, Department of Maxillofacial Orthognathics, Tokyo Medical and Dental University, Japan

AIM: Skeletal facial asymmetry is considered to affect the asymmetry of the condyle path. Previous studies have reported on the relationship between condylar movement and facial morphology using posteroanterior cephalograms, with only a few exceptions using three-dimensional (3D) computed tomography (CT) analysis. As such, the relationship between 3D facial morphology and condylar movement remains to be fully elucidated. Therefore, this study sought to evaluate the hypothesis that 3D mandibular morphology is correlated with condylar movement in facial asymmetry subjects. SUBJECTS AND METHOD: Forty-four adult subjects, excluding those with a skeletal Class II malocclusion, were divided into two groups: facial asymmetry with a menton deviation greater than 4 mm (FA, n = 22, 11 males, 11 females, age: 22.2 ± 4.7 years) and non-facial asymmetry with a menton deviation less than 4 mm (NA, n = 22, 11 males, 11 females, age: 25.6 ± 6.4 years). 3D facial morphology was measured using CT. Mandibular functional movement was recorded by computerized axiography (Cadiax®), and condylar path length, horizontal condylar inclination, and the Bennet angle on protrusion were measured. Side-to-side asymmetry [shifted side (SS) versus non-shifted side (nSS)] in mandibular morphology was calculated and condylar movement was assessed using asymmetry ratio (nSS/SS:AR). A Wilcoxon t-test was used to compare measurements between SS and nSS and a Mann-Whitney U-test to compare measurements between the FA and NA groups. Spearman correlation coefficient by rank was used for correlations between 3D mandibular morphology and condylar movement (P < 0.05). RESULTS: Significant differences in the ARs for the measurements of mandibular morphology and condylar movement were found between the FA and NA groups. In the FA group, significant negative correlations were exhibited between mandibular morphology and condylar movement i.e. the ARs of ramal height and condylar unit length versus the AR of condylar path length, as well as the AR of condylar unit length versus the Bennet angle. No significant correlations were found between any of these measurements in the NA group. CONCLUSION: In support of the hypothesis, the results suggest that 3D mandibular morphological asymmetry is associated with condylar movement in facial asymmetry subjects. e109

207 INVESTIGATION OF BACTERAEMIA FOLLOWING PIEZOCISION Z Ileri1, M Akin1, D Findik2, A Erdur1, H Turk Dagi2, Departments of 1Orthodontics and 2Medial Microbiology, Selcuk University, Konya, Turkey

AIM: To investigate the presence of transient bacteraemia following piezocision. SUBJECTS AND METHOD: Thirty subjects (24 girls, 6 boys) with a mean age of 19.6 ± 0.7 years. All patients had a Class I skeletal and dental relationship and underwent non-extraction orthodontic treatment with the Damon-Q system. Piezocision was performed following placement of the orthodontic appliance at the same appointment in all patients. Two 20 mL venous blood samples were taken prior to and 30-60 seconds after the first microincision following an aseptic technique. Samples were inoculated into BACTEC™ Plus aerobic and anaerobic blood culture bottles and blood culturing was carried out by means of the BACTEC blood culture Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 analyzer. The results were analyzed statistically using the McNemar test, at the P < 0.05 level. RESULTS: No bacteraemia was detected in the pre-treatment samples, but it was in three post-operative blood samples. However, this result was not statistically significant (P = 0.250). The respective bacteria were: Gemella sanguinis, Streptococcus pluranimalium and Streptococcus mitis/oralis. CONCLUSION: Pizocision might possibly be related to transitory bacteraemia. Hence, orthodontists should consider the possibility of bacterial endocarditis in at-risk patients when including piezocision in the treatment plan.

208 MECHANICAL PROPERTIES OF ADHESIVES USED FOR FIXED RETAINER BONDING A Iliadi1, J Gugger2, T Eliades2, S Zinelis1, G Eliades1, 1Department of Biomaterials, School of Dentistry, University of Athens, Greece and 2Department of Orthodontics and Paediatric Dentistry, Centre of Dental Medicine, University of Zurich, Switzerland

AIM: The mechanical characterization of bonding adhesives for fixed retainer systems. MATERIALS AND METHOD: Cylindrical specimens (diameter: 15 mm, height: 2 mm, n = 5) were prepared employing five different materials; two restorative composites (Empress Direct, Z-Nano), two orthodontic adhesives (Transbond XT, Transbond LR) and one flowable (Accolade). The materials were light-cured (LED, 40 seconds, 1.2 W/cm2), the directly irradiated surfaces were ground and polished, and then subjected to Instrumented Indentation Testing according to ISO 14577-1. Force to indentation depth curves were monitored during testing employing a 10 N load in a universal hardness testing machine (Zwick ZHU0.2/Z2.5). The mechanical properties tested were the indentation modulus (EIT), the ratio of elastic to total work (ηIT) and Vickers hardness. The results were statistically analyzed by one way ANOVA and significant differences among groups were allocated by post hoc Student-Newman-Keuls multiple comparison analysis (a = 0.05). RESULTS: The mean values and standard deviations for material, EIT (GPa), ηIT (%), and HV were: Empress Direct: 9.7 ± 0.5, 35.7 ±1.0, 50 ± 4; Z-Nano: 9.7 ± 0.3, 49.2 ± 0.5, 88 ±7; Transbond XT: 15.0 ± 0.5, 30.7 ± 1.7, 68 ± 5; Accolade: 6.6 ± 0.3, 38.1 ± 1.0, 35 ±2; Transbond LR: 17.3 ± 0.3, 33.6 ± 1.1, 96 ± 4. CONCLUSION: Significant differences exist in the mechanical properties of the bonding adhesives tested and thus differences in their clinical performance are anticipated.

209 METHODOLOGICAL VARIATION IN ASSESSING THE SETTING OF ORTHODONTIC ADHESIVE RESINS A Iliadi1, C Herzog2, S Baumgartner2, T Eliades2, G Eliades1, 1Department of Biomaterials, School of Dentistry, University of Athens, Greece and 2Department of Orthodontics and Paediatric Dentistry, Centre of Dental Medicine, University of Zurich, Switzerland

AIM: To assess the effect of instrumental analysis on the setting status of orthodontic adhesive resins. e110

MATERIALS AND METHOD: Fourteen metallic brackets were bonded with resin composite orthodontic adhesive (Transbond XT, 3M Unitek) to recently extracted premolars according to the manufacturer’s instructions. All teeth were embedded in epoxy resin and sectioned bucco-lingually. Fourier transform infrared microscopy (FTIRM) and Raman microscopy (RM) were employed for the estimation of the degree of cure (%DC) in the composite. One-way ANOVA was used to analyze data (n = 7, a = 0.05). RESULTS: Samples showed significantly lower %DC when measured with FTIR relative to Raman (52.4 ± 3.2% by FTIR and 61.4 ± 2.6 by RM; P < 0.05). RM significantly overestimated the %DC probably because of the high energy incident beam, which introduced post-irradiation conversion. CONCLUSION: Standardization of the procedure and use of identical instrumentation is suggested to ensure homogeneity of methodology of studies and comparability of results.

210 BOND FAILURE OF FIXED ORTHODONTIC RETAINERS: A SYSTEMATIC REVIEW*** Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 A Iliadi1, C Katsaros2, D Kloukos2, N Pandis2, P Pazera2, Departments of Orthodontics, 1University of Athens, Greece and 2University of Bern, Switzerland

AIM: To evaluate the risk of failure of different fixed orthodontic retention protocols and to assess the evidence on the association of failure with retainer material, adhesive and number of bonded teeth. MATERIALS AND METHOD: The electronic databases, Medline, Embase and Central, were searched with no restrictions for publication date or language. Detailed search strategies were developed for each database. Screening for inclusion eligibility, quality assessment of studies and data extraction was performed independently by two authors using individualized data collection forms. The main outcome was the average risk of bond failure for the study period. Randomized controlled trials and prospective studies were evaluated according to the criteria outlined in the Cochrane Handbook for Systematic Reviews. Retrospective studies were graded according to predetermined criteria by Bondemark. RESULTS: Twenty-four studies satisfied the inclusion criteria. Five randomized controlled trials (RCTs), two of which were of low-to-moderate level of quality, were identified. Seven studies had a prospective design and all were of low quality, except one. Twelve studies were retrospective. The large ‘between study heterogeneity’, possibly attributed to a lack of standardized protocols, and the low quality of the available studies did not permit solid conclusions to be drawn regarding the optimal intervention protocol. The quality of trial reporting was, in general, poor. Three studies assessing glass-fibre retainers [RCT (1) and prospective (2)] reported bond failures from 11 to 71 per cent, whereas 18 studies evaluating multistranded retainers [RCTs (5), prospective (4) and retrospective (9)] reported failures ranging from 12 to 50 per cent. Two comparisons were performed; polyethylene woven ribbon versus multistranded (OR: 1.40; 95% CI: 0.82-2.40) and glass-fibre reinforced versus multistranded wire retainers (OR: 3.84; 95% CI: 2.52-5.87). No statistically significant differences were observed for the former comparison (OR: 1.40; 95% CI: 0.82-2.40), whereas statistically significant differences were indicated for the latter (OR: 3.84; 95% CI: 2.52-5.87). Nevertheless, a slight tendency in favour of multistranded retainers was observed. CONCLUSION: The quality of the available evidence is low. No conclusive evidence was found in order to guide orthodontists in the selection of the best protocol, and best wire type, adhesive and number of bonded teeth attached to the retainer.

211 PHARMACOLOGICAL REGULATION OF OSTEOCLAST DIFFERENTIATION IN ORTHODONTIC TOOTH MOVEMENT K Inami1, H Sawai2, Y Momma-Katao1, M Yoshimi-Shishido1, N Matsumoto1, Departments of 1Orthodontics and 2Internal Medicine, Osaka Dental University, Osaka City, Japan

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AIM: In orthodontic tooth movement, osteogenesis is promoted on the tension side, where osteoblasts play a central role, whereas bone resorption is induced by osteoclasts on the pressure side. To regulate osteoclast differentiation in orthodontic tooth movement, the effects of nitric oxide, oestrogen and caspase on osteoclast differentiation in RAW264 cells, mouse bone marrow macrophages and mice were investigated. MATERIALS AND METHOD: Mouse monocytic RAW264 cells were maintained in MEM-α at 37°C in a humidified

5 per cent CO2 incubator. RAW264 cells 5,000 cells/well were incubated in 96-well plates overnight. The cells were then treated with RANKL and various biological factors. Mouse bone marrow cells were obtained from the tibia of nine-week-old male ddY clean mouse, and cultured in 96 well plates (5.0-103 cells/0.25 mL/well) in the presence of 50 ng/mL mouse M-CSF. After 3 days, non-adherent cells were removed from the culture, and the adherent cells were further cultured for 3 days with varying concentrations of RANKL and various biological factors in the presence of 50 ng/mL M-CSF. Experimental tooth movement was induced by elastic insertion as described previously, with modifications. Eight-week-old male ddY mice were anaesthetized by inhalation of Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 sevoflurane and an intraperitoneal injection of pentobarbital. An orthodontic elastic was inserted between the maxillary first and second molar. RESULTS: NOC-18 (a long-acting nitric oxide donor), ICI 182,780 (an oestrogen receptor antagonist) and Z-VAD- fmk (a pan-caspase inhibitor) augmented RANKL-induced osteoclast differentiation of RAW264 cell and mouse bone marrow macrophage. Furthermore, NOC-18 augmented osteoclast differentiation during experimental tooth movement in mice. CONCLUSION: Various biological factors are involved in osteoclast differentiation. Further, the effect of nitric oxide on osteoclast differentiation has been shown in vivo as well as in vitro. This investigation may help to better understand the causes of root resorption in orthodontics, for primary teeth and alveolar bone resorption in periodontics, bone resorption of the temporal mandibular joint and internal root canal resorption in endodontics.

212 EX VIVO IMAGING OF THE AUTONOMOUS INTRACELLULAR Ca2+ RESPONSES OF OSTEOBLASTS AND OSTEOCYTES IN BONE Y Ishihara1, Y Sugawara1, H Kamioka1, N Kawanabe1, T Yamashiro2, 1Department of Orthodontics, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama and 2Department of Orthodontics and Dentofacial Orthopedics, Osaka University Graduate School of Dentistry, Suita, Japan

AIM: Bone cells form a complex three-dimensional network consisting of osteoblasts and osteocytes embedded in a mineralized bone matrix. Ca2+ acts as a ubiquitous secondary messenger in various physiological cellular processes and transduces numerous signals to the cell interior and potentially to the genome. However, the intracellular Ca2+ dynamics of bone cells have not been evaluated in intact bone. MATERIALS AND METHOD: A novel ex vivo live Ca2+ imaging system that allows the dynamic autonomous intracellular Ca2+ concentration (Ca2+)i responses of intact calvarial explants to be observed without damaging the bone network is demonstrated. RESULTS: This live imaging analysis provided evidence for the occurrence of repetitive and autonomic (Ca2+)i responses in osteoblasts and osteocytes in living bone explants. Thapsigargin, an inhibitor of the endoplasmic reticulum that induces the emptying of intracellular Ca2+ stores, abolished these (Ca2+)i responses in both osteoblasts and osteocytes, indicating that Ca2+ release from intracellular stores plays a key role in the (Ca2+)i responses of these bone cells in intact bone explants. Another possible (Ca2+)i transient system to be considered is gap junction (GJ) through which Ca2+ and other messenger molecules move, at least in part, across cell-cell communications; therefore, the role of GJ in the maintenance of the autonomic (Ca2+)i responses observed in intact bone was also investigated. Treatment with three distinct GJ inhibitors significantly reduced the proportion of responsive osteocytes, indicating that GJs are important for the maintenance of (Ca2+)i responses in osteocytes, but less in osteoblasts.

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CONCLUSION: Bone cells in intact bone explants showed autonomous (Ca2+)i responses that required the release of intracellular Ca2+ stores. In addition, osteocytes specifically modulated these oscillations via cell-cell communication through GJ, which maintains the observed (Ca2+)i responses of bone cells.

213 EVALUATION OF UPPER AIRWAY VOLUME IN GROWING SKELETAL CLASS II PATIENTS AFTER MANDIBULAR ADVANCEMENT WITH FUNCTIONAL APPLIANCES S Isidor, G Di Carlo, P M Cattaneo, Section of Orthodontics, Aarhus University, Denmark

AIM: To assess, three dimensionally, upper airway modification after mandibular advancement with functional appliances in Class II growing patients compared with a control group. MATERIALS AND METHOD: Pre-and post-treatment cone beam computed tomographic scans of 20 patients were selected from a group of previously treated patients. Their ages were in the range of 9 to 12 years. The Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 test group was matched with a control group, in order to exclude the effect of growth. Total and partial volumes (lower nasopharynx, velopharynx and oropharynx) of the upper airway was calculated. Non-parametric tests were used to evaluate the data. RESULTS: In the activator group, all partial volumes as well as total volume were significantly larger at the end of treatment (P < 0.003), while only velopharynx was significantly different in the control group (P = 0.04). Differences in volume of the upper airway between the functional and control group showed that a statistical difference was present only for oropharynx (P = 0.022) and total volume (P = 0.025), with the activator group showing a larger volume increase. CONCLUSION: An increase in upper airway volume was found after mandibular advancement performed with functional appliances. This was mainly due to an increase at the oropharynx. However, to assess the stability of these changes it would be necessary to have a long-term follow-up.

214 CEPHALOMETRIC AND HISTOLOGICAL ANALYSIS OF ORTHOPAEDIC EFFECTS OF BONE-ANCHORED MAXILLARY PROTRACTION IN A BEAGLE MODEL Y Ito, T Kawamoto, K Moriyama, Department of Maxillofacial Orthognathics, Tokyo Medical and Dental University, Japan

AIM: There are some clinical reports on bone-anchored maxillary protraction (BAMP) using Class III elastics between miniplates implanted for skeletal anchorage in the upper and lower jaws. However, there is currently no basic information on the biology of this treatment modality. Hence, the aim of this study was to establish an animal model of BAMP using beagles, and to verify the effects of such treatment in this model. MATERIALS AND METHOD: Ten immature (90-day-old) male beagles were used. After arrival at the facility at 90 days of age (day –30), all animals were quarantined for 10 days. On day –20, one miniplate per jaw quadrant was placed and secured with screws. From days 0 to 60, miniplates in the dogs in the intermaxillary traction group (group T, n = 5) were loaded with coil springs. In the control group (group C, n = 5), the miniplates underwent no force application. Every 20 days from day –20, all dogs were assessed by measuring body weight, taking photographs, and acquiring standardized lateral cephalometric radiographs using a specially designed cephalostat. Cephalometric analyses were performed, and the two groups were compared using linear and angular analyses. New bone formation was labelled by double-fluorochrome administration with calcein (20 mg/kg) on day 45 and tetracycline (30 mg/kg) on day 55. The animals were sacrificed on day 60, and bone sections of the zygomaticomaxillary sutures were analyzed using histomorphometry with fluorescence microscopy. The two groups were compared with the Mann-Whitney U-test (P < 0.05). RESULTS: Cephalometric analysis indicated significant maxillary advancement and retroclination of the maxillary incisors in group T, with concomitant significant posterior relocation of the condyles and proclination of the mandibular incisors. In histomorphometric analysis, the BV/TV in group T was significantly smaller than that in

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group C (P < 0.01), and the MAR and BFR/BS in group T were significantly larger than those in group C (P < 0.01). Vigorous bone apposition at the zygomaticomaxillary suture was only detected in group T. CONCLUSION: Use of this newly developed animal model supports the application of BAMP for clinical orthopaedic treatment.

215 PREFERENCES OF ANTERIOR TOOTH PROPORTION BY ORTHODONTISTS, GENERAL DENTISTS AND LAYPERSONS B Izquierdo Gómez, M López Marí, F Cascales Moya, A Vicente Hernández, L A Bravo González, Ortodoncia Department, Universidad de Murcia, Spain

AIM: To determine how different tooth proportions can affect the aesthetic evaluation of the smile among orthodontists, general dentists and laypersons. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 MATERIALS AND METHOD: Using Adobe Photoshop C3 (Adobe systems Inc., San Jose, California, USA), four images of a smile were generated with different tooth proportions: golden mean, golden, Preston and recurring aesthetic dental (RED). These photographs were evaluated by orthodontists, general dentists, and laypersons aged between 40 and 60 years of age. The proportion of male-female subjects was 25:25 in all groups. Each participant was asked to fill out a web questionnaire giving each image a value of 1 to 5, with 1 being the most negative value aesthetically and 5 the most positive aesthetically. Data were analyzed using the Kruskal-Wallis (P < 0.05) and Mann-Whitney tests applying the Bonferroni correction (P < 0.016) RESULTS: No significant differences were found between orthodontist, general dentists and laypersons in the evaluation of the images with golden mean, golden and Preston proportions (P > 0.05). Regarding the RED proportion the Kruskal-Wallis test detected a global significant difference (P < 0.05). However the Mann- Whitney test (applying the Bonferroni correction) did not detect this significant difference (P > 0.016) between the groups of evaluators when they were compared two by two at the level of significance fixed. CONCLUSION: The aesthetic preferences of orthodontists, general dentists and laypersons are similar when evaluating different anterior tooth proportions.

216 EVALUATION OF THE SURFACE ROUGHNESS OF ENAMEL ADJACENT TO ORTHODONTIC BRACKETS BY MEANS OF FOCUS VARIATION MICROSCOPY T Jäcker, D Visel, P-G Jost-Brinkmann, T M Präger, Abteilung für Kieferorthopädie, Charité - Universitätsmedizin Berlin, Germany

AIM: To prospectively investigate in situ the surface roughness (Sa) of the enamel surrounding orthodontic brackets in relation to different enamel conditioning methods. SUBJECTS AND METHOD: Fifteen healthy probands (23-32 years, 8 males, 7 females) with good oral hygiene participated in this 28 day study. All participants wore a removable splint being fixed to the teeth, for at least 20 hours daily. In this appliance, four enamel specimens from extracted human third molars were embedded on both buccal sides. One specimen [group A] remained untreated, the three others were provided with an orthodontic bracket (Victory APC II, 3M Unitek). In group B enamel conditioning was performed by the self- etching primer iBond Gluma inside, in group C by the fluoride-releasing self-etching primer Transbond Plus, and in group D, by the conventional acid-etch-technique (35% phosphoric acid and Transbond XT). Sa was evaluated extraorally by means of a three-dimensional (3D) scanning microscope (FVSM, Alicona Imaging, Grambach/Graz, Austria), a non-contact optical microscope based on the focus variation concept. The baseline measurement (T0) was taken immediately after bracket application and before incorporating the appliance, the final measurement on day 28 (T4). The results were investigated for normal distribution (Komolgorov-Smirnov-test) and subsequently t-tests for paired samples (P < 0.05) were performed, assessing the difference of the Sa-value

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between T4 and T0 for each group separately. The change in Sa-value in all four groups was compared by means of a one way ANOVA (P < 0.05). RESULTS: In all four groups a significant difference between the Sa-value measured at T0 and T4 could be observed. However, no significant difference could be found between the four groups. CONCLUSION: Regardless of the method of enamel conditioning, the Sa of enamel may decrease if good oral hygiene is applied. Focus variation 3D scanning microscopy is a powerful tool for evaluating the surface topography of enamel adjacent to orthodontic brackets.

217 MECHANICAL LOADING INFLUENCES THE EFFECTS OF BISPHOSPHONATES ON HUMAN PERIODONTAL LIGAMENT FIBROBLASTS C Jacobs, I Dirks, S Schramm, S Grimm, H Wehrbein, Department of Orthodontics, University of Mainz, Germany Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 AIM: There is increasing evidence that mechanical loading caused by orthodontic tooth movement can affect the effects of bisphosphonates. The aim of the study was to investigate the changes in human periodontal ligament fibroblasts (HPdLF) when tensile strain (TS) was applied combined with the presence of clodronate or zoledronate. MATERIALS AND METHOD: TS is thought to mimic that found in vivo during orthodontic treatment. HPdLF were cultured with 5 µM and 50 µM clodronate or zoledronate for 48 hours and applied to TS for 12 hours in vitro. Different magnitudes of TS (5% and 10%) were applied to HPdLF to mimic low and high forces. Viability was verified by MTT assay and apoptosis rate via Caspase 3/7 assay. Gene expression of receptor activator of nuclear factor kappa-B ligand (RANKL) and osteoprotegerin (OPG) were investigated using real-time polymerase chain reaction. OPG was also analyzed by ELISA and RANKL by immunocytochemical staining. A P-value of less than 0.05 was considered statistically significant. RESULTS: Zoledronate (50 µM) reduced the viability of HPdLF (76% versus 100%), whereas clodronate (50 µM) did not affect the viability of HPdLF. Five per cent TS combined with zoledronate decreased cell viability to 53 per cent; 10 per cent TS and clodronate to 79 per cent with increased caspase 3/7 activity. Clodronate (5 µM) led to a slight increase of OPG gene expression, zoledronate (5 µM) decreased OPG gene expression. Combined with 5 per cent TS, both led to increased OPG gene expression (2-3-fold). ELISA demonstrated the highest OPG values for clodronate or zoledronate with 5 per cent TS. Zoledronate increased gene expression of RANKL (4- fold). Combined with 5 per cent TS this increase was abolished. Ten per cent TS in combination amplified the increase of RANKL ending up with a 9-fold gene expression by clodronate and a 5-fold gene expression by zoledronate. RANKL protein was also detected via immunofluorescence. CONCLUSION: Mechanical loading alters the effects of bisphosphonates on the viability, apoptosis rate and OPG/RANKL system of HPdLF, dependent on the applied strength. Low forces and bisphosphonates increase factors for bone apposition, whereas high forces combined with bisphosphonates stimulate factors for osteoclastogenesis.

218 TREATMENT EFFECTS AND SIDE-EFFECTS OF FIXED APPLIANCE ORTHODONTIC TREATMENT: A META- ANALYSIS ON INITIAL WIRES, WIRE SEQUENCES AND BRACKETS A Jäger1, C Bourauel2, I Konstantinidis3, K Papadopoulou1, S Papageorgiou1, Departments of 2Orthodontics and 2Oral Technology, University of Bonn, Germany and 3Mount Sinai School of Medicine, New York, USA

AIM: Fixed-appliance therapy is an integral part of contemporary orthodontic treatment, but clinical evidence remains scarce. The objective of this review was to systematically appraise the therapeutic effects and side- effects of orthodontic brackets and wires used during the fixed-appliance phase of orthodontic treatment. MATERIALS AND METHOD: Medline and 18 other databases were searched for randomized and quasi- randomized clinical trials without any restrictions up to April 2012. After duplicate study selection and data

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extraction, the risk of bias of individual studies was assessed with the Cochrane risk of bias tool and risk of bias across studies was assessed with the Grades of Recommendation, Assessment, Development and Evaluation approach. Random-effects meta-analyses, mixed-effects subgroup analyses and sensitivity analyses were performed with mean differences or risk ratios and the corresponding 95 per cent confidence and prediction intervals. RESULTS: Regarding initial archwires or archwire sequences, a total of 16 trials with 1108 patients were identified. Significantly higher irregularity correction was achieved by austenitic-active nickel titanium (NiTi) initial wires compared with martensitic stabilized NiTi initial wires. Use of a sequence including martensitic- active CuNiTi wires was associated with significant changes in treatment duration and pain after wire insertion compared with a sequence of martensitic-stabilized NiTi wires. Regarding brackets, a total of 25 trials with 1321 patients were identified. The duration of orthodontic treatment was on average 2.01 months longer among patients with self-ligating brackets (95% confidence interval: 0.45 to 3.57). The 95 per cent prediction interval Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 for a future trial indicated that the difference could be considerable (–1.46 to 5.47 months). Statistically significant differences in post-treatment intercanine and intermolar width were found between self-ligating and conventional brackets, which were clinically unimportant. Treatment characteristics, outcomes, and side-effects were clinically similar between the two bracket types. For most bracket characteristics, the evidence is insufficient. Some meta-analyses included trials with a high risk of bias, but sensitivity analyses indicated robustness. CONCLUSION: Based on existing evidence, no clinical recommendation can be made regarding the various archwire characteristics, bracket material or different ligation modules. For self-ligating brackets, no conclusive benefits could be proven, while their use was associated with longer treatment duration.

219 ADHESIVE REMNANTS AND ENAMEL LOSS FOLLOWING REMOVAL OF BONDED MOLAR TUBES J Janiszewska-Olszowska1, K Tandecka2, T Szatkiewicz2, K Sporniak-Tutak3, K Grocholewicz1, Departments of 1General Dentistry and 3Dental Surgery, Pomeranian Medical University, Szczecin and 2Department of Fine Mechanics, Koszalin University of Technology, Poland

AIM: To perform a precise measurement of the volume and height of adhesive remnants as well as the volume and depth of enamel loss resulting from debonding molar tubes from human enamel. MATERIALS AND METHOD: The buccal surfaces of 15 extracted human molars were directly scanned with an optic blue-light three-dimensional (3D) scanner to the nearest 2 μm. After 20 second etching, molar tubes were bonded to the buccal surfaces and debonded after 24 hours storage in 0.9 per cent saline. 3D scanning proceeded after debonding. Superimposition and comparison were undertaken and shape alteration of the entire object was analyzed using specialized computer software. Residual adhesive height as well as enamel loss depth were obtained for every location of the entire buccal surfaces. Residual adhesive volume and enamel loss volume were calculated for every tooth. RESULTS: The maximum height of adhesive remaining on the enamel surface was 0.76 mm and the volume on particular teeth ranged from 0.047 mm3 to 3.24 mm3. The median adhesive remnant volume was 0.988 mm3. Mean depths of enamel loss for particular teeth ranged from 0.0076 to 0.0416 mm. The greatest maximum depth of enamel loss was 0.2 mm. The median volume of enamel loss was 0.15 mm3 and the maximum volume 1.484 mm3. CONCLUSION: Debonding molar tubes leaves a certain amount of adhesive on the enamel, however the interface fracture pattern varies for particular teeth. Bond failure visually occurring at the interface between bonding material and enamel results in a significant amount of enamel loss.

220 FIXED ACRYLIC BITEPLATES: QUALITY OF LIFE P Jindra, Institute of Clinical and Experimental Stomatology, Charles University, Prague, Czech Republic

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AIM: To evaluate the quality of life of patients treated with fixed acrylic biteplates. MATERIALS AND METHOD: A questionnaire study was performed. Forty one questionnaires were sent to patients, who had been treated with multibracket appliances and fixed acrylic biteplates. RESULTS: Patients reported the following difficulties: chewing (85%), speech disturbances (80%), adhering of food particles (60%), pain (45%), cheek and lip soreness (40%), tongue soreness (40%). The speech disturbances mentioned were mainly fricatives, rotacismus bohemicus and stop alveolar consonants. Sixty five per cent of patients mentioned that speech disturbances were noticed by other people. The time needed for adaptation to a fixed acrylic biteplate was, on average, 5 weeks. The ratio of subjective adaptation was, on average, 79 per cent. Some short-term speech disturbances were also mentioned after biteplate removal. Spectral analysis was also used for speech studies. CONCLUSION: A fixed acrylic biteplate is a difficult appliance with respect to adaptation. Thorough information Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 about possible adaptation problems is necessary during informed consent.

221 THE IMPORTANCE OF NATURAL HEAD POSTURE IN ORTHODONTIC AND ORTHOGNATHIC TREATMENT PLANNING F Juhasz1, N Vajda2, B Croy2, B Nemes1, 1Department of Pedodontics and Orthodontics, 2Semmelweis University, Budapest, Hungary

AIM: Establishing easily recognisable and reproducible reference points and planes is necessary in cephalometric analysis. Most analyses use the Sella-Nasion line or the Frankfort horizontal plane. These intracranial reference planes vary greatly compared with natural head posture (NHP) i.e. the extracranial reference plane that uses the true vertical and horizontal planes. Thus the application of internal reference planes is questionable in orthodontics and especially in orthognathic treatment planning. SUBJECTS AND METHOD: Fifty patients were examined to compare their intracranial reference lines to their true horizontals. All subjects were healthy, free of craniomaxillofacial discrepancies and had not previously been treated orthopaedically. In Adobe Photoshop, photographs and cephalograms were superimposed and the angle between the intracranial reference planes (Sella Nasion, Frankfort horizontal) and the horizontal plane were measured. Lines representing the true vertical axis were shown in the background of the photographs. RESULTS: The mean angle between the SN line and the true horizontal line was 6.97 degrees, with a standard deviation of 5.74 degrees. The lowest angle was –5.3 degrees and the highest 17.8 degrees which gives a 23.1 degrees range of variation. The mean angle between the Frankfort horizontal and the true horizontal line was – 2.28 degrees with a standard deviation of 4.68 degrees. The lowest angle was –13.4 degrees while the highest was 7.4 degrees, thus the range of variability was 20.8 degrees. CONCLUSION: The number of software products that make not only cephalometric and photographic analysis and documentation possible, but enable resizing and superimposition of photographs and cephalograms is increasing. With the visual indication of the true horizontal or vertical lines, NHP gives a real reference plane to orthodontic or orthognathic treatment planning. By increasing the sample size it becomes possible to measure the relationship of NHP and different facial types.

222 A SURVIVAL ANALYSIS STUDY OF ORTHODONTIC MINIPLATES W-Y Jung, L Lin, S-J Kim, Y-G Park, S-H Kim, Department of Orthodontics, Kyung Hee University, Seoul, Korea South

AIM: To present the survival and complication rates of miniplates. SUBJECTS AND METHOD: Two hundred and seventeen patients who had undergone orthodontic treatment with fixed appliances and C-tube. C-tube (Jin Biomed Co., Bucheon, Korea) is a type of orthodontic miniplate. They

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are made in three types: I-type, T-type, and cross-type for different anatomic sites. The number of C-tubes examined in this study was 341. Survival was classified as a C-tube that functioned in the mouth regardless of the complications. Success was defined as survival without any complication. Kaplan-Meier survival curves were plotted and the log rank test was used to identify the variables associated with failure. Prognostic variables were identified with the Cox proportional hazard model. RESULTS: Fourteen miniplates had to be removed, and 32 plates showed complications. The cumulative 2-year survival and success rates without any complication were 0.91 and 0.80, respectively. Oral hygiene maintenance and clinician experience were the most important variables for miniplate survival. CONCLUSION: The survival rate of miniplates was excellent. Oral hygiene maintenance and clinician experience may play an important role when placing a miniplate.

223 RISK FACTORS IN DEVELOPING SEVERE INCISOR ROOT RESORPTION ASSOCIATED WITH IMPACTED Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 MAXILLARY CANINES K Kaczor-Urbanowicz1, A Becker1, M Zadurska2, S Chaushu1, Departments of Orthodontics, 1Hebrew University of Jerusalem and 2Medical University of Warsaw, Poland

AIM: A minor degree of benign resorption of maxillary incisor roots in association with an impacted maxillary canine is a well-recognized phenomenon and it is generally of limited clinical significance. Severe incisor root resorption (SIRR) is rare and it threatens the viability of the tooth. The aim of this study was to investigate differences in the prevalence of SIRR in relation to gender and location of untreated impacted maxillary canines. MATERIALS AND METHOD: Panoramic and periapical radiographs taken of the maxillary incisors of 55 untreated patients (11-15 years old) with severely resorbed roots, associated with canine impaction. The amount of SIRR was measured directly on the radiographs and was examined by two orthodontists using a viewer. The following variables were recorded: gender, age, position of the impacted canines in relation to the adjacent teeth (palatally, buccally or in line with the dental alveolus). The patients were classified according to gender, canine location and affected incisor type. Resorption was considered severe when it affected at least one-third of the length of the root of the incisor. RESULTS: There was a markedly elevated prevalence (83%) of females in the examined sample, in comparison with males (17%). Patients with palatally impacted maxillary canines (75%) that were mesially angulated and positioned in the middle third of adjacent incisor root, were at much higher risk of developing SIRR compared with subjects with buccally impacted canines or mid-alveolus canines. CONCLUSION: SIRR, as opposed to minor root resorption, associated with an impacted canine is significantly more frequently found among females, suggesting that genetic or hormonal aetiologic factors play a significant role. SIRR is more frequently found in severely displaced, palatally impacted canines, which are mesially angulated and positioned in the middle third of adjacent incisor root. Accordingly, patients with impacted maxillary canines should be screened for SIRR, particularly females with severely displaced, palatally impacted canines.

224 EFFECTS OF AGEING ON CELL PROLIFERATION AND ORTHODONTIC TOOTH MOVEMENT ɫɫ T Kageyama1, K Yamada1, N Sahara2, 1Department of Orthodontics and 2Hard Tissue Research, Institute for Oral Science, Matsumoto Dental University, Nagano, Japan

AIM: To investigate the effects of ageing on the amount of tooth movement and concomitant changes of cell proliferation in the periodontal tissue adjacent to orthodontically treated tooth roots. MATERIALS AND METHOD: Wistar rats (n = 32) of four different age groups (10, 30, 50, and 80 weeks of age). The maxillary first molars (M1) were retracted mesially with a closed coil-spring for 2 weeks. Twenty-four age- matched untreated rats were used as the controls. The amount of tooth movement was measured as the

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distance between the M1 and the maxillary incisor at the gingival level. Parahorizontal serial sections of the M1 were made after tooth movement. The changes in periodontal tissue turnover were assessed histochemically and immunohistochemically. The sections were stained for tartrate resistant acid phosphatase activity or CD34 activity. RESULTS: Two weeks after the start of tooth movement, the amount of tooth movement was found to decrease with age and was significantly different among the four age groups. Quantitative analysis demonstrated that, in the experimental groups, the number of CD34 positive cells in the periodontal membrane increased significantly compared with that of each age-matched untreated group. However, the rate of increase decreased in an age- related manner. CONCLUSION: These results suggest that the age-dependent decrease angiogenesis activity in periodontal tissue, in response to mechanical forces, might decrease the amount of tooth movement. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 ɫɫ Winner of an EOS poster award

225 CLINICAL EVALUATION OF PLATE-TYPE TEMPORARY ANCHORAGE DEVICES E Kakuno1, M Onishi2, R Kanomi1, 1Kanomi Orthodontic Office, Himeji and 2Osaka Dental University, Osaka, Japan

AIM: Temporary anchorage devices (TADs) have recently been used for orthodontic treatment. TADs are classified into two types, screw- and plate-types. The aim of this study was to evaluate the clinical application of plate-type TADs. MATERIALS AND METHOD: Two hundred and fifty four plate-type TADs were used in 133 patients for orthodontic treatment. Orthodontic force was loaded one week after implantation. The plate-type TADs had various shapes, Y-, I-, T- and L, and the appropriate shape was chosen for each patient. Age and gender of the patients and implantation sites were investigated, and success rate and clinical problems were examined. RESULTS: TADs were used in 32 males and 101 females. The mean age at implantation was 23 years; approximately half were under 20 years of age. Two hundred and forty four plates were implanted into the zygomatic process of the maxilla, and 10 into the mandibular molar or canine region. The use of mandibular TADs was considerably less than maxillary TADs. The success rate was 98.3 per cent; only one TAD dropped off after 6 weeks, and three TADs could not be used as skeletal anchorage because of mobility. All TAD failures were in the mandible. Swelling and mobility were typical clinical problems. Swelling was found in 37 cases (14.6%), with 11 patients having recurrent swelling. This occurred at any time during maxillary treatment. The tip of the plate was exposed in the oral cavity, and dental plaque covered the plate; it could be cause of infection. Mobility was observed in six cases (2.3%) within six months of implantation. Three of them could use as anchorage during orthodontic treatment, while three patients required reimplantation. The causes of mobility were thin cortical bone, swelling, weak fixation and technical skill. CONCLUSION: Plate-type TADs show high success rate and are very effective for orthodontic anchorage. Most clinical problems resulted from poor oral hygiene. Oral hygiene control was the key factor in the application of TADs.

226 TONSILLOTOMY VERSUS TONSILLECTOMY – REGARDING DENTOFACIAL MORPHOLOGY AND POST- OPERATIVE GROWTH J Kallunki1, A Marcusson2, E Ericsson3, 1The Center for Orthodontics and Pedodontics, Norrköping, 2Department of Dentofacial Orthopaedics, University Hospital, Linköping and 3Medical and Health Sciences, and the Anesthesia and Intensive Care, Linköping University, Sweden

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AIMS: Primarily to analyse two different methods of tonsil surgery, tonsillectomy (TE) and tonsillotomy (TT), regarding post-operative dentofacial growth in children with tonsillar hypertrophy. A secondary aim was to analyse these results in relation to cephalometric standards. SUBJECTS AND METHOD: Sixty four subjects (39 boys, 25 girls), mean age 4.8 years ±4 months were randomized to a complete removal of the pharyngeal tonsil, TE, (n = 31) or a partial removal, TT, (n = 33). Pre- and 2 year post-operative study material were obtained and analysed. The results were compared with cephalometric standards. RESULTS: Pre-operative, children with hypertrophic tonsils displayed an increased vertical relationship (P < 0.05) compared with cephalometric standards. Post-operatively, no significant difference could be detected between the two surgical procedures regarding dentofacial growth. Mandibular growth with an anterior inclination was significant (P < 0.001/TE, P < 0.01/TT) for both groups. An increased upper and lower incisor inclination was noted (P < 0.01/TE,TT). The vertical relationship decreased (P < 0.001/TE, P < 0.05/TT) as well as the mandibular Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 angle (P < 0.01/TE, P < 0.001/TT). Reduction was also significant for the sagittal intermaxillary (P < 0.001/TE,TT) relationship. These post-operative results, together with a more prognathic mandible (P < 0.05/TE,TT) and chin (P < 0.001/TE, P < 0.01/TT), might indicate a more horizontal direction of mandibular growth. CONCLUSION: TE and TT yielded equal post-operative dentofacial growth in children treated for hypertrophic tonsils. This result should be considered when deciding upon surgical technique.

227 RELATIONSHIP BETWEEN THE BALANCE OF LIP-CLOSING FORCE AND TONGUE PRESSURE AND THE BUCCO-LINGUAL INCLINATION OF THE FIRST MOLARS M Kanazawa1, M Murakami1, Y Takehana1, Y Masuda2. K Yamada1, Departments of 1Orthodontics and 2Oral and Maxillofacial, Matsumoto Dental University, Shiojiri, Nagano, Japan

AIM: To investigate the relationship between the balance of lip-closing force and tongue pressure and the bucco-lingual inclination of the first molars. SUBJECTS AND METHOD: Maximum lip closing force and tongue pressure were recorded in 19 orthodontic patients using a multidirectional lip-closing force meter and modified tongue pressure measuring devices. The bucco-lingual inclinations of the upper and lower first molars were analyzed on anterior cephalograms. RESULTS: The ratio of total lip-closing force to tongue pressure showed a significant positive correlation with the bucco-lingual inclination of the lower right and left first molars. The ratio of the sum of the ipsilateral upper and lower lip closing force to tongue pressure showed a significant positive correlation with the ipsilateral bucco-lingual inclination of the lower first molars. CONCLUSION: The balance of lip-closing forces and tongue pressure is related to the bucco-lingual inclination of the lower first molars.

228 EFFECT OF MINI-IMPLANT COUPLING ON THEIR PRIMARY STABILITY I Kapogianni, M Nienkemper, R Hönscheid, D Drescher, Department of Orthodontics, University of Duesseldorf, Germany

AIM: To evaluate the influence mini-implant coupling using plates on their primary stability. MATERIALS AND METHOD: Twenty mini-implants (Benefit system) with a diameter of 2 mm and a length of 9 mm were inserted in artificial bone made of polyurethane foam (saw bone). Mini-implant couples were connected by a plate at short (SD: 7 mm) and long (LD: 14 mm) distances. Single mini-implants (SI) were used as the controls. Implant stability was measured by resonance frequency analysis (RFA) and Periotest (PT) in line (IL) as well as perpendicular (PP) to the plate. The results of the different coupling set-ups were compared with each other and to the SI group.

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RESULTS: The stability of the mini implants varied greatly depending on the coupling configuration and the direction of measurement. RFA analysis of SI showed a mean implant stability quotient (ISQ) value of 23 ± 1.93 (IL and PP). PT resulted in mean values of 2.29 ± 1.2 (IL) and 2.52 ± 1.82 (PP). LD coupling of the implants increased RFA values to a mean value of 40.3 ± 1.95 (IL) whereas PP values remained nearly unchanged: 27.08 ± 1.9. PT values resulted in –1.64 ± 1.23 (IL) and 3.8 ± 1.1 (PP). Short coupling showed RFA values of 43.9 ± 2.6 (IL) and 26.7 ± 1.9 (PP), PT 1.8 ± 1.3 (IL) and 4.47 ± 1.1 (PP). Statistical analysis revealed the following stability rank: LD-IL, SD-IL > LD-PP, SD-PP > SI. CONCLUSION: The coupling of two orthodontic mini implants has a strong impact on the primary stability of the orthodontic anchorage system. It appears that stability measured IL with the coupling plate was greatly enhanced. Depending on the insertion site and local bone quality, the clinician can employ coupling of two orthodontic mini-implants to provide more stability. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 229 CONE BEAM COMPUTED TOMOGRAPHIC EVALUATION OF PHARYNGEAL AIRWAY CHANGES IN CLASS II PATIENTS TREATED WITH THE TWIN-BLOCK FUNCTIONAL APPLIANCE S Karacay, E Yildirim, M Erkan, Dental Service, Gulhane Military Medical Academy, Istanbul, Turkey

AIM: Mandibular deficiency in skeletal Class II malocclusions is considered as a risk factor for the respiratory function due to reduced oropharyngeal airway dimensions. The purpose of this study was to evaluate the three- dimensional (3D) volumetric changes in the posterior airway space (PAS) of patients with a retrognathic mandible treated with the Twin Block functional appliance. MATERIALS AND METHOD: Pre-(T1) and post- (T2) treatment cone-beam computed tomography (CBCT) records of 30 patients (16 male, mean age 12.83 ± 1.17 years; and 14 female mean age 12.5 ± 1.23 years) treated with Twin Block functional appliance were used to evaluate changes of the upper and lower parts of the PAS volume, SNA, SNB, ANB, effective maxillary length (Co-A), effective mandibular length (Co-Gn), and distance between the left and right condyles (CoL-CoR). Wilcoxon signed-rank tests was used to assess the presence of significant differences between the intervals T1 and T2, and Mann-Whitney U tests to compare the scores of male and female participants. Significance was set at P < 0.05. RESULTS: Statistically significant increases were determined in upper PAS volume, lower PAS volume, total PAS volume, SNB, ANB, Co-Gn, and CoL-CoR measurements (P < 0.01). No statistically significant differences were found in the SNA, and Co-A measurements. There were no significant differences between the genders. CONCLUSION: The study showed an overall increase in airway dimension. Thus, functional therapy may be considered beneficial in reducing upper airway collapsibility in patients with skeletal Class II malocclusions.

230 DENTOFACIAL CHANGES ASSOCIATED WITH EXPANSION-CONSTRICTION PROTOCOL AND FACEMASK THERAPY H Karamehmetoglu1, S Akbulut2, S I Ramoglu1, A Yagci2, Departments of Orthodontics, 1Bezmialem Vakif University, Istanbul and 2Erciyes University, Kayseri, Turkey

AIM: To compare the skeletal and dental effects of conventional expansion and expansion-constriction protocol in maxillary protraction therapy with a facemask in mixed dentition patients. SUBJECTS AND METHOD: Two groups; conventional rapid maxillary expansion and facemask (RME+FM) group and expansion-constriction and facemask (EC+FM) group. Twenty eight, Class III patients with an ANB angle of 0 degrees or less were included in this prospective clinical study. The RME+FM comprised nine girls and six boys (mean age: 8.7 ± 1.1 years) and the EC+FM group four girls and nine boys (mean age: 9.6 ± 0.9 years). A splint type tooth- and tissue-borne modified bonded RME appliance with hooks located between the canine and laterals for traction was used. A total force of 700 g was applied in both groups for 16-18 hours per day. In the RME+FM group, Hyrax screws were activated every 12 hours for one week. At the end of this period, RME was

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stopped and the patients were instructed to wear the FM. In the EC+FM group, the screws were activated every 12 hours for one week. Subsequently, the screws were deactivated every 12 hours for one week followed by expansion and constriction for the following 5 weeks. After this protocol, the patients were instructed to use the FM. Intra-group comparisons were tested with the paired t-test and inter-group changes with an independent t-test. RESULTS: SNA improved 3.2 ± 1.6 and 3.3 ± 2.7 degrees, and ANB improved 4.4 ± 1.6 and 5.6 ± 1.5 degrees in the RME+FH and EC+FM groups, respectively. No significant difference was found between the groups for the measured values. CONCLUSION: RME+FM and EC+FM have similar dental and skeletal effects in Angle Class III mixed dentition patients.

231 THE EVALUATION OF ANOMALY IMPROVEMENT GRADES OF ORTHODONTIC TREATMENT RESULTS Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 O H Karataş, E Toy, Department of Orthodontics, Faculty of Dentistry, Inonu University, Malatya, Turkey

AIM: To evaluate the anomaly improvement grades of orthodontic treatment results and to detect differences between genders in improvement grades. MATERIALS AND METHOD: Pre- and post-treatment orthodontic models and cephalometric radiographs of 60 patients. Their mean age was 16.73 ± 2.98 years, including 22 males (mean age, 15.75 ± 2.97) and 38 females (mean age, 17.71 ± 2.00). Before and after treatment orthodontic study models carefully examined and the occlusal features were scored using the Index of Complexity Outcome and Need (ICON) index. RESULTS: According to the improvement grade, the numbers of greatly improved, substantially improved, and moderately improved cases were 30 (50%), 20 (33.3%), and nine (15%), respectively. The number of minimally improved and not improved or worse cases was one (1.7%). Although the improvement grades of females were better than those of males, this difference was not statistically significant (P > 0.05). CONCLUSION: The treatment results were similar to those of other cities in Turkey. Use of the ICON is recommended as an evaluation tool.

232 ASSESSMENT OF THE SHAPE AND SIZE OF THE SELLA TURCICA IN TURKISH SUBJECTS O H Karataş1, H İ Mutaf2, F Öztürk3, R M Çelik4, Departments of Orthodontics, Faculties of Dentistry, 1Inonu University, Malatya, 2Cumhuriyet University, Sivas, 3Pamukkale University, Denizli and 4Selçuk University, Konya, Turkey

AIM: To evaluate the shape and size of the sella turcica in Turkish subjects in different age groups. MATERIALS AND METHOD: Lateral cephalometric radiographs of 200 individuals (88 males, 112 females) with an age range of 7-17 years. All were healthy Caucasians, with no apparent facial disharmony. The inclusion criteria were good quality lateral cephalograms and absence of congenital craniofacial anomalies or syndromes. The sella turcica on each radiograph was analysed and measured to determine the shape of the sella, in addition to the linear dimensions of length, depth, and diameter. Comparisons between the dimensions of the sella turcica of males and females in each age group were performed using a Student’s t-test. RESULTS: The sella turcica presented with a normal morphology in 40 per cent of subjects. No significant differences in linear dimensions between genders could be found except for the depth of sella turcica in the 8 year old age group. Sella size in the older age group was larger than in the younger age group. The depth of sella turcica was almost constant throughout the observation period, and the length and diameter increased with age. CONCLUSION: Sella shape and dimensions reported in this study of growth and development of individuals can be used as reference standards for further investigations involving the sella turcica area in Turkish subjects.

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233 CHEMICAL STABILITY OF RHODIUM COATED NICKEL TITANIUM ORTHODONTIC WIRE IN ARTIFICIAL SALIVA AND COMMERCIAL FLUORIDE AGENTS V Katic1, L Curkovic2, M Ujevic Bosnjak3, S Spalj1, 1Department of Paediatric Dentistry and Orthodontics, University of Rijeka, 2University of Zagreb and 3Croatian Institute of Public Health, Zagreb, Croatia

AIM: Evaluation of the chemical stability of rhodium coated nickel-titanium (RhNiTi) orthodontic wire in artificial saliva and commercial fluoride agents. MATERIALS AND METHOD: Ten centimetre long specimens of RhNiTi wire were immersed in 10 ml of artificial saliva (1.5 g/l KCl, 1.5 g/l NaHCO3, 0.5 g/l, NaH2PO4-H2O, 0.5 g/l KSCN, 0.9 g/l lactic acid, pH=4.8) and incubated at 37°C. All experiments were performed in triplicate. Artificial saliva samples were collected after 3, 7, 14, 21 and 28 days of immersion. The amounts of eluted Ni2+ and Ti4+ ions in artificial saliva from the tested wires were measured by means of inductively coupled plasma-optical emission spectroscopy, an axially viewed Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 Thermo Elemental ‘IRIS Intrepid II’ XSP, Duo, (Thermo Electron Corporation). Between collection of saliva, the wires were immersed for 5 minutes at 37°C in commercial fluoride agents as imitation of regular weekly treatment: Elmex gel© (7500/5000 ppm of fluoride in the form of amine fluorides/sodium fluoride), MI Paste Plus (900 ppm of fluoride in the form casein phosphopeptide-amorphous calcium phosphate fluoride), and Mirafluor-k-gel (6150 ppm of sodium fluoride). After fluoridation, the wires were rinsed with distilled water and immersed in fresh artificial saliva. The chemical stability of RhNiTi wire was also determined by immersion only in artificial saliva. The fluoride agents were chosen because of their commercial availability, identical methods of application, various fluoride ion concentrations, various chemical formulations, and differences in pH (Mirafluor-k-gel 5.1; Elmex gel© 5.5; MI Paste Plus 6.6). RESULTS: Release of Ni2+ ions from RhNiTi orthodontic wires decreased in the following order: artificial saliva > MiPaste > Elmex > Mirafluor. Release of Ti4+ ions from Rh NiTi orthodontic wires decreased in following order: MiPaste > Mirafluor > Elmex > artificial saliva. CONCLUSION: Chemical stability of RhNiTi wires increases with increased fluoride concentrations because rhodium and fluoride form a protective layer.

234 ORTHOGNATHIC QUALITY OF LIFE: CRANIODENTOFACIAL CHARACTERISTICS AND PERSONALITY TRAITS V Katic, M Mlacovic-Zrinski, A Pavlic, S Spalj, Department of Paediatric Dentistry and Orthodontics, University of Rijeka, Croatia

AIM: To quantify the relationship between craniodentofacial characteristics and orthognathic quality of life and personality traits. SUBJECTS AND METHOD: Validation of the Orthognathic Quality of Life Questionnaire (OQoLQ) was performed on a convenient sample of 375 subjects (35% male) aged 8-41 years (median 22, interquartile range 20-24 years). The cross-sectional study included 149 university students and patients (39% male) aged 11-39 years (median 21, interquartile range 19-23 years). The questionnaire was self-administered and included OQoLQ, the Big Five Inventory and Self-Esteem Scale. Craniodentofacial characteristics were assessed by the Index of Complexity, Outcome and Need and Index of Orthodontic Treatment Need (Dental Health and Aesthetic Components), the craniofacial indices of Martin and Saller, and photogrammetric profile analysis. Explanatory factor analysis and Pearson correlation were used for data analysis. RESULTS: Factor analysis detected four subscales of OQoLQ similar to the original instrument. Internal consistencies were: social aspect - Cronbach alpha (α) = 0.82, average inter-item correlation (r) = 0.40; facial aesthetics α = 0.83, r = 0.56; oral function α = 0.83, r = 0.56; awareness of dentofacial aesthetics α = 0.77, r = 0.48. The OQoLQ did not correlate with measurable craniodentofacial characteristics. Self-esteem correlated with social aspects (r = –0.569) and facial aesthetic (r = –0.398) dimensions of OQoLQ. Self-perceived smile

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aesthetics correlated with oral function (r = 0.270). Extraversion correlated with social aspects (r = –0.302) and facial aesthetics (r = –0.250), while neuroticism correlated with the social aspect of OQoLQ (r = 0.253). CONCLUSION: Orthognathic quality of life does not correlate with measurable craniodentofacial characteristics, and correlation with personality traits and self-esteem is low.

235 THE INFLUENCE OF CRANIOFACIAL MORPHOLOGY ON MANDIBULAR BORDER MOVEMENTS N Kawanabe1, T Kataoka1, N Shiraga1, T Takano-Yamamoto2, T Yamashiro3, 1Department of Orthodontics, Okayama University Hospital, 2Division of Orthodontics and Dentofacial Orthopedics, Tohoku University, Sendai and 3Department of Orthodontics and Dentofacial Orthopedics, Osaka University, Japan

AIM: Although they are widely used as a diagnostic sign of temporomandibular disorder, mandibular border movements reflect not only condylar movement but also other factors. In the present study, the effect of Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 craniofacial morphology on three different mandibular border movements; maximum jaw opening, maximum jaw protrusion, and maximum jaw laterotrusion was investigated. SUBJECTS AND METHOD: One hundred female subjects were selected from outpatients visiting the orthodontic clinic of Okayama University Hospital. The mandibular border movements were measured by an optical recording system in three-dimensions as 6 degrees of freedom. The craniofacial morphology was evaluated using lateral cephalograms. RESULTS: Craniofacial morphology had different influences on each mandibular border movement. In particular, during maximum jaw laterotrusion, lower incisor movement strongly reflected condylar movement, and the influence of craniofacial morphology on mandibular border movement was minimal. CONCLUSION: Lower incisor movement during maximum jaw laterotrusion appears to be suitable to evaluate condylar movement.

236 ADVANTAGES OF CRYOPRESERVATION OF HUMAN PERIODONTAL LIGAMENT CELLS USING A MAGNETIC FIELD T Kawata1, M Kaku2, 1Department of Oral Science Orthodontic Division, Kanagawa Dental University, Yokosuka and 2Department of Orthodontics and Craniofacial Developmental Biology, Hiroshima University, Japan

AIM: To establish a long-term tooth cryopreservation method that can be used for tooth autotransplantation. MATERIALS AND METHOD: Human periodontal ligament (PDL) cells were frozen in 10 per cent dimethyl sulphoxide (Me2SO) using a programmed freezer with a magnetic field. Cells were cryopreserved for 7 days at – 150°C. Immediately after thawing, the number of surviving cells were counted and the cells were cultured; cultured cells were examined after 48 hours. RESULTS: A 0.01 mT of a magnetic field, a 15-minute hold-time, and a plunging temperature of –30°C led to the greatest survival rate of PDL cells. Based on these findings, whole teeth were cryopreserved under the same conditions for 1 year. Organ culture revealed that the PDL cells of cryopreserved tooth with a magnetic field could proliferate as much as a fresh tooth, although the cells did not appear in the cryopreserved tooth without a magnetic field. Histological examination and the transmission electron microscopic image of cryopreserved tooth with a magnetic field did not show any destruction of cryopreserved cells. In contrast, severe cell damage was seen in cells frozen without a magnetic field. CONCLUSION: The above results indicate that a magnetic field programmed freezer is available for tooth cryopreservation.

237 COMPARISON OF TOOTH-BORNE AND HYBRID DEVICES IN SURGICALLY ASSISTED RAPID MAXILLARY EXPANSION. A PROSPECTIVE CLINICAL CONE BEAM COMPUTED TOMOGRAPHIC STUDY

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E Kayalar1, S Firatli1, M Schauseil2, S V Kuvat3, U Emekli3, Departments of 1Orthodontics and 3Plastic, Reconstructive and Aesthetic Surgery, Istanbul University, Turkey and 2Department of Orthodontics, Philipps University of Marburg, Germany

AIM: To compare the dental and skeletal effects of tooth- and tooth-bone borne (hybrid) devices in surgically assisted rapid maxillary expansion (SARME). SUBJECTS AND METHOD: Twenty adult patients with a similar transverse maxillary deficiency. The sample was randomly divided into two groups. In the first group (n = 10 tooth-bone borne, hybrid group), two mini-implants were inserted anteriorly in the palate for skeletal anchorage and bands were applied to the first molars. Conventional banded tooth-borne appliances were used in the second group (n = 10). Each patient had undergone SARME. Five days post-surgery, the active expansion phase was started. Expansion of 7 mm was applied in 14 days (0.5 mm per day) in both groups. Each patient underwent a three-dimensional computed Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 tomography (cone beam) examination pre-operatively (T0) and at the end of the active expansion phase (T1). Measurements were performed on the scanned images at the skeletal, dental and periodontal levels. Transverse skeletal and dental maxillary expansion, root resorption and vestibular bone resorption of the anchorage teeth were evaluated. RESULTS: Both groups had similar overall skeletal maxillary expansion, declining from the anterior to the posterior. Skeletal expansion was significantly greater in the anterior area. Vestibular bone resorption was only found in the conventional tooth-borne group. Tipping of the anchorage teeth was also significantly greater in this group. There was no significant root resorption in either group as an immediate effect of the devices (T0 to T1). CONCLUSION: Tooth-bone borne (hybrid) devices are effective for SARME and can be preferred to reduce early adverse effects of tooth-borne devices such as dental tipping and vestibular bone resorption.

238 JUVENILE IDIOPATHIC ARTHRITIS: CLINICAL FINDINGS VERSUS MAGNETIC RESONANCE IMAGING OF THE TEMPOROMANDIBULAR JOINT H Keller1, G Markic1, C Kellenberger2, R Saurenmann3, 1Department of Orthodontics and Pediatric Dentistry, Center of Dental Medicine, University of Zurich and Departments of 2Diagnostic Imaging and 3Rheumatology, University Children’s Hospital Zurich, Switzerland

AIM: To investigate whether in children with juvenile idiopathic arthritis (JIA) there is a correlation of clinical parameters with magnetic resonance imaging (MRI) findings of the temporomandibular joints (TMJ) in terms of inflammation and deformation. SUBJECTS AND METHOD: Seventy six patients with a diagnosis of JIA were included in this study. Clinical examination evaluating pain, asymmetry, retrognathia, antegonial notching and clicking/crepitation of the TMJ, and MRI were independently performed within a 3 month period, with blinded experts as examiners. MRI’s were analyzed by a paediatric radiologist assessing inflammatory activity on fat-saturated T2w and contrast- enhanced T1w images and TMJ deformity on three-dimensional fast spoiled gradient echo images. Chi2-tests were performed to evaluate the correlations between clinical and MRI findings. RESULTS: TMJ involvement was diagnosed with MRI in 53 patients (70%) and 92 joints (61%). Signs of enhancement and condylar deformity were observed in 51 patients (67%) and 84 joints (55%), and in 25 patients (33%) and 39 joints (26%), respectively. Neither anamnestic (P = 0.59; P = 0.22), muscular (P = 0.50; P = 0.95) nor joint (P = 0.66, P = 0.60) pain were significantly correlated with TMJ enhancement or deformity. Retrognathia (P = 0.62; P = 0.13) and TMJ clicking/crepitation (P = 0.87; P = 0.70) also did not significantly correlate with enhancement or deformity. Antegonial notching, assessed by palpation, was not significantly associated with TMJ enhancement but correlated significantly with TMJ deformity (P = 0.01*). Severe

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asymmetry, as assessed visually, revealed a significant correlation with both synovial enhancement (P = 0.00*) and TMJ deformity (P = 0.00**). CONCLUSION: Only clinical parameters associated with morphological changes correlated significantly with TMJ pathology observed on the MRI.

239 EVALUATION OF THREE-DIMENSIONAL INTERRADICULAR AREAS FOR MINISCREW IMPLANT PLACEMENT IN THAI PATIENTS WITH CLASS II SKELETAL PATTERN: A CONE BEAM COMPUTED TOMOGRAPHIC STUDY N Khumsarn1, V Patanaporn1, D Jotikasthira1, A Janhom2, Departments of 1Orthodontics and Pediatric Dentistry and 2Oral Biology and Diagnostic Sciences, Chiang Mai University, Thailand

AIM: To evaluate three-dimensional interradicular areas and cortical bone thickness in Thai patients with a II skeletal pattern, and to determine the safe and suitable sites for orthodontic miniscrew implant placement by Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 using cone beam computed tomography (CBCT). MATERIALS AND METHOD: CBCT images of 12 pre-treatment Thai orthodontic patients with a Class II skeletal pattern were examined. The mesiodistal distance (MD), buccolingual alveolar process width (BL), and buccal cortical thickness (B-C) of interradicular areas were measured in three interradicular areas, from the distal aspect of the first premolar to the mesial aspect of the second molar of the maxilla and mandible (on both the right and left sides), at 2, 4, 6, 8, and 10 mm heights from the cementoenamel junction (CEJ). RESULTS: In the maxilla, the MD ranged from 1.46 to 3.77 mm; the greatest MD was between the second premolar and first molar. The BL ranged from 7.12 to 16.73 mm; with the greatest BL between the first and second molar. The B-C ranged from 0.64 to 1.37 mm; the greatest B-C was between the first and second premolar. In the mandible, the MD ranged from 2.12 to 5.00 mm; the greatest MD was between the first and second premolar. The BL ranged from 6.20 to 14.89 mm; with the greatest BL between the first and second molar. The B-C ranged from 0.91 to 3.12 mm; the greatest B-C was between the first and second molar. In both jaws, the MD, BL, and B-C gradually increased from the CEJ to the apex. CONCLUSION: The safe and suitable sites for placing miniscrew implants in interradicular areas were located between the second premolar and first molar at a height of 10 mm in the maxilla; between the first and second premolar at 6, 8 and 10 mm heights, between the second premolar and first molar at a 10 mm height, and between the first and second molar at 8 and 10 mm heights in the mandible.

240 COMPARISON OF CONDYLE-FOSSA RELATIONSHIP BETWEEN SKELETAL CLASS III MALOCCLUSION PATIENTS WITH AND WITHOUT ASYMMETRY: A RETROSPECTIVE THREE-DIMENSIONAL CONE BEAM COMPUTED TOMOGRAPHY STUDY H O Kim1, W Lee2, Y-A Kook1, Y Kim1, 1Department of Orthodontics, St. Mary’s Hospital and 2Department of Oral and Maxillofacial Surgery, Uijeongbu St. Mary’s Hospital, The Catholic University of Korea, Seoul, Korea South

AIM: To investigate whether temporomandibular joint (TMJ) condyle-fossa relationships are bilaterally symmetric in Class III malocclusion patients with and without asymmetry compared with those with normal occlusion. The hypothesis was a difference in condyle-fossa relationships exists in asymmetric patients. SUBJECTS AND METHOD: Group 1 comprised 40 Korean normal occlusion subjects and groups 2 and 3 those diagnosed with a skeletal Class III malocclusion, who were grouped according to the presence of mandibular asymmetry: Group 2 included symmetric mandibles, while group 3 included asymmetric mandibles. Pre- treatment three-dimensional cone-beam computed tomography (CBCT) images were obtained. Right- and left- sided TMJ spaces in groups 1 and 2 or deviated and non-deviated sides in group 3 were evaluated, and the axial condylar angle was compared. RESULTS: The TMJ spaces demonstrated no significant bilateral differences in any group. Only group 3 had slightly narrower superior spaces (P < 0.001). The axial condylar angles between groups 1 and 2 were not

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significant. However, group 3 showed a statistically significant bilateral difference (P < 0.001); toward the deviated side; the axial condylar angle was steeper. CONCLUSION: Even in the asymmetric group, the TMJ spaces were similar between deviated and non-deviated sides, indicating a bilateral condyle-fossa relationship in patients with asymmetry that may be as symmetrical as that in patients with symmetry. However, the axial condylar angle had bilateral differences only in asymmetric groups. The mean TMJ space value and the bilateral difference may be used for evaluating condyle-fossa relationships with CBCT.

241 CORRELATION ANALYSIS OF THREE-DIMENSIONAL CHANGES OF HARD AND SOFT TISSUES S-J Kim1, T-Y Lee2, H-S Baik1, 1Department of Orthodontics, College of Dentistry, YSU, Seoul and 2Weiss dental clinic, Seoul, South Korea Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 AIM: To examine the correlation between soft and hard tissue changes three-dimensionally in Class III orthognathic patients using cone beam computed tomographic (CBCT) images and to provide indicators for orthognathic surgery. MATERIALS AND METHOD: CBCT images were used within 2 weeks pre-surgery and at 6 months post-surgery in adult Class III patients (9 males, 9 females, mean age 23.5 years) who underwent Le Fort I osteotomy and bilateral intraoral vertical ramus osteotomy. The subjects were divided into two groups: group 1 with no mandibular asymmetry (less than 2 mm of menton deviation from the facial midline) and group 2 with mandibular asymmetry (more than 4 mm of menton deviation from the facial midline). CBCT images were reconstructed and three-dimensional (3D) data of landmarks were calculated. Correlations and proportions of changes of the soft tissue to hard tissue were also obtained. RESULTS: 1) There were significant correlations of ΔB’ to ΔB and ΔPog’ to ΔPog in both groups on the horizontal axis (P < 0.05). The proportions of ΔB’ to ΔB, and ΔPog’ to ΔPog in group 1 were 0.53 and 0.67, respectively and those of group 2, 0.77 and 0.88, respectively. 2) There were significant correlations of ΔB’ to ΔB, ΔPog’ to ΔPog and ΔMe’ to ΔMe on the sagittal axis in both groups (P < 0.05). Correlation coefficients of ΔB’ to ΔB, ΔPog’ to ΔPog and ΔMe’ to ΔMe in group 2 were greater than in group 1. The proportions of ΔB’ to ΔB, ΔPog’ to ΔPog, and ΔMe’ to ΔMe in group 1 were 0.94, 0.84, and 0.96, respectively and those of group 2, 0.95, 0.91, and 1.03, respectively. 3) There were no significant correlations between changes in soft and hard tissues on the vertical axis in either group (P > 0.05). 4) There were significant correlations of the 3D distances between ΔB’ to ΔB, ΔPog’ to ΔPog and ΔMe’ to ΔMe in both groups (P < 0.05). The proportions of ΔB’ to ΔB, ΔPog’ to ΔPog, and ΔMe’ to ΔMe in group 1 were 0.92, 0.79, and 0.95, respectively and those of group 2. 0.92, 0.88, and 0.97, respectively. CONCLUSION: In Class III orthognathic patients with mandibular asymmetry, the proportions of ΔB’ to ΔB, ΔPog’ to ΔPog, and ΔMe’ to ΔMe on the horizontal and sagittal axes and the 3D distances were different from patients with no mandibular asymmetry. Clinicians must consider these results in the diagnosis and treatment planning of Class III mandibular asymmetry patients.

242 EFFECT OF ALVEOLAR BONE LEVEL AND TOOTH INCLINATION ON PERIODONTAL STRESS IN A MAXILLARY CENTRAL INCISOR: A FINITE ELEMENT ANALYSIS Y-h Kim, M Lee, J Ryu, C-j Hwang, Department of Orthodontics, College of Dentistry, Yonsei University, Seoul, Korea South

AIM: To examine inclined teeth to determine the effect of alveolar bone loss on the magnitude and distribution of stresses within the periodontal ligament, a maxillary central incisor was examined with finite element analysis-simulations of minimum force (i.e., controlled tipping).

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MATERIALS AND METHOD: Three-dimensional models (n = 20) of maxillary central incisors with different facial inclinations and alveolar bone loss. The axis of the normal incisor was inclined at 60 degrees from the occlusal plane. The long axes of the abnormal incisor models were inclined facially at 5, 10, 15, or 20 degrees, relative to the axis of the normal incisor model. Alveolar bone loss was assumed to be equivalent in the buccolingual and mesiodistal directions. In the model with no loss, the alveolar bone and cementoenamel junction were 1 mm apart. RESULTS: With more bone loss, apical displacement (Δ) increased with constant Mt/F and inclination values. However, the effect of bone loss on Δ was minimized as Mt/F approached Mt/Fcont . When the Mt/F ratio was varied from Mt/Fcont towards either 0 or 10, the maximum compressive stress increased. In teeth with more alveolar bone loss, stress changed more sharply with changes in the Mt/F ratio. Also, the effect of bone loss on stress increased when the Mt/F approached 0 or 10. Increases in incisor inclination caused reductions in Mt/Fcont. As the incisor facial inclination increased, the Mt/Fcont decreased. In contrast, increases in alveolar Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 bone loss caused increases in Mt/Fcont CONCLUSION: Increases in bone loss cause increases in apical root displacement and maximum compressive and tensile stresses, and these effects are enhanced with changes in the M/F ratio. This suggests that an inadequate force system may cause larger apical displacement and greater stress on the root apex in patients with alveolar bone loss compared with those without bone loss.

243 STABILITY OF MAXILLARY AND MANDIBULAR ANTERIOR ALIGNMENT IN NON-EXTRACTION CASES DURING THE RETENTION PERIOD S Kiran, E Oztas, Department of Orthodontics, Istanbul University, Turkey

AIM: To evaluate the stability of maxillary and mandibular incisor alignment during the retention period in subjects submitted to non-extraction orthodontic treatment which were under retention with upper Essix appliances and lower canine to canine fixed lingual retainers. MATERIALS AND METHOD: Dental casts and cephalometric measurements of 12 patients (7 females, 5 males) at a mean initial age of 13.88 years (±1.04 years) were evaluated at three different time points (T1-pre-treatment, T2-post-treatment and T3, 1 year in retention). The variables assessed on dental casts for the maxillary and mandibular arches were: Little's Irregularity Index, intercanine, interpremolar and intermolar widths, arch length and perimeter, while the cephalometric variables measured were SN-MP, IMPA, maxillary incisor to SN, interincisal angles and mandibular incisor to NB and pogonion to NB distances. Statistical analysis was performed by Friedmann and Dunns multiple comparison test for the subgroups when necessary. Pearson’s correlation coefficients were used to investigate possible associations between the evaluated variables. RESULTS: There were no significant changes in most arch dimension measurements and cephalometric variables, during and after treatment and at the end of 1 year retention period. Only changes in overjet, overbite, IMPA, interincisal and 1-NB/mandibular plane angles and interpremolar distances in the maxilla were found statistically significant between T1-T2 and T1-T3 stages (P < 0.05). No statistically significant differences were found between these measurements between T2 and T3 (P > 0.05). Maxillary and mandibular incisor crowding did not relapse. CONCLUSION: Night time wear of an upper Essix appliance and lower canine to canine fixed lingual retainer provided good stability of mandibular and maxillary arch alignment after non-extraction treatment during a retention period of 1 year. Further longitudinal follow ups are necessary in order to test the effectiveness of these retention appliances on preventing relapse in the long-term.

244 FUNCTION NORMALIZATION IN ORTHODONTICS T Klimova, N Nabiev, A Rusanova, N Pankratova, MSMSU, Moscow, Russia

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AIM: According to some experts orthodontic treatment should be primarily aimed at normalization of function. Therefore one of the problems of modern orthodontic treatment is the implementation of informative methods for identifying muscular dysfunction and the development of effective methods for removing it. The aim of this research is to improve, in patients with distal occlusion of the dentition, muscular disorders diagnosis and implementation of their correction by new generation computerized medical diagnostic equipment. SUBJECTS AND METHOD: Seventy subjects aged 15-18 years divided into two groups, 35 with a physiological and 35 with a distal occlusion (DO). Surface electromyography and computerized electromyograph (Electromyograph BKN, Biotronic) was used to investigate the biopotentials (BP) of the right and left temporal, masseter, suprahyoid and sternocleidomastoid muscles. The condition of the mandible during physiological rest and physiological occlusion were recorded. For correction of the bioelectric activity of maxillofacial area muscles the MIO-STIM device was used. RESULTS: In patients with DO, the muscles at rest and during occlusion of the dentition are in a state of high Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 bioelectrical activity (BA), which indicates their hypertonicity. The greatest increase of BA was developed in the temporal (1.8 times in the right and 2.9 on the left) and suprahyoid (3.6 on the right and 2.4 on the left) muscles in comparison with parameters in individuals with physiologic occlusion. Electro-neuro-stimulation by the MIO- STIM device in patients with DO, led to a significant reduction in the temporal (1.7 times) and suprahyoid (1.3 times) muscle biopotential during rest of the mandible; during the occlusion of 2.5 and 2.7 times, respectively. CONCLUSION: The use of modern diagnostic equipment is necessary for various orthodontic treatments.

245 A KINESIOGRAPHIC STUDY OF DIFFERENT MANDIBULAR MOVEMENTS T Klimova, N Nabiev, A Rusanova, N Pankratova, L Persin, Department of Orthodontics, MSMSU, Moscow, Russia

AIM: Kinesiography is the study of mandibular movements in three-dimensional projection. The velocity analysis of the mandible is also studied. According to the maximum movement of the mandible, the posture graph was displayed. Kinesiographic research is needed to control treatment before, during and after it. The aim of this research was to study the characteristics of mandibular movements and to determine the age norm of patients with physiological occlusion. SUBJECTS AND METHOD: Ninety three patients aged 7-15 years with physiological occlusion in three age groups: 7-9, 10-12 and 13-15 years. Mandibular movements were studied using the kinesiographic method on the Kinesiograph tracking device (Biotronic, Italy). The following functional tests were executed: maximal descending and lifting of the mandible, side (lateral) movements and maximal forward mandibular movement. RESULTS: It was found that, according to age, there is an increase in the kinesiographic indices in the sagittal plane, such as mandibular motion trajectory length and the value of the diagonal and distance of mandibular movement to the initial position. The angle between the diagonal and vertical planes did not show any difference and the angle indices at the beginning and end of descent and lifting of the mandible did not change with age. In all groups the mandibular movement ending angle was larger than the motion beginning angle. In the frontal plane mandibular descending motion trajectory and the length of the descending and lifting trajectories increased with age. Mandibular angle indices at the beginning and ending of descent and lifting did not change with age. Graphic images of mandibular side motions were the most informative in the frontal plane. Linear and angular parameters in age groups with this motion did not differ. Mandibular left and right motion lengths were equal. The distance of mandibular forward movement during maximal protrusion increased with age, and the descent and lift angles decreased. In the frontal plane mandibular descent during forward movement was lowest in the third group. CONCLUSION: The present research indicates the necessity of having age group indices of mandibular movements.

246 INDICATION AND TIMING OF SOFT TISSUE AUGMENTATION AT THE MAXILLARY AND MANDIBULAR INCISORS IN ORTHODONTIC PATIENTS. A SYSTEMATIC REVIEW e129

D Kloukos1, T Eliades2, A Sculean3, C Katsaros1, Departments of 1Orthodontics and Dentofacial Orthopaedics and 3Periodontology, University of Bern and 2Department of Orthodontics and Paediatric Dentistry, University of Zurich, Switzerland

AIM: To assess the indication and timing of soft tissue augmentation for prevention or treatment of gingival recession when a change in the inclination of the incisors is planned during orthodontic treatment. MATERIALS AND METHOD: Electronic database searches of the literature were performed. The following electronic databases, with no restrictions on publication language or date, were searched: Medline, Embase, Cochrane, and Central. Two authors performed study screening, data extraction and quality assessment independently and in duplicate using individualized data collection forms. RESULTS: No randomized controlled trial was identified. Two studies with a low-to-moderate level of evidence were included: one of prospective and retrospective data collection and one retrospective study. Both Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 implemented a periodontal intervention before orthodontics. Thus, best timing of soft tissue augmentation could not be assessed. The limited available data from these studies appear to suggest that soft tissue augmentation of buccolingual gingival dimensions before orthodontics may yield satisfactory results with respect to the development or progression of gingival recessions. However, the strength of the available evidence is not adequate in order to change or suggest a possible treatment approach in daily practice based on solid scientific evidence. CONCLUSION: Despite the clinical experience that soft tissue augmentation of buccolingual gingival dimensions before orthodontic treatment may be a clinically viable treatment option in patients considered at risk, this treatment approach is not based on solid scientific evidence. Moreover, the present data do not allow conclusions to be drawn on the best timing of soft tissue augmentation when a change in the inclination of the incisors is planned during orthodontic treatment and thus, there is a stringent need for randomized controlled trials to clarify these open issues.

247 MANAGEMENT OF WHITE SPOT LESIONS BY RESIN INFILTRATION: LONG-TERM DURABILITY OF AESTHETIC IMPROVEMENT IN VIVO*** M Knösel, A Eckstein, H-J Helms, University of Göttingen, Germany

AIM: To assess the long-term durability of the aesthetic improvement of white-spot lesions (WSL) achieved by resin infiltration (Icon, DMG) in comparison with baseline and untreated WSL. SUBJECTS AND METHOD: Twenty subjects with WSL after multibracket treatment were recruited for lesion infiltration using a randomized split-mouth design. Spectrophotometric follow-up assessments of colour and lightness (CIE-L*a*b*) data of WSL in comparison with surrounding sound enamel were carried out prior to infiltration (baseline), after 1 day, 1 week, 4 weeks, 3 months, 6 months, 1 year, and 1.5 years. Effects of infiltration and time elapsed on colour differences were analysed by multi-factorial ANOVA and pairwise comparisons. RESULTS: There was an assimilation of infiltrated WSL to the colour of adjacent enamel that was found to be colour stable over 1.5 years. CONCLUSION: Resin infiltration is a technique that is suitable for long-term improvement of the aesthetic appearance of WSL.

248 RSK2 CONTROLS CEMENTUM FORMATION AND MINERALIZATION T Koehne1, A Derer2, B Kahl-Nieke1, M Amling3, J-P David3, Departments of 1Orthodontics and 3Osteology, University of Hamburg and 2Department of Internal Medicine, University of Erlangen-Nurenberg, Germany

AIM: Molecular insights into cementogenesis are needed to facilitate manipulation of root development during organogenesis and root repair after orthodontically induced resorption. Humans with an inactive mutation of e130

the ribosomal S6 kinase Rsk2 suffer from Coffin-Lowry syndrome, an X-linked mental retardation associated with progressive tooth loss. Rsk2 has previously been shown to protect against tumour necrosis factor-alpha (TNF-α) induced inflammatory bone loss. Here it is demonstrated that the Rsk2 regulates cementogenesis and that its activation in cementoblasts is independent of TNF-α signalling. MATERIALS AND METHOD: Micro-computed tomographic (µCT) imaging, backscattered electron imaging, non- decalcified histology and immunohistology was used to analyze Rsk2-deficient (Rsk2-/y) mice and TNF-α overexpressing mice lacking Rsk2. RESULTS: Using µCT imaging progressive alveolar bone loss and apical root shortening was observed in Rsk2-/y mice. Further analysis, using undecalcified histology and backscattered electron imaging, demonstrated hypoplasty of acellular and cellular cement with a high fraction of unmineralized cement matrix. This phenotype was associated with disorganization of the periodontal ligament and root resorption by tartrate-resistant acid phosphatase positive osteoclasts. Interestingly, it was observed that mice ectopically expressing the human Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 TNF-α a model for inflammatory arthritis, did not exhibit alveolar bone loss, whereas the temporomandibular joint was severely affected. Importantly, overexpression of TNF-α did not aggravate alveolar bone loss in Rsk2- /y mice. CONCLUSION: Rsk2 is a positive regulator of cementum formation and mineralization that acts in a TNF-α independent manner and could be targeted for the prevention and repair of root resorption.

249 MORPHOLOGICAL CHANGE OF THE TEMPOROMANDIBULAR JOINT AFTER AN ORTHODONTIC TREATMENT IN SKELETAL CLASS II MALOCCLUSION D Koide, T Kageyama, K Takeo, M Hoshino, A Aoki, Matsumoto Dental University, Nagano, Japan

AIM: Temporomandibular joint (TMJ) morphology might change after orthodontic treatment due to the change of load to the TMJ. However, details of morphological change in the TMJ have not been elucidated. The aim of the present study was to investigate the morphological change of the TMJ after orthodontic treatment in patients with a skeletal Class II malocclusion using TMJ sagittal arthrotomograms. SUBJECTS AND METHOD: Seventeen adult patients with a skeletal Class II malocclusion had longitudinal TMJ sagittal arthrotomograms taken before and after orthodontic treatment and following retention. RESULTS: Condylar pass and eminence to the Frankfort horizontal plane angles and total height of the fossa significantly increased from before to after treatment, and from after treatment to after retention. The antero- posterior width of the fossa significantly decreased from before treatment to after treatment, and from after treatment to after retention. CONCLUSION: These results suggest that the height and the eminence inclination of the glenoid fossa might increase because of the change of load to the TMJ due to the lingual inclination of the upper anterior teeth after orthodontic treatment.

250 EVALUATION OF MANDIBULAR DEVIATION ON AUTONOMIC NERVOUS RESPONSE BY PUPILLOGRAPHY S Koizumi, S Miyake, T Kawata, Department of Oral Science, Orthodontic Division, Kanagawa Dental University, Yokosuka, Japan

AIM: To objectively evaluate the effect of change the mandibular position on the autonomic nervous response, pupillary light response was investigated by videopupillography. SUBJECTS AND METHOD: Twelve healthy subjects (10 males, 2 females; mean age 30.5 years). Pupillography changes were measured during clenching in four mandibular positions; 1) intercuspal position (ICP), 2) using 0.5 mm thick polyvinyl chloride sheets that were formed to the shape of the maxillary dentition (control sprint), 3) using a custom-made sprint that forced the mandible to a retrusive position (retrusion sprint), 4) using a custom-made sprint where therapeutic reference position diagnosis was established by axiograph (TRP sprint).

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RESULTS: There was no significant difference in any parameters of the pupillography between the ICP, control sprint and TRP sprint. The experimental retrusion sprint significantly decreased papillary constriction ratio compared with that of ICP. On the other hand, the TRP sprint significantly increased the retrusive-position and induced a decrease of the maximum velocity of miosis. CONCLUSION: The mandible forced into a retrusive position induces parasympathetic hypofunction. In contrast, a therapeutic reference position enhances parasympathetic nervous activity. Therefore, mandibular position influences autonomic function, which in turn changes the pupillography. Assessment of pupillary light reflex might be promising tool in objectively evaluating mandibular position.

251 THE EVIDENCE FROM SYSTEMATIC REVIEWS PUBLISHED IN THE ORTHODONTIC LITERATURE. WHERE DO WE STAND? D Koletsi1, T Eliades2, N Pandis3, 1Department of Orthodontics, University of Athens, Greece, 2Department of Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 Orthodontics and Paediatric Dentistry, University of Zurich, Switzerland and 3Department of Orthodontics and Dentofacial Orthopedics, University of Bern, Switzerland

AIMS: To investigate the presence and characteristics of meta-analyses included in systematic reviews (SRs) published in leading orthodontic journals and the Cochrane Database of Systematic Reviews (CDSR) covering the orthodontic literature. A further objective was to assess the quality of evidence provided. MATERIALS AND METHOD: Electronic searching was implemented in order to identify SRs published in five major orthodontic journals and the Cochrane database between January 2000 and November 2013. Inclusion of a meta-analysis within each SR and a number of review characteristics were recorded. Quality assessment of the overall body of evidence from meta-analyses was conducted in line with the Cochrane risk of bias tool across included studies, detection of publication bias, identification of the degree of inconsistency and imprecision as described by the Grading of Recommendations Assessment, Development and Evaluation working group. RESULTS: One-hundred and thirty seven SRs were identified and quantitative synthesis was present in 35 of the identified SRs (25.5%). Fifteen meta-analyses were identified in the American Journal of Orthodontics and Dentofacial Orthopedics (43%), followed by 11 in the CDSR (31%). The number of trials combined to produce a summary estimate was small for most meta-analyses. The median number of trials per meta-analysis was three, with an interquartile range (IQR) of three. The median number of meta-analyses for different outcomes within the same SR was three (IQR = 5). Thirty-one out of 35 meta-analyses (89%) used a forest plot for graphical presentation of the individual trial estimates and the summary estimate. Assessment of the quality of evidence from the meta-analyses was rated as high risk of bias overall in 20/35 of selected meta-analyses (57%); serious to very serious inconsistency and imprecision was detected for 25 (71%) and 15 (43%) of the meta-analyses, respectively. Publication bias was also suspected for 13/35 of the studies (37%). CONCLUSION: Overall, a limited number of SRs included quantitative synthesis combining very few trials. The overall quality of evidence from the selected orthodontic SRs is low and indicates the lack of high quality individual studies which may be combined mathematically.

252 PROPERTIES OF A CUSTOMIZED BRACKET BASE AND BONDING*** A Komori, E Imai, K Nagashima, E Ootsuka, Division of Orthodontics, Nippon Dental University Hospital, Tokyo, Japan

AIM: Direct bonding of orthodontic brackets is commonly used, but the technique requires sensitive procedures. A new concept of direct bonding has been developed to achieve precise bracket positioning with a simple procedure. The purposes of this study is to introduce the concept of customizing a bracket base, and to evaluate the bonding properties of the material used in the system. MATERIALS AND METHOD: The new system is characterized by a large bonding base fabricated with customized resin, which can achieve a good fit and precise bracket positioning while enhancing bond strength with a large e132

bonding area. Ninety bovine mandibular incisors were used in this study. Progressively finer polishing of the enamel surface was performed with 120 to 2400 grit waterproof abrasive paper. Thirty specimens were assigned to an experimental group. The bonding base of the metal brackets was formed with 0.5 mm thick customized resin. The formed brackets were bonded with resin-reinforced glass ionomer cement (RGIC, Fuji Ortho LC, GC Corp., Japan). The remaining specimens were assigned to a control group. Two bonding agents were used: RGIC and bis-GMA based composite resin (Transbond XT, 3M Unitek, USA). All bonding agents were handled according to the manufacturers’ instructions. Each bracket was exposed for 20 seconds to a light curing unit at the incisal and gingival margins. After storage at 37°C for 24 hours and thermal cycling from 5°C to 55°C and back 2000 times, bond testing was performed. A universal testing machine (Shimadzu Co. Ltd., Japan) was used to measure the shear bond strength. The amount of residual adhesive was classified with the adhesive remnant index after shear bond testing. RESULTS: Orthodontic brackets formed with customized resin showed similar bond strength compared with the Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 control groups. There was no significant difference between the experimental and control groups. No significant difference was seen in bond strength between 24 hours and thermal cycling. CONCLUSION: The newly developed customized resin base was shown to have retentive strength in comparison with the conventional bonding system.

253 THE ROLE OF PATIENT’S AGE ON THE RESPONSE OF HUMAN PERIODONTAL LIGAMENT FIBROBLASTS TO MECHANICAL STIMULATION AND DIFFERENTIATION D Konstantonis1,2, A Papadopoulou1, T Eliades3, E Basdra4, D Kletsas1, 1Institute of Biosciences and Applications, NCSR ‘Demokritos’, Athens and Departments of 2Orthodontics and 4Biological Chemistry, Medical School, University of Athens, Greece and 3Department of Orthodontics and Paediatric Dentistry, University of Zurich, Switzerland

AIM: To investigate the effect of patient’s age on proliferative capacity, osteoblastic differentiation and activation of signalling pathways of human periodontal ligament fibroblasts (hPDLF) under mechanical stimulation. MATERIALS AND METHOD: Human teeth explants from different age groups (range: 10-38 years) were utilized and primary cultures of hPDLF were established. To determine the percentage of hPDLF cells that can proliferate, the DNA synthesis was quantified by estimating the BrdU incorporation. Additionally, the ability of isolated periodontal fibroblasts towards osteoblastic differentiation was assessed by Von Kossa staining. The activation of MAPK signalling pathways was also studied using Western analysis. RESULTS: The primary fibroblast cultures from all age group donors had similar BrdU incorporation rates and therefore DNA synthesis, indicating no accumulation of senescent cells. The ability of hPDLF to differentiate seems to be independent of the donor’s age. Using Western analysis it was found that mechanical stimulation led to the activation of all MAPK signalling pathways (ERK, SAPK/JNK and p38) by phosphorylation and provoked phosphorylation of the transcription factor c-Jun, a component of the AP-1 transcription complex, in cells of young and mature donors. This activation was immediate, starting 15 minutes after initiation of cell stretching. CONCLUSION: The ability of hPDLF to respond to mechanical stimulation and activate pivotal signalling pathways (e.g. the ERK, JNK and p38 MAPK) is not affected by the age of the donor. Adult orthodontic patients will benefit from the results, which elucidate the issue of age in orthodontic treatment.

254 IONIZING RADIATION INDUCES PREMATURE SENESCENCE OF HUMAN PERIODONTAL LIGAMENT FIBROBLAST LEADING TO REDUCED DIFFERENTIATION ɫɫ D Konstantonis1, A Papadopoulou1, T Eliades2, E Basdra3, D Kletsas4, 1Department of Orthodontics, Institute of Biosciences and Applications, NCSR 'Demokritos'• and School of Dentistry, University of Athens, Greece, 2Department of Orthodontics and Paediatric Dentistry, University of Zurich, Switzerland, 3Department of

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Biological Chemistry, Medical School, University of Athens, Greece and 4Institute of Biosciences and Applications, NCSR 'Demokritos', Athens, Greece

AIM: To investigate the characteristics and ability for osteoblastic differentiation of human periodontal ligament fibroblast (hPDLF) that became senescent after exposure to ionizing radiation (IR). MATERIALS AND METHOD: Human teeth explants were utilized and primary PDL cultures were established. Early passage cells were repeatedly exposed to 4 Gy of γ-radiation at a rate of 6 Gy/minute, up to a cumulative dose of approximately 50 Gy. Osteoblastic differentiation was assessed by the production of calcified matrix (Alizarin Red staining) and gene expression for Runx2, Osx, OPN, ALP, p21, MMP2, Col1 was estimated by qRT- PCR analysis. Western blot analysis was employed using specific antibodies for p38MAPK, p21WAF1, p16INK4a and the pRb protein. The expression of bone-specific factor Runx2 was also evaluated after the addition of a p53 inhibitor. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 RESULTS: The IR senescent (IS) hPDLF cells had significantly decreased ability for osteoblastic differentiation, as found by Alizarin red staining and alkaline phosphatase activity assay. Furthermore, they have a decrease in expression of collagen type I and an increased representation of the matrix metalloprotease MMP-2, thus indicating a catabolic phenotype. Also, they exhibited a considerably decreased expression of several genes involved in osteoblastic differentiation, such as Col 1, Runx 2, Osx, ALP and osteopontin. IS cells overexpressed the phosphorylated form of p38MAPK and the cyclin-dependent kinase inhibitors p21WAF1 and p16Ink4a as well as the hypophosphorylated form of pRb protein. Finally, the down-regulation of Runx2 was found to be p53-dependent manner. CONCLUSION: IS hPDLF express a catabolic phenotype and a significantly decreased ability towards osteoblastic differentiation, thus affecting tissue development and integrity. The results provide important information regarding bone regeneration ability under IR.

ɫɫ Winner of an EOS poster award

255 LATERAL INCISOR ANOMALIES IN PATIENTS WITH A CLEFT LIP AND PALATE M Konvalinková, M Koťová, Department of Orthodontics and Cleft Defects, Clinic of Stomatology, 3rd Medical Faculty of Charles University, University Hospital Královské Vinohrady, Prague, Czech Republic

AIM: To ascertain the frequency of occurrence of developmental anomalies of the lateral incisor in the cleft area. MATERIALS AND METHOD: The plaster models and dental pantomograms (DPTs) of 50 patients were collected. There were 25 bilateral cleft lip and palate patients (BCLP) (20♂, 5♀) and 25 unilateral cleft lip and palate patients (UCLP) (18♂, 7♀) 9 right sided and 16 left sided clefts. The age of the patients when the DPTs and dental casts were obtained was 6.9 and 8.2 years. The results were subjected to statistical analysis. RESULTS: In the primary dentition the following anomalies of the lateral incisor on the cleft side were found: agenesis five patients (10%; 4 UCLP, 1 BCLP); abnormal shape seven patients (14%; 3 UCLP, 4 BCLP); supernumerary lateral incisors five UCLP (3 normally shaped, 2 abnormally shaped), 12 BCLP (5 normally shaped, 4 abnormally shaped, 3 with one-side abnormally shaped and on the contralateral side a normally shaped lateral incisor was present). The lateral incisor was present in the lateral segment in 17 UCLP cases (70.8%), in BCLP patients, 22 on the right side (88%); 20 on the left side (80%). In the permanent dentition agenesis of the lateral incisor was diagnosed in 14 patients (28%; 5 UCLP, 9 BCLP) and an abnormal shape in 21 (42%; 13 UCLP, 8 BCLP). Supernumerary lateral incisors were found in seven UCLP (3 normally shaped, 4 abnormally shaped), seven BCLP (3 normally shaped, 4 abnormally shaped supernumerary lateral incisor). The lateral incisor was present in the lateral segment in 18 UCLP (72%), BCLP 13 on the right side (52%), 14 on the left side (56%). McNemar's symmetry test proved normally shaped lateral incisors to be more frequent in the primary than in the permanent dentition (P = 0.007). Differences in localization were not statistically significant. e134

CONCLUSION: In cleft patients agenesis of the lateral incisor was less common than the morphological anomalies of the lateral incisor, especially in the permanent dentition. The lateral incisor was, in most cases, located in the lateral segment. Supernumerary lateral incisors occurred more frequently in the permanent dentition in the UCLP group whilst in the BCLP group these were more frequent in the primary dentition.

256 SKELETAL EFFICIENCY OF RAPID MAXILLARY EXPANSION IN DIFFERENT AGE-GROUPS BASED ON DIASTEMA DEVELOPMENT N Koritsánszky, A Káldy, M Balázs, B Nemes, Department of Pedodontics and Orthodontics, Semmelweis University, Budapest, Hungary

AIM: Several studies and clinical practice supports the notion that in pre-pubertal patients, rapid maxillary expansion (RME) is more effective than in older age groups. The purpose of this study was to measure the Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 skeletal effect in different age-groups, therefore determining the optimal age for RME. MATERIALS AND METHOD: In this retrospective photoanalytical study the patients were classified as pre- pubertal: cervical vertebral maturation (CVM) stage 1-2 (n = 13), pubertal CVM 3-4 (n = 11) and post-pubertal (who refused surgery) CVM 5-6 (n = 9) age groups. Patient who required expansion of 5-7 mm were selected. The appliance was activated 0.4 mm/day. Within 2 days of the end of expansion occlusal photographs were taken. The expansion on the screw and the diastema between the central incisors [-central incisor diastema (CID)] caused by expansion was measured. The width of the screw-body served as reference by calculating the widths. From these two values a ratio was calculated to show the skeletal efficiency of RME. RESULTS: The following ratios were measured: central incisor diastema CID/expansion. Pre-pubertal: 0.74, pubertal: 0.66, post-pubertal: 0.38. No significant differences were found between the pre-pubertal and pubertal age groups regarding diastema width, however in the post-pubertal age group the skeletal effect significantly decreased. CONCLUSION: RME is more effective in the pre-pubertal and pubertal age groups than in post-pubertal subjects.

257 THE RELATIONSHIP BETWEEN THE POSITION OF THE MAXILLARY CANINES AND MAXILLARY ARCH LENGTH AND WIDTH M Kosecka1, M Dobrowolska-Zarzycka2, E Tokarska3, K Marcin4, K Gołkiewicz5, Private Practice, Lublin, 2Department of Jaw Orthopedics, Medical University of Lublin, 3Private Practice, Puławy, 4Rzeszow University of Technology and 5Dental Medical Center, Lublin, Poland

AIM: To examine whether there is a relationship between the position of the maxillary canines and arch length and width. SUBJECTS AND METHOD: Two hundred and seventy five subjects were enrolled to diagnose the position of the upper canines. Angulation and sector location were measured on panoramic radiographs. The intermolar width and arch length of the maxilla were measured on dental casts. RESULTS: The position of the upper canines in sector 2 or higher and a mean alpha angle more than 15 was significantly greater when the intermolar width of the maxilla was smaller and the dental arch length was shorter (P < 0.001). CONCLUSION: Diagnosis of maxillary canine position using geometric measurements on panoramic radiographs and dental casts allows estimation of the orthodontic treatment approach and may avoid impaction of the upper canine.

258 ANALYSIS OF ELEMENTAL CHANGE IN PTH STIMULATED OSTEOBLAST LIKE CELLS ANALYSED BY X-RAY MICROANALYSIS: EVIDENCE OF SODIUM CHANNELS INVOLVEMENT R Kotby1, F McDonald1, A Grigoriadis2, A Warley3, 1Department of Orthodontics, 2Dental Institute and 3Ultrastructural Imaging, King's College London Dental Institute, U.K. e135

AIM: To define the role of Potassium (K+) and Sodium (Na+) channels in human osteoblast-like cells (Saos-2) stimulated with PTH. MATERIALS AND METHOD: Saos-2 cells were cultured, split and seeded onto gold electron microscopy grids covered with Pioloform and allowed to grow. On reaching confluence (a) Saos-2 cells were exposed to 2.5 pM PTH for a period of 0, 15, 30 and 60 seconds (n = 3); (b) Saos-2 cells were incubated in 30 µL/10 mL Lig then each gold grid was inverted into a 50 µL drop of 2.5 pM PTH for 0, 15, 30 and 60 seconds individually (n = 3); (c) Finally, Saos2 were incubated in 100 µL/10 mL Ba2+ for 10 minutes then each grid was inverted into a 50 µL drop of 2.5 pM PTH for 0, 15, 30 and 60 seconds individually (n = 3). All grids were washed for 10 seconds by dipping into ice-cold distilled water and then cryofixed by plunging into (LN2) (–196°C). The cells were freeze dried and coated with before analysis using a FEI T12 electron microscope fitted with an EDAX EDS detection system. Areas of cytoplasm were analyzed and the concentrations for Na, Mg, P, Cl and K were Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 determined in (a) control (PTH only cells) (n = 10) for each time point, (b) (Ba2+ + PTH) stimulated cells (n = 10) for each time point, and (c) Lig + PTH stimulated cells (n = 10) for each time point. RESULTS: After stimulation with PTH, Saos-2 cells showed a decline in concentrations of all elements up to 15 seconds. However, the concentrations recovered to control values by 60 seconds. Pre-incubation of Saos-2 cells with Lig followed by PTH stimulation suppressed the decrease previously seen with PTH only at 15 seconds (K+ concentrations), whereas pre-incubation of Saos-2 cells with Ba2+ had no effect on ionic changes. CONCLUSION: Na+ channels may be directly involved in the process of volume change after PTH stimulation, but K+ channels are not directly involved.

259 CLINICAL AUDIT OF ORTHODONTIC TREATMENT DURATION OF PATIENTS TREATED BY KINGS COLLEGE HOSPITAL POSTGRADUATE ORTHODONTIC TRAINEES R Kotby1, A Moran1, M S Ali2, G Mack1, 1King’s College London Dental Institute and King’s College Hospital and 2Community Center, Bradford, U.K.

AIM: To investigate orthodontic treatment duration for patients treated by trainees in a teaching hospital over a period of 30 months (October 2009-April 2012). MATERIALS AND METHOD: Four logbooks containing records of patients treated by postgraduate orthodontic trainees were used and a total of 94 patients met the criteria. Inclusion criteria: patients who completed treatment with fixed appliances and extractions, Impaction, hypodontia, non-routine i.e. pre-fixed [upper removable appliance (URA), headgear (HG) or rapid maxillary expansion (RME), functional]. Exclusion criteria: orthognathic, upper removable appliance only, cleft lip and/or palate, incomplete treatment i.e. early debond, still in treatment, transfer cases. Analysis was carried out using mean, standard deviation and standard error with treatment duration as the dependent variable RESULTS: The reported results for the total number of months in orthodontic treatment met the gold standard. The shortest treatment time was seen in patients who had fixed appliance therapy without any extractions, followed by impaction, extraction, and hypodontia cases. Whereas, the longest treatment time was seen in patients who were treated non-routinely with pre-fixed appliances such as functional, HGr, URA, or RME devices. The mean number of appointments followed the same trend as seen previously with the number of months in treatment, fixed appliance without extractions being the least with a mean of 11 appointments and pre-fixed appliance therapy being the most with a mean of 20 appointments. A correlation was been found between the number of months in treatment and the number of emergency appointments attended. The more emergency appointments, the longer the patient was in treatment. CONCLUSION: To maintain the results of this audit the following measures are proposed: ensure that postgraduate students are aware that each patient should be given advice and made aware of elements that could potentially delay treatment such as poor oral hygiene or dietary habits, which lead to fractures and also

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regarding mishandling of removable appliances and frequent breakage. This audit should be repeated again after 30-36 months to ensure that treatment is completed within a reasonable period of time.

260 JAW MORPHOLOGY IN CHILDREN WITH CLASS III MALOCCLUSIONS IN THE PRIMARY DENTITION – A THREE-DIMENSIONAL EVALUATION B Krneta1, A Zhurov2, S Richmond2, M Ovsenik1, 1Department of Dental and Jaw Orthopaedics, Medical Faculty, University of Ljubljana, Slovenia and 2Department of Applied Clinical Research & Public Health, School of Dentistry, Cardiff University, U.K.

AIM: To evaluate and identify morphological characteristics of the jaws of Class III (CIII) children in the primary dentition, using a three-dimensional (3D) laser surface scanning method for more effective, improved diagnosis and enhanced treatment planning. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 SUBJECTS AND METHOD: Two groups of children participated, 21 children (aged 5.4 ± 0.5 years) with a Class III malocclusion and 43 children (aged 5.7 ± 0.8 years) without a Class III malocclusion (non-CIII). A ClIII malocclusion was diagnosed during clinical examination of the face (concave or straight profile, retruded upper lip, prominent lower lip, prominent chin), which were besides an anterior crossbite and a mesial step, the diagnostic criterion of a primary molar relationship for the CIII group. The criterion for the non-CIII group was a flush terminal plane primary molar relationship. Images of the children’s dental casts were obtained using a 3D laser scanning device (Minolta Vivid VI910). The palatal volume and gingival surfaces of the jaws were restricted and measured. To statistically assess the differences between the two groups, the analysis of variance (ANOVA) was used. P values less than 0.05 were considered statistically significant. RESULTS: The CIII children had lower values for palatal volume, the gingival surface area of the maxilla and higher values for the gingival surface area of the mandible than the non-CIII children. However, the differences between the two groups were not statistically significant (P > 0.05). Furthermore, the maxillary/mandibular gingival surface areas ratio in CIII children (1.05 ± 0.09), when compared with non-CIII children (1.14 ± 0.17) was found to be significantly lower (P = 0.029). The lower maxillary/mandibular gingival surface areas ratio in the CIII children was more affected by the lower gingival surface area of the maxilla than that of the mandible compared with non-CIII children. CONCLUSION: 3D assessment of jaw morphology could be used in diagnosis of Class III malocclusions for more effective and objective treatment planning in the primary dentition. Orthopaedic expansion of the palate should, besides orthopaedic traction of the maxilla, be arguably indicated as the treatment protocol in CIII malocclusion in the primary dentition.

261 HOW PAINFUL IS RAPID MAXILLARY EXPANSION? COMPARISON BETWEEN GROWING AND ADULT PATIENTS? M Kuc-Michalska, A Karska, Orthodontic private practice, Zabrze, Poland

AIM: To assess the relationship between pain, age and the opening of the midpalatal suture in patients treated with the Haas appliance on acrylic splints using the semi-rapid maxillary expansion (RME) protocol. MATERIALS AND METHOD: Questionnaires completed by 74 subjects (48 females, 26 males) treated simultaneously with the Haas appliance on acrylic splints and a lower fixed appliance. The patients were divided into two age groups: growing patients (GPs) after the pubertal growth peak (CS4-6) according to the cervical vertebral maturation method aged 12 to 18 years (33 patients) and adult patients (APs) aged 18.1-42 years (41 patients). Opening of the midpalatal suture was based on the presence or absence of a midline diastema and maxillary occlusal radiograph. All patients were treated using the same protocol of turning the screw once a day. The pain level was described by patients according to a numerical rating scale. To describe the pain level, comparison was made between the feelings of pain in the same patient during two procedures: turning the

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screw of the Haas appliance and standard fixed appliance treatment with the use of nickel titanium arches. Statistical analysis was undertaken using the chi-square method. RESULTS: The midpalatal suture was opened in 47 patients (63.7%) of the total sample, 63.6 per cent in GPs and 63.4 per cent in APs. The youngest female patient without a diastema was aged 12 years, and the oldest female patient with a diastema was 42 years. Differences between the pain level during treatment with the Haas appliance in GPs compared with APs were statistically significant (χ2(3) = 17.87 P = 0.000467). Twenty one GPs (63.6%) and 10 APs (24.4%) had a higher pain level with the use of the Haas appliance compared with the fixed appliance. Comparisons between the two age groups with and without a diastema were statistically insignificant. CONCLUSION: Contrary to the common opinion concerning pain during RME in adult patients, a high pain level rarely occurs in adults compared with growing patients. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 262 NON-SURGICAL ORTHODONTIC TREATMENT OF CLASS III MALOCCLUSIONS IN POST-PUBERTAL AND ADULT PATIENTS M Kuc-Michalska, A Karska, A Filipek, Orthodontic private practice, Zabrze, Poland

AIM: To illustrate the results of non-surgical orthodontic treatment of nine Class III patients aged 12-42 years SUBJECTS AND METHOD: The youngest female patient started treatment after the pubertal growth peak (CS4 in the cervical vertebral maturation method) and the other patients after completion of growth (CS6). The first phase of treatment consisted of the combined use of a facemask, the Haas appliance on an acrylic splint (activated 10-28 turns, once per day), a lower fixed appliance, and Class III elastics. A full fixed appliance and Class III elastics were used in the second stage. RESULTS: All patients achieved an improved skeletal relationship, a correct dental relationship and visible enhancement in the appearance of the middle face, lip profile and position of the chin. The positive changes in dentoskeletal cephalometric variables from the beginning to the end of active treatment were recorded especially in Wits appraisal, SNA angle and ANB angle. CONCLUSION: The successful results of non-surgical treatment performed on skeletal post-pubertal patients and even on patients after the completion of growth suggest that the method could be an alternative to surgical treatment of patients with moderate Class III malocclusion. Treatment time was considerably longer in one patient treated before the completion of growth with respect to the young adult and adult patients.

263 PLAQUE ADHESION, CORROSION AND CRUMBLING OFF OF SINTERED STEEL ORTHODONTIC BRACKETS DURING TREATMENT R B Kuitert, R Farhan, A Zentner, Department of Orthodontics, ACTA, Amsterdam, Netherlands

AIM: Assessment of the amount and severity of plaque and calculus, corrosion and crumbling off of sintered orthodontic brackets at bracket removal at the end of active treatment. MATERIALS AND METHOD: Fifty two brackets (from upper and lower canines and lateral incisors, four brackets/patient) from two brands were retrieved from 13 patients that had treatment with full fixed appliances. Ten as received brackets of both brands were also assessed. Age at debonding varied from 14 to 48 years; treatment time from 4 to 45 months. Retrieved brackets were assessed before and after plaque and calculus removal. Plaque and calculus, corrosion and crumbling off were assessed on reflected light optical photomicrographs (× 150 to 250). Only the external bracket surface was evaluated and divided into seven areas where semi-quantitative assessment was carried out by two observers. RESULTS: All retrieved brackets showed corrosion in almost all seven areas. Extensive corrosion had already occurred after 4 months of treatment. Age, gender, upper or lower jaw, brand, plaque and calculus and crumbling seemed unrelated to corrosion. Crumbling off was found in all patients with a large variation in the

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number of areas, occurring most frequently at the edges of the distal slot and on the edges of the mesh pad. Plaque and calculus was found in most areas of most patients, a few patients showing only a few affected areas. Plaque often accumulated in the middle area and in the slots of the brackets. New brackets of both brands differed from the factory leaflets, often showing very rough surfaces, cracks and furrows suggesting a possible relationship with crumbling, corrosion and plaque adhesion. CONCLUSION: Even after 4 months of treatment sintered steel brackets suffer deterioration characterized by extensive corrosion and crumbling off, mainly at edges of the slots. At the end of treatment plaque and calculus accumulate mainly in the central area and the slots of the brackets. The effect of these changes on treatment progress remains to be investigated.

264 SMILE AESTHETICS IN RELATION TO BRACKET CHOICE E Kuppens1, F Boute2, R Buyl3, B Vande Vannet4, Departments of 1GF, 3BISI and 4Orthodontics, Vrije Universiteit Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 Brussel, Brussel and 2Private Practice, Brasschaat, Belgium

AIM: The aesthetics of the frontal view of a smile are important to the final outcome of orthodontic treatment. The aims of this study were to explore if there is conformity between five different orthodontists concerning the type of bracket choice, where to find potential differences and lastly if cephalometric radiographs are needed for treatment planning. SUBJECTS AND METHOD: Five experienced orthodontists (4 females. 1 male) reviewed 50 casts (mean age 20.62 years; 36% male, 64% female) on the placement of brackets on the central upper incisors, with different types of torque (low ‘L’, standard ‘S’ or high ‘H’) without knowledge of radiographic data. The study examined whether there were similarities between the orthodontists. To avoid bias, they did not review their own patients. Combinations of four choices were obtained. The following combinations, ‘HHHH’, ‘SSSS’, ‘LLLL’, ‘HSSS’, ‘HSSS’ and ‘SHHH’, were given a score of 0 ‘SSSL’ a score of 1,‘SSLL’, ‘HSSL’ and ‘SLHH’ a score of 2 and ‘HHLL’, ‘SLLL’, ‘HLLL’ and ‘LHHH’ a score of 3. The null hypothesis states that there is no agreement between observers in the type of bracket they choose. RESULTS: Tooth 11 exhibited a strong correlation, corresponding to score 0, between the different practitioners for 82 per cent of the ratings. Score 2 (weak correlation) occurred in 14 per cent and score 3 (very weak correlation) in 4 per cent of the ratings. Eighty six per cent of the ratings of tooth 21 exhibited strong correlation (score 0), 10 per cent score 2 and 4 per cent score 3. CONCLUSION: There is some evidence to reject the null hypothesis. The results showed, for both central upper incisors, great similarity concerning the choice of bracket type between the five orthodontists. Differences were often found in cases where one or more observers selected low torque. Hence operators should reflect on their choice of bracket prescription carefully before placing this type of bracket. However there was agreement for bracket choice at the central incisors in 82 per cent without using cephalometric analysis in treatment planning. This questions the use of cephalometrics for experienced orthodontists.

265 INFLUENCE OF MOUTH RINSES ON THE FORCE DECAY OF ELASTIC CHAINS J Łyczek, J Antoszewska, B Kawala, J Dytko, A Adamek, Department of Orofacial Orthopedics and Orthodontics, Medical University of Wrocław, Poland

AIM: Due to several advantages elastic chains are one of the most commonly used materials in contemporary orthodontic practice. However, rapid reduction of the force delivered by elastic chains is a major drawback of their application. Elastic modules are under the constant influence of physical and chemical factors related to dietary consumption and oral hygiene maintenance, which alter their structure and result in further force reduction. The aim of this study was to evaluate the impact of various mouth rinses` on the force decay of elastic chains.

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MATERIALS AND METHOD: Seven hundred and ninety two six-module fragments of elastic chain were stretched between two pins mounted in custom made plastic plates and stored in Ringer’s solution simulating oral cavity environment throughout 28 days. The probes in the study group were subject to immersion in 10 selected mouth rinses every 12 hours for 30 or 60 seconds according to the manufacturers’ instructions. Probes placed in distilled water for the same period served as a control group. An electronic gauge was used to measure the force level at the time of mounting the probes on pins and after 24 hours and 7, 14, 21 and 28 days. ANOVA and post-hoc NIR tests with a significance level at P < 0.05 enabled statistical analysis of force reduction. RESULTS: Force reduction over time was statistically significant both in the control and study groups. However, force decay was significantly higher in the study group. Probes inserted for 60 seconds in a mouth rinse demonstrated significantly more pronounced loss of force than those immersed for 30 seconds. Blanx and BioRepair mouth rinses contributed to the most intense force decrease whereas the Listerine Zero group displayed the least force reduction. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 CONCLUSION: The use of mouth rinsing agents increases the force decay of elastic chains. The chemical composition of the liquid, as well as the rinsing time, are the two most important factors responsible for the weakening of the force. Thirty second use of alcohol free mouth rinses, such as Listerine Zero, may be advised over those periods in which elastic chains are crucial for the treatment mechanics.

266 CONDYLE SPATIAL CHANGES IN RAPID MAXILLARY EXPANSION M Lagravere, L McLeod, G Heo, Y Hernandez, Department of Dentistry, University of Alberta, Edmonton, Canada

AIM: To determine the presence of condylar spatial changes in patients having rapid maxillary expansion (RME) treatment compared with a control group. SUBJECTS AND METHOD: Thirty-seven patients with maxillary transverse deficiency (11-17 years old) were randomly allocated into two groups (one treatment group – tooth borne expander, Hyrax - and one control group). Cone-beam computer tomographs (CBCT) were obtained from each patient at two time points (initial and at appliance removal at 6 months). CBCTs were analyzed using Avizo software and landmarks were placed on the upper first molars and premolars, cranial base, condyles and glenoid fossa. Descriptive statistics, intraclass correlation coefficients and one-way ANOVA analysis were used to determine if there was a change in position of the condyle with respect to the glenoid fossa and cranial base. and if there was a statistically significant difference between the groups. RESULTS: Descriptive statistics showed that changes in condyle position with respect to the glenoid fossa were minor in both groups (<1.9 mm average for both groups). The largest difference in both groups was found when measuring the distance between the left and right condyle heads. When comparing changes between the groups, no significant difference was found between changes in the condyles (P > 0.05). CONCLUSION: RME treatment results in mild effects/changes on condylar position. Nevertheless, these changes do not present a significant difference with controls thus not being a limitation for applying this treatment.

267 THE JUVENILE IDIOPATHIC ARTHRITIS SPLINT WITH PROTRUSION SCREW – AN APPLIANCE FOR THE ACUTE INFLAMMATORY PHASE N Lausen, C Pantel, B Kahl-Nieke, Department of Orthodontics, Center for Dental and Oral Medicine, Medical Center Hamburg-Eppendorf, Hamburg, Germany

AIM: The treatment of patients with juvenile idiopathic arthritis (JIA) remains a challenge in orthodontic practice, since fixed appliances are restricted to non-acute phases of the disease. In contrast, during acute inflammatory periods splints are used to relieve the temporomandibular joint (TMJ) and to reduce inflammation. However, correcting the vertical dimension and unlocking the mandible can be difficult in

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patients with a deep overbite and retroclination of the upper incisors. This study evaluated the clinical use of a splint constructed with a protrusion screw. This appliance simultaneously protrudes the upper incisors and unloads the joint during active arthritis periods. SUBJECTS AND METHOD: Ten acute-phase JIA patients aged between 9-15 years with a deep overbite and retroclination of the upper incisors. Impressions of the maxilla and mandible and a joint-related registration with a facebow were taken in order to customize the splint in the articulator. The patients were advised to wear the splint 24 hours per day and activate the screw 0.25 mm (1 turn) weekly. RESULTS: One week after insertion of the splint, pain was markedly reduced and four weeks later little discomfort was noticed. Considerable protrusion of the upper incisors was observed after a period of four months. This movement allowed the mandible to slide forward in a sagittal direction. CONCLUSION: By using splints with protrusion screws it is possible to simultaneously relieve the TMJ, unlock the mandible and protrude the upper incisors. This combination appliance enables the orthodontist to begin dental Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 correction during acute JIA-phases and thereby facilitate the repositioning of the TMJ. An alternative way of protruding the incisors could be a fixed appliance such as a ‘two-by-four’ appliance. A major disadvantage of the latter method is that metal bands and brackets do not permit diagnostics investigations such as magnetic resonance tomography.

268 POST-SURGICAL STABILITY AFTER MANDIBULAR SETBACK SURGERY WITH MINIMAL ORTHODONTIC PREPARATION FOLLOWING UPPER PREMOLAR EXTRACTION N-K Lee, S-W Moon, Department of Orthodontics, Seoul National University Bundang Hospital, Kyoungki-Do, Korea South

AIM: To compare the patterns of surgical change and post-surgical relapse between patients with mandibular setback surgery with minimal orthodontic preparation (MS-MO) and those with sufficient orthodontic preparation (MS-SO) after upper premolar extraction (UPE). SUBJECTS AND METHOD: Twenty-six patients were allocated to two groups based on the duration of pre- surgical orthodontic preparation: MS-MO/UPE (n = 15; 5.53 ± 3.14 months) and MS-SO/UPE (n = 11; 13.00 ± 5.33 months). Lateral cephalograms were taken during the initial examination (T0), at splint removal (4 weeks after surgery; T1), and immediately after debonding (T2). To evaluate the surgical changes (T1 versus T0) and relapse (T2 versus T1), linear, angular, and dental measurements were used and analyzed using paired t- and independent t-tests. RESULTS: Although there was no significant difference in skeletodental pattern at T0 between the two groups, the MS-MO/UPE group showed a significantly larger amount of mandibular setback than the MS-SO/UPE group from T0 to T1. The two groups exhibited significant anterior and superior movement of the mandible from T1 to T2. However, the MS-MO/UPE group manifested greater counterclockwise rotation and forward movement of the mandible than the MS-SO/UPE group. Owing to such relapse of the mandible, the MS-MO/UPE group exhibited limited retraction of the upper incisors, whereas the MS-SO/UPE group showed slight labioversion of the upper incisors. CONCLUSION: Compared with the MS-SO/UPE group, the MS-MO/UPE group showed a larger amount of surgical setback and greater post-surgical counterclockwise rotation and forward movement of the mandible.

269 CORRELATION OF OCCLUSAL EVALUATION WITH THE PEER ASSESSMENT RATING INDEX, THE OBJECTIVE GRADING SYSTEM AND THE T-SCAN III SYSTEM S-M Lee, Department of Orthodontics, College of Dentistry, Dankook University, Chungnam, Korea, South

AIM: Evaluating occlusion in orthodontics is important with respect to function and stability. The purpose of this study was to evaluate the usefulness of the T-scan III system as an objective tool for occlusal evaluation and

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to determine difference between two occlusal indices by comparing measurements of T-scan III (Tekscan Inc., Boston, Massachusetts, USA) and two occlusal indices [Peer Assessment Rating (PAR) index and the American Board of Orthodontics Objective Grading system (OGS)], and analyzing correlation among these. SUBJECTS AND METHOD: Among 77 healthy adult volunteers 29 people were excluded due to severe skeletal deformities and occlusal interference resulting in difficulty in measuring T-scan elements. Thus 48 (39 male, 9 female) subjects were examined. The PAR index and OGS were measured using dental models, and 12 occlusal assessments each in maximum intercuspation, protrusive movement, lateral movement using T-scan III system, and then analyzed correlation among these. Reproducibility was also evaluated. RESULTS: The T-scan III system had clinical reproducibility (P < 0.05). PAR index and OGS had significant correlation with several measurements of the T-scan III system (P < 0.05). Since OGS had more measurements of significant correlation than the PAR index, OGS can be considered to be a more objective measuring method. CONCLUSION: The T-scan III system is an objective, quantitative and efficient method of occlusal evaluation Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 which can replace occlusal indices.

270 THE USE OF Z-BENDS IN CLASS III PATIENTS WITH AN ANTERIOR CROSSBITE C Leethanakul, C Sripongpankul, Department of Preventive Dentistry, Faculty of Dentistry, Prince of Songkla University, Hatyai, Songkhla, Thailand

AIM: The incorporation of Z-bends into a mandibular archwire has been used for simultaneous incisor intrusion and molar extrusion to reduce mandibular overclosure and to improve the facial profile in Class III patients. The objective of this study was to investigate the cephalometric changes resulting from Z-bends in a group of Class III anterior crossbite patients. SUBJECTS AND METHOD: Nine Class III anterior crossbite growing patients with mandibular overclosure were treated with lower 2 ×4, 0.016 inch stainless steel Z-bent wire in combination with light vertical Intermaxillary elastics. Cephalometric changes were measured after 6 months of treatment. Pre- and post-treatment data were compared using Wilcoxon’s signed rank test at the level of significance of 0.05. RESULTS: The mandibular incisors were significantly intruded and retroclined at the rate of 0.3 ± 0.2 mm/month and 1.3 ± 1.8 degrees/month respectively (P < 0.05). The mandibular first molars were significantly extruded at the rate of 0.2 ± 0.3 mm/month (P < 0.05), leading to an improvement of facial contour angle from 3.2 ± 4.8 to 4.2 ± 5.1 degrees (P < 0.05). CONCLUSION: The mandibular Z-bent archwire was effective not only in intruding and retroclining the incisors, but also in extruding the first molars, which subsequently clockwise rotated the mandible and improved the Class III facial profile.

271 EVALUATION OF MAXILLARY MOLAR DISTALIZATION SYSTEM USING THREE-DIMENSIONAL DIGITAL MODELS Y Lena, G Önçağ, Department of Orthodontics, Faculty of Dentistry, Ege University, Izmir, Turkey

AIM: To investigate the maxillary first premolar changes that occurs during Class II molar correction with a maxillary molar distalization device the MGBM-System (Maino, Giannelly, Bernard, Mura). MATERIALS AND METHOD: The pre- and post-distalization dental three-dimensional (3D) digital models of 10 patients with a Class II malocclusion treated with MGBM-System were compared. The age range of the group at the beginning of treatment was 14-16 years. A newly developed intraoral skeletal anchorage system was used for molar distalization. Before distalization of the upper first and second molars, self-tapping orthodontic miniscrews were progressively inserted in the palatal bone between the first and second bicuspids with a hand screwdriver. The miniscrews were 1.5 mm in diameter and 6 mm long. A transpalatal arch was bonded to the first bicuspids and attached to palatal miniscrews with 0.010 ligature wires. A sectional 0.016 × 0.022 inch

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stainless steel wire with a NiTi coil spring from first bicuspid to first molar and 0.017 × 0.025 inch superelastic Nitinol wire for the second molars was used. After achieving an overcorrected Class I relationship, dental casts are obtained. Digital models were superimposed using the palate as a reference area via surface-to-surface matching software using rugae-palate superimposition and the changes in premolar tooth movement were calculated. 3D measurements and mesial movements of the premolars were recorded. The means and standard deviations were calculated for the pre- and post-distalization measurements by one sample t-test. RESULTS: The first and second molars were successfully distalized into an overcorrected Class I relationship in all patients. The system did not require patient cooperation. There was anchorage loss on premolars. The mean maxillary premolar mesial movement was 1.55 mm. CONCLUSION: Although the system is efficient for distalizing the maxillary permanent molars using skeletal anchorage, more research is needed to discover the rationale behind the premolar mesialization. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 272 LONG-TERM EVALUATION OF ORTHODONTIC TREATMENT OUTCOME: SEVEN YEARS POST-TREATMENT C F Leung, H Ebrahim, A Karsten, J Huggare, Department of Dental Medicine, Division of Orthodontics, Karolinska Institutet, Huddinge, Sweden

AIM: To investigate the occlusal condition and residual treatment need seven years after orthodontic intervention. SUBJECTS AND METHOD: Thirty-two patients were recalled seven years after their fixed orthodontic appliance was debonded. In order to evaluate the occlusal status, impressions for study casts were made. For assessment of occlusion, the Peer Assessment Rating (PAR) index and Index of Complexity, Outcome and Need (ICON) was used. The residual treatment need was estimated using the Index of Orthodontic Treatment Need (IOTN) and Swedish Medical Board Index for treatment priority (SMBI). The indices were calculated based on measurements on the study models pre-treatment (T0), post-treatment (T1) and at the seven-year follow-up (T2). Drop-out analysis was carried out. The indices scores and residual treatment need at T0, T1 and T2 were compared. RESULTS: Regarding occlusal condition, the PAR index at T2 showed a reduction of 60.8 per cent compared with T0. Anterior crossbite and contact point displacement scores at T2 were significantly different from T1. The contact point displacement scores increased from 0.62 at T1 to 2.16 at T2. The ICON showed that 81 per cent of patients remained moderately to greatly improved at T2, however, with a significant deterioration in individual patients’ improvement grades. Regarding long-term residual treatment need, no significant change was found between T1 and T2, although assessments made with SMBI showed a tendency for increased treatment need. CONCLUSION: Most patients seemed to retain their improved occlusion over the follow-up period and residual treatment need remained low. Compared with the ICON, evaluation of residual treatment need with IOTN or SMBI seems to be a reasonable way to measure quality and outcome of orthodontic treatment in the long-term.

273 SKELETAL ALTERATIONS FOLLOWING RAPID C Lilli, A Giordano, E Porcelli, M Castellano, G Galluccio, Department of Oral and Maxillo Facial Sciences, Sapienza University of Rome, Italy

AIM: To evaluate changes in head posture and craniocervical angulation after rapid palatal expansion (RPE) in subjects with transverse maxillary deficiency. MATERIALS AND METHOD: This cephalometric study was performed on the lateral radiographs of 14 patients (8 females, 6 males, aged 6-10 years) before and after treatment. A paired t-test and linear regression were used to compare the pre- and post-treatment values. To evaluate changes in cervical posture following palatal expansion, the following were compared: the cervical lordosis angle, the downward opening angle between the mandibular and true vertical lines before and after treatment with mode of breathing and skeletal Class.

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RESULTS: The correlation coefficients indicated a significant correlation between skeletal Class and craniocervical angulation. CONCLUSION: The results suggest an ongoing change in head posture possibly due to a change in mode of breathing as a result of RPE, contributing to a change in skeletal Class. No correlation was found between cervical lordosis and RPE.

274 ELECTRON ENERGY LOSS SPECTROSCOPIC ANALYSIS OF THE INTERFACE OF ORTHODONTIC IMPLANT SURFACES AND CORTICAL BONE IN HUMANS J-B Lim, J-S Kim S-J Kim, Y-G Park, S-H Kim, Department of Orthodontics, Kyung Hee University, Seoul, Korea South

AIM: To investigate the presence and pattern of chemical osseointegration on the interface of orthodontic Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 implant surfaces using scanning transmission electron microscopy/electron energy loss spectroscopy (STEM/EELS) analysis. SUBJECTS AND METHOD: For temporary skeletal anchorage during orthodontic treatment, C-implants® were placed in about 100 patients and removed after use. Among them, five implants had the appearance of osseointegration to the naked eye. These were placed in saline solution, frozen and fixed with ethane solution within 1 hour. These five implants were prepared as transmission electron microscopy (TEM) specimens using the SEM FIB (Focused Ion Beam, FEI Company) in situ protocol. After obtaining a full image of the specimen using Tecani F20 Cryo Stem, the region of interest was divided into Ti, interface and bone section, and then observed with EELS. RESULTS: The existence of hydroxyapatite was confirmed by observation of selected area electron diffraction within bone tissue. When line profile energy dispersive X-ray spectroscopy was performed on the portion including the interface, the interface in which titanium, oxygen, calcium, and phosphorus were observed at the same time was identified. Using EELS analysis, the interface showed peaks of carbon, calcium, phosphorus, titanium, and oxygen existed concurrently. In the phosphorus spectrum, it had similar shapes to those of calcium phosphate in the mixed and bone tissue layers. Comparing the oxygen spectrum in the interface and the reference spectrum of energy loss near edge spectrum, the possibilities of the existence of tricalcium phosphate, titanium oxide or calcium titanate in the interface were acknowledged. CONCLUSION: The intimate interaction of the two materials was confirmed to be irrelevant to the existence of the interface. It was found that calcium phosphate placed closer to titanium in the bone tissue layer more resembled calcium phosphate than hydroxyapatite. Therefore, when an interacted layer is absent, it is possible to conclude that the amorphous calcium phosphate is bound to the titanium oxide of the implant by electrostatic force.

275 ORTHODONTIC TOOTH MOVEMENT USING CORTICOTOMY WITH GRAFT MATERIALS J-B Lim, K-B Lee, K-A Kim, H-W Ahn, S-H Kim, Kyung-Hee University, Seoul, Korea South

AIM: To investigate and compare the effects of application of coticotomy-augmentation in combination with irradiated cortical bone (ICB: irradiated cortical bone allograft, Rocky Mountain Tissue Bank, Aurora, Colorado, USA) or synthetic bone (MBCP+: Micro-Macroporous Biphasic Calcium Phosphate, Biomatlante, France) on periodontal tissue reconstruction of uncontrolled buccal tipping tooth movement in beagle dogs. MATERIALS AND METHOD: The study employed four male beagle dogs and was designed as a split-mouth model, composed of two sites: group A, corticotomy-augmentation combined with ICB graft, and buccal tipping movement and group B, corticotomy-augmentation combined with synthetic bone MBCP+ graft and buccal tipping movement. Groups A and B were randomly assigned. The mandibles and maxillae of all experimental

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animals were dissected, and the block specimens containing the experimental areas were obtained. Histologic examinations were performed. RESULTS: There were significant differences in the width of the keratinized tissue decrease between baseline and 6 weeks of healing in group A (P = 0.018). There were significant differences in probing depth (PD) between baseline and 6 weeks of healing in group B (P = 0.004). PD was increased 0.438 mm. Most of grafted ICB particles were resorbed and replaced with new bone. Grafted MBCP+ particles were resorbed slowly compared with ICB. New bone formation at the buccal side was more prominent in group B. CONCLUSION: Both ICB and MBCP+ have similar effects on periodontal tissue reconstruction.

276 EFFECTS OF TWO DIFFERENT PROTOCOLS OF DISTALIZATION ON THE VERTICAL DIMENSION: A CONTROLLED CLINICAL TRIAL IN GROWING SUBJECTS R Lione1, C Pavoni1, L Franchi2, P Cozza1, 1Department of Clinical Sciences and Translational Medicine, University Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 of Rome ‘Tor Vergata’ and 2Department of Surgery and Translational Medicine, University of Florence, Italy

AIMS: To compare the influence, on the vertical dimension, of cervical headgear (CHG) and the pendulum (PDG) used with fixed appliances, and to evaluate changes in oral health-related quality of life (OHQoL) during therapy. SUBJECTS AND METHOD: The CHG group consisted of 40 subjects (15 males, 25 females) with a mean age of 11.6 years. The PDG sample comprised 40 subjects (18 males, 22 females) with a mean age of 12 years. The inclusion criteria were late mixed or permanent dentition, Class II or edge-to-edge molar relationship, ANB between 2 and 7 degrees and lower arch crowding less than 5 mm. Lateral cephalograms were analysed before treatment (T0) and at the end of fixed therapy (T1) with a mean T0-T1 interval of 3.2 years. The effects of the two protocols were compared with a control group with the same mean ages at T0 and T1, skeletal, and occlusal characteristics. An independent samples Student t-test was used to analyse between-group differences for each cephalometric variable (P < 0.05). At the end of active distalization the United Kingdom OHQoL questionnaire was given to each subject to assess the negative and positive impacts on QoL of the two therapies. The results of the questionnaires were contrasted by means of the Mann-Whitney test (P < 0.05). RESULTS: Total molar correction was identical in the two groups (2.9 mm), and both appliances were equally effective in achieving a Class I molar relationship. The CHG restricted maxillary forward displacement thus improving skeletal maxillomandibular relationships (SNA –1.2°; ANB –1.8°). The two treatment protocols did not affect facial divergency when compared with the control group. The CHG had a significant negative impact on appearance, comfort, and sleep, and the PDG on eating and breath odour. CONCLUSION: Both distalizers were effective in correcting dental Class II malocclusions without increasing the vertical dimension in growing subjects. Both protocols did not differ for overall impact on the QoL but only for some aspects.

277 AUDIT OF THE APPROPRIATENESS OF ORTHODONTIC REFERRALS R Little, L Barreto, Department of Orthodontics, Birmingham Dental Hospital, U.K.

AIM: To evaluate the appropriateness of orthodontic referrals to Birmingham Dental Hospital. MATERIALS AND METHOD: A prospective audit was carried out between September and December 2012. The gold standard was that 100 per cent of referrals should be appropriate; each referral should meet at least eight out of 10 criteria to be deemed appropriate. A proforma was completed for 120 consecutive new patients from two consultant clinics. RESULTS: The majority of referrals were from general dental practitioners (57%), followed by tertiary care practitioners (25%), and specialist practitioners (18%). More than 90 per cent compliance was achieved for referrer details, reason for referral, awareness of the reason for referral and willingness to wear appliances. Areas for improvement included demographic details, medical history, timing of the referral, appropriate Index

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of Orthodontic Treatment Need (IOTN), level of oral hygiene/dental health and potential compliance. Twenty two referrals (18%) fulfilled all specified criteria and 95 referrals (79%) were deemed appropriate. CONCLUSION: Although the gold standard was not met, 79 per cent of referrals were found to be appropriate and this compares favourably with other similar audits. This audit has emphasised the need for further education of referring dental practitioners regarding the use of the IOTN, timing of treatment and interception, the importance of good oral health, and the inclusion of full demographic details and medical history in referral letters. A regional Managed Clinical Network proforma requires further development. It is to be used by all referring practitioners to standardise referrals. The plan is to re-audit in one year’s time following implementation of the recommendations.

278 FROM EUROPEAN ORTHODONTIC SOCIETY CONGRESS ABSTRACT TO FULL-TEXT JOURNAL ARTICLE: PUBLICATION STATUS AND PREDICTORS Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 C Livas1, N Pandis2, Y Ren1, 1University Medical Centre Groningen, Netherlands and 2University of Bern, Switzerland

AIMS: To examine the publication status of oral and poster presentation abstracts included in the scientific programme of the 82nd and 83rd European Orthodontic Society (EOS) congresses, held in 2006 and 2007, and to identify factors associated with full-length publication. MATERIALS AND METHOD: A systematic search of PubMed and Google Scholar databases was performed in April 2013 using author names and keywords from the abstract title to locate abstract and full-article publications. Information regarding mode of presentation, type of affiliation, geographical origin, statistical results and publication details were collected and analyzed using univariable and multivariable logistic regression. RESULTS: Approximately 51 per cent of the EOS 2006 and 55 per cent of the EOS 2007 abstracts appeared in print more than 5 years post-congress. A mean period of 1.32 years elapsed between conference and publication date. Mode of presentation (oral or poster), use of statistical analysis, and research subject area were significant predictors for publication success. CONCLUSION: On average 52.2 per cent of the abstracts presented at the two EOS conferences reached full publication. Abstracts presented orally, including statistical analysis, were more likely to be published.

279 THREE DIMENSIONAL ANATOMICAL STRUCTURES OF THE INFRAZYGOMATIC CREST IN THAI PATIENTS WITH CLASS I AND CLASS II SKELETAL PATTERNS: A CONE BEAM COMPUTED TOMOGRAPHIC STUDY C Lohalertkit, D Jotikasthira, V Patanaporn, K Poolsin, A Janhom, Department of Orthodontics and Pediatric Dentistry, Faculty of Dentistry, Chiang Mai University, Thailand

AIM: To compare anatomical structures of the infrazygomatic crest in Thai patients with Class I and Class II skeletal patterns. MATERIALS AND METHOD: Forty eight cone beam computed tomographs of the infrazygomatic crest (12 Class I and 12 Class II skeletal patients). Buccal cortical bone thickness at the mid-point between the first and second molars, buccal plate thickness at the distobuccal root of the first molar and the mesiobuccal root of the second molar at four vertical levels were measured. Biting depth was measured for all combinations of each vertical level [from 5.0 to 8.0 mm from the buccal cemento-enamel junction (CEJ) of the first molar] and in each direction (from 55 to 70° to the maxillary molar occlusal plane). RESULTS: The buccal cortical bone thickness in patients with a Class I and Class II skeletal pattern ranged from 1.18 to 1.31 mm, and from 1.21 to 1.37, respectively. The buccal plate thickness at the distobuccal root of the first molar ranged from 2.91 to 3.16 mm in patients with a Class I skeletal pattern, and from 2.98 to 3.10 mm in patients with a Class II skeletal pattern. The buccal plate thickness at the mesiobuccal root of the second molar

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was from 2.91 to 3.82 mm and from 3.06 to 4.18 mm, respectively, in patients with Class I and Class II skeletal patterns. The biting depth ranged from 5.27 to 8.77 mm in patients with a Class I skeletal pattern, and from 4.94 to 7.77 mm in patients with a Class II skeletal pattern. There was no statistically significant difference for all measured variables between Class I and Class II skeletal patterns. CONCLUSION: The anatomical structures of the infrazygomatic crest in patients with Class I and Class II skeletal patterns were insignificantly different, so it is suggested that in Thai patients with either a Class I or Class II skeletal pattern, the combination of either a 5.0 or 6.0 mm vertical level from the buccal CEJ and each direction (from 55° to 70° to the maxillary molar occlusal plane) might provide a safe guideline for adequate buccal cortical bone thickness as well as correct biting depth during miniscrew implant placement.

280 EFFECT OF DENTAL MIDLINE ANGULATION ON THE AESTHETICS OF A SMILE: EVALUATION BY DENTAL PROFESSIONALS AND LAYPERSONS Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 M López-Marí, F Cascales-Moya, L López-Ruiz, A Vicente, L A Bravo-González, Universidad De Murcia, Spain

AIM: To determine the aesthetic evaluation of orthodontists, general dentists and laypersons of different degrees of midline angulation. MATERIALS AND METHOD: A frontal facial photograph of a smiling female was altered using Adobe Photoshop C3 (Adobe Systems Inc., San Jose, California, USA) to create three images of the same smile with varying midline angulations in 10 degree increments (0, 10 and 20°). These photographs were evaluated by three groups: orthodontists and general dentists with over 10 years’ experience, and laypersons aged between 40 and 50 years. The proportion of male-female subjects was 25:25 in each group. Each image was awarded a mark, giving a value of 1 to 5 depending on aesthetic preference, 1 being the lowest value and 5 the highest. Data were analyzed applying the Kruskal-Wallis test (P < 0.05) and the Mann-Whitney test applying the Bonferroni correction (P < 0.016). RESULTS: There were no significant differences (P > 0.05) between the three groups in their aesthetic evaluation of the smile with no midline angulation and 10 degrees of angulation. However, the image with the 20 degree midline angulation was marked as significantly more aesthetic by laypersons than by orthodontists (P < 0.016). CONCLUSION: A midline angulation of 10 degrees was undetectable by both dental professionals and lay persons. However, a 20 degree midline angulation smile was perceived negatively to a greater degree amongst orthodontists than amongst laypersons.

281 INFLUENCE OF THE LEVEL OF THE LATERAL INCISOR GINGIVAL MARGINS ON THE PERCEPTION OF SMILE AESTHETICS L López-Ruiz, B Izquierdo-Gómez, M López-Marí, L A Bravo-González, A Vicente, Murcia, Spain

AIM: To evaluate how the vertical position of the gingivae of the maxillary lateral incisors influences the aesthetic perception of orthodontists, general dentists and laypersons. MATERIALS AND METHOD: Using Adobe Photoshop C3 (Adobe systems Inc., San Jose, California, USA) four frontal images of the same smile were created: one with an adequate relationship between the gingival margins of central and lateral incisors while in the other three the vertical height of the gingival margins of the lateral incisors was increased by 0.75 mm relative to the adjacent central incisor (0.75, 1.25 and 2 mm of gingival increment). These photographs were evaluated by orthodontists (n = 50), general dentists (n = 50), and laypersons (n = 50). The average age of the three groups was 40-50 years. The proportion of male-female subjects was 1:1 in each group. Each image was awarded a mark, giving a value of 1 to 5 depending on aesthetic preference, 1 being the lowest value, and 5 the highest. Data were analyzed using the Kruskal-Wallis (P < 0.05) and the Mann-Whitney test applying the Bonferroni correction (P < 0.016).

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RESULTS: No significant differences were found (P > 0.05) between the three groups in the evaluation of the image with an adequate relationship between the gingival margins of the central and lateral incisors, and those in which the height of the gingival margins of the lateral incisors were increased 0.75 and 1.25 mm relative to the adjacent central incisor. On the other hand, the image with the gingival margin at the level of 2 mm was marked as significantly more aesthetic by general dentists and laypersons than by orthodontists (P < 0.016). CONCLUSION: Orthodontists have a higher level of clinical perception than dentists or laypersons, as orthodontists perceived the image showing 2 mm of alteration in the vertical height of the gingival margins of the maxillary lateral incisors in relation to the gingival height of the central incisors, significantly less aesthetic than general dentists and laypersons.

282 THE POLISH FACE IN PROFILE: A CEPHALOMETRIC BASE LINE STUDY B W Loster1, S Williams1, J Loster2, Departments of 1Orthodontics and 2Prosthodontics, Medical Faculty, Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 Jagiellonian University, Kraków, Poland

AIM: As dentofacial cephalometric characteristics are related to the ethnic background of the individual it is important that the cephalometric norms, with which any individual patient is compared, reflect individuals sharing a similar ethnic background. The aim of this study was to investigate the dentofacial morphology and soft tissue characteristics of a number of young adolescent individuals, thus establishing a series of values which could serve as comparative material in future treatment planning of malocclusion for Polish individuals. The study was approved by the bioethical committee. MATERIALS AND METHOD: Standardised digital cephalometric recordings (low dose protocol) of 122 Individuals (♂35 , ♀87) average age 17 years 6 months, (minimum 16 years 9 months, maximum 19 years 3 months). None had received orthodontic treatment and all were included irrespective of occlusion. Measurement was performed by the same observer using a Facad computer system. All data was calculated digitally. The results were tabulated in two sections (1) Björk analysis (slightly abridged) and (2) soft tissue profile. RESULTS: There was close similarity in form between the two groups for virtually all parameters, with the exception of the vertical jaw relationship (NL/ML) which was significantly reduced in the case of the Polish material (mean = 21.18° s.d. 5.81° P < 0.01). The reduced vertical jaw relationship was a result of an anterior inclination of the mandible (30.05° s.d. 6.08°) accompanied by a high mandibular ramus (β angle), both indicating a difference in the relative heights of the mandibular ramus between the two groups and suggesting a stronger anterior rotational mandibular growth pattern in the Polish group. The soft tissue results echoed the dentoskeletal dimension revealing a proportionally low lower face height. CONCLUSION: The series of morphological similarities and differences between young Polish and Swedish adults should be taken into consideration when interpreting the output of cephalometric analysis. The differing mandibular morphology could indicate a good growth pattern for treating Class II patients though the development of a deep bite must be expected. Adoption of the results is recommended when treating Polish patients.

283 ADHESION BY ORAL STREPTOCOCCI ON DIFFERENT COMMERCIAL WIRE*** A Lucchese1, M Manuell3, E Gherlone3, 1Department of Orthodontics and 3Dental School, University Vita e Salute, San Raffaele Hospital, Milano and 2Private Practice, Bologna, Italy

AIM: To compare early bacterial adhesion and biofilm formation on a variety of commercial archwires used in different orthodontic phases. SUBJECTS AND METHOD: Thirty patients, 13 males and 17 females (mean age 16.2 years). All patients received oral hygiene instruction at baseline and at each regular check up and were asked to refrain from any clorexidine use during the study. Round nickel titanium, round stainless steel, multistrand stainless steel, beta -titanium

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were removed and analysed. Statistical analysis (ANOVA) was performed using SPSS version 10.0 (SPSS Inc., Chicago, Illinois, USA). RESULTS: Significant differences were evidence in both early adhesion and biofilm formation among the studied archwires. Stainless steel was less prone to colonization, while multistrand were the most prone ones. The rate of growth of the different tested species on the various materials were significantly different. CONCLUSION: This study confirms the necessity of having particular oral health care in different treatment periods regarding periodontal disease and caries lesions.

284 COMPARISON OF CHONDROITIN SULPHATE LEVELS IN GINGIVAL CREVICULAR FLUID DURING ORTHODONTIC TOOTH MOVEMENT BETWEEN SELF-LIGATING AND CONVENTIONAL BRACKET SYSTEMS P Luengrojjanakul1, D Jotikasthira1, P Kongtawelert2, P Pothacharoen2, S Ongchai1, Departments of 1Orthodontics and Pediatric Dentistry and 2Biochemistry, Chiang Mai University, Thailand Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021

AIM: To compare chondroitin sulphate (CS) levels in gingival crevicular fluid (GCF) during the unloaded and the loaded periods of orthodontic tooth movement (levelling) between self-ligating and conventional bracket systems. SUBJECTS AND METHOD: Thirteen patients (3 males, 10 females; aged 19.28 ± 2.28 years) who required non- extraction orthodontic treatment. Self-ligating (Damon® 3MX) and conventional bracket (Mini diamond®) systems were bonded on either the right or left maxillary teeth (using a split mouth technique). Tooth levelling was carried out using 0.014 inch copper nickel titanium archwire. GCF samples around the left and right maxillary canines and first premolars were collected using Periopaper® strips during the unloaded (day 0) and loaded periods (days 1, 3, 5, 7, 14, 21 and 28). The CS levels in GCF were measured by competitive ELISA with WF6 monoclonal antibody, and were compared by the Wilcoxon signed-rank test. RESULTS: During the unloaded (baseline) periods, from canines and premolars bonded using the self-ligating and conventional bracket systems, the medians of CS levels were 2.52, 2.18, 1.62 and 3.37 ng/μg of total protein, respectively. During the 4-week loaded (experimental) periods, from canines bonded using the self- ligating and conventional bracket systems, the medians of CS levels ranged from 2.29 to 11.5, and from 2.18 to 12.73 ng/μg of total protein, respectively, and those on day 5 (after initial force application) were significantly higher than those at baseline. However, from canines bonded using the conventional bracket system, the median of CS levels on day 14 was also significantly higher than that at baseline. From premolars bonded using the self-ligating and conventional bracket systems, the medians of CS levels ranged from 0.92 to 8.63, and from 2.13 to 6.44 ng/μg of total protein, respectively, and those on days 1, 5 and 14 (after initial force application) were apparently, though not significantly, higher than those at baseline. CONCLUSION: Both self-ligating and conventional bracket systems cause similar alveolar bone remodelling as biochemically revealed by similar cyclical pattern of detected CS levels in GCF around the teeth during orthodontic movement.

285 IMPACT OF TOOTH ALIGNMENT ON SMILE ATTRACTIVENESS T Lundqvist, S Ibstedt, J Huggare, Department of Dental Medicine, Karolinska Institutet, Stockholm, Sweden

AIM: To find out how young adults perceive smile attractiveness with modified tooth alignment, with a focus on the effect of gender and previous orthodontic treatment. MATERIALS AND METHOD: Photographs of a young woman and a young man smiling were animated to express anterior crowding and a median diastema. Sixty five 19-year olds were asked to rank the attractiveness of the smiles on a scale of 1-5, where 1 = not attractive and 5 = very attractive. Every other girl started by ranking the photographs of the female and every other with the photographs of the male, and the same for the boys.

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RESULTS: A diastema was ranked worse than crowding. Moderate and severe crowding was ranked significantly higher in the female than in the male. There was no significant differences when ranking the same or opposite gender. Those with a history of orthodontic treatment were more restricted in their ranking. CONCLUSION: The positive effect on perceived smile attractiveness followed by orthodontics might be less in females than in males, at least when it comes to correction of anterior crowding.

286 A STANDARD PROTOCOL FOR HISTOPATHOLOGICAL RAT PERIODONTAL ANALYSIS IN ORTHODONTIC RESEARCH M Macedo Crivelini1, V Honda Gomes de Oliveira1, M A Borella Rodrigues2, A Fernando Fabre2, M R de Mendonça2, Departments of 1Pathology and Clinical Propaedeutic and 2Pediatric and Community Dentistry, Univ Estadual Paulista, Aracatuba, Brazil Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 AIM: Orthodontic research that microscopically assesses the periodontal structures in animals is an issue that should be improved standardize both methodology and data collection protocols, since at present several reports describe only the histopathological features. The aim of this study was to establish a macroscopic protocol to standardize the histological cuts of the mesiobuccal and distobuccal upper first molar roots of rats. MATERIALS AND METHOD: Ten hemimaxillae of male Wistar rats, aged 45 days, were processed following a rigid macroscopic protocol to obtain cuts that cover the entire longitudinal extent of the roots, showing the root pulp and the periapical foramen. The periodontal spaces of furcation, cervical, middle and apical thirds were measured by histometry, as well as their cell nuclei counted. RESULTS: Pearson's coefficient and normal distribution tests of numerical results indicated that the histological cuts had the same section level, showing similar dimensions. CONCLUSION: The results ensured reliability in data collection of the samples of experimental groups.

287 STABILITY OF NON-SURGICAL RAPID MAXILLARY ALVEOLAR EXPANSION IN ADULTS D Makedonas, Modern Orthodontic Care, Athens, Greece

AIM: Palatal expansion in adults has been performed on a very limited basis due to poor stability and associated complications. Instead, surgically assisted rapid maxillary expansion (SARME) has been recommended. The aim of this study was to investigate the stability of intermolar and interpremolar width and maxillary arch length, three years after expansion treatment in adults. SUBJECTS AND METHOD: Twenty two adults (21 to 36 years old) with bilateral transverse arch deficiency treated with non-surgical expansion using a modified Hyrax appliance. Study casts were taken before, after, and three years after termination of treatment. Intermolar and interpremolar width, palatal height, and maxillary arch depth, length and molar axial angulation were assessed from maxillary dental casts. Transverse expansions of 2.5 to 7 mm, adequate to correct the malocclusions, were performed. Appliance activation was performed once every two days for 3 weeks to avoid pain, swelling, and ulceration. The average total treatment time was 14 months. Recalls were performed three years after termination of active treatment. RESULTS: Expansion produced significant increases in intermolar and interpremolar width and maxillary arch length after at the level of the lateral walls of the palate. Minor molar tipping, minimal gingival recession, and minimal root resorption of the maxillary molars was observed after treatment. The amount of relapse was not significant three years post- treatment (P > 0.05). CONCLUSION: Maxillary alveolar expansion is a stable alternative to SARME in adults for most cases of minor maxillary transverse deficiencies.

288 TREATMENT TIME ANALYSIS OF ALIGNMENT OF IMPACTED MAXILLARY CANINES IN ADULTS D Makedonas, Modern Orthodontic Care, Athens, Greece

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AIM: Duration, cost, success rate, and incidence of complications are parameters of consideration when treating impacted maxillary canines. The aim of this study was to evaluate a possible correlation between treatment time and the radiographic position of palatally impacted canines. MATERIALS AND METHOD: Treatment records and cone beam computed tomographs of 36 adult consecutive patients (28 to 53 years old; 23 unilateral, 13 bilateral) with ectopic palatal canines successfully treated with surgical exposure and orthodontic traction were analyzed. The height of the impacted canine, mesiodistal position of the canine tip relative to the midline, angulation of the long axis to the upper midline, and the anteroposterior position of the canine root apex, was measured. RESULTS: Multiple regression analysis showed that initial canine angulation and the horizontal position of the canine crown relative to adjacent teeth and the maxillary dental midline showed a statistically significant correlation with the duration of treatment. No significant correlation was found with other variables, including Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 gender, vertical height, distance between the canine cusp tip and the occlusal plane, and position of the canine apex. CONCLUSION: The mesiodistal position of the canine and the angulation of the long axis appear to provide an accurate estimate of treatment duration. However, individual characteristics such as bone density and metabolism seem to have a strong impact on treatment time. Prediction of treatment duration for orthodontic alignment of palatally impacted maxillary canines is rather vague.

289 RELEASE OF BIOLOGICALLY HAZARDOUS COMPONENTS FROM ORTHODONTIC ADHESIVE SYSTEMS K Małkiewicz, M Zadurska, Department of Orthodontics, Medical University of Warsaw, Poland

AIM: Treatment with fixed orthodontic appliances requires application of bonding systems. Light-polymerized orthodontic adhesives are similar in chemical composition to composite restorative materials, whose chemical stability is unsatisfactory. Of particular concern is the release of bisphenol A (BPA) and its derivatives into the environment, which has been previously reported for dental composites used in conservative dentistry. However, the available literature provides very few reports on BPA release from orthodontic adhesives. The aim of this study was an in vitro assessment of the release of biologically harmful BPA and its derivatives from orthodontic adhesive systems as a potential health risk factor for patients. MATERIALS AND METHOD: The levels of BPA and its polymers in eluates of six commonly used orthodontic adhesives: Light Bond, Transbond XT, Resilience, Aspire, GrēnGloo and ConTec LC were assessed. The solutions were obtained after 1 and 24 hours, and 7 and 31 days of material sample storage in water. The presence and concentration of chemicals in the assessed eluates were identified using the high performance liquid chromatography method. The data were statistically analyzed at the 0.05 significance level. RESULTS: The highest (P < 0.05) BPA concentration at the level of 32 µg/ml was observed in Resilence eluates after 1 hour of storage in water. The highest (P < 0.05) concentration of BPA derivatives was found in solutions obtained after 1-hour incubation of Contex LC adhesive at the level of 371 µg/ml. The identified chemical compound concentrations were significantly highest (P < 0.05) after 1 hour compared with those observed after 24 hours, 7 days and 31 days of storage in water. CONCLUSION: Most of the assessed orthodontic adhesive resins investigated released biologically harmful BPA or its derivatives. The highest release of BPA and its derivatives into aqueous solutions occurred in the early stages of incubation.

290 ROOT RESORPTION ASSESSMENT AFTER TWO DIFFERENT RAPID MAXILLARY EXPANSION APPLICATIONS BY MICROCOMPUTED TOMOGRAPHY*** S Malkoc1, F Ozturk2, E Toy1, E Hatunoglu1, E B Kucuk1, Departments of Orthodontics, 1Inonu University, Malatya and 2Pamukkale University, Denizli, Turkey

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AIM: To evaluate the volume and number of root resorptions in premolars subjected to full acrylic capping [bonded rapid maxillary expansion (RME)] and hygienic rapid maxillary expansion (banded RME) appliances. SUBJECTS AND METHOD: Thirty subjects who required RME and maxillary first premolar extractions as part of their orthodontic treatment. The patients were randomly separated into six groups each consisting of five subjects: group 1, 0 days after bonded RME; group 2, 0 days after banded RME; group 3, 30 days after bonded RME; group 4, 30 days after banded RME; group 5, 120 days after bonded RME; group 6, 120 days after banded RME. After the observation periods, the teeth were extracted, and the samples were analyzed with microcomputed tomography (µCT). The hardware device used was a µCT scanner (SkyScan 1072). The morphology of the root surfaces was assessed by CTAn software (SkyScan) for identification of root resorption, craters, and numerical assessment of volumes. Data were analyzed by Mann Whitney-U adjusted with Bonferroni tests. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 RESULTS: No significant difference was found in the amount of total root resorption or numbers between the bonded and banded RME groups for 0 and 30 days (P > 0.05). However significant differences were found between the bonded and banded RME groups at 120 days (P < 0.05). Significant differences were also found for all observation periods within either bonded or banded RME groups (P < 0.05). CONCLUSION: Following bonded or banded RME, significant root resorptions were observed for all first premolar teeth. In addition, no healing was found in the root surface after 120 days. As the findings are based on only five patients, verification in a larger study sample are needed.

291 EARLY LOW INVASIVE TREATMENT OF ANTERIOR OPEN BITES WITH A VERTICAL HOLDING APPLIANCE G Mampieri, M Greco, A Giancotti, University of Rome Tor Vergata Fatebenefratelli Hospital, Italy

AIM: To evaluate dentoskeletal effects on hyperdivergent growing patients with atypical swallowing, oral habits (thumb sucking) and a severe anterior open bite (AOB) treated by means of a modified vertical holding appliance (VHA). SUBJECTS AND METHOD: Eleven early mixed dentition patients with Class I malocclusion, atypical swallowing, oral habits (thumb sucking) and AOB. All subjects presented with an increased skeletal vertical pattern (SN/GoGn mean: 38.5°), and reduced overbite (mean: –2 mm). Panoramic and lateral radiographs were taken at the beginning (T1) and end (T2) of treatment. All patients were treated by means of a removable modified transpalatal bar, made of 0.9 inch stainless steel wire with a resin pad covering the omega loop. The button was designed to be at the height of the occlusion in order to achieve vertical control by tongue pressure. Moreover, in order to maintain bar flexibility and to gain the possibility to expand the upper arch transversally, two adjunctive loops were modelled laterally to the resin button. RESULTS: The modified vertical holding appliance improved the AOB, reducing divergence (mean: 1.2°) by means of tongue pressure on the resin button. Tongue pressure on the button provided an opportunity to educate tongue movements correcting the atypical swallowing and discouraging oral habits. CONCLUSION: The VHA is a valid alternative to removable devices in obtaining excellent results without compromising comfort and does not depend on patient compliance.

292 THREE-DIMENSIONAL PERMANENT MOLAR CHANGES AFTER RAPID MAXILLARY EXPANSION ON PRIMARY MOLARS G Manti, A Caprioglio, R Fastuca, P A Zecca, M Rosa, University of Insubria, Varese , Italy

AIM: According to the equilibrium theory, the tongue, muscles, soft tissues of the cheeks, and occlusal function play a role in determining the final buccolingual position of the teeth. Ideally the most stable orthodontic movement might be spontaneous movement of the teeth. The purpose of this study was to evaluate the

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spontaneous dental effects on permanent molars following rapid maxillary expansion (RME) by means of cone beam computed tomography (CBCT). SUBJECTS AND METHOD: Fifty two subjects in the early mixed dentition, with an average age of 7,5 years. The sample matched the following inclusion criteria: maxillary transverse deficiency with or without anterior crowding. A Haas appliance, banded on the maxillary second primary molars, was used. After ethical consensus, CBCT scan were performed before treatment (T0) and after 12 months (T1). Eight planes and 22 angular measurements were traced on multiplanar reconstructions for evaluation of the posterior tooth tips, torque and rotations. A Shapiro-Wilk test confirmed the normal distribution of the investigated values. The mean and standard deviation differences were calculated for the measurements. A paired t-test was used to compare the mean differences between T0 and T1 and P < 0.005 was set. RESULTS: Statistical analysis showed significant differences between T0 and T1 for all the variables investigated. The upper molars showed an increase of negative torque and the lower molars a decrease of negative torque. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 Tip and rotation showed an increase for the upper molars. CONCLUSION: Second primary molars, as banded teeth for the correction of maxillary transverse deficiency, allowed a catch-up of normal growth for the first upper permanent molars and improvement of lower intermolar width.

293 A SIMPLE AND RELIABLE CLINICAL SCREENING METHOD OF SKELETAL CLASS II MALOCCLUSIONS A Marcinkowska-Mitus1, M Mitus-Kenig2, E Pawlowska3, 1Department of Orthodoncy, 5th Military Research Hospital with Polyclinic Independent Public Healthcare Centre, Krakow, 2Department of Stomatological Prevention and Hygiene, Jagiellonian University Collegium Medicum, Krakow and 3Department of Orthodoncy, Medical University, Lodz, Poland

AIM: An Angle Class II malocclusion is diagnosed mainly from the buccal side on cast models. However, this approach is not sufficient to confirm the skeletal Class II malocclusion with high accuracy. The aim of this study was to investigate the usefulness of both buccal and lingual assessment of cast models in the diagnosis of a skeletal Class II malocclusion. SUBJECTS AND METHOD: One hundred and fifty patients (88 females, 62 males) with a tendency to a Class II molar relationship diagnosed on cast models. The average age was 16.2 years (range 8.5-41.7 years). One hundred and seventeen (78%) and 33 (22%) patients were in the permanent and mixed dentition, respectively. No patient had undergone orthodontic treatment. The results of cast analysis were compared with cephalometric radiographic assessment (skeletal Class II definition: ANB angle >4° and Wits measurement ≥2 mm). A detailed statistical analysis was made using Statistical 10.0 software. RESULTS: In 81 patients a full, bilateral Angle Class II molar relationship both from buccal and lingual side on the cast model was observed. The rest of the patients had an Angle Class II molar relationship unilaterally or only from the buccal/lingual side. or a combination of both above. In the full, bilateral Angle Class II molar relationship group, 77 patients were skeletal Class II according to Wits measurement and 78 patients based on ANB angle. Detailed receiver operating characteristic (ROC) curve analysis revealed a sensitivity of 96 and 95 per cent, a specifity of 44 and 30 per cent, a positive predictive value of 69 and 70 per cent and a negative predictive value of 83 and 86 per cent of this method based on Wits and ANB criteria, respectively. CONCLUSION: Assessment of cast models from both the buccal and lingual sides is a simple and reliable screening method allowing prediction of a skeletal Class II malocclusion. It accelerates the diagnostic phase permitting, at the very beginning, a focus on specific components of a Class II malocclusion.

294 ANALYSIS OF THE FRONTAL OCCLUSAL PLANE POSITION IN TEMPOROMANDIBULAR DISORDER PATIENTS WITH MANDIBULAR ASYMMETRY

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M Markova1, A Tsiruk1, L Persin1, N Markov2, I Rubleva1, 1Department of Orthodontics, Moscow State University of Medicine and Dentistry and 2Department of Functional Diagnostics, Central Research Institute of Dentistry and Maxillofacial Surgery, Moscow, Russia

AIM: To determine the frontal occlusal plane incline in patients with temporomandibular dysfunction (TMD) and midline mandibular asymmetry. The aetiology of TMD is multifactorial and may be related to postural disorders of the vertebral spine. SUBJECTS AND METHOD: Twenty five patients (mean age 20.8 years) with a Class I molar relationship, with midline mandibular asymmetry. There were 15 TMD subjects. Photographs (incline of frontal occlusion plane), lateral and frontal cephalograms, electromyography (EMG), computer optical topography (COT), stabilometry and magnetic resonance imaging of the temporomandibular joint data were studied. RESULTS: All 15 patients (100%) had facial asymmetry, violation of the symmetry of facial lines with HIP-plane Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 on frontal cephalograms, inclination of frontal occlusal plane to the right side (right part lower than left). Analysis of the EMG data of the temporalis muscle at rest showed increased muscle activity on the left side (79.2%, with maximum volitional contraction; 100% on the right). For the masseter muscle at rest it was 0 per cent on the right side and 100 per cent on the left, with a maximum volitional contraction of 39.6 and 59.4 per cent on the right and left sides, respectively. The findings for the sternocleidomastoideus at rest were: right side 19.8 per cent, left side 79.2 per cent, indicating a constant increase of muscle activity on the left side. On MRI the position of the articular disc was in total anterior dislocation with full reposition on the right was 49.5 per cent. On COT for 100 per cent of patients there was the presence of postural curvature compared with the shoulder and pelvic girdle relative to the horizontal. Deviation of the shoulder and girdle was observed in 49.5 per cent on the right and 16.5 per cent on the left. Stabilometry revealed displacement of the centre of gravity to the left posterior in 66 per cent of subjects, to the right and forward in 33 per cent. CONCLUSION: In TMD patients with midline mandibular asymmetry the frontal occlusal plane is higher on the side where the TMJ problems are less expressed, and muscle problems are more expressed; this is of important diagnostic value. All patients showed incorrect posture (balance) that required a comprehensive approach to treatment.

295 THE INFLUENCE OF RHEUMATOID ARTHRITIS IN THE TEMPOROMANDIBULAR JOINT. EXPRESSION OF HUMAN DISEASE IN TNF-α TRANSGENIC MOUSE MODEL. A HISTOLOGICAL PILOT STUDY M-P Maroulakos1, L Khaldi2, I Dontas3, M Makou1, A Tsolakis1, 1Orthodontic Department, School of Dentistry and 3Laboratory for Research of the Musculoskeletal System, University of Athens and 2General Hospital 'Agios Savvas', Athens, Greece

AIM: To evaluate the influence of alterations, on the physiologic development and the histologic appearance of the temporomandibular joint (TMJ) of growing rheumatoid arthritis (RA) hTNF transgenic mice, compared with normal controls. MATERIALS AND METHOD: Eight male mice were used in this pilot study. Four of them were human TNF transgenic (Tg197) mice from a mixed background CBA × C57BL/6 and the last four mice were normal controls. At 28 days of age the experiment started. The total experimental period was set at 4 weeks. At the end of the experiment, the animals were sacrificed in an ether chamber, following which their heads were dissected and the soft tissues were removed leaving the mandibular condyles and glenoid fossa untouched. A histological preparation and evaluation was made. RESULTS: Histological analyses were performed on the TMJs of all transgenic lines. Histopathological features of symmetric polyarthritis were observed in all transgenic animals and the development of the disease was followed in detail in the progeny of Tg197. All histological characteristics were compatible with human RA.

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CONCLUSION: The TNF-α Tg mouse remains an outstanding model of RA, that mimics the human disease. This experimental study confirmed the susceptibility of TMJ in transgenic mice with RA. All the histological features compatible with RA were revealed.

296 USING THE BRUX CHECKER IN THE DIAGNOSIS OF SLEEP BRUXISM IN CHILDREN*** Y Martyts1, G Slavicek2, 1Department of Pediatric Dentistry, I.Ya. Horbachevsky Ternopil State Medical University, Ternopil, Ukraine and 2Steinbeis Transfer Institute Biotechnology Interdisciplinary Dentistry, Stuttgart, Germany

AIM: For the diagnosis of functional disorders such as bruxism in children, it is considered that the Brux Checker is the most convenient, affordable and simple method that will be positively perceived both by parents and children. SUBJECTS AND METHOD: Children in two different stages of the mixed dentition (early versus late) were Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 included in this study after their parents signed an informed consent form and fulfilment of all in- and exclusion criteria. Sixty children (aged 6-12 years) were recruited. Two groups were created (6-9 years, considered as early the mixed dentition, and 10-12 years, considered as the late mixed dentition). After taking accurate alginate impression, a BruxChecker® was fabricated. All children used a BruxChecker® device for one night in order to show tooth contacts during sleep. Tooth contacts were registered for all teeth present, regardless of permanent or primary. In addition, a third group was analyzed consisting of children, who were investigated twice, once in the early mixed and once in the late mixed dentition phase. RESULTS: Tooth contacts are found in 100 per cent of the participants in this study. In almost 50 per cent the BruxChecker® foil was perforated. The first permanent molars and primary canines were involved in bruxing activities in 100 per cent. Other teeth, both temporary and permanent, were also involved in both groups. There were no significant differences between the two groups. No adverse events were reported. The children appeared very interested and committed. CONCLUSION: Tooth contacts during sleep seem to be very common in children in the stage of mixed (early and late) dentition. No differences are detectable in the investigated development stages. The first permanent molars are immediately and always included in nocturnal occlusal activities. Primary canines are also used for bruxing whenever present. This may be due to the fact of frequently changed occlusal architecture in these development stages, no particular classification as reported by Onodera and Sato could be detected in the sample of this study.

297 ATTITUDES TO THE NEED FOR ORTHODONTIC TREATMENT AS EXPRESSED BY PATIENTS AND PARENTS M Mazurkiewicz-Janik, S Williams, A Niżankowska-Jędrzejczyk, A Hille, B W Loster, Department of Orthodontics, Dental Institute, Faculty of Medicine, Jagiellonian University Medical College, Cracow, Poland

AIM: To compare the attitude of patients and their parents to proposed orthodontic treatment. MATERIALS AND METHOD: The survey consisted of a questionnaire study concerning 993 school children examined (mean age 11 years 7 months, maximum 14 years 9 months, minimum 9 years 3 months, 495 males, 498 females) of which 208 had been treated orthodontically and 785 were untreated. The untreated children were divided into groups where treatment was indicated (266), not indicated (250), minor discrepancies were noticed (175) and an observation group (94). The following questions were asked: 1) Do you think you need orthodontic treatment? 2) What is your parents’ attitude to the appearance of your teeth? Indication for orthodontic treatment need was estimated by the ‘evidence based’ evaluation (EBE). RESULTS: Amongst the child population that would benefit from the orthodontic treatment (266), 162 (60.9%) felt that treatment was necessary, but only 99 (37.2%) of parents were positive to orthodontic treatment. Among 250 children with no treatment indications, 80 (32.0%) children still thought they needed treatment and 58 (23.2%) parents were in favour of orthodontic treatment. In the group of 175 children with minor discrepancies 83 (47.4%) children found orthodontic treatment necessary as did 53 (30.3%) parents. In the e155

observation group (94), 31 (33.0%) children felt that there was a need of orthodontic treatment, compared with 22 (23.4%) of their parents. CONCLUSION: There still exists need for information for parents about the nature and aetiology of malocclusion and reasonable indications for orthodontic treatment.

298 NADPH OXIDASE SUBUNIT NOX4 AS A MEDIATOR OF OXIDATIVE STRESS AND INFLAMMATORY STIMULI IN THE PERIODONTIUM ɫɫ S Memmert1, L Gölz1, A Jäger1, W Götz1, S Frede2, Clinics of 1Orthodontics and 2Anesthesiology and Intensive Care Medicine, Rheinische Friedrich-Wilhelms-Universität Bonn, Germany

AIM: NADPH oxidase (NOX) proteins, members of the electron transport chain, catalyse the reduction of oxygen to superoxide. NADPH oxidase family members are expressed in a variety of tissues, especially NOX4 can be Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 found ubiquitously, and represent the only known enzyme system whose primary biological function is to produce reactive oxygen species (ROS). Oxidative stress, which is characterized by an accumulation of ROS, seems to play a crucial role in the aetiology and pathogenesis of different oral and dental diseases. However, the biological reactions of NOX in the periodontium, especially under hypoxic and inflammatory stress, are as yet unknown. The objective of this study was therefore, to define the role of NOX4 in the periodontal ligament. It was hypothesized that oxidative stress as well as inflammatory stimuli are mediated by NOX4 expression through ROS formation in periodontal ligament (PDL) cells. MATERIALS AND METHOD: Human primary PDL fibroblasts were cultured under hypoxic conditions and/or stimulated with lipopolysaccharide (LPS) of Porphyromonas gingivalis, for various periods of time. A fourth unstimulated group served as control. The mRNA expression and protein synthesis of NOX4 and redox systems were analyzed using RT-PCR, Western blots, immunostaining and specific ROS assays. Furthermore, periodontal human tissues were obtained from healthy and periodontally diseased patients for immunohistochemical staining. One-way ANOVA and the post-hoc multiple comparison Tukey test were applied. RESULTS: Cultivation under hypoxic conditions and stimulation with LPS induced a significant increase in the constitutive mRNA expression of NOX4 compared with the control. The combination of both stimuli excited an even higher upregulation of NOX4, which was statistically significant. Protein levels of NOX4 analyzed by Western blot showed similar results. Furthermore, the ROS formation assay demonstrated that LPS and hypoxia generate a significant increase of ROS compared with the control. Immunostaining revealed an intensive NOX4 accumulation in inflamed periodontal tissues compared with healthy samples, which supported the findings. CONCLUSION: Hypoxic and inflammatory stimuli caused oxidative stress in periodontal cells and tissues, which seemed to be NOX4 dependent. The results suggest that NOX4 plays an important role during oral inflammatory diseases.

ɫɫ Winner of an EOS poster award

299 MINISCREW TORQUE LOSS AFTER PLACEMENT: IN VIVO AND IN VITRO RESEARCH M Migliorati1, S Drago1, D Dalessandri2, I Schiavetti3, A Silvestrini-Biavati1, Departments of 1Orthodontics and 3Biostatistics, Genoa University and 2Department of Orthodontics, Brescia University, Italy

AIM: To evaluate relaxation of bone around screws one week after insertion, both in vivo and in vitro. MATERIALS AND METHOD: In vivo set-up: a total of 29 miniscrews were placed in 20 patients who underwent orthodontic treatment. Maximum insertion torque (MIT) was evaluated at insertion time (T1). One week later, torque was measured again by applying a quarter turn (T2); no load was applied on the screw during the first week. Maximum removal torque (MRT) was also measured at the end of clinical use (T3). In vitro set-up: a total of 20 miniscrews were placed in pig rib bone samples. MIT was evaluated at T1. Bone samples were kept in a

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saline solution and a controlled environment for one week during which the solution was refreshed daily. On day 7, torque was measured again by applying a quarter turn (T2). RESULTS: Unloaded miniscrews showed at T2 a loss of rotational torque of 40.9 per cent in vivo and 36.3 per cent in vitro. No statistical differences were observed between the two different experimental set-ups. Removal torque in vivo was lower than at T1 but greater than at T2. CONCLUSION: Bone relaxation was observed after the first week in both models; MRT was greater than torque registered at T2. The in vitro experimental set-up provided a reliable torque study model during the first week.

300 MINISCREWS VERSUS A TRADITIONAL ANCHORAGE SYSTEM IN IMPACTED MAXILLARY CANINE TREATMENT: A PILOT STUDY M Migliorati1, G Sinfonico1, M Piras1, I Schiavetti2, A Silvestrini-Biavati1, Departments of 1Orthodontics and 2Biostatistics, Genoa University, Italy Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021

AIM: The elective treatment of maxillary impacted canine consists of surgical crown exposure, application of traction and orthodontic treatment for extrusion and canine placement in the arch. The key factor for success is the anchorage system. Miniscrews or temporary anchorage devices (TADs) are a good alternative to traditional anchorage systems. The purpose of this research was to compare miniscrews and cantilevers (group 1) with a TMA sectional and transpalatal arch (group 2) to treat maxillary impacted canines; two parameters were evaluated: time required for traction in the two different groups and miniscrew failure rate. SUBJECTS AND METHOD: Twelve patients with impacted maxillary canine were enrolled in the study, and then divided in two treatment groups on the basis of anchorage device. In the test group, alloy type IV miniscrews were inserted in the interradicular bone in an area between the first premolar and first molar (group 1), while in the control group a traditional anchorage system was used (group 2). After anchorage placement (according to the group), a period of 4 weeks was allowed to elapse before canine crown surgical exposure and application of elastic traction. The time taken for orthodontic traction was calculated from surgery (T0) up to the date of canine engagement in the arch (end of traction, i.e. T1). In group 1 miniscrews failure was evaluated. An independent samples t-test was used to assess any difference between the two groups. RESULTS: The average time for canine traction in group 1 was 192.75 days (SD 51.3), while in group 2 it was 156 days (SD 29.5). Miniscrew failure did not occur, while in group 2 one patient stopped orthodontic treatment as the traction broke. The mean difference between the two groups was 36.75 (95% IC: 9.17-82.67; standard error: 21.26). No statistically significant difference was found (P = 0.11). CONCLUSION: There were no significant differences in canine traction speed between two treatment groups.

301 QUALITY OF LIFE OF CLASS III ORTHOGNATHIC PATIENTS TREATED WITH THE SURGERY-FIRST APPROACH J A Miguel1, D Feu2, B H Oliveira1, Departments of 1Preventive Dentistry and 2Orthodontics, State University of Rio de Janeiro, Brazil

AIM: The surgery-first (SF) approach is a treatment modality that involves little or no orthodontic pre-surgical preparation . This study investigated health-related quality of life (HRQoL) of Class III orthognathic patients treated with the SF and traditional (TA) approach two years after the start of treatment. SUBJECTS AND METHOD: Sixteen surgical Class III patients; eight treated with SF and eight with TA. Quality of life was assessed using three questionnaires: the Orthognathic Quality of Life Questionnaire (OQLQ), the Oral Health Impact Profile - Short Version (OHIP-14), and the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36), translated and validated into Portuguese. The tests were repeated at seven timepoints: baseline (T0), one month after appliance placement (T1), and three months (T2), six months (T3), one year (T4) and two years (T5) after the start of treatment. For both groups there was an evaluation stage after orthognathic surgery.

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RESULTS: The SF group had a significant reduction in OQLQ (P < 0.001) and OHIP-14 scores (P < 0.001) at T5. These changes started after orthognathic surgery, and were progressive throughout the evaluation periods. The SF-36 showed significant changes in physical functioning, role-physical, and social functioning domains (P < 0.001). In the TA group all patients were still in the pre-operative orthodontic preparation phase after two years of monitoring, and a significant deterioration in the OQLQ scores was observed (P < 0.001), as well as in the OHIP-14 (P < 0.001) and aesthetic self-perception (P < 0.001). CONCLUSION: Class III orthognathic patients treated with SF do not experience the HRQoL decreases of those undergoing the TA before surgery. Follow-up of these patients until treatment completion is necessary to assess whether improvement in HRQoL is independent of the treatment approach used.

302 PSYCHOMETRIC PROPERTIES OF THE BRAZILIAN VERSION OF THE ORTHOGNATHIC PATIENTS’ QUALITY OF LIFE QUESTIONNAIRE Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 J A Miguel1, E Gava1, B Heloisa Oliveira2, Departments of 1Orthodontics and 2Preventive Dentistry, State University of Rio de Janeiro, Brazil

AIM: To assess the construct validity and reliability of the Brazilian version of the Orthognathic Quality of Life Questionnaire (B-OQLQ) in order to verify whether the psychometric properties of the original questionnaire had been maintained during the cross-cultural adaptation process. SUBJECTS AND METHOD: A cross-sectional study was performed and 101 patients in need of orthodontic- surgical treatment were recruited. The B-OQLQ was self-completed. The mean age of the participants was 26.51 years (SD = 9.25), of which the majority were female (58.42%; n = 59). Construct validity was assessed using Spearman’s correlation coefficient between the B-OQLQ and the Oral Health Impact Profile (OHIP-14) scores and between the B-OQLQ and subjective health indicators’ scores. Reliability was assessed in terms of internal consistency and stability (test-retest) using Cronbach’s alpha and the Intraclass Correlation Coefficient (ICC), respectively. RESULTS: Significant correlations were found between the B-OQLQ scores and the following: OHIP-14 total score (rs = 0.70, P < 0.001), perception of oral health (rs = –0.24, P = 0.02), single item evaluation of quality of life (rs = –0.29, P = 0.03), satisfaction with physical appearance (rs = –0.40, P < 0.001), and satisfaction with facial appearance (rs = –0.39, P = 0.0001). Cronbach’s alpha and the ICC were 0.95 and 0.90, respectively. The domains of B-OQLQ causing the most impact on quality of life included ‘social aspects of deformity’(13.0; SD = 10.54) and ‘facial aesthetics’ (11.81; SD = 6.23). CONCLUSION: The Brazilian version of the OQLQ was shown to be valid and reliable with good psychometric properties and may thus be considered an appropriate tool to assess the impact of dentofacial deformities on the quality of life of individuals with this condition.

303 REGIONAL AUDIT TO ASSESS PATIENT CO-OPERATION AND ITS EFFECT DURING ORTHODONTIC TREATMENT C Miller1, D Miller2, A Teague1, 1Orthodontic Department, Liverpool Dental Hospital and 2Haydock Dental Practice, St Helens, U.K.

AIMS: To assess patient co-operation factors; the proportion of failed appointments, extra appointments and appointments with breakages in patients undergoing orthodontic treatment, and to determine the relationship of these factors to overall treatment duration. MATERIALS AND METHOD: A prospective regional audit was carried out in the Mersey and North Wales regions. All active clinicians in the Mersey Audit Group completed a standardised data collection proforma on 10 consecutive patients completing orthodontic treatment during a 6 month period (October 2012-March 2013).

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The gold standards were for each patient <5 per cent of appointments should be unscheduled, <5 per cent should be failed appointments and <10 per cent of appointments should have appliance breakages. RESULTS: A total of 252 patients were included across 10 hospital and two community sites. There were a total of 4992 appointments recorded. Forty per cent of patients had <5 per cent of unscheduled appointments, 65 per cent had <5 per cent failed appointments and 44 per cent had <10 per cent of appointments with breakages. In total, 7.0 per cent of appointments were failed, with 35 per cent of patients having at least one failed appointment. Patients presented with breakages at 16 per cent of all appointments. At 7.6 per cent of scheduled appointments there was a breakage present. Unscheduled appointments accounted for 8.6 per cent of all appointments, with breakages present at 96.7 per cent. There was no increase in the total number of visits or treatment duration when the standard for unscheduled appointments was not met. However, when the gold standards for failed appointments and breakages were not met, the treatment duration increased from 23 to 25 months and from 22 to 25 months, respectively. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 CONCLUSION: Failing to attend appointments and sustaining breakages can prolong overall treatment duration. Unscheduled appointments have implications on all parties. However, they did not increase the overall treatment duration or the overall number of appointments when the standard was not met. Patients should be informed of the consequences of breakages and missed appointments during the consent process. Staff should take action, wherever possible, to reduce the percentage of failed appointments and the frequency of breakages.

304 SIMULTANEOUS EXPANSION OF THE MAXILLA AND DISTALIZATION OF THE UPPER MOLARS – LONG- TERM RESULTS OF A NEW APPROACH M Mitus-Kenig1, M Durka-Zajac2, 1Department of Stomatological Prevention and Hygiene, Jagiellonian University Collegium Medicum, Krakow and 2Department of Orthodoncy, Pomeranian University, Szczecin, Poland

AIM: A new appliance (Patent No 392545) was designed combining features of the Haas appliance with acrylic splits, and the Pendex appliance with TMA distalizing springs. It is designed for simultaneous expansion of the maxilla and distalization of the upper permanent molars. The aim of this study was to prospectively assess the long-term safety, efficacy and stability of treatment using this newly designed appliance for simultaneous expansion of the maxilla and distalization of the upper molars. SUBJECTS AND METHOD: Between 2009 and 2013, twenty-eight patients were enrolled into the study. The average age was 12.2 years. In the average follow-up of 30 (range 24-42) months no adverse effects connected to the new appliance were observed. The average treatment time was 4.8 months. In all patients a narrow maxilla and maxillary were observed. In 12 patients there was complete absence of space for the upper second premolars, and in the rest patients a complete and partial absence of space for the upper canines. Ten patients had a Class III malocclusion and the rest a Class II malocclusion. Moreover, 10 patients were diagnosed with a so called ‘high-angle’. RESULTS: During treatment distalization of the upper permanent molars was 3.7 mm in comparison with the control group treated with the Pendex appliance (3.8 mm; P > 0.05). There were also no statistically significant differences in anterior and posterior maxillary expansion (in comparison with the Haas appliance (2.8 versus 2.6 mm and 3.7 versus 4.0 mm, respectively P > 0.05). After a minimum of at least 2-years follow-up, the treatment results were stable and there was no significant change in the achieved primary distalization and expansion. CONCLUSION: The new appliance was safe and effective, both at the short and long-term observation. It reduces the loss of anchorage (Hyrax screw action) and extrudes the upper molars and premolars (acrylic splints). Additionally, teeth 16, 26 have a tendency to buccal crossbite which later increases the stability of the treatment results.

305 EFFECTS OF MOLAR DISTALIZATION ON THE UPPER SECOND PREMOLAR AND SECOND MOLAR

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J Miyano, R Kanomi, Kanomi dental office, Himeji, Japan

AIM: The effects of facebow headgear (F-HG) in children with a Class II malocclusion have been evaluated in investigations mainly focused on the maxillary first molar (U6), maxillary skeletal complex, mandibular growth, and facial profile. However, the effects of F-HG on the maxillary second premolar (U5) and second molar (U7) remain unclear. Therefore, this study aimed to clarify the indirect effects on the tooth germs of U5 and U7 during molar distalization using F-HG. SUBJECTS AND METHOD: Forty patients in the early mixed dentition period were classified into two groups. The treatment group (TG) consisted of 20 patients with a Class II malocclusion treated with F-HG. The control group (CG) comprised 20 patients treated without F-HG, with only maxillary and mandibular expanders. Cone beam computed tomographs (CBCT) of the patients in the TG were examined and compared with those of patients in the CG. Anterior nasal spine (point α) and the anterior border of the right and left openings of greater palatal Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 foramen (point β and γ) were set as the representative landmarks. The horizontal reference plane was determined by the three landmarks, and the vertical reference plane was perpendicular to the horizontal plane, including point β and γ. The quantity of distalization was measured for U6, U5 and U7. The distance between the vertical plane and each tooth was measured pre- and post-treatment in both groups and compared. Distalization of U6, U5 and U7 were evaluated using scatter diagrams, and the correlation coefficient of Pearson was calculated in both groups. RESULTS: U6, U5 and U7 in the TG were significantly distalized compared with the CG, with sufficient distal movement observed in the TG, whereas mesial movement was indicated in the CG. A positive correlation was observed between the distalization of U6, U5 and U7. CONCLUSION: Distal movement of U6 may not only extend the dental arch but also affect the eruption position of tooth germs of the permanent teeth. Therefore, F-HG during the mixed dentition period was confirmed as an efficient treatment option for children with a Class II malocclusion.

306 INVESTIGATION OF THE BONE PROPERTIES OF OSTEOPROTEGERIN KNOCKOUT MICE WITH PATHEMA SIMILAR TO JUVENILE PAGET’S DISEASE K Miyazawa, M Yoshizako, C Yamane, M Tabuchi, S Goto, Department of Orthodontics, Aichi-Gakuin University, Nagoya, Japan

AIM: Juvenile Paget’s disease shows high-turnover osteoporosis, and the trabecular bone becomes sparse and density is low because osteoclasts and osteoblasts are remarkably activated and greatly accelerated bone turnover. Osteoprotegerin knockout mice (OPG KO) lack osteoprotegerin which controls proliferation and differentiation of osteoclast. It has been reported that the pathema of OPG KO and Juvenile Paget’s disease is similar. In this study, the bone tissue of OPG KO was examined in detail. MATERIALS AND METHOD: Eight-, twelve- and sixteen-week-old male OPG KO and wild type mice (WT) were used. The following were evaluated: 1) plasma biochemical parameters, 2) investigation of the bone structure of the femur, the lumbar vertebra and measurement of the parietal bone using micro-computed tomography, 3) biomechanical parameters of vertebral body compression, femur mid-shaft three point bending and Knoop hardness of the parietal bone, and 4) histomorphometry analyses of the lumbar vertebra and parietal bone. RESULTS: In plasma biochemical parameters, the serum alkaline phosphatase level in OPG KO increased about five times compared with WT. The serum TRACP-5b level also increased. In investigation of the bone structure, both of the femur and the lumbar vertebra in OPG KO was lower than that in WT. Cortical bone thickness of the femur in OPG KO was thinner than that in WT. As a result, in vertebral body compression and femur mid-shaft three point bending in OPG KO was lower than that in WT. In addition, osteoclast numbers of the lumbar vertebra were higher in OPG KO than WT. On the other hand, parietal bone thickness was thicker in OPG KO

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than WT and there was no significant difference between OPG KO and WT in Knoop hardness and osteoclast numbers of the parietal bone. CONCLUSION: OPG KO lacking osteoprotegerin show a pathema similar to Juvenile Paget’s disease, and a markedly decreasing bone mass and mechanical strength in the femur and the lumbar vertebra. As for the parietal bone, a histologic difference unlike other parts was recognized.

307 EVALUATION OF THE INDEX OF ORTHODONTIC TREATMENT NEED IN A YOUNG ROMANIAN POPULATION R Mocanu1, K Martha2, A Ogodescu3, S Rosu4, I Zetu1, Departments of 1Orthodontics and 4Prevention, UMF 'Gr. T Popa', Iasi, 2Department of Orthodontics, UMF Tg Mures, and 3Department of Orthodontics, UMF 'Victor Babes', Timisoara, Romania Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 AIM: To evaluate the benefit of the Index of Orthodontic Treatment Need (IOTN). The proportional correlation of the two components of the IOTN [aesthetic component (AC) and dental health component (DHC)] were also followed regarding the need for orthodontic treatment. SUBJECTS AND METHOD: The sample included 1126 patients, aged between 6 and 28 years, presenting a wide range of orthodontic pathologies. The diagnosis was based on clinical examination and radiographic and study model evaluation. The IOTN scores were given for AC and DHC. Statistical analysis was performed using SPSS17 for Windows. RESULTS: The highest percentage of subjects (36.24%) showed a moderate aesthetic need, but associated with a high demand in terms of dental health. A low need in terms of dental health was associated with a particularly low or no aesthetic need. CONCLUSION: AC does not always capture the real orthodontic treatment needs imposed by the dentomaxillary anomaly. To limit the bias of the AC, it proved important to complement the assessment with the DHC.

308 COATING NICKEL TITANIUM ARCHWIRES WITH DIAMOND-LIKE CARBON FILMS: MORPHOLOGY AND ROUGHNESS STUDY A Molina Martínez1, G Martín González2, C Atienza Vicente3, C Palazón Martínez2, Departments of 1Dentistry and 2Sciences, Catholic University of Valencia and 3Biomechanics Institute, Valencia, Spain

AIM: To investigate the effects of a diamond-like carbon (DLC) coating on surface properties of orthodontic nickel-titanium (NiTi) wires. MATERIALS AND METHOD: Four different NiTi archwires (n = 12) were investigated: Type 1 (ProFlex®, 0.014 inch); Type 2 (ProFlex®, 0.016 × 0.022 inch), Type 3 (Thermaloy®, 0.014 inch); and Type 4 (Thermaloy®, 0.016 × 0.022 inch), corresponding to two commercial brands (Orthodontic Design & Production and Rocky Mountain Orthodontics). The specimens were analyzed before and after application of the surface coating, through scanning electron microscopy and energy dispersive X-ray spectrometer. To study the alloy surface morphology, the images were processed using ImageJ (Image Processing and Analysis in Java). The surface roughness measurements were carried out with an atomic force microscope. A repeated measures design was used for statistical analysis. The repeated measures factor was ’DLC-coating’, and intersubject factors ’Manufacturer’ and ’Section’. RESULTS: An increased number of defects after treatment could be observed in both commercial brands [F (1, 7) = 19.192, P = 0.003]. However, the total defective area decreased after treatment [F (1, 7) = 18.178, P = 0.004]. There are no changes in surface roughness after DLC treatment in terms of manufacturer [F (1, 7) = 5.191, P = 0.057], or wire section [F (1, 7) = 0.202, P = 0.667].

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CONCLUSION: Although the number of defects after DLC coating increased, the total area occupied by defects was significantly lower in the coated samples. No statistically significant differences were observed in NiTi surface roughness by DLC surface coating.

309 THE EFFECTS OF MECHANICAL STIMULI DURING FUNCTIONAL REPOSITIONING OF THE MANDIBLE IN GROWING RATS W Mongkolsawan, Q Li, A Bilgin, O Dalci, M A Darendeliler, Department of Orthodontics, University of Sydney, Surry Hills, Sydney, Australia

AIM: To investigate the effects of low-magnitude, high-frequency (LMHF) mechanical stimuli on the mandible during functional repositioning in growing rats. MATERIALS AND METHOD: Thirty nine 5-week-old Sprague-Dawley rats randomly divided into five groups; Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 baseline control (BaseL; n = 6), age-matched controls (Cont; n = 6), functional appliance group (App; n = 9), vibration group (Vib; n = 9), and functional appliance with vibration group (App+Vib; n = 9). Bite plates were cemented on the upper posterior teeth of App and App+Vib for repositioning the mandible in the vertical dimension. LMHF mechanical vibration (30 Hz, 0.3 g) was applied to Vib and App+Vib by mean of whole-body vibration; 20 minutes/day, 5 days/week, for 30 days. The right mandible was harvested for linear and angular measurements, and subsequently for condylar volumetric and bone histomorphic analyses using microcomputed tomography. RESULTS: Linear and condylar volumetric measurements indicated a significant increase in ramal height and condylar volume in both Vib and App+Vib when compared with BaseL. There were differences in the histomorphometrics of endochondral bone among the experimental groups but no difference when compared with the Cont. Vib showed an increase (P < 0.05) of bone surface density and bone surface/volume ration when compared with App+Vib. CONCLUSION: LMHF mechanical stimuli encourages adaptive remodelling and consequently enhances endochodral ossification. The application of LMHF mechanical signals combined with a functional mandibular repositioning appliance still requires further investigation.

310 SKELETAL MATURATION BASED ON RADIOGRAPHS OF THE CERVICAL VERTEBRAE. A PILOT STUDY M A Montasser1,2, G Viana3, C A Evans3, 1Department of Orthodontics, Mansoura University, Egypt and 2Royal commission medical center, Yanbu, KSA and 3UIC, Chicago, USA

AIM: To identify the growth intervals during the growth spurt for boys and girls based on assessment of cervical vertebrae maturation (CVM) from lateral cephalographs. MATERIALS AND METHOD: One hundred and twenty lateral cephalometric radiographs of high quality and good contrast for boys and girls with an age range from 7 to 17 years. CVM stages were assessed directly from the radiographs according to the method described by Hassel and Farman, which adopted a visual subjective assessment of the skeletal changes and used three parts of the cervical vertebrae namely: the odontoid process of (CV2), the body of the third cervical vertebra (CV3), and the body of the fourth cervical vertebra (CV4). The method classified CVM into six stages; initiation, acceleration, transition, deceleration, maturation, and completion. RESULTS: The acceleration stage (CVM2) of the growth spurt occurred at a mean age of 11 years 8 months for girls and 12 years 4 months for boys. Growth decelerate (CVM4) occurred at a mean age of 14 years 2 months for girls and 14 years 10 months for boys. Growth completion (CVM6) occurred at a mean age of 15 years 1 month for girls and 15 years 6 months for boys.

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CONCLUSION: Girls were ahead of boys in reaching any of the six CVM stages by a mean of 1 year 2 months. The results of this study did not support the notion of a tendency for a change in the skeletal maturation pattern either in boys or girls.

311 THE RELIABILITY AND REPRODUCIBILITY OF THREE-DIMENSIONAL SOFT-TISSUE ANALYSIS USING THREE- DIMENSIONAL STEREOPHOTOGRAMMETRY S-W Moon, N-K Lee, Department of Orthodontics, Seoul National University Bundang Hospital, Kyoungki-Do, Korea South

AIM: To evaluate the reliability of three-dimensional (3D) stereophotogrammetry, which is a white light scanner. MATERIALS AND METHOD: Three-dimensional (3D) photographs were captured of 14 subjects at two-time Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 points: baseline (T0) and 2 weeks later (T1). On both occasions every effort was made to use the same procedure and position to avoid errors of reliability. The 25 soft-tissue landmarks were assigned on the 3D facial images by one investigator using the surface-based registration method (Morpheus®) to register the photographs acquired. They were represented by a coordinate system (x, y, and z). A Bland-Altman plot between the two images was used to test reliability. Intraclass correlation coefficient (ICC) was also calculated to evaluate the accuracy of superimposition of the two images. RESULTS: Among all landmarks, right and left cheilion, right and left christaphiltri and cervical point showed more than 1.0 mm difference between the two images. Especially in the z plane, the differences were notable. This phenomenon might be due to the direction of pointing. When the investigator set the landmarks on the image, the front of the face was used for the initial and standard plane. Moreover, the position of cheilion and christaphiltri can be changed easily by a variety of expressions and cervical point is not remarkable. ICC analysis of all of landmarks was more than 0.95 indicating very high reliability. CONCLUSION: The 3D photographs for soft tissue analysis using a white light scanner proved to be accurate and reliable and could be used in evaluation of facial changes at various timepoints.

312 CLINICAL PHOTOGRAPHY IN KINGSTON HOSPITAL P Mooney1, G Xavier1, A Jones2, Departments of Orthodontics, 1King's College London Dental Institute and 2Kingston Hospital, U.K.

AIM: To assess the quality of clinical photographs taken within the department; to identify common causes of poor photographs and to make changes required to improve the quality of the clinical photographs and to undertake a re-audit. SUBJECTS AND METHOD: Two assessors will prospectively analyse 100 sets of extra-oral photographs (frontal, smiling, lateral oblique and lateral) and Intra-oral photographs (anterior, buccal and upper and lower occlusal) against a set criteria. The set of photographs will then be graded as 1 if there are no faults, 2 if there are some errors but the photographs still give an accurate representation of the patient’s skeletal pattern and malocclusion and 3 if the photographs give an inaccurate representation as a result of faults. The gold standard for this audit is that 90 per cent should be grade 1, 10 per cent should be grade 2 and 0 per cent should be grade 3. RESULTS: Operators who are assessed with be provided with feedback and if the gold standard is not met then any additional training that is required will be arranged. In addition steps will be taken to eradicate any causes of photographic errors that are highlighted from the audit. Once these changes have been made a re-audit will be carried out in 6 months time.

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CONCLUSION: From this audit it is anticipated that if good clinical photographs are not already being produced then changes will be made that will improve the quality to ensure that they are a valuable asset in the patient’s records, thus improving patient care.

313 MESIAL MOVEMENT OF THE FIRST MOLAR IN ORTHODONTIC TREATMENT AFTER EXTRACTION OF THE MAXILLARY FIRST PREMOLAR J Mori, Mori Orthodontic Office, Nishijin, Sawara-ku, Fukuoka, Japan

AIM: Orthodontic treatment with premolar extractions and headgear is undertaken to decrease molar mesial movement during distal movement of the incisor and canines with complicated bends in the wires. The aim of this presentation is to introduce comparison of the amount of mesial movement of the maxillary first molar, between eight cases using ‘Natural orthodontic treatment’ (NOT) which was made based on treatment using Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 simultaneous distal movement of the central, lateral incisor, and canine, and eight subjects who underwent contraction of the central and lateral incisor after the retraction of canines. SUBJECTS AND METHOD: Two groups were compared and examined with lateral roentgenographic cephalograms taken before and after treatment. In the ‘natural’ group were eight subjects who had extraction of the mandibular first premolar or mandibular second premolar by NOT. They were aged from 13 years 10 months to 40 years 11 months, and their average treatment period was 18 months. The control group contained eight patients who underwent contraction of the central and lateral incisor after retraction of the canine. Their ages ranged from 13 years 1 month to 29 years 11 months, and their average treatment period was 26 months. RESULTS: No statistically significant changes angular measurement changes were observed in the positions of the maxillary first molars. The natural group tended to have a significantly greater amount of change in S-U6 than the controls in distance measurements and it also tended to have less changes in U6-A. CONCLUSION: Statistical significance was not noted in the amount of mesial movement of the maxillary first molar between two groups, but it was recognized in distance measurements. Comparing the two groups, extrusion of the maxillary first molar resulted in mesial movement in the control group. Extrusion of the maxillary first molar and the amount of mesial movement is less using NOT.

314 MORPHOLOGIC CHARACTERISTICS, LOCATION AND ASSOCIATED COMPLICATIONS OF MAXILLARY AND MANDIBULAR SUPERNUMERARY TEETH AS EVALUATED USING CONE BEAM COMPUTED TOMOGRAPHY J Mossaz1, D Kloukos1, N Pandis1, C Katsaros1, M Bornstein2, Departments of 1Orthodontics and Dentofacial Orthopaedics and 2Oral Surgery and Stomatology, University of Bern, Switzerland

AIM: To evaluate the location and morphologic characteristics of supernumerary teeth, and to assess the frequency and extent of root resorption of adjacent teeth using cone beam computed tomography (CBCT). MATERIALS AND METHOD: CBCT scans of 82 patients with a total of 101 supernumerary teeth in the maxilla or mandible were evaluated independently by two orthodontists. Data regarding the type, shape, and three- dimensional location of the supernumeraries including the frequency and extent of associated root resorption of adjacent teeth. were recorded and evaluated for possible correlations. RESULTS: Males were affected more than females with a ratio of 1.65:1. Most of the patients (80.5%) exhibited one single supernumerary tooth, while 15.8 per cent had two and 3.7 per cent had three supernumeraries. Mesiodens were the most frequently diagnosed type of supernumerary teeth (48.52%), followed by supernumerary premolars (23.76%) and lateral incisors (18.81%). Supernumeraries were most commonly conical in shape (42.6%) with a normal or inclined vertical position (61.4%). Root resorption of adjacent teeth was detected for 22.8 per cent of the supernumerary teeth, most frequently for supernumerary premolars. There was a significant correlation between root resorption of adjacent teeth and the type and shape of a tooth.

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A significant number of mesiodens were located either in intimate contact with the cortical bone of the nasal floor, the incisal canal, or the roots of one of the adjacent central incisors. Interrater agreement for the measurements performed showed kappa values ranging from 0.55 to 1, with a kappa value of 1 for type and shape of the supernumerary teeth. CONCLUSION: CBCT provides accurate information about the location and shape of supernumerary teeth as well as the prevalence and degree of root resorption of neighbouring teeth with a moderate to high interrater correlation.

315 ALVEOLUS CHANGES IN CLEFT LIP AND PALATE PATIENTS TREATED WITH NASOALVEOLAR MOULDING S Muddaiah1, B Shetty1, T P Sirajuddin1, M Bendeus Hagg2, 1Department of Orthodontics and Dentofacial Orthopedics, Coorg Institute of Dental Sciences, Virjapet, India and 2Private practice, Orthodontics, Landskrona, Sweden Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021

AIM: To quantify the treatment changes with pre-surgical nasoalveolar moulding (PNAM). SUBJECTS AND METHOD: Ten infants less than 6 months of age with a cleft lip and palate (CLP; 5 unilateral, 5 bilateral) with displaced cleft and non-cleft segments were treated with the PNAM technique as described by Grayson. Lip taping was done with surgical adhesive tapes (Dynopl). Moulding plate was fabricated with hard clear acrylic and lined with a thin coat of soft liner and was adjusted to gradually approximate the cleft alveolar segments. The appliance was secured extra orally to the cheeks, bilaterally by surgical tapes, which had an orthodontic elastic band at one end. When the cleft alveolar gap was reduced to 5 mm or less, the nasal stent (0.036 gauge stainless steel) was added. Data was collected at two time periods: pre- and post-PNAM. The following reference points were used in UCLP patients: anterior most point on the non-cleft and cleft segments respectively; landmarks on canine sulcus on the non-cleft and cleft segments respectively; tuberosity points on the non-cleft and cleft segments respectively; in BCLP patients two reference points were added, i.e. I - Incisal point, and the lateral most point on the premaxillary segment. RESULTS: The width of anterior alveolar segment [decreased from 9.90 mm (SD 3.47) to 7.90 mm (SD 3.44), the difference –2.0 mm (SD 0.67) being statistically significant (P < 0.001)0. The middle alveolar width increased in width from 25.9 mm (SD 3.10) to 26.4 mm (SD 3.30) (N.S. P = 0.7310). The posterior segmental width was reduced from 32.2 mm (SD 4.68) to 31.9 mm (SD 2.84) (N.S. P = 0.9999). CONCLUSION: PNAM was effective in reducing the alveolar cleft width in the anterior region.

316 THE EFFECTS OF BOTOX INJECTIONS ON A GUMMY SMILE S Muddaiah, S Somaiah, S P Shankar, Dr Sibinair, Department of Orthodontics, Coorg Institute of Dental Sciences, Virajpet, India

AIM: To assess the effect of botulinum toxin type A (BTX-A ) in the treatment of a gummy smile. SUBJECTS AND METHOD: Ten patients (2 males, 8 females) who had a smile with gingival display (mean 4.5 mm, SD 0.28; range 3-5 mm) before treatment (T0). The patients received BTX-A, 100 U diluted with 4 ml of saline solution. Under sterile conditions, 2.5 units of BTX-A were injected at four sites, two on each side of the face. The injection sites were the overlapping points of (i) Elevator labiisuperioris alaeque nasi and levator labii superioris muscles (ii) Levator labii superioris and zygomaticus minor muscles. The patients were followed at 14 (T1), 30 (T2), 60 (T3), and 90 (T4) days post-injection, with changes documented photographically. The distance measured was from the lowest margin of upper lip perpendicular and superior to the mid portion of the left maxillary central incisors gingival margin (gingival display) when the patients smiled. RESULTS: At T1, the mean gingival display had declined to, on average, 0.9 mm (SD 0.72 mm), and the average lip-drop (T0-T1) was 3.7 mm (SD 0.62 mm; P < 0.001). Gingival display gradually increased from T1 to T4, when average gingival display was 2.8 mm (SD 0.86 mm), significantly less (P < 0.001) compared with T0 values, but significantly more gingival display than at T2 (P < 0.001) e165

CONCLUSION: BTX-A injections for the correction of gummy smiles were effective in the short term.

317 CANINE RETRACTION WITH A NICKEL TITANIUM SPRING OR TITANIUM MOLYBDENUM ALLOY T-LOOP S Muddaiah1, S Somaiah1, J Jacob1, U Hagg2, 1Department of Orthodontics and Dentofacial Orthopedics, Coorg Institute of Dental Sciences, Virjapet, India and 2Department of Orthodontics, The University of Hong Kong, China

AIM: To compare the efficacy of a modified nickel titanium (NiTi) retraction spring and T loop in canine retraction. SUBJECTS AND METHOD: The split mouth study included 10 patients (6 males, 4 females, mean age 27.5, range 15-40 years) with maxillary canines in a similar position in relation to the midline. Each patient had a NiTi spring (0.016 × 0.022 inch• NiTi wire placed on one maxillary canine (NiTi-group), and a T loop (0.016 × 0 .022 inch) Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 titanium molybdenum alloy (TMA group) on the other maxillary canine. A transpalatal arch was inserted to prevent rotation of the first maxillary molars and also to define the amount of canine distalization. Treatment changes were evaluated by comparing occlusograms and dental pantomographs obtained before and after retraction of the maxillary canines to assess the rate of retraction, the amount of distal tipping, and the anchorage loss of the first molars. RESULTS: There was no significant difference in the amount of canine retraction in the NiTi group (mean 5.6 mm SD 1.91) and TMA group (mean 5.5 mm SD 1.45). The duration of canine retraction was significantly longer (5.2 weeks; P < 0.05) in the TMA group (mean 18.9 weeks SD 4.9) than in the NiTi group (13.7 weeks SD 5.5). The amount of distal tipping of the canine differed significantly (–4.50) between the two groups, being –5.7° (SD 2.79°) the in NiTi group compared with –9.9° (SD 4.95°) in the TMA group, whereas there was no statistical difference in the loss of molar anchorage being 2.0 mm (SD 0.82) and 1.5 mm (SD 0.53), respectively. CONCLUSION: Retraction of the maxillary canine with a NiTi loop was faster and the amount of distal tipping less when compared with the T loop, whereas there was no difference in anchorage loss.

318 LASER SCAN ANALYSIS OF TOOTH MOVEMENTS FOLLOWING ORTHODONTIC TREATMENT A Muchitsch1, B Wendl1, H Winsauer2, M Pichelmayer1, M Muchitsch3, Clinical Department of Orthodontics, Medical University of Graz, 2Private Practice, Bregenz and 3Technical University, Graz, Austria

AIM: The three-dimensional (3D) evidence of orthodontic tooth movement and the exploration of their extent, direction and relationship measured by 3D laser scanning were the aims of the current study. SUBJECTS AND METHOD: Fifteen patients (7 females, 8 males) at an average age of 14.9 years (minimum 11 years, maximum 35 years) who had initially undergone mesial or distal movement using pressure springs with or without a Nance appliance as well as tension springs and headgear. Thereby 39 teeth movements of canines, premolars and molars were implemented. Pre- and post-movements (within 43-123 days) plaster casts were taken, laser scanned and virtually measured. Statistical evaluation was performed using scatterplots, regression analysis, Pearson correlation coefficient and the Chi-square test. RESULTS: Evaluating the changes of dental position, typical paradigms could be detected. Any distal movement was followed by significant (P < 0.0001) distal tipping and external rotation. The extent of these movements showed a positive correlation according to Pearson (r = 0.512). Every mesialisation using pressure springs was followed by significant (P < 0.0001) mesial tipping and internal rotation of the treated teeth. The insignificant (P = 0.905) side-effects, buccal and palatal tipping, occurred at all dental movements. CONCLUSION: Performing orthodontic treatment, desired and undesired patterns of dental movements can be identified using 3D laser scan measurements. In this study investigation found a tipping in the predominant direction of movement and a rotation around the vertical coordinate axes of all measured teeth. A correlation between treatment time and translation or rotation of teeth related to one of the axes in the coordinate system was statistically verifiable only between the extent of distalisation and external rotation. e166

319 RELATIONSHIP BETWEEN MULTIDIRECTIONAL LIP-CLOSING FORCE AND LATERAL CRANIOFACIAL MORPHOLOGY IN CHILDREN M Murakami1, M Kanazawa1, R Mizuno1, Y Masuda2, K Yamada1, Departments of 1Orthodontics and 2Oral and Maxillofacial Biology, Matsumoto Dental University, Shiojiri, Japan

AIM: To clarify the relationship between the balance of upper and lower lip-closing force (LCF) in children. SUBJECTS AND METHOD: Twenty five patients in the mixed dentition. LCF with maximum effort was measured by the multi-direction LCF measurement system, which can simultaneously measure LCF from eight directions. RESULTS: Total LCF (TLCF) showed a significant positive correlation to the FMIA and significant negative correlations to convex, SNA, ANB, and U1-FH angle. Total upper LCF (TULCF) showed a significant negative correlation to convex. Total lower LCF (TLLCF) showed a significant positive correlation to the FMIA and Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 significant negative correlations to ANB and U1-FH angle. These results suggest that a large LCF might be involved in maxillary retrusion and lingual inclination of the upper and lower incisors. CONCLUSION: In children, TLCF, TULCF and TLLCF may directly relate to the maxillary position of the inclination of the upper and lower incisors.

320 ASSESSMENT OF ACCURACY OF REPRODUCTION BETWEEN PLASTER, THREE-DIMENSIONAL PRINTED AND DIGITAL SCANS OF DENTAL MODELS V Mydlova1, J Jonekova1, S Dianiskova1, A Thurzo2, Departments of Orthodontics, 1Medical Faculty Slovak Medical University, Bratislava and 2The clinic of dentistry and maxillofacial surgery of Medical faculty - Comenius University, Bratislava, Slovakia

AIM: To evaluate if plaster dental models could be replaced with three-dimensional (3D) printed dental models, and to measure the accuracy of reproduction between plaster and 3D printed dental models. MATERIALS AND METHOD: Fourteen plaster models of the upper and lower jaws of patients, 14 3D printed dental models of lower and upper jaw of patients and 14 digital scans of lower and upper jaw of patients were measured. The same measurements were applied to plaster models, 3D printed dental models and digital scans. The following statistical evaluation methods were used: Lilliefors significance correction, Levene’s test for equality of variances, t-test for equality of means and the Mann-Whitney test. The parameters measured were the vertical length of the upper and lower central incisors, the width of upper and lower central incisors, transverse arch width according to McNamara, the mesiodistal dimensions of the first molars and the distance between the distal edges of upper and lower incisors. These parameters were implemented on each model. In total 70 parameters on models and scans were compared. RESULTS: Statistically significant differences in the t-test for equality of means were observed only in parameters MNs (P = 0.003), lls (P < 0.001), DR3d (P < 0.001), SR3d (P = 0.002). Evaluation in Mann-Whitney test were statistically significant only for the variable MD6s (P = 0.023). The correlation was significant at the 0.01 level (two-tailed) in overall measurement. No clinically significant differences between plaster models, digital scans and 3D printed models measurements were observed. CONCLUSION: The accuracy of the measured parameters on 3D printed dental models and digital scans was acceptable compared with traditional plaster study models. According to the results these three technologies as reproductions of dental models are equivalent without the risk of loss of quality or measurement errors.

321 COMPARISON OF OCCLUSAL FORCES IN OCCLUSIONS WITH MISSING LOWER FIRST MOLARS J Y Myung1, M J Son1, J m Park2, M J Kim1, Y S Chun1, Divisions of 1Orthodontics and 2Prosthodontics, Ewha Womans University/Mokdong Hospital, Seoul, Korea South

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AIM: To investigate any changes in occlusal forces when a lower first molar is missing and with varying degrees of mesial tipping and extrusion of adjacent and antagonistic teeth, using a strain gauge. MATERIALS AND METHOD: Artificial teeth with the lower right first molar missing were used for all five models. For models 2 to 5, the lower second molars were gradually tipped mesially so the second molar tipping angle of model 5 was 20 degrees greater than that of model 1. The upper molars were extruded according to varying degrees of second molar tipping. Masticatory forces were applied by a universal testing machine and subsequent occlusal forces were measured by attached strain gauges. The changes in occlusal forces for each model were measured. RESULTS: When chewing food, the occlusal force of the lower second molar gradually decreased in models 3, 4 and 5 (P < 0.05) CONCLUSION: When the lower first molar is missing, the lower second molar tips forward. The occlusal force of the lower second molar decreases significantly as the angle of tipping increases. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021

322 DEVELOPMENT OF A THREE-DIMENSIONAL FACIAL SCAN EVALUATION METHOD A Nadazdyova, A Thurzo, P Stanko, Department of Orthodontics, Clinic of Dentistry and Maxillofacial Surgery, Medical Faculty, Comenius University, Bratislava, Slovakia

AIM: To define a method for reliable and complex facial scan evaluation as a tool for treatment planning and to define a set of points, lines, angles and surfaces according to other known studies including respectable anthropometric and plastic surgery studies. The primary aim was to establish an exact method with high inter- and intraobserver reliability to evaluate the facial proportions. MATERIALS AND METHOD: Fifty random facial scans with a natural facial expression were chosen from 1273 scans made on a Di3D scanner. All scans were evaluated by three observers who were given the same instructions and description of the observed parameters. Intra- and interobserver errors were evaluated. Intraclass correlation coefficients (ICC) were used for detecting intra- and interobserver agreement for each particular scan. The observed parameters were: alar curvature, alare, columella constructed point, cheilion, christa philtri, endocanthion, exocanthion, glabella, labiale superius, nostril base, nostril top, orbitale superius, pronasale, sellion, subnasale, orbitale, zygion, porion, subspinale, inferior stomion, upper stomion, tragion, trichion, labial inferius, soft tissue gonion, sublabiale, soft tissue pogonion, soft tissue gnathion, soft tissue porion, pupil reconstructed point. The scans were taken in the natural head position. RESULTS: Except for the soft tissue cephalometric points: gonion, orbitale and zygion, the results showed sufficient consistency in the repeated measurements for each operator. Labiale superius was the most reproducible landmark. Some landmarks showed greater reliability in certain planes of space; glabella was more reliable in the Z than the Y axis and subnasale was more reproducible in the Y-axis in males compared with females. CONCLUSION: The results showed insufficient reproducibility of the landmarks: soft tissue gonion, orbitale, zygion which renders them unusable for exact soft tissue evaluation. High reproducibility of observed soft- tissue parameter landmarks is essential for accuracy of any analyses based on them.

323 CORRELATION OF CHRONOLOGICAL AGE, DENTAL MATURITY STAGE AND SKELETAL MATURITY FROM RADIOGRAPHS E Nakas1, A Zukanovic1, T Lauc2, I Rupic3, I Galic4, 1Orthodontic Department School of Dental Medicine University of Sarajevo, Bosnia and Herzegovina, 2Department for Anthropology,, Faculty of Humanities and Social Sciences, University of Zagreb, 3Dental Clinic Apolonija, Zagreb and 4Study of Dental Medicine, School of Medicine, University of Split, Croatia

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AIM: To determine the correlation between tooth calcification, cervical skeletal maturity and chronological age (CA) in children, and to analyze if some teeth can be used as a marker for skeletal maturity and CA estimation. MATERIALS AND METHOD: Panoramic dental images and lateral cephalograms of 231 orthodontic patients (127 girls, 104 boys) aged from 5.9 to 15.8 years. Skeletal maturity was assessed using Baccetti’s cervical vertebral maturation (CVM) method. Tooth calcification stages of the first seven mandibular teeth from the left side were determined using the scoring system of Demirjian. Correlation among calcification stages, skeletal maturity stages and CA was assessed using Spearman rank correlation coefficients. RESULTS: A positive correlation between dental maturity and cervical vertebral maturity was found for the mandibular second premolars (rho = 0.684, P ˂ 0.001), second molars (rho = 0.674, P ˂ 0.001), first premolars (rho = 0.664, P˂ 0.001), and canine (rho = 0.574, P˂ 0.001) teeth. The lowest correlation was found for the first incisors and the first molars. There was a high positive correlation between dental stage development and CVM stages. Demirjian’s method overestimated the age of girls by 1.24 ± 1.03 years, and the age of boys by 0.80 ± Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 1.03 years. Willems’ method overestimated the age of girls by 0.36 ± 0.98 years, and that of boys by 0.44 ± 0.98 years CONCLUSION: Mandibular premolars and second molars are the most valuable indicators for skeletal maturation stage, while both dental age methods overestimated the CA of the sampled children

324 COMPLICATIONS AND DIFFICULTIES DURING PRE-OPERATIVE NASOALVEOLAR MOULDING THERAPY B Nemes1, F Van den Ende2, S Hoste2, G Swennen2, K Nagy3, Departments of 1Pedodontics and Orthodontics and 31st Department of Pediatrics, Semmelweis University, Budapest, Hungary and 3Cleft and Craniofacial Center, St- John Hospital, Bruges, Belgium

AIM: Pre-operative nasoalveolar moulding (PNAM) therapy is known to be an effective tool prior to primary surgery in unilateral and bilateral cleft lip palate patients. The aim of this prospective study was to analyze the complications of PNAM and their severity during moulding therapy. MATERIALS AND METHOD: The following PNAM protocol was adopted: 1. Impression at the age of 1 week with alginate impression material. 2. Insertion of the palatal guidance plate and initiation of non-surgical lip adhesion before the age of two weeks. 3. Addition of unilateral or bilateral nasal stents to the palatal guidance in combination with approximation of the lip segments by taping on the cheeks. 4. Gradual build-up of the nasal stents during the following weeks, until the time of primary lip closure. 5. Application of a silicone nostril retainer for 3 months post-operatively. A total of 39 unilateral and 12 bilateral cleft patients treated with PNAM, were analysed prospectively. RESULTS: There were no complications during impression taking. The parents of one of the 51 (2%) patients refused PNAM treatment, and in one case (2%) the parents were non-compliant towards insertion of the palatal guidance plate. There were two cases (3.9%), where the parents applied the palatal guidance plate but refused the addition of nasal stents. In two other cases (3.9%) there was mild ulceration of the inner nasal mucosa, due to wrong positioning of the nasal conformer, that healed uneventfully after modification of the nasal stent;. There were two bilateral cases (3.9%) with buckling of the alar cartilages due to anatomical reasons. In 36 (7 bilateral, 29 unilateral) patients (70.6%) there was poor compliance in using the silicone nasal conformer after primary lip and nose repair, even if the parents fixed it with perforated tape. CONCLUSION: No severe complications and difficulties in PNAM were observed. The parents of cleft palate patients showed excellent compliance in handling the PNAM devices pre-operatively. Post-operative management of the silicon nasal conformer, for maintaining and improving nasal aesthetics, however, was poor. Patients with PNAM without a post-operative nostril retainer still showed better functional and aesthetic results than patients without any pre-operative treatment.

325 CRANIOFACIAL GROWTH AND MORPHOLOGY IN LONG-TERM SURVIVORS AFTER CHEMOTHERAPY IN 12- YEAR-OLD CHILDREN e169

O Nemeth, P Kivovics, J Horvath, Department of Community Dentistry, Semmelweis University, Budapest, Hungary

AIM: To prospectively investigate the long-term effects of chemotherapy on the oral health of children with the primary focus on craniofacial growth. SUBJECTS AND METHOD: Thirty-eight children (mean age: 12.3 ± 0.58 years) that underwent chemotherapy between 1 month and 7 years of age. A total of 32 linear and angular variables group from the lateral cephalograms of the subjects were measured and compared with standard reference values. These variables compared the long-term effects of different anti-neoplastic agents; the subjects were grouped according to the drug(s) received: Vincristine Vincristine and Doxorubicin, Methotrexate, Ifosfamide and Platina agents. RESULTS: There was a statistically significant difference in 10 measurements. A statistically significant deviation was shown in subjects treated with Vincristine, Vincristine and Doxorubicin. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 CONCLUSION: Craniofacial growth in children is affected long-term after completion of cancer therapy. The clinical relevance of this finding is unclear and further studies need to be performed to answer this question.

326 SURGICAL PREPARATION AS PART OF THE FUNCTIONAL TREATMENT OF MALOCCLUSION T Nespriadko, I Skrypnyk, O Tsylenko, Bogomolets National Medical University, Kiev, Ukraine

AIM: According to the literature a small vestibulum is often caused by pathologies of the soft tissue cavity of the mouth. The prevalence of this disease is about 62.6 per cent. Mechanical trauma of the marginal periodontium can be caused by the influence of the lips, chin, cheek, and facial muscles which promote an inflammatory gum process, localized and generalized periodontitis, malocclusion and even dental arch defects. Tongue tie or ankyloglossia belongs to congenital development anomalies and according to the literature and, is found in 10.7 per cent of cases. Elimination of mechanical regional periodontal trauma and creation of optimal conditions for subsequent orthodontic treatment is a priority for surgical preparation of the soft tissues. SUBJECTS AND METHOD: Twenty nine patients aged of 14-17 years. Distal occlusion was found in 23 (79%), an attached upper lip fraenulum in 19 (82%),17 (80%) had ankyloglossia and 14 (83%) a small oral vestibulum. A mesial occlusion was observed in two (7%) patients. two patients (9 %) had an abnormal upper lip fraenum, two (10%) ankyloglossia and two (12%) a small mouth vestibulum. A crossbite was present in two (7%), among them short fraenulum of the upper lip in one (4%) one (5%) with ankyloglossia and one (6%) with a small mouth vestibulum. An open bite was observed in two (6%) patients, a short upper lip fraenulum in one (4%), ankyloglossiain one (5%) and one (6%) with a small mouth vestibulum. RESULTS: All patients had surgical correction of soft tissues of the mouth cavity: Z-shaped by Limberg, U-shaped by Diefenbach and plastic tunnelling of the mouth cavity vestibulum. These interventions were carried out before orthodontic treatment which allowed the treatment time to be reduced by 4 months, decreased relapse by 30 per cent and prevented development of periodontal problems.

327 PARAMETERS FOR THE PRENATAL DIAGNOSIS OF MANDIBULAR MICROGNATHIA J Neuschulz1, I Schaefer1, L Wilhelm2, B Braumann1, 1Department of Orthodontics, University Hospital, Cologne and 2Practise for prenatal diagnosis, Cologne, Germany

AIM: Prenatal screening of severe dysgnathia such as mandibular micrognathia is mainly based on subjective assessments. Objective measurements such as the foetal length of the upper and lower jaw have not yet been integrated in routine prenatal diagnostics. Thus, this study aimed to calculate parameters from measurements of the foetal jaws that can be easily and routinely incorporated in prenatal sonographic diagnostics in order to help identify foetal mandibular micrognathia.

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MATERIALS AND METHOD: Ultrasound sequences of 313 consecutive patients were recorded and analyzed between the 19th and 29th gestation week (Toshiba Aplio MX®). Landmarks of the upper and lower jaw were digitally identified on the screen and evaluated regarding their reproducibility. Representative distances were defined in order to measure the length of upper and lower jaws (SpA-SpP = upper jaw length, UL; Rami-SymMe = lower jaw length, LL) and their relationship to femur length (FL) and gestational age (GA) was evaluated. A quotient of UL and LL was derived. Out of this data, parameters for UL and LL were calculated and analyzed. RESULTS: The correlation coefficients (R) between LL and GA (R = 0.845) as well as between LL and FL (R = 0.839) were high. Additionally, there was moderate correlation between UL und GA (R = 0.691) and between UL and FL (R = 0.656). Regression analysis showed a relationship of UL to LL with a coefficient of 0.628 ± 0.043. CONCLUSION: With the help of the calculated parameters, it was possible to evaluate foetal growth of the upper and lower jaw. On this basis, it is conceivable to generate a sensitive and reproducible method for the prenatal diagnosis of severe dysgnathia such as mandibular micrognathia. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021

328 THE EFFECT OF EARLY ADENOIDECTOMY ON NASAL CAVITY VOLUME AND UPPER DENTAL ARCH DIMENSIONS IN CHILDREN WITH RECURRENT MIDDLE EAR INFECTION P Niemi1 J Numminen2, M Rautiainen2, M Helminen3, T Peltomäki4, 1Department of Maxillofacial Surgery and Oral Diseases, Satakunta Central Hospital, Pori, 2Department of Otorhinolaryngology and 4Oral and Maxillofacial Unit, Tampere University Hospital, 3Pirkanmaa Hospital District and School of Health Sciences, Tampere University, Finland

AIM: To examine effect of routine adenoidectomy on nasal cavity volume and upper arch dimensions in children with recurrent episodes of middle ear infection. SUBJECTS AND METHOD: Children who had several events of acute otitis media during two first years of life were randomly allocated to two treatment groups: tympanostomy tube placement without adenoidectomy (group 1, n = 63) or tympanostomy tube placement with adenoidectomy (group 2, n = 74). At 5 years the children were re-examined (group 1, n = 41 and group 2, n = 59). At this time an otorhinolaryngologist and orthodontist undertook a clinical examination including acoustic rhinometry and rhinomanometry to measure nasal cavity volume and nasal airway resistance, and an occlusal bite index to measure upper dental arch transverse and sagittal dimensions. Differences between measurements in the two treatment groups were determined with a t-test and Kruskal-Wallis test. RESULTS: There were no statistically significant differences between the two treatment groups in the nasal or upper dental arch measurements. Dental arch measurements were also well in line with reference values of healthy children. CONCLUSION: Combining routine adenoidectomy with tympanostomy tube insertion in the treatment of recurrent middle ear infection does not seem to make any difference in terms of upper dental arch development or nasal cavity volume and airway resistance at 5 years compared with tympanostomy tube insertion only.

329 CHANGES OF MINI-IMPLANT STABILITY DURING THE HEALING PERIOD IN HUMANS: IMPACT OF INSERTION SITE AND IMPLANT LENGTH M Nienkemper1, B Wilmes1, A Pauls2, D Drescher1, 1Department of Orthodontics, University of Düsseldorf and 2Private Practice, Frankfurt, Germany

AIM: To evaluate the changes of mini-implant stability during the initial healing period in humans and the impact of mini-implant length and insertion site on their stability. SUBJECTS AND METHOD: Nineteen patients (mean age 15.5 ± 7.3 years) who received a mini-implant of a size of 2 × 9 mm inserted into the anterior palate were examined (control group). Implant stability was assessed using resonance frequency analysis (RFA) immediately after insertion (T0) and two (T1), four (T2), and six (T3) weeks

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later. Data was compared with that of 20 consecutively treated patients (15.6 ± 7.2 years) with longer mini- implants (2×11 mm) and to 21 patients (13.7 ± 4.6 years) with 2 × 9 mm paramedian mini-implants. RESULTS: The stability of the control group (36.1 ± 6.1 implant stability quotient (ISQ) at T0) decreased highly significantly between T1 and T2 (P < 0.001) by 7.9 ± 5.9 ISQ values. From T2 on RFA it remained nearly unchanged (–1.7 ± 3.5 ISQ; P > 0.05). Stability of the longer implants (33.4 ± 3.5 ISQ) decreased highly significantly from T0 to T1 by 5.3 ± 3.5 ISQ values (P < 0.001) and significantly from T1 to T2 (P < 0.05) by 3.5 ± 3.7 ISQ values. From T2 on RFA remained largely unchanged (–1.7 ± 3.9 ISQ; P > 0.05). At T1 stability of the longer implants was significantly lower than that of the control group. Initial stability was 26.60 ± 5.28 ISQ (RFA) and remained relatively constant showing no significant differences between measurement times. Overall RFA values of the paramedian inserted implants decreased non-significantly by 2.25 ± 6.85 ISQ to a level of 24.35 ± 5.39 after six weeks. Compared with the control group, significant differences were present at T0 and T1 (T0: – 9.54 ISQ, P < 0.0001; T1: –3.69, P = 0.041).From T2 onwards there were no significant differences between the Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 test and control groups. CONCLUSION: Mini-implant stability is subject to changes during the healing process. Although primary stability and development differed between the groups, from week four on there were no significant differences compared with the control group, and stability remained at a constant level.

340 EVALUATION OF ORTHODONTIC TREATMENT INDICATION AMONGST POLISH SCHOOL CHILDREN A Niżankowska-Jędrzejczyk, S Williams, M Mazurkiewicz-Janik, P Pełka, B W Loster, Department of Orthodontics, Jagiellonian University Medical College, Cracow, Poland

AIM: An evaluation of the indication for orthodontic treatment amongst a child population can be important in the planning of orthodontic services and education of orthodontic specialists. At the same time it involves a clear attitude to the indication for orthodontic treatment. The aim of this study was to determine the indication for orthodontic treatment among a typical Polish child population and the effect of employing standardised methods when choosing subjects for treatment. SUBJECTS AND METHOD: A single clinical examination of 993 school children (mean age: 11 years 7 months, maximum 14 years 9 months, minimum 9 years 3 months; 495♂ 498♀) performed by a team of experienced orthodontists (after suitable calibration) using a specially devised questionnaire. Two methods of evaluation were employed, namely the index of orthodontic treatment need (IOTN) dental and aesthetic, and the ‘evidence based’ evaluation (EBE) recommended by the Danish Ministry of Health in connection with orthodontic services for all school children. RESULTS: The EBE system revealed that 34 per cent (345) of the child population would benefit from treatment, 31 per cent had no treatment indication whereas 23 per cent had minor discrepancies. A small group of 11 per cent represented an observation group where the final occlusion was still uncertain. Considering the dental health component of the IOTN, the prevalence of malocclusion expressed by grade was: grade 5 - 7 per cent, 4 – 15 per cent, 3 - 21 per cent, 2- 35 per cent and 1 - 21 per cent, respectively. The aesthetic component of the IOTN demonstrated a greater spread of totals with the majority in the lowest grades (88% grades 1-5) indicating that relatively few would require treatment on aesthetic grounds alone. Comparing selection for treatment by the EBE (345) with IOTN (grades 3, 4 and 5, 424) a greater number would be offered treatment since grade 3 contained nine individuals not considered for treatment by the EBE method. CONCLUSION: The EBE and IOTN method recommend orthodontic therapy for a similar number of children though slight differences in the selection results exist.

341 GENETIC FACTORS RELATED TO EXTERNAL APICAL ROOT RESORPTION POST-ORTHODONTIC TREATMENT: A SYSTEMATIC REVIEW

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M L Noguera-Wu1, A Iglesias-Linares2, R M Yañez-Vico1, E Solano-Reina1, R Calvo Parra Martinez3, Departments of Orthodontics, 1University of Seville and 2Complutense University of Madrid, Spain and 3Newcastle University, Newcastle-upon-Tyne, U.K.

AIM: To perform a literature review to evaluate different genetic polymorphisms as predisposing factors in the pathology of external apical root resorption (EARR) post-orthodontic treatment. MATERIALS AND METHOD: A survey of articles published from 1970 to October 2013 regarding the possible effects of different genetic polymorphisms on EARR post-orthodontic treatment was performed using several electronic databases: PubMed, Scopus, EBSCOhost and Scirus. The following terms were used in the database: [apical root resorption• AND (polymorphisms• OR SNPs) AND orthodontics]. The inclusion criteria were: (1) Studies focused on EARR secondary to orthodontic treatment; (2) Studies of at least one gene polymorphism associated with the process of EARR; (3) Studies with a control group; (4) Studies with a one beam computed Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 tomographic scan, periapical radiographs, panoramic or lateral cephalometric radiographs used as diagnostic methods. The methodological quality of the papers was classified: clinical trials were assessed using the Cochrane Risk of Bias Tool, based on: sequence generation, allocation concealment, blinding of patients, blinding of outcome assessors, incomplete outcome data, selective reporting, and other bias. The non- randomized clinical trials were assessed using the methodological index for non-randomized studies. RESULTS: After selection according to the inclusion/exclusion criteria, a total of 11 articles were selected for the final assessment. The quality standards of these articles ranged from medium to high levels. The genetic polymorphisms included were IL-1A -899 and -889, IL-1B +3954 and +3953, IL-1RN +2018 and VNTR, TNFRSF11B, TNFRSF11A, P2RX7, TNSALP, TNF alpha, TNFRSF11A and Vitamin D receptor gene. Controversy in results, odds ratio and inter-ethnic variability was present in the reported articles. Certain genetic polymorphisms have stronger relationships with the presence and severity of EARR (IL-1B and IL-1RN). Moreover different criteria to identify EARR were used in the literature as well as different methods for assessment of EARR. CONCLUSION: The aetiology of the EARR is multifactorial and could lead to possible discrepancies. Therefore, a solid unique diagnostic criterion is needed to evaluate EARR. Further ethnic-based studies, with vast population representation are required to determine the real influence of cited SNPs in the EARR process.

342 EXTERNAL APICAL ROOT RESORPTION POST-ORTHODONTIC TREATMENT: PREVALENCE AND DIAGNOSTIC METHODS M L Noguera-Wu1, A Iglesias-Linares2, R M Yañez-Vico1, E Solano-Reina1, R Calvo Parra Martinez3, Departments of Orthodontics, 1University of Seville and 2Complutense University of Madrid, Spain and 3Newcastle University, Newcastle-upon-Tyne, U.K.

AIM: To perform a review of the literature to evaluate the prevalence and diagnostic methods used in the pathology of external apical root resorption (EARR) post-orthodontic treatment. MATERIALS AND METHOD: A survey of articles published from 1950 to October 2013 regarding the prevalence and diagnostic methods of EARR post-orthodontic treatment was performed using several electronic databases: PubMed, Scopus, EBSCOhost and Scirus. The keywords used in the databases were ['apical root resorption'• AND 'orthodontic'• AND ('prevalence'• OR 'diagnosis')]. The inclusion criteria were: (1) Studies focused on post- orthodontic EARR; (2) Studies with information of the prevalence of EARR; (3) Studies with diagnostic method made with a cone-beam computed tomography (CBCT) scan, periapical radiographs, panoramic or lateral radiographs. (4) Studies with specific criteria to define EARR secondary to orthodontics. RESULTS: Most of the studies included in the review report that 90 per cent of the orthodontic patients present some EARR, of which 60 to 65 per cent present mild EARR of less than 2 mm, 33 per cent present moderate EARR from 2 to 4 mm of root shortness, and from 1 to 5 per cent of the patients present severe root resorption of more than 4 mm or one-third of the original root length. Nevertheless, different diagnostic methods and different criteria were been found in the literature. Moreover, inter-ethnic variability was present in EARR. e173

Whilst a CBCT scan is the most reliable diagnostic test, it is the method that exposes the patient to the highest radiation dose. The reliability of the different methods to determine EARR is followed by panoramic, periapical and lateral cephalometric radiographs. CONCLUSION: Knowledge of the prevalence and the possibility of diagnosing the pathology of EARR is especially important in orthodontics. The prevalence of EARR is high. Nevertheless there is a wide variation between ethnicity and different definitions of EARR are found in the literature. Despite the CBCT scan having been shown as the most accurate method in the diagnosis of EARR, the routine diagnostic test performed on a daily basis in orthodontic practice is the panoramic radiograph as a CBCT scan results in a very high radiation dose and has difficult access.

343 EVALUATION OF THE EFFECTS OF MODIFIED CLASS II ACTIVATORS ON THE MAXILLA AND MANDIBLE Z Novruzov1, O Ozdiler2, S Halil3, 1Department of Pediatric Dentistry, Azerbaijan Medical University, Baku, Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 Azerbaijan, 2Department of Orthodontics, Baskent University, Ankara, Turkey and 3Clinic of dental city, Baku, Azerbaijan

AIM: Class II (distal) malocclusions are the most frequently encountered, therefore the most widely treated anomaly by orthodontists. According to the investigations of Ingervall and Kim, Class II malocclusions are present in 12 and 49 per cent, respectively, of orthodontic anomalies. In Azerbaijan 10 per cent of anomalies are Class II. Dental and skeletal factors are involved in development of Class II malocclusions. Both maxillary protrusion and mandibular retrusion are evident in the development of skeletal Class II, but commonly seen is mandibular retrusion. In the treatment of this disorder, where aesthetics, phonation and function are lost, orthodontics play a major role. Functional devices are widely utilized in the treatment of Class II anomalies. These devices are the ones which direct the force of a special muscle group with the aid of the dentition to the basal bone system by changing the function and position of the mandible. MATERIALS AND METHOD: The study was conducted on hand-wrist radiographs, together with lateral cephalometric radiographs at the beginning and at end of modified twin-block appliance treatment of a total 18 individuals. Fifteen Class II individuals treated with a twin-block comprised the control group. Differences between the groups were evaluated. RESULTS: The modified twin-block group restricted maxillary development more than that in the twin-block group. However, stimulation of mandibular development was not caused by the twin block design. CONCLUSION: The provocation of the mandibular development by the amount of the activation and the daily use of the device.

344 PATIENTS’ EXPERIENCE ON THE OUTCOMES OF SURGICAL-ORTHODONTIC TREATMENT IN ADULTS WITH MAXILLARY OR BIMAXILLARY OSTEOTOMIES S Nyblom, T Hulkko, K Jari, R Myllykangas, R Pahkala, Department of Dentistry, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland

AIM: To evaluate subjective treatment outcomes in patients with Le Fort I or bimaxillary osteotomy. SUBJECTS AND METHOD: Twenty nine females and 11 males (mean age 31.8 years, SD 13.9) who underwent maxillary (n = 24) or bimaxillary (n = 16) osteotomy between 1999 and 2011. The most common primary diagnoses of the patients were maxillary hypoplasia/retrognathia, mandibular hyperplasia/prognathia, anterior open bite and crossbite. About 2.0 years (SD 0.5) after orthognathic surgery the patients were asked to fill in a questionnaire about their subjective symptoms of temporomandibular dysfunction (TMD) and satisfaction with their treatment outcome. For statistical evaluation, chi-square statistics and multiple regression analysis were used. RESULTS: Altogether three-quarters of the patients were very satisfied with the outcome of treatment, whilst 95 per cent of the patients thought that the result was what they expected or even better. Although only 10 per e174

cent of the subjects expressed dissatisfaction with their facial appearance at baseline, 80 per cent of the patients thought that their facial appearance was improved by treatment. Furthermore, in 61 per cent treatment had a positive effect on their self-confidence. Chewing ability improved in 83 per cent of the subjects, orofacial pain disappeared in two thirds of them, and almost half of the patients got relief in their TMD symptoms. Multiple logistic regression analysis showed that subjects who experienced that their facial appearance and self-confidence improved expressed the highest satisfaction with the treatment outcome. CONCLUSION: Although most of the subjects with maxillary or bimaxillary osteotomies seemed to benefit from surgical-orthodontic treatment in their orofacial functions and pain, the most satisfied with treatment outcome were those with improved facial appearance and self-confidence. The results indicate the importance of psychosocial factors in addition to functional and morphological aspects when treatment alternatives are considered. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 345 COMPUTER ASSISTED CEPHALOMETRIC TRACING VERSUS HAND TRACING: REPEATABILITY, METHOD ERROR AND EFFICIENCY S Oiknine1, M Bouchiba2, N Donaldson3, D Bister1, Departments of 1Orthodontics and 2Oral Surgery, 3Guy's Hospital , London, U.K.

AIM: To assess the reproducibility of computerized and hand traced lateral cephalograms and assess method error and efficacy (time taken to complete a tracing) and compare the values with existing norms used for cephalometry. MATERIALS AND METHOD: Sommer (2009) proposed that the difference between hand traced and computer traced radiographs is clinically acceptable when measurements do not exceed 2 degrees. Forty lateral cephalograms of Caucasian patients presenting with a Class I incisor relationship were reused for this audit. All 40 lateral cephalograms were analyzed using the Eastman analysis. The radiographs were traced four times by the same assessor, twice by hand and twice by computer using Dolphin® (version 10.5.265). RESULTS: The repeatability of both methods showed good agreement for most measurements, only the lower anterior face height (LAFH) showed modest agreement. The method error showed a high consistency between the measurements, which demonstrated good agreement between the methods. Surprisingly the values found for the 40 Caucasian cephalograms used for this audit differed significantly from the Eastman standard for SNA, SNB, UMX, and LAFH. The mean difference in the tracing time between the methods was 57.8 seconds more for the hand-tracing, which is statistically significant but may not be clinically significant. However the time to prepare the radiographs for tracing was not taken into consideration, which may have a significant impact on the tracing time. CONCLUSION: Both hand-tracing and computerized tracing using Dolphin® software were found to be compatible for most cephalometric values investigated and method error was generally ‘very good’. The cephalometric values of the Class I sample used in this audit differed significantly from the Eastman Norms. Computerized tracing time was significantly shorter than hand tracing; however the preparatory work was not measured.

346 DENTAL AGE ASSESSMENT: DEVELOPMENT OF A REFERENCE DATA SET FOR ISRAELI CHILDREN, ADOLESCENTS AND EMERGING ADULTS AGED BETWEEN 3 AND 26 YEARS S Oiknine1, G Roberts2, V Lucas2, F McDonald1, S Chaushu3, Departments of 1Orthodontics and 2Paediatrics, King's College London Dental Institute, U.K. and 3Department of Orthodontics, Hebrew University and Hadassah Dental School, University, Jerusalem, Israel

AIM: To establish a reference data set (RDS) of Israeli Caucasians subjects. MATERIALS AND METHOD: Dental panoramic tomographs (DPTs) of 1482 Israeli Caucasians aged between 3 and 26 years were used to establish a RDS. The tooth development stages system described by Demirjian (1973) was e175

used to assess all teeth on the left side of the maxilla and mandible, and all third molars. The accuracy of dental age (DA) assessment was tested with a separate sample of DPTs of 50 females and 50 males of known chronological age (CA) assessed in the same way. This was the validation sample. The summary data for the individual tooth development stages (TDS), comprising the number (n-tds), mean (x-tds), standard deviation (sd- tds) and standard error (se-tds), were used to estimate the age of the validation sample using several methods of calculation including meta-analysis and both the weighted and unweighted mean. RESULTS: There was no significant difference between CA and DA in the male group; the mean difference was 0.56 months. There was a significant difference of 3.85 months in the female group. The most precise method of calculating DA in males was weighted mean by n-tds and meta-analysis by sd with random effect, and in females, weighted mean by se-tds. There was no significant difference in the age at attainment of TDSs between the Israeli Caucasians and UK Caucasians CONCLUSION: These data demonstrate that the estimated DA is very close to CA in males and within 4 months Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 for females

347 A PILOT STUDY OF A PROPOSED PROSPECTIVE CHONDROGENIC MEDIUM FOR GENERATING CHONDROCYTES FROM DEDIFFERENTIATED FAT CELLS N Okita1, Y Honda2, N Kishimoto3, Y Hashimoto4, N Matsumoto1, 1Department of Orthodontics, 2Institute of Dental Research, 3Department of Anesthesiology and 4Department of Biomaterials, Osaka Dental University, Japan

AIM: Congenital defects of cartilage are crucial in patients with cleft lip and/or palate. Although multipotent dedifferentiated fat cells (hDFAT cells) are believed to be prospective cell sources for cartilage regenerative medicine, their application is limited because of a lack of efficient methods to differentiate these cells into the chondrocyte lineage. Strontium (Sr) ions, a component of potent antiosteoporotic drugs, are widely applied in the management of bone diseases, including osteoporosis, to stimulate bone regeneration but are less frequently used in cartilage regeneration. Considering previous studies relevant to signalling pathways of osteoblastogenesis with Sr ions, it was hypothesized that Sr ions may act as effective stimulants to facilitate chondrogenic differentiation of hDFAT cells. The present study was designed to investigate whether Sr ions efficiently promote in vitro chondrogenic differentiation of hDFAT cells, and to elucidate its detailed signalling pathways. MATERIALS AND METHOD: hDFAT cells were obtained using a ceiling culture method with fat tissues isolated from human neck subcutaneous tissue. The human mesenchymal stem cell line (RCB2153) was used as a control. Both cell types were cultured in the following three media for up to two weeks to induce chondrogenic differentiation: (1) basal medium, (2) chondrogenic medium (3) chondrogenic medium with Sr at various concentrations. To determine the efficacy of Sr in inducing chondrogenic differentiation, Alcian blue staining, quantitative polymerase chain reaction assay, and immunoprecipitation and immunoblots was performed. A calcium-sensing receptor inhibitor (NPS2143) and other inhibitors were utilized to elucidate detailed signalling pathways involved in Sr-induced chondrogenic differentiation of hDFAT cells. RESULTS: The Sr-containing medium induced significant chondrogenic differentiation of hDFAT cells in a dose- dependent manner, whereas its effect on RCB2153 cells was negligible, at least at the same concentration range. Chondrogenic differentiation was readily inhibited using NPS2143, indicating that the calcium-sensing receptor signalling pathway may be involved to some extent in mediating Sr-induced chondrogenic differentiation. CONCLUSION: Sr ions are potent stimulants of chondrogenic differentiation of hDFAT cells. Therefore, an Sr- containing chondrogenic medium can increase the possibility of the use of hDFAT cells in cartilage regeneration.

348 CARIES PREVENTIVE MEASURES IN ORTHODONTIC PRACTICE: HOW TO REACH CONSENSUS WHEN EVIDENCE IS SCARCE e176

B Oosterkamp1, W van der Sanden2, A M Kuijpers-Jagtman1, Departments of 1Orthodontics and Craniofacial Biology and 2Global Oral Health, Radboud UMC, Nijmegen, Netherlands

AIM: White spot lesions (WSL), are a side-effect of orthodontic treatment causing aesthetic problems and increasing the risk of deeper enamel and dentine lesions. While many strategies have been developed for prevention of WSL, the available literature however is equivocal leading to great variability in preventive measures between orthodontist (Derks, 2007). The aim of the present study was to develop statements on the basis of which a caries risk based Clinical Practice Guideline can be developed in order to help orthodontists select preventive measures based on the best available evidence . MATERIALS AND METHOD: A nominal group technique (The RAND-e Modified Delphi Procedure) was used. This method is specifically suitable for reaching consensus on a topic when the available scientific literature does not provide sufficient information about the indications for the most appropriate treatment. Eleven Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 multidisciplinary expert panel members rated a total of 264 practice and evidence based statements related to management of WSL. In order to provide panel members with the same level of knowledge, a total of six articles obtained by systematically reviewing the literature were read by the panel in preparation for three consensus rounds. According to the method, a threshold of 75 per cent of all ratings within any three-point section of the nine-point scale regarding a specific statement was accepted as consensus. RESULTS: After the first and second consensus rounds, consensus was reached on 37.5 and 31.1 per cent of statements, respectively. For the remaining 31.4 per cent of statements consensus was reached during a 4 hour consensus meeting. CONCLUSION: Statements on management of WSL derived from a systematic review of the literature combined with expert opinion were formally integrated towards consensus through a nominal group technique. These statements formed the basis for development of a caries risk based clinical practice guideline on management of WSL before and during orthodontic treatment.

349 INFLUENCE OF OESTROGEN DEFICIENCY AND ALTERED DIETARY LOADING ON RAT CONDYLAR CARTILAGE M Orajärvi, A Raustia, P Pirttiniemi, University of Oulu, Finland

AIM: According to epidemiologic studies, females comprise the majority of temporomandibular disorder (TMD) patients, having more TMD-symptoms and clinical signs than males. The aim of this study was to examine how oestrogen deficiency and altered dietary loading affect condylar cartilage, especially proliferation of cartilage cells and number of osteoclasts. MATERIALS AND METHOD: Fifty six rats divided into four groups. Ovariectomy was performed at the age of 60 days in two experimental rat groups. Rats in the first ovariectomized group were fed a normal (pressed pellet) diet, and those in second experimental group a soft (powder) diet. Half of the control rats were fed a normal diet, the rest a soft diet. Half of the rats were sacrificed at the age of 67 days, the rest at the age of 87 days. The cranium of the rat was cut sagittally, separating the right and left temporomandibular joint. The sections were embedded in paraffin and cut into 5 μm sections in a sagittal direction. Immunohistochemistry (PCNA, Cathepsin K) and tartrate resistant acid phosphotase staining were performed. RESULTS: Both 67 and 87 days old ovariectomized rats fed a normal diet had a significantly higher proportional number of PCNA positive cells in the most superior and posterior segments of condylar cartilage than control rats fed a normal diet (P < 0.05). Eighty seven day old ovariectomized rats fed a normal diet had a significantly higher proportional amount of PCNA positive cells than ovariectomized rats fed a soft diet in the most superior and posterior segments (P < 0.05 and P < 0.001, respectively). Eighty seven day old ovariectomized rats of both diet groups had a significantly lower number of osteoclasts than the corresponding control rats (P < 0.001). CONCLUSION: The present results show that ovariectomy (i.e. oestrogen deficiency) increases the proliferation of cartilage cells, and altered dietary loading has an effect only on proliferation within ovariectomized rats. The e177

number of osteoclasts was lower in ovariectomized rats, which could partly explain the thicker condylar cartilage due to the slower resorption rate in cartilage bone interface.

350 CORRELATION BETWEEN MALOCCLUSION AND ARTICULATION DISORDERS IN PRESCHOOL CHILDREN FROM GDANSK, SOPOT AND GDYNIA M Orzelska, M Suchecka, A Wojtaszek-Słomińska, Medical University of Gdansk, Poland

AIM: Many studies have been conducted to determine the dependence between malocclusions and speech defects. On the one hand, dysfunctional occlusion is an important factor, which influences articulation quality, especially dentalized sounds. On the other hand a dysfunction such as a speech defect, may lead to malocclusions. On the basis of the previous studies it cannot be established how strong the correlation between present malocclusions and speech impediment is. The aim of this study was to determine the connection Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 between malocclusions and speech impediment. SUBJECTS AND METHOD: Two hundred and twenty two children aged from 2.5 to 6 years attending kindergartens in Gdansk, Sopot and Gdynia. The children were divided into three groups according to age: group 1 children aged from 2.5-3.5 years, group 2, 3.5-4.5 years, and group 2, 4.5-6 years. The study included an interview with the parents/guardians and orthodontic clinical examination based on the World Health Organisation guidelines. RESULTS: The most common malocclusion was distoclusion (approximately 20%). In group 2 there was also a significant incidence of mesioclusion (approximately 8%). All patients with a Class III malocclusion and 70 per cent of patients with an open bite were diagnosed with a speech impediment. The foregoing abnormality was observed only in 41 per cent of Class II children. The results showed strong statistical correlation between speech impediment and mesioclusion or an open bite. CONCLUSION: A correlation was found between malocclusions and speech impediment, especially in the case of mesioclusion (100%) and open bites (70%). In children with a Class II malocclusion, speech impediment was observed only in 41 per cent. It is important to emphasize that the same factor (for example thumb sucking) can result in a malocclusion as well as speech impediment. Orthodontic and logopedic prevention is recommended in preschool children.

351 COMPARISONS OF ORAL HYGIENE AND PERIODONTAL STATUS IN GROWING PATIENTS USING FIXED AND REMOVABLE ORTHODONTIC APPLIANCES. A Osmólska-Bogucka, E M Czochrowska, M Zadurska, Department of Orthodontics, Medical University of Warsaw, Poland

AIM: To compare the periodontal status of orthodontic patients treated with fixed versus removable appliances. SUBJECTS AND METHOD: One hundred and twenty orthodontic patients (9-14 years) treated with fixed (60 patients, FA group) and removable (60 patients, RA group) appliances. The mean age of patients was 12.9 in the FA and 10.5 in the RA groups. The control group included 60 patients (mean age: 11.3 years, range: 9 to 14 years) before the start of orthodontic treatment. Measurements of plaque index (PI), gingival bleeding index (GI), pocket depth (PD) and clinical attachment level (CAL) were performed. RESULTS: PI was not significantly different between all groups. GI, PD and CAL were significantly higher in the FA group compared with the RA and control groups. No significant differences were seen between the RA and control groups. CONCLUSION: Patients who are using fixed appliances may be at higher risk of periodontal breakdown, which should be monitored during treatment.

352 COMPARISON OF THE OCCURRENCE OF PARAFUNCTIONS IN CHILDREN AND THEIR PARENTS e178

A Osmólska-Bogucka, O Buczek, M Bilińska, M Zadurska, Department of Orthodontics, Medical University of Warsaw, Poland

AIM: To compare the occurrence of parafunctions in children and their parents. SUBJECTS AND METHOD: One hundred children (52 girls, 48 boys) aged between 9-12 years and their parents (82 mothers, 17 fathers). To analyze the frequency of non-occlusal parafunctions two types of questionnaires were completed by the parents. The first questionnaire concerned parafunctions among children and the second was about oral habits among adults. RESULTS: Non-occlusal parafunctions were observed in 72 children (72%): Forty two girls (72.4%) and 30 (62.5%) boys. The most common oral habits included biting foreign objects 44 children (61.1%) and nail biting 38 children (52.8%). The sample of 70 parents (70.0%) admitted performing parafunctional behaviour, the most common of which included biting foreign objects (41.7%) and nail biting (38.9%). There was no significant Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 difference between parents and children who bite foreign objects or bite their nails (P > 0.05). CONCLUSION: Parents who bite foreign objects and nails may transmit these parafunctions in a process of internalisation.

353 TOOTH CONTACT AND BRAIN FUNCTION T Otsuka, K Sasaguri, T Kawata, Oral Science Orthodontic Division, Kanagawa Dental University, Yokosuka, Japan

AIM: The tactile sensation of the teeth is involved in various oral functions, such as chewing, speech, and bruxism. However, little is known about the mechanism underlying these phenomena. In this study, to evaluate the mechanism underlying these phenomena, functional magnetic resonance imaging was used in healthy humans and their brain region activity during tactile stimuli of each part of the tooth assessed. SUBJECTS AND METHOD: Ten healthy subjects (5 males, 5 females, aged 26 to 32 years, mean age 29.3) with no history of any psychiatric or neurological illness. Five splints were created with contact specific teeth (incisor, canine, first premolar, first molar, second molar) by the resin-piled mandibular splint. The subject wore the each splint and performed four cycles of 21 seconds of bruxism (grinding and clenching) and 21 seconds of resting. For each subject, functional (T2 weighted) images followed by an anatomical (T1 weighted) image were acquired using a 1.5-T horizon MRI scanner. Statistical analysis was based on the general linear model approach using SPM5. Abnormality with the splint was scored on a visual analogue rating scale (VAS). RESULTS: Group analysis showed that bruxism (grinding and clenching) with all splints was associated with significant increases in the ‘bold’ signal in the sensory and motor cortexes of the oral region. In addition, the activation area of bruxism at the molar region (first molar, second molar) was not only the sensorimotor cortex, but also the limbic area (amygdala, anterior cingulate cortex). There was a significant increase in the psychophysiological score (P < 0.05, paired t-test) in the ‘unpleasant’ scale with bruxism at the molar region compared with others. CONCLUSION: These results suggest that specific contact of the molar region may prevent a healthy occlusal condition.

354 FACTORS AFFECTING COOPERATION IN PATIENTS TREATED WITH FIXED ORTHODONTIC APPLIANCES O Özdıler1, A Bahat Yalvaç2, G Çobanoǧlu1, F Aydin Mustafa1, A Șenol1, 1Department of Orthodontics, Faculty of Dentistry, University of Ankara and 2Private Practice, Ankara, Turkey

AIM: The success of orthodontic treatment depends on a number of factors; knowledge and skills of clinician, patient cooperation, active cooperation of the parents and mutual adaptation are some of them. Problems in patient cooperation can prolong the duration of treatment and bring unwanted results by negatively affecting the ideal treatment plan and mechanics. Therefore, increasing patient cooperation by specifying patient

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expectations is of importance for the efficient and smooth advancement of treatment. The aim of this study was to evaluate factors affecting patient cooperation. SUBJECTS AND METHOD: Forty two questions were asked of 360 individuals with an average age of 16.8 years, who were treated with fixed orthodontic appliances. RESULTS: According to the survey, the treatment period for 86.3 per cent of the patients was 1-4 years. During treatment 18.3 per cent used extraoral appliances and 66.9 per cent intraoral elastics. Positive results obtained during the treatment were connected to compliance with treatment instructions by 37.8 per cent of patients, to the success of the physician by 47 per cent and to both factors by 14.6 per cent. On the other hand, 85.1 per cent of the subjects stated that a positive result was achieved as a result of good hygiene instruction increasing their interest in the treatment. This survey revealed that orthodontic treatment increased the frequency of tooth brushing of the patients. CONCLUSION: Development of methods to predict the patient cooperation should lead to shortening of Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 orthodontic treatment time in order to gain economic and social contribution of orthodontics increases.

355 APICAL ROOT RESORPTION OF MAXILLARY PREMOLARS AND MOLARS AFTER INTRUSION WITH ZYGOMATIC SKELETAL ANCHORAGE E Oztas, O Capan, G Marsan, Department of Orthodontics, Faculty of Dentistry, Istanbul University, Turkey

AIM: To evaluate radiographically apical root resorption of maxillary first and second premolars and first molar after intrusion using zygomatic plates as skeletal anchorage in open-bite cases. SUBJECTS AND METHOD: Twelve consecutively treated open-bite patients who had received titanium miniplates in their zygomatic bones for use as skeletal anchorage to apply orthodontic intrusive forces to the maxillary teeth. The total treatment time was 6 months and tooth lengths were measured on pre- and post- treatment panoramic radiographs of all patients. The mesiobuccal and distobuccal roots of the left and right maxillary first molars and buccal roots of the first and second premolars were measured. The difference between the pre- and post-treatment tooth lengths was defined as apical root resorption. RESULTS: Comparison of the differences in root resorption of the study group, using the paired t- test for samples, showed statistically significant differences for the first and second premolars and first molar roots (P < 0.05). The highest mean difference in apical root resorption was 1.3 mm for the first premolars while the lowest was 0.54 mm for the distobuccal roots of the first molar, just above the threshold. CONCLUSION: Apical root resorption of the maxillary first and second premolars and first molar after intrusion using zygomatic skeletal anchorage was clinically significant and this application should be performed with much less force and more treatment time to avoid side-effects.

356 COMPARISON AND APPLICABILITY OF THE GREULICH-PYLE METHOD IN CENTRAL AND EAST ANATOLIAN TURKISH CHILDREN F Öztürk1, O H Karataş2, H İ Mutaf3, H Babacan1, Departments of Orthodontics, Faculties of Dentistry, 1Pamukkale University, Denizli, 2Inonu University, Malatya and 3Cumhuriyet University, Sivas, Turkey

AIM: To identify, using the Greluich-Pyle (GP) method, the bone development of Turkish children in the Central and Eastern Anatolian regions and compare the two regions. SUBJECTS AND METHOD: Eight hundred and forty nine subjects (375 boys, 514 girls) between 7-17 years. The selection criteria included, normal growth and development, physically and mentally healthy with no previous history of chronic or acute illnesses, no past trauma or injury to the hand-wrist region, no congenital or acquired malformations of the hand-wrist area, no hormonal disorders, good quality hand-wrist films. The radiographs were randomly selected. Bone age (BA) from plain radiographs of the left hand-wrist by GP standards were estimated

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RESULTS: The total mean differences between BA and chronological age (CA) for girls and boys were 1.19 ± 1.2 (P < 0.05) and 0.90 ± 1.2 (P < 0.05) years, respectively in Malatya and 0.28 ± 0.6 (P > 0.05) and –0.10 ± 0.3 (P > 0.05) years, respectively in Sivas. There were significant differences between BA and CA in all age groups for girls and boys in Malatya and 10 and 13 year old girls and 12, 13, 15, and 16 year old boys in Sivas. When the difference between BA and CA individuals living in Malatya and Sivas were compared, the results were statistically significant. CONCLUSION: Individuals living in Malatya complete earlier bone development compared to individuals living in Sivas.

357 SURFACE OPTIMIZATION OF NICKEL TITANIUM ORTHODONTIC ARCHWIRES WITH DIAMOND-LIKE CARBON COATING C Palazón Martínez1, A Molina Martínez1, G Martín González2, C Atienza Vicente3, Departments of 1Dentistry and Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 2Sciences, Catholic University of Valencia and 3Valencia Biomechanics Institute, Polytechnic University of Valencia, Spain

AIM: To evaluate the surface effects of a diamond-like carbon coating (DLC) over commercially available nickel titanium (NiTi) orthodontic wires. MATERIALS AND METHOD: DLC films were deposited on orthodontic NiTi archwires (n = 12). Type 1 (ProFlex®, 0.014 inch) ; Type 2 (ProFlex®, 0.016 × 0.022 inch), Type 3 (Thermaloy®, 0.014 inch); and Type 4 (Thermaloy®, 0.016 × 0.022 inch), corresponding to two commercial brands (Orthodontic Design & Production and Rocky Mountain Orthodontics), using a magnetron sputtering technique. The physical vapour deposition coating equipment allows different layers to be deposited by a combination of three magnetrons. As-received wires and DLC treated wires were observed by scanning electron microscopy. Surface roughness was measured by atomic force microscopy. Mechanical properties (load-deflection and sliding resistance) were measured with a universal testing machine. For statistical analysis, a repeated measures design was used. The repeated measures factor was the ‘DLC-coating’, and intersubject factors ‘Manufacturer’ and ‘Section’. RESULTS: Although as-received and DLC-coated wires from both manufacturers had an increased number of defects after treatment [F (1, 7) = 19.192, P = 0.003], the total defective area was decreased after treatment [F (1, 7) = 18.178, P = 0.004]. Quantitative analysis of the surface roughness confirmed that the DLC-coating process did not affect surface roughness [F (1, 7) = 3.148, P = 0.119]. Flexibility and resistance to sliding were similar for DLC-coated and as-received wires [F (1, 7) = 0.011; P = 0.920] [F (1, 7) = 0.551; P = 0.482]. CONCLUSION: 1. The surfaces of NiTi orthodontic wires can be successfully modified by a magnetron sputtering technique to create a DLC layer; 2. The DLC layer has a lower defective area than as-received wires; 3. The DLC- coating process keeps the unique properties of the NiTi alloy: the superelasticity and sliding resistance.

358 DOES ANAEMIA AFFECT CRANIOFACIAL GROWTH? P Panigrahi1, G Jacob2, 1University of Sharjah, United Arab Emirates and 2Department of Orthodontics, P.M.S- C.D.S.R., Trivandrum, India

AIM: This cross-sectional study was conducted to assess and establish a correlation between nutritional status, specifically the role of anaemia and growth status of 70 children undergoing orthodontic treatment. SUBJECTS AND METHOD: All subjects were randomly selected. Their ages ranged between 10-16 years for boys and 8-14 years for girls. The experimental group had an haemoglobin percentage of less than 12 mg% and the control group had ≥12 mg%. All children were subjected to history taking, intra-oral examination, anthropometric and laboratory investigations. Body mass index (BMI) was calculated using metric formulae and their percentiles estimated based on growth charts. The complete haemogram was estimated by automated ABX blood cell counter and serum electrolytes and calcium by the photometric method.

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RESULTS: The overall prevalence of anaemia was 55.7 per cent. No statistical significance was seen between the genders. The mean BMI value of the boys and girls in the experimental group was significantly reduced compared with the controls. A total of 56.3 per cent of boys and 56.5 per cent of girls in the experimental group were below the 5th percentile. The same percentage of boys and 39.1 per cent of girls in experimental group were below the 3rd percentile. There was a significant reduction of serum calcium level among boys and girls, but only boys had a reduced electrolyte level. CONCLUSION: A significant correlation was established between BMI and Hb% which indicated reduced growth status among the anaemic patients. Thus supplements will be required in these patients before functional therapy.

359 CHANGES OF SUBSTANCE P IN CREVICULAR FLUID IN RELATION TO ORTHODONTIC MOVEMENT S Panzi, A Caprioglio, L Levrini, Department of Orthodontics, University of Insubria, Varese, Italy Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021

AIM: Substance P (SP) is a tachykinin released from both the central and peripheral endings of primary afferent neurons and functions as a neurotransmitter. As a transmitter signalling pain, SP is involved in nociception and is an extremely potent vasodilator. Studies have demonstrated higher levels of SP in teeth undergoing constant orthodontic forces by traditional fixed appliance. The aim of the present study was to investigate whether SP is present in gingival crevicular fluid (GFC) and its concentration in teeth undergoing intermittent orthodontic forces using removable aligners. MATERIALS AND METHOD: A split-mouth study was performed collecting GFC of 38 young female subjects (average age 15.4 years). The test teeth were subjected to a movement of 1 degree inclination toward the fornix, considering the long axis as a guide for the movement. At the same time teeth without movement were used as the control. Sampling was performed at the end of the first week of removable aligner treatment. RESULTS: SP is present in the gingival sulcus in teeth undergoing orthodontic forces but not in the control teeth. The average value of SP concentration obtained from the experimental teeth was 13.4 ± 6.8 pg , while that of the control group was 4.2 ±0.6 pg. CONCLUSION: Higher levels of SP are present in teeth subjected to orthodontic force compared with controls.

360 LONGITUDINAL CHANGES IN DENTAL ARCH DIMENSIONS FROM THE MIXED TO THE PERMANENT DENTITION V Paoloni, C Pavoni, R Lione, P Cozza, Department of Orthodontics, University of Rome Tor Vergata, Italy

AIM: To investigate the longitudinal changes in dental arch dimensions during the transition from the mixed to the permanent dentition. MATERIALS AND METHOD: Dental casts of 24 Caucasians (15 females, 9 males, mean age 9.13 years), with complete records from the mixed to the permanent dentition. They all showed bilateral Class I permanent molars (either flush terminal plane or mesial step) and a Class I primary canine relationship. The casts represented two time points: T1 mixed dentition stage, with second primary molars and primary canines still present; T2, three years after T1, permanent dentition stage, with all permanent teeth erupted except for the third molars. Cast measurements were made by the same trained operator using a digital calliper at 0.02 mm precision. Maxillary and mandibular intermolar widths, maxillary and mandibular intercanine widths, curve of Wilson, and posterior and anterior transverse discrepancies were measured. Reproducibility of the measurements was estimated by repeating the measurements 10 days from the first measurement by the same examiner. Dahlberg’s formula on 30 repeated measurements that were selected randomly from the total of the observations was used to assess differences among the measurements. The method error was less than 0.1 mm for linear measurements. The paired t-test was used to verify the significance of the values. The results were considered statistically significant at P < 0.05.

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RESULTS: There were statistically significant changes from the mixed to the permanent dentition in upper and lower intercanine widths. The anterior transverse discrepancy was also significantly different from T1 to T2. CONCLUSION: During the transition from the mixed to the permanent dentition dental arch widths significantly change. However when the posterior transverse occlusal relationship is established and the first permanent molars are in functional occlusion, the clinician should expect changes only in the anterior region with a significant increase in intercanine width due to replacement of the primary canines.

361 BIOMECHANICAL BEHAVIOUR OF THE ORTHODONTIC FIXED-APPLIANCE AND ASSOCIATED FACTORS: A FINITE ELEMENT ANALYSIS COUPLED WITH THE TAGUCHI METHOD S Papageorgiou1, L Keilig2, I Hasan2, A Jäger1, C Bourauel2, Departments of 1Orthodontics and 2Oral Technology, School of Dentistry, University of Bonn, Germany Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 AIM: To determine the relative effects of changes in bracket or wire factors on the biomechanical response of the periodontal ligament (PDL), the orthodontic bracket and the wire. MATERIALS AND METHOD: Eighteen CAD and finite element (FE) models corresponding to a Taguchi L18 array were constructed to simulate mechanical responses of the bracket/wire complex fixed to the tooth. Three- dimensional models of the right lower canine to second premolar along with the corresponding PDLs, alveolar bone, adhesive layers, edgewise brackets, ligatures and a wire segment were created. A conventionally-ligated discovery® bracket (Dentaurum, Pforzheim, Germany) was used for all teeth. Investigated factors included: (i) bracket material (stainless steel, polycarbonate, ceramic), (ii) bracket width (3.0 mm, 4.5 mm), (iii) slot size (0.018 inches, 0.022 inches), (iv) wire material (β-Ti, martensitic-stabilized NiTi, austenitic-active NiTi), (v) wire cross-section size (0.016 inch, 0.018 inch), (vi) wire cross-section shape (round, square, rectangular), (vii) adhesive material (composite resin, resin-modified glass ionomer cement) and (viii) tooth deflection. The total wire length was constant, while stress/strain measurements were made from the middle tooth in the FE software package MSC.Marc/Mentat 2010 (MSC Software Corp., Santa Ana, California, USA). Finally, the Taguchi method was employed to determine the contribution of each bracket or wire factor in stress and strain development. RESULTS: Material and design factors highly influence the developed stresses/strains in the PDL, the bracket and the wire. Selection of wire material showed a large influence on the resulting strains in the PDL. Depending on the model configuration, the magnitude of strains differed by a factor of 2 between steel and NiTi wires. Inter-bracket distance, varying according to bracket width, likewise significantly affected the magnitude of developed stresses and strains. CONCLUSION: Computer methods coupled with the Taguchi method can be useful in considering the relative contribution of each factor to the mechanical response, while reducing the number of experiments needed.

362 SHAPE COVARIATION BETWEEN THE UPPER AND LOWER DENTAL ARCH A Papagiannis, D Halazonetis, Department of Orthodontics, National and Kapodistrian University of Athens, Greece

AIM: To evaluate the shape of the dental arch in an orthodontic population and establish patterns of shape variability and of covariation between the upper and lower dental arch. MATERIALS AND METHOD: Dental casts of 133 white subjects (61 males, 72 females; ages 10.6 to 26.6 years) were scanned and digitized in three-dimensions. A set of 22 and 24 landmarks for the upper and lower dental arch, respectively, were placed on the incisal margin of the anterior teeth and the cusps of the canines, premolars and molars. Geometric morphometric methods were applied (Procrustes’ superimposition and principal component analysis on the Procrustes coordinates). Sexual dimorphism and allometry were evaluated with permutation tests and age-size and age-shape correlations were computed. Two-block partial least squares analysis (2B-PLS) was used to assess covariation of shape between the arches. e183

RESULTS: The extent of dental arch diversity that characterises an orthodontic population was established. The first four principal components were found to represent shape patterns that are often encountered and recognised in clinical practice, accounting for 31, 13, 9 and 8 per cent and 32, 12, 8 and 6 per cent of total variance for the upper and lower dental arch, respectively. Upper and lower arches covaried significantly (RV coefficient 33%). The main pattern of covariation (PLS1) between the dental arches was arch width (80% of total covariance), whereas the second component (PLS2) related maxillary canine vertical position to mandibular canine labiolingual position (11% of total covariance). No shape sexual dimorphism was found for either upper or lower arch forms (10,000 permutations, upper: P = 0.098, lower: P = 0.117), nevertheless, there was a statistically significant size difference between males and females (P < 0.000). Allometry was statistically significant, but low, for both upper and lower dental arches (upper: R2 = 0.0528, P < 0.000, lower: R2 = 0.0587, P < 0.000, 10,000 permutations). Age and shape were correlated (upper: R2 = 0.0370, P = 0.0001, lower: R2 = 0.0587, P = 0.0046, 10,000 permutations); the correlation between size and age was not statistically significant Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 (upper: R2 = 0.0157, P = 0.1511, lower: R2 = 0.0038, P = 0.483). CONCLUSION: Extensive dental arch shape variability was captured. Covariation patterns showed that the dental arches were tightly integrated in width and depth. Integration in the vertical dimension was weak, mainly restricted to maxillary canine position.

363 THREE-DIMENSIONAL FINITE ELEMENT ANALYSIS OF BONE STRAIN AROUND ORTHODONTIC MINI- IMPLANTS WITH FINE THREADING H H Park1, T K Kim2, Y S Moon1, S J Sung1, 1Department of Dentistry, Division of Orthodontics, University of Ulsan, College of Medicine, Asan Medical Center, Seoul and 2Smile Again Dental Clinic, Seoul, Korea South

AIM: To compare the bone strain around orthodontic mini-implants with fine threading to conventional orthodontic mini-implants when orthodontic forces are applied. MATERIALS AND METHOD: Three dimensional finite element models of the orthodontic mini-implant, cortical bone and cancellous bone were constructed. The alveolar bone was considered to be an ideal segment with a cortical bone thickness of 2 mm with an enclosed cancellous bone. Two different types of mini-implant were inserted at different angles. The miniscrews were loaded with a force of 200 g. The maximum strain of the bone around the mini-implant was measured for each model. RESULTS: 1. With a 90 degree insertion angle, the maximum strain of the bone was higher in the fine threading orthodontic mini-implant model than the conventional orthodontic mini-implant model. 2. With a 45 degree insertion angle, the maximum strain of the bone was lower in the fine threading orthodontic mini-implant model than the conventional orthodontic mini-implant model. CONCLUSION: Considering these results, the fine threading orthodontic mini-implant may provide better stability than the conventional orthodontic mini-implant in terms of the bone strain when inserted at a particular angle.

364 NON-SURGICAL TREATMENT OF MILD ANGLE CLASS III PATIENTS; IS IT WORTH THE EFFORT? A Partos, F Bazargani, Department of Orthodontics, Postgraduate Dental Education Center, Örebro, Sweden

AIM: Class III malocclusions are often amongst the most challenging in an orthodontic practice. The aim of this ongoing retrospective study is to evaluate the stability of Class III non-surgical treatment at least 3 years after the start of retention. MATERIALS AND METHOD: A list of patients with an Angle Class III pre-treatment diagnosis was obtained from the digital archive. The inclusion criteria were negative overjet, Class III molar relationship and debond during years 2004-2010. The exclusion criterion was orthognathic surgery. Study casts and clinical photographs were compared at the end of active treatment and at least 3 years post-treatment. Descriptive statistics were used for analysis of the material and an attempt to correlate stability to pre-treatment variables was made. e184

RESULTS: A total of 67 subjects were identified as eligible for the evaluation. Up to this point in time 26 (17 females, 9 males) of the total number have been able to participate and have undergone a follow-up examination. Some of the patients had study casts at the start of retention but mostly the end result was documented with intraoral clinical photographs. The mean age at the end of treatment for the analyzed cases was 15.9 years and the mean post-treatment time was 5.6 years. The average active treatment time with fixed appliances and Class III elastics was 22.4 months. Preliminary data indicate 61 percent of patients with little or no relapse. CONCLUSION: Treatment with fixed appliances and Class III elastics might be a feasible treatment approach in mild Class III subjects with a negative overjet. This ongoing study highlights the need for complete records at the end of active treatment in order to make long-term evaluations viable. The current study also demonstrates the necessity of follow-up as a sustainable routine for quality assessment in rural clinics. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 365 EVALUATION OF MAXILLARY HARD AND SOFT TISSUE CHANGES AFTER RAPID PALATAL EXPANSION AND FACEMASK THERAPY IN THE EARLY MIXED DENTITION A Pasaoglu, S Dogan, Department of Orthodontics, Ege University, Izmir, Turkey

AIM: To evaluate hard and soft tissue changes after using rapid palatal expansion (RPE) and Delaire type facemask in children with Class III malocclusions in the early mixed dentition. SUBJECTS AND METHOD: Fifteen patients; 8-11 years of age, with a Class III malocclusion. All had maxillary deficiency with normal mandibular development. Treatment started using RPE and after expansion was completed, a Delaire facemask was used for 6 to 9 months until a positive overjet of 5 mm was achieved. Cephalometric records were taken before RPE and after facemask therapy with the lips were in a relaxed, natural position, which allows an accurate structure of the lip, centric relationship and natural head position. The cephalometric analysis of Arnett (1999) was used to determine the changes and a Student’s t-test to evaluate the differences between the initial and final data. RESULTS: No statistically significant differences were found between the values for boys and girls. There was a statistically significant increase in overjet (P < 0.01, P < 0.001), while there was significant decrease in ULA-Sn- TVL (P < 0.01). There were statistically significant increases in high midface projection values: Sn to Gb' (mm), Sn to soft OR' (mm), CB'-Sn (mm), SP'-Sn (mm) (P < 0.05, P < 0.01) and in A' (mm), ULA-Sn (mm) (P < 0.001). Also, there were statistically significant increases in oral pharyngeal airway space at the Mx1 level (mm) and nasopharynx airway at point A level (mm) values (P < 0.01). CONCLUSION: Early treatment of Class III malocclusions with RPE and facemask resulted in a decisive improvement on hard and soft tissues. The facemask is effective in producing favourable soft and hard tissue changes when it is used in the correction of a skeletal Class III malocclusion. It should be considered as one of the most important options at the orthodontist’s disposal for treating Class III patients in the early mixed dentition.

366 MANDIBULAR CONDYLAR HYPERPLASIA DIAGNOSIS AND ORTHODONTIC POST-SURGICAL TREATMENT: REVIEW OF THE LITERATURE AND CLINICAL EXPERIENCE L Pavese, C Zangrillo, A Giordanok, G Galluccio, P Cascone, Post-graduate School in Orthognatodontics - Sapienza University of Rome, Italy

AIM: To review the literature on condylar hyperplasia (CH) and its orthodontic treatment after surgery. MATERIALS AND METHOD: The PubMed database was consulted using keywords CH, facial asymmetry, condylectomy, and temporomandibular joint (TMJ). The searches retrieved 127 articles from 1985 to 2013. Reports and animal experimentations were excluded. Eighty seven articles were chosen for the study. This

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contribution discusses the orthodontic post-surgical treatment of one patient affected by CH. Diagnosis of CH is clinical, supported by computerized tomography and single photon emission computed tomography. RESULTS: Mandibular dynamics are maintained with no significant changes when a high condylectomy is performed; however patients who underwent surgery had higher rates of TMJ osteoarthritis. Indirect bonding allowed a reduction in chair time and increased patient compliance. CONCLUSION: Using combined surgical and orthodontic treatment in CH therapy, the occlusal cant was kept under control. In addition the dental midline was restored, the facial aesthetics were improved and TMJ dysfunction was resolved.

367 DO PERSONALITY TRAITS MEDIATE THE RELATIONSHIP BETWEEN CRANIODENTOFACIAL FEATURES AND SELF-ESTEEM? A Pavlić, M Mlacović Zrinski, V Katić, S Špalj, Department of Pediatric Dentistry and Orthodontics, University of Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 Rijeka, Croatia

AIM: The influence of craniodentofacial features on self-esteem is well known, since they affect facial and smile aesthetics. However, as it seems that personality traits could mediate this relationship, the aim of this study was to investigate this phenomenon. SUBJECTS AND METHOD: The study was cross-sectional and the convenience sample included 150 patients and university students (61.3% female) aged 11-39 years (median 21 years, interquartile range 19-23 years). The questionnaire was self administered and included the Rosenberg Self-Esteem Scale and the Big Five Inventory for measuring personality traits. The craniodentofacial features were determined by the Martin-Saller craniofacial indices, the Index of Complexity, Outcome and Need and photogrammetric facial profile analysis. Self-perceived smile aesthetics were assessed by the Aesthetic Component of Index of Orthodontic Treatment Need. Multiple linear regression was used for statistical analysis. RESULTS: When excluding personality traits from consideration, a decreased lower lip retrusion and more pointed nose proved to be the only significant predictors of self-esteem and accounted for 4.5 and 3.2 per cent of the variability, and the whole model for 11 per cent (P < 0.001). After including personality traits into the regression model, significant predictors of higher self-esteem were decreased lower lip retrusion, more pointed nose, higher extraversion and agreeableness, and a lower degree of neuroticism. Their individual contribution was 4.9, 1.9, 4.7, 3.2 and 6.3 per cent of variability in self-esteem. The whole model accounts for 30 per cent of variability (P < 0.001). CONCLUSION: Personality traits account for a significant part of variability in self-confidence in addition to lower lip position and nose appearance, where the influence of lip position increases while that of the appearance of the nose decreases. Personality traits mediate the relationship between craniodentofacial features and self- esteem.

368 CEPHALOMETRIC ANALYSIS OF MORPHOLOGICAL CHARACTERISTICS OF CLASS II MALOCCLUSION J Pavlovic, A Vujacic, V Vukicevic, S Simic, Department of Orthodontics, University of Pristina, Kosovska Mitrovica, Serbia

AIM: Class II malocclusion are complex anomalies of the skeletal and dental systems. The aim of this study was to determine more precisely the morphological characteristics of this malocclusion using cephalometric analysis. MATERIALS AND METHOD: Pre-treatment cephalometric radiographs of 30 patients aged 18-30 years, previously clinically diagnosed with a Class II malocclusion were analysed and compared with radiographs of 30 patients with a Class I malocclusion. Three linear and two angular cranial base dimensions and nine angular and four linear measurements from the facial skeleton were analysed.

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RESULTS: There were no statistically significant differences in cranial base angle (SNBa) and anterior cranial base length (S-N) between Class II and Class I subjects. The angle of maxillary prognathism (SNA) was not significantly different between Class I and Class II, but SNB and SNPg angles were significantly smaller. The length of maxillary base (A`-SnP) was longer and the length of the mandible (Pg`-MT1/MT) was significantly smaller with an acute gonial angle (Ar-Go-Me) and larger articular angle (GoArSN). CONCLUSION: The morphological characteristics of a Class II malocclusion are: normognathic and longer maxilla, retrognathic and shorter mandible with an acute gonial angle and open articular angle.

369 OCCLUSAL STATUS OF POLISH ADOLESCENTS EVALUATED BY DIFFERENT SYSTEMS P Pełka, S Williams, K Grzegocka, J Szyper-Szczurowska, S Motyl, Department of Orthodontics, Jagiellonian University Medical College, Cracow, Poland Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 AIM: For the majority of individuals the occlusion in late adolescence should be established and reflect the success of orthodontic care and therapy during the formative years. The aim of the present study was to evaluate the occlusion of Polish late adolescent individuals who had received dental care, including orthodontics while growing up. MATERIALS AND METHOD: Evaluation of 160 sets of study models of high school students from 16 to 18 years of age from the Krakow region. All subjects who were randomly selected and demonstrated a permanent dentition, were divided into two groups according to previous orthodontic treatment, yes (80 subjects) or no (80 subjects). Evaluation of the occlusion and in particular the need for orthodontic treatment was made by three established methods. All the casts were firstly evaluated in a blind trial using the Peer Assessment Rating (PAR) index. This evaluation was performed by four independent observers and the mean of the four estimations was calculated. In a second estimation the Index of Orthodontic Treatment Need (IOTN) (dental) score for each set of models was assessed and finally the indication for orthodontic treatment was estimated according to the ‘evidence based estimation’ as recommended and used by the Danish municipal orthodontic service. RESULTS: The simplest result came from the Danish method. Of the individuals who had never received orthodontics 34 per cent (40%) exhibited an indication for orthodontic treatment, 19 per cent (16%) exhibited no indication and 46 per cent (44%) exhibited minor occlusal discrepancies which did not indicate treatment. The figures in brackets are for individuals who had received previous orthodontic treatment. Considering the IOTN index, groups 1-5 scored 24 (16%), 44 (50%), 23 (23%), 9 (9%) and 1 (3%) per cent; where the figures in brackets indicate patients who had received orthodontic treatment. The values of the PAR index tended to follow the severity of the malocclusion (IOTN) though a large degree of intergroup overlapping was observed. CONCLUSION: The occlusions of Polish adolescents reveal an amount of malocclusion seen in other European countries in younger individuals where orthodontic treatment would be forthcoming. Early orthodontic treatment does not seem to improve the situation.

370 COATING NICKEL TITANIUM ARCHWIRES WITH DIAMOND-LIKE CARBON FILMS: MECHANICAL PROPERTIES G Pérez Pastor1, A Molina Martínez1, G Martín González2, C Palazón Martínez1, Í Morales Martín3, Departments of 1Dentistry and 2Sciences, Catholic University of Valencia and 3Biomechanics Institute, Valencia, Spain

AIM: This study investigated the effects of a diamond-like carbon (DLC) coating on flexural and frictional properties of orthodontic nickel-titanium (NiTi) archwires. MATERIALS AND METHOD: Four superelastic NiTi orthodontic archwires (0.014 and 0.016 × 0.022 inches), corresponding to two commercial brands (Orthodontic Design & Production and Rocky Mountain Orthodontics) were selected. The flexibility and the resistance to sliding of the as-received and DLC-coated wires were

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evaluated with a universal testing machine. For statistical analysis a repeated measures design was used. The repeated measures factor was the ‘DLC-coating’ and intersubject factors were ‘Manufacturer’ and ‘Section’. RESULTS: Regarding flexibility, there are no differences between the as-received and coated wires for all deflection measurements (3, 2, 1 and 0.5 mm) [F (1,7) = 0.011; P = 0.920]. Orthodontic Design & Production wires had greater flexural strength than those from Rocky Mountain Orthodontics [F (1, 7) = 336.158, P < 0.005]. The as-received and coated samples showed greater rigidity for the wire section 0.016 × 0.022 inches [F (1, 7) = 53,752; P < 0.005]. Although descriptive data showed that all types of wire decreased resistance after surface coating, statistically there was no effect of treatment on sliding resistance [F (1,7) = 0.551, P = 0.482]. Both as- received and coated archwires showed differences in sliding resistance by section [F (1, 7) = 12.346, P = 0.010], which was higher for the 0.016 × 0.022 inch diameter wire. CONCLUSION: No effects were found of DLC coating in terms of flexibility. The DLC surface coating had no significant effect on sliding resistance; the resistance was the same before and after treatment. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021

371 A RE-AUDIT OF THE QUALITY OF DIGITAL LATERAL CEPHALOMETRIC RADIOGRAPHS J Perry, J Ho-A-Yun, A Puri, Victoria Hospital, Kirkcaldy, U.K.

AIM: To improve the quality of digital lateral cephalometric radiographs requested by the Orthodontic Department at Victoria Hospital, Fife, UK. MATERIALS AND METHOD: The standard was determined from a previous audit cycle in 2011, involving the Health Protection Agency (HPA) ratings of radiographic quality. It advised that a minimum of 85 per cent of cephalograms should be rated as grade one, 10 per cent as grade 2, 5 per cent as grade 2* and 0 per cent as grade 3. The extra grade 2* was added to the standard HPA ratings due to the complexity of cephalograms. Two significant changes have occurred since the previous audit. A new picture archiving and communications system (PACS) has been introduced and a new charged coupling device cephalometric machine has been installed. Thirty five consecutive radiographs requested by the Orthodontic Department starting from the 5th June 2013 were analysed. The cephalograms were viewed in blocks of 10 units at a time, by a single observer, on a 17 inch monitor with PACS software allowing visual enhancement. A proforma used for data collection was adapted from methodology set out by the Royal College of Surgeons of England to assign each image a grade from 1 to 3. RESULTS: Of the 35 radiographs analysed, 89 per cent were found to be grade 1, this represents a slight improvement from 85 per cent of radiographs rated as grade 1 in the initial cycle of the audit. The percentage of radiographs rated as grade 2 increased slightly from 10 per cent in the initial audit to 11 per cent in the re- audit. No radiographs were rated as grade 2* in the re-audit compared with 5 per cent of radiographs in the original audit. No radiographs received a rating of grade 3 in either audit. The standard set from the previous audit was achieved. CONCLUSION: Improvements in the quality of digital lateral cephalometric radiographs, following changes implemented since the previous audit have been demonstrated. Correct head positioning procedures and the importance of appropriate use of paediatric settings and collimation have been discussed at a local audit meeting for the orthodontic and radiology departments at Victoria Hospital.

372 PREVALENCE OF INCISOR ROOT RESORPTION ASSOCIATED WITH MAXILLARY CANINE IMPACTION J Petrovska1, D Petrovski2, Departments of 1Orthodontics and 2Prosthodontics, Faculty of Dentistry, University 'Sv. Kiril i Metodij', Skopje, Former Yugoslav Republic of Macedonia

AIM: An ectopically positioned maxillary canines, associated with resorption of an incisor root is a complicated anomaly that varies according to factors such as the position of the canine, lack of space and guidance and

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developmental stages of neighbouring teeth. The aim of this study was to determine the prevalence of root resorption of the central and lateral incisors when maxillary canine impaction occurs. MATERIALS AND METHOD: Radiographs of 62 patients, diagnosed with maxillary canine impaction were examined. The children were aged between 9-15 years, mean age 12.5 years and had uni- and bilateral impactions. RESULTS: The impacted maxillary canines were more uni- than bilateral, more palatally than buccally placed, and root resorption of the lateral incisors was more frequent than that of the central incisors. Detectable slight root resorptions were more often present than severe to moderate root resorption. CONCLUSION: Resorption of the incisor roots in patient with canine impaction is caused by pressure and physical contact between the root of the incisor and crown of the canine. It is fundamental to detect, prevent and to intervene early, so the complications will be reduced. Careful clinical supervision is recommended from 9 to 11 years of age. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021

373 ASSESSING THE IMPACT OF TECHNOLOGY ON MYOFUNCTIONAL MAXILLO-FACIAL MUSCLE ACTIVITY AREAS IN THE TREATMENT OF MALOCCLUSION O Petrychenko, L Konstantin, K Vasylyna, P.L. Shupik National Medical Academy of Post-graduate Education, Kiev, Ukraine

AIM: To study the bio-potentials of muscles of the maxillofacial area as a method of objective evaluation of orthodontic treatment pathology. MATERIALS AND METHOD: To treat tooth anomalies, standard devices with a myofunctional action such as: T4K, T4A, T4B, ‘Myobrace’ and individually manufactured elastoaligners were used. One hundred and eleven investigations were conducted before and after myofunctional treatment. The functional condition of the maxillofacial area was performed using electromyography (EMG). Correlation analysis of the indicators of chewing electromyography of the temporal and mentohyoid muscles was carried out. RESULTS: For the masticatory and temporal muscles a positive relationship between the amplitudes and bioelectric potentials were average, and among the parameters of duration they were strong. CONCLUSION: EMG showed that the use of myofunctional devices allows avoidance of more pressure on the masticatory muscles, lips and changes the position of the tongue, thereby contributing to growth and development of the upper jaw and a correct position of the mandible.

374 EVALUATION OF THE PRESENCE AND DEVELOPMENT OF THIRD MOLAR BUDS IN PATIENTS AGED 8-18 YEARS IN A POLISH POPULATION B Pietrzak-Bilińska1, M Bilińska2, K Małkiewicz1, M Zadurska1, 1Department of Orthodontics and 2Students’ Scientific Group at the Department of Orthodontics, Medical University of Warsaw, Poland

AIMS: To estimate, in a group of patients aged 8-9 years, the presence of the third molars buds and in a group of 10-18 years old the quantity of third molar agenesis and its association with gender, location of agenesis and the stage of development of the buds. A further aim was to examine the correlation between the degree of their formation in relation to gender, age and location. MATERIALS AND METHOD: Five hundred panoramic radiographs of patients aged 8-18 years divided into two groups. The first group consisted of 119 radiographs of patients aged 8-9 years and the second group 381 radiographs of 10-18 year olds. In the first group the presence of the third molar buds (%) was estimated. In the second group the presence or absence of the third molar buds were evaluated. The developmental stage was assessed according to the classification of Moorrees. RESULTS: The developmental phase of 1189 buds was evaluated. In the first group, 60 per cent of patients had third molar buds present on the panoramic radiographs. In the second group, agenesis of third molars was present in 27 per cent of patients. No correlation with gender or location was observed. There were no e189

statistically significant differences between gender and third molar agenesis or between the locations of buds according to gender. There was a statistically significant correlation between age and the developmental stage of the bud but no statistically significant correlation between the stage of development, gender, and location of the buds. In 13 per cent buds were observed in patients older than 10 years. CONCLUSION: To evaluate the presence of third molar agenesis, radiographic examination should not be performed in patients younger than 10 years.

375 EFFICIENCY OF RETENTION: FACTORS FOR SUCCESS AND FAILURE J Plaskacz, B Rybka, Private Practice, Rzeszów, Poland

AIM: The assessment of retention efficiency and the determination of the reasons for the diversity in the results. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 MATERIALS AND METHOD: Diagnostic models of 70 patients who completed the retention protocol used in our practice. The Peer Assessment Rating Index was measured before and after treatment as well as after 22 months after the fixed appliances were debonded. The influence of age, gender, morphological features, kind of malocclusion and type of treatment was measured as determinants of the retention results. The level of cooperation with the retention protocol was established. RESULTS: The results achieved during the retention treatment phase can be regarded as satisfactory, the level of cooperation in complying with the retention protocol was judged as unsatisfactory. CONCLUSION: The area for the greatest opportunity for improvement in retention results is in better cooperation in complying with the retention protocol. In the area where relapse is anticipated custom designed retainers should be considered.

376 SOLITARY MEDIAN MAXILLARY CENTRAL INCISOR: A REVIEW OF SIX CASES S Poelmans1, T Kawamoto2, K Devriendt3, A Verdonck1, C Carels4, 1Department of Oral Health Sciences- Orthodontics, Katholieke Universiteit Leuven and Dentistry, University Hospitals Leuven, Belgium, 2Department of Maxillofacial Reconstruction and Function, Division of Maxillofacial/Neck Reconstruction, Graduate School, Tokyo Medical and Dental University, Japan, 3Department of Human Genetics, Katholieke Universiteit Leuven and Centre for Human Genetics, University Hospitals Leuven, Belgium, and 4Department of Orthodontics and Craniofacial Biology, College of Dentistry, Radboud University Nijmegen Medical Centre, Netherlands

AIMS: To describe the dentofacial and genetic characteristics found in six patients with a solitary median maxillary central Incisor (SMMCI), and review the literature on its aetiology. MATERIALS AND METHOD: Six patients clinically diagnosed with SMMCI were documented using dentofacial and orthodontic records. In all patients, array comparative genomic hybridization (aCGH) analysis was performed for their genetic diagnosis. Medline and Embase were searched for articles on SMMCI. RESULTS: Besides a SMMCI, all types of dentofacial and occlusal variations were observed in the six patients. Moreover there was a remarkable variability of phenotypic manifestations associated with a SMMCI, ranging from mild holoprosencephaly (HPE) signs to not typically HPE-related disorders. Different ranges of intellectual disability were found in 5 out of 6 patients. With aCGH two different copy number variants (CNVs) were observed. In two patients a deletion at 18p11 was found and another patient had a deletion at 7q36. These regions respectively comprise TGIF1 and SHH genes, and these patients showed very mild HPE phenotypes. In the fourth patient no genetic alterations were found in the HPE candidate regions and no other anomalies could be detected besides the SMMCI. In patients 5 and 6 the associated clinical features deviated from the classical HPE features. SMMCI is a rare congenital dental defect (1 in 50.000 live births), which mostly represents a minor form of the clinical spectrum of HPE. Different genetic alterations have been found to be associated with isolated as well as syndromic SMMCI. These involve point mutations in the SHH-, PTCH1-, GLI2- TGIF-, SALL4-, FGF8- or SIX3-genes as well as CNVs including these genes. e190

CONCLUSION: SMMCI has a heterogeneous genetic aetiology and can represent the minor form of the broad clinical HPE spectrum or can be associated with other severe developmental disorders. If SMMCI is diagnosed in the dental/orthodontic clinic, the patient should be referred to a clinical geneticist for diagnosis and genetic counselling as even individuals with minor forms of HPE could pass on the severe form to their children.

377 THE EFFECTS OF A FACEMASK ON MALAR PROJECTION AND SOFT TISSUE O Polat, F I Ucar, Z Ileri, Z M Baka, F A Basciftci, Department of Orthodontics, Selcuk University, Konya, Turkey

AIM: To evaluate the effects of a facemask on malar projection and soft tissues on lateral cephalograms. SUBJECTS AND METHOD: Thirty three skeletal Class III patients (13 males, 20 females) who had an anterior crossbite and were treated with a facemask. Lateral cephalometric radiographs were taken before (T1) and after (T2) facemask treatment. Radiographic measurements were performed by the same investigator. In order Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 to determine soft tissue distance changes between soft pogonion, soft B point, lower lip, upper lip, subnasal sulcus, pronasale point and perpendicular to the SN plane through the S point was taken as the vertical reference plane (VR). For the malar projection the distance between the cheek bone and VR was calculated. Kolmogorov Simirnov test showed homogenous data distribution. Gender differences were evaluated by the independent sample t-test and treatment differences between T1 and T2 values were analysed by paired t-tests. RESULTS: In the soft tissue measurements only T1 (64.9 ±5.7) and T2 (67.6 ± 5.3) facemask treatment distance between the upper lip and VR were found to be significantly increased. All other soft tissue and malar projection measurements were not significant. CONCLUSION: Facemask treatment resulted in a significant difference but only on upper lip position.

378 COVARIATION OF THE SHAPE OF THE HUMAN CRANIOFACIAL COMPLEX AND FIRST MOLARS G Polychronis, D Halazonetis, Department of Orthodontics, National and Kapodistrian University of Athens, Greece

AIMS: To evaluate shape covariation of the craniofacial complex and first molars and to identify how age might affect this relationship. In addition, shape variability, allometry and sexual dimorphism of the craniofacial complex were assessed. SUBJECTS AND METHOD: Two hundred and twenty Greek subjects divided into two groups by age (110 adult, 110 prepubertal) with equally distributed gender. Dental casts and their corresponding lateral cephalometric radiographs were scanned by three-dimensional structured light and optical scanners, respectively. A comprehensive set of morphological landmarks and surface and curve semi-landmarks were placed on the maxillary and mandibular right first molar occlusal surfaces and the craniofacial complex (265, 274 and 71 landmarks, respectively). Geometric morphometric methods, including principal component (PC) and partial least squares analyses, were used to assess shape variation and covariation. RESULTS: Craniofacial complex vertical dimension was the main parameter of shape variation, followed by anteroposterior deviations. The first two PCs comprised more than half of shape variability. The male craniofacial complex was larger (4-5.7%) than the female and was characterized by a prominent chin and a clockwise rotation of the cranial base (adult group only). Allometry was weak (percentage variance explained: 2.1%, P = 0.0002) and statistically significant only when examined for the sample as a whole; mandibular prognathism was associated with increased centroid size. Covariation proved to be statistically significant only between the lower first molar and the craniofacial complex [Escoufier RV coefficient (RV) = 14.05%, RV = 12.31% and P = 0.0099, P = 0.0162, for the prepubertal and adult groups, respectively]. A Class III tendency with a large mandibular gonial angle was correlated with tooth elongation and a distolingual, mesiobuccal and distal cusp height decrease for both age groups.

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CONCLUSION: Lower first molar shape was found to covary with the shape of the craniofacial complex but covariation was weak. As age progressed, this relationship changed in a minor way probably due to environmental factors that act on the craniofacial complex.

379 EVALUATION OF RELAPSE IN THE VERTICAL PLANE –A COMPARATIVE STUDY OF HYPODIVERGENT AND HYPERDIVERGENT SUBJECTS M Popescu, O Popoviciu, O Eftene, E Ionescu, Department of Orthodontics and Dentofacial Orthopedics, University of Medicine and Pharmacy ‘Carol Davila’, Bucharest, Romania

AIM: Both a deep and an open bite display an increased level of therapeutic difficulty, related less to active treatment and more to maintenance of the results. Thus vertical relapse is common. The aim of this study was a comparative analysis of the post-treatment evolution of vertical parameters in open versus deep bite Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 adolescent orthodontic patients. SUBJECTS AND METHOD: Two groups of adolescent patients were selected, presenting a deep bite (18 subjects, mean age 13.2 years at treatment commencement) or open bite (15 subjects, mean age 14.3 years at the start of treatment). The following parameters were recorded and compared for all subjects, pre-treatment, at the end of treatment and in retention: overjet, overbite, sagittal occlusal relationship of the first molars, lower canine width (cervical and canine level) on study models and FMA, IMPA, hFA/hFP (Horn), mandibular angle, inter-incisive angle on profile cephalograms. RESULTS: A higher frequency of relapse, manifested by re-opening of the bite in subjects with an open bite and a hyperdivergent growth pattern was observed. During growth, hypodivergent deep bite subjects showed higher stability of the therapeutic outcome. CONCLUSION: The retention appliances used in open bite subjects, either fixed or removable, cannot maintain the vertical occlusal relationships.

380 EVIDENCE BASED USE OF ELASTOPOSITIONER ‘CORRECTOR’ IN PATIENTS WITH TEMPOROMANDIBULAR JOINT FUNCTIONAL DISORDERS N Popova, O Arsenina, A Popova, A Komarova, K Piksaykina, Department of Orthodontics, Central Research Institute of Dentistry and Maxillofacial Surgery, Moscow, Russia

AIM: To investigate the polyaetiology of disorders in the temporomandibular joint and to develop a diagnostic criteria and algorithm of orthodontic interventions in patients with temporomandibular dysfunction (TMD) caused by myofunctional disorders. SUBJECTS AND METHOD: Complex evaluation of 212 subjects (aged 5-40 years) with TMD and different types of malocclusions. The functional methods of examination were: electromyography of masticatory muscles, stabilometry and computerized dental occlusal analysis (T-Scan). RESULTS: Reduction of muscle activity was observed at rest after 1 month of ‘corrector; use. At 3 months there was a decline of electromyography muscle tone at rest and an improvement in the coordination of the muscles. The T-Scan showed occlusal relationship disorders before treatment. A reduction of premature contacts and an increased number of antagonist occlusal contacts was found after 3 months of using the Corrector. Stabilometry showed a reduction of energo coefficient for maintaining the posture after adaptation period. CONCLUSION: The Corrector is effective in the reduction of painful symptoms of patients with dysfunction, elimination of hypertonus and discoordination of the masticatory muscles.

381 ASPECTS OF RELAPSE IN BUCCAL ECTOPIA OF THE UPPER CANINE O Popoviciu, M Popescu, O Eftene, E Ionescu, Department of Orthodontics and Dentofacial Orthopedics, University of Medicine and Pharmacy ‘Carol Davila’, Bucharest, Romania

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AIM: Usually removable retention devices are preferred in the upper arch. In clinical practice we are often confronted with small variations in canine position in cases where active treatment included the correction of marked canine malpositions. The aim of this research was to undertake a comparative study of canine position following treatment with or without extractions in Class I and II anomalies, having as a common element the upper canine buccal ectopia. MATERIALS AND METHOD: Pre- and post-treatment and retention study models and profile cephalograms of adolescent patient treated without extractions (22 subjects, mean age 14,1 years at the beginning of treatment) and with extractions (19 subjects, mean age 14.8 years) for Class I and II anomalies, including upper canine buccal ectopia. The following parameters were recorded and compared for all subjects: sagittal position of the canine, measured on study models, from the midline to the incisive point, transverse buccal displacement of the canine from the dental archline, vertical distance of the canine cusp to the occlusal plane and FMA, IMPA, hFA/hFP (Horn), mandibular angle, inter-incisive angle measured on profile cephalograms. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 RESULTS: In most cases, at the end of treatment the canine was aligned within the dental arch and in a correct vertical position. The highest relapse was observed in the hyperdivergent patients treated without extractions, particularly to vertical displacements and mesiobuccal rotations. CONCLUSION: Fixed retention might be considered for the buccal canine ectopia, especially patients treated without extractions.

382 ORTHODONTIC ROOT RESORPTION SEVERITY IN RELATION TO PATIENT’S AGE AND GENDER C T Preoteasa, E Ionescu, E Preoteasa, Faculty of Dental Medicine, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania

AIM: Evaluation of the severity of orthodontic root resorption, in relation to age and gender characteristics. SUBJECTS AND METHOD: A cross-sectional study was conducted on patients who had undergone prior orthodontic treatment. Root shortening was assessed using serial panoramic radiographs. Group comparison was made using independent t- and Mann-Whitney tests, and correlation was evaluated using Spearman’s non- parametric test. RESULTS: Four hundred and forty upper and lower incisors (from 55 patients, of whom 41 were female) were measured. The mean root shortening observed was 1.32 mm. Most teeth presented root resorption below 2 mm (n = 344; 78%). Mean root resorption in males was statistically significantly greater than in females (t = 0.56; P = 0.003), but the difference did not present an increased real value (1.28 mm: 1.40 mm). In addition males generally presented more teeth with root resorption greater than 2 mm (mean 2.29:1.56; Mann-Whitney test ranks 34.21:25.88, P = 0.084). No significant correlation was found between the severity of root resorption and age, but in patients below 19 years, root resorption severity was more uniform compared with other age groups. In patients older than 19 years, the most severe and least severe forms of root resorption were encountered, which may suggest that individual susceptibility plays a more important role of this complication in older patients. CONCLUSION: Orthodontic root resorption is a complication that is of decreasing severity, which may depend on general factors such as age and gender.

383 FUNCTIONAL AND MORPHOLOGICAL CHARACTERISTICS OF MALOCCLUSION IN PREMATURELY BORN SUBJECTS J Primozic1, F Farcnik2, J Primozic3, 1Department of Orthodontics and Dentofacial Orthopaedics, University of Ljubljana, 2Orthos, Institute of dental and maxillofacial orthopaedics, Ljubljana and 3Izola General Hospital, Slovenia

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AIM: To evaluate the influence of premature birth on the prevalence of functional and morphological characteristics of malocclusion in the primary dentition phase, considering also confounding variables, such as type of feeding and oral habits. MATERIALS AND METHOD: Through questionnaires and clinical examinations of 80 prematurely born subjects (42 females, 38 males, aged 24.46 ±1.77 months) and 113 controls (50 females, 63 males, aged 25.42 ±2.64 months) in the primary dentition phase data about feeding modalities, sucking habits and functional and morphological characteristics of malocclusion was collected and the two groups were compared for differences (chi-square test). Further, logistic regression analysis was used for risk assessment. RESULTS: The prevalence of functional and morphological characteristics of malocclusion in the primary dentition phase was not significantly different (P > 0.05) in prematurely born children as compared with the controls and premature birth was not a risk indicator for any functional or morphological characteristics of malocclusion. The main significant risk indicators for morphological malocclusion characteristic of a Class II Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 division 1 malocclusion were dummy (OR = 3.13; P < 0.01) and thumb sucking (OR = 4.41; P < 0.05), while dummy sucking alone was a risk indicator for anterior open bite (OR = 12.19; P < 0.001), regardless of prematurity. CONCLUSION: The prevalence of functional and morphological characteristics of malocclusion in the primary dentition phase was not significantly different in prematurely born children and premature birth was not a risk indicator for any functional or morphological characteristics of malocclusion.

384 A COMPARATIVE ASSESSMENT OF PERCEPTION OF FACIAL PROFILE AESTHETICS A Puigdollers1, D Fernandez-Alvarez1, A Molina1, Mª B Ruiz-Navarro2, E Espinar2, Departments of Orthodontics, 1Universidad Internacional de Cataluña, Barcelona and 2Universidad de Sevilla, Spain

AIM: To evaluate the perception of facial attractiveness in 86 profile digital images. The specific aim was to determine whether there is concordance between different groups of observers in their perceptions of facial profile attractiveness. MATERIALS AND METHOD: Profile digital black and white images were used. One hundred silhouettes with different skeletal pattern were mixed and booklets were created. Forty-eight examiners (12 orthodontists, 12 oral surgeons, 12 orthodontic postgraduate students and 12 laypersons) scored the profiles on a visual analogue scale. RESULTS: Intraexaminer reliability was good (P = 0.09), and general concordance was found between groups in their perceptions of facial attractiveness. Orthodontists were the most critical in rating attractiveness. A profile with slight lip protrusion and correct chin projection was classified as the most attractive profile. On the other hand the least attractive was a profile with a lack of chin projection (skeletal Class II). CONCLUSION: The preferences of facial attractiveness were generally in disagreement.

385 APPS FOR SMARTPHONES: POTENTIAL AND USEFULNESS IN ORTHODONTICS A Putrino1, M R Abed2, C Candido1 V Calace1 G Galluccio2, 1Post-Graduate School in Orthognatodontics and 2Department of Oral and Maxillo Facial Sciences - Sapienza University of Rome, Italy

AIM: The rapid and continuous evolution of mobile technology is changing our profession and life. Smartphones, tablets and other portable devices allow orthodontists to enter patients’ records easily and everywhere. Patients may benefit from orthodontic apps (OA), improving therapy and its results. MATERIALS AND METHOD: English, German, Spanish and Italian OA on the main operating systems (Apple, Blackberry, Android, Windows) and scientific literature (PubMed Database) were reviewed concerning this topic, distinguishing programmes for patients and clinicians (Key words: braces, orthodontic, orthodontist). They were tested on four mobile devices (Samsung GalaxyII, Blackberry Z30, IPad2, Nokia Lumia).

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RESULTS: From 250 initial apps 27.5 per cent were for orthodontists (products, meetings, publications and tooth ratio calculators) and 20 per cent for patients (elastic and aligners reminders, products, therapeutic progresses, orthodontic emergencies). The remaining 52.5 per cent were not OA but games or advertisement for private dental activities. CONCLUSION: Care of problems related to privacy especially with underage patients as OA are catchy programs with a high potential to become useful tools supporting therapy time and orthodontic practice. In this perspective we are going to develop apps designed for us and our patients.

386 EXPECTATIONS FOR ORTHODONTIC THERAPEUTIC RESULTS AND PERCEPTION OF FACIAL AESTHETICS USING A DIGITAL MORPHING TOOL A Putrino1, M R Abed2, S Migliaccio1, A Silvestri2, G Galluccio2, 1Post-Graduate School in Orthognatodontics and 2Department of Oral and Maxillo Facial Sciences - Sapienza University of Rome, Italy Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021

AIM: Morphing can be useful to elicit profile facial aesthetics preferences in orthodontic patients. This study aimed to determine general aesthetic preference and to find out whether it was affected by gender, age or personal profile. MATERIALS AND METHOD: The English language literature on PubMed (Keywords: morphing, video imaging, facial aesthetics) was reviewed. Thirty patients (12-20 years old; 15 males; 15 females) at the early stage of therapy were selected. Using Viewbox Software Version 3.1.1 a series of four distinct images from initial lateral cephalograms and photographs translated into soft-tissue changes of the nasal tip and third lower of the face were digitized. They were asked to evaluate their and other patients ’morphed photographs. Independent sample t-tests and analysis of variance (ANOVA) were used to compare the preferences of the patients divided for gender and age. RESULTS: Both genders preferred the orthognathic profile whereas convex and concave profiles were the least preferred. Age, contrary to the own patient’s profile, did not seem to have any influence. CONCLUSION: Patients have high expectations of orthodontic treatment. Explaining its limits and viewing possible results prevents disappointments. Self-perception and opinions on attractive facial traits should be never neglected by orthodontists.

387 MINISCREW STABILITY: A SYSTEMATIC REVIEW*** A Putrino, C Lilli, E Barbato, G Galluccio, M R Abed, Postgraduate School in Orthognatodontics, Sapienza University of Rome, Italy

AIM: This systematic review aimed to define the factors associated with miniscrew stability such as characteristics, clinical and patient factors. MATERIALS AND METHOD: Pubmed was screened for the following eligibility criteria: papers published between 2005 and 2012, concerning miniscrews used only as orthodontic anchorage, human and in vitro studies, prospective and retrospective clinical studies, meta-analysis, reviews and systematic reviews. RESULTS: Fifty four articles met the inclusion criteria: the literature varied in sample selection, methodology and success/stability definition. Miniscrew failure was related to their insertion in/close to anatomical structures, so the choice of insertion site and miniscrew characteristics depends on bone quality and quantity . The experience of the clinician in the surgical procedure plays a fundamental role in miniscrew success. CONCLUSION: The heterogeneity of the literature does not permit an unequivocal answer to the posed questions; more studies are needed.

388 EVALUATION OF SKELETAL STRUCTURES IN PATIENTS WITH A SECONDARY CLEFT PALATE TREATED IN EARLY CHILDHOOD B Racka-Pilszak, A Wojtaszek-Słomińska, Department of Orthodontics, Medical University of Gdansk, Poland e195

AIM: To evaluate the craniofacial morphology of patients with a cleft of the secondary palate. MATERIALS AND METHOD: Standard cephalometric radiographs of 64 patients with a cleft of the secondary palate, aged 7 to 14 years, treated in early childhood. The control group consisted of 56 children aged 7-14 years with no congenital defects in the facial part of the skull and with a normal bone relationship. Study subgroup (B1) and the control subgroup (K1) included patients aged 7 to 10 years. Study subgroup (B2) and the control subgroup (K2) included patients aged 10-14 years. In both groups, craniofacial morphology and changes of the soft tissues were analyzed on the basis of the cephalometric radiographs. All the data collected were statistically were analyzed. RESULTS: Compared with the control group, in both subgroups of children with congenital defect a significant statistical retrusion and length shortening of the jaw were observed. Posterior rotation of the mandible, due to a significant mandibular as well as NS/ML angle increase and anterior/posterior face height ratio reduction was Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 observed. The inclination the angles of the upper and lower incisors were smaller in the research group than in the control group. No adverse changes in the soft tissue profile of patients with a cleft of the secondary palate (probably because of the upper lip width increase) were observed. CONCLUSION: It can be concluded that a cleft of secondary palate causes developmental and growth changes of the facial part of the skull. In the above group shortening and retrusion of the jaws as well posterior rotation of the mandible was observed. 389 A MULTI-CYCLE AUDIT OF THE QUALITY OF ORTHODONTIC CLINICAL PHOTOGRAPHY S Radia, G Mack, King’s College Hospital, London, U.K.

AIM: High quality photography is essential for case presentations and medico-legal purposes. The objectives of this audit were to assess the standard of clinical photographs taken by first year orthodontic trainees, and to identify and address common errors early in the training pathway. MATERIALS AND METHOD: A retrospective audit carried out with cycles 1 and 2 from October to December 2011 and 2012, respectively. The gold standard was that 90 per cent of clinical photographs should be of an acceptable standard meeting the Institute of Medical Illustrators National Guideline criteria. In cycle 1, one independent assessor retrospectively evaluated 30 sets of randomly selected clinical photographs taken by year 1 trainees. Each set contained nine pre-treatment photographs stored on a database. Each photograph was ranked on a scale of 1-4 and thereafter graded ‘acceptable’ or ‘unacceptable’. Errors were identified, and detailed training and equipment changes were implemented. In cycle 2, the same assessor evaluated 40 random sets of photographs using the same methodology. RESULTS: A total of 600 photographs were assessed with only 88 per cent of photographs graded acceptable within cycle 1, but implemented changes improved the evaluated quality to 98 per cent in cycle 2. CONCLUSION: Specific training and equipment provision allowed improvement of the quality of year 1 trainee photographs to exceed the gold standard. Further development and training and further audit are required to maintain the enhancement of this key clinical skill within future intakes of trainees.

390 EFFECT OF AN ORTHODONTIC BITE CORRECTOR APPLIANCE ON STABILITY AFTER LE FORT I MAXILLARY ADVANCEMENT A Raouf Khalifa1, A Aboel ezz2, S Shahen3, Orthodontic Departments, 1Six October University, 6 october, 2Cairo University, Giza, and 3Dentist/software designer, Giza, Egypt

AIM: To evaluate the effect of an orthodontic bite corrector appliance on stability of the skeletal tissues after Le Fort I maxillary advancement, using a recent method of three-dimensional (3D) analysis. SUBJECTS AND METHOD: Twelve adults (4 females, 8 males), with a skeletal Class III malocclusion with maxillary deficiency. All patients underwent a LeFort I maxillary osteotomy to reposition the maxilla forwards. Rigid fixation with bone plates and screws was used in all subjects to stabilize the maxilla. All patients had pre- and e196

post-surgical orthodontic treatment. The sample was divided after surgery into two groups, each consisting of six patients: test group patients (appliance group) and control group patients (no appliance group, using vertical elastics). Hard tissue changes and stability after Le Fort I maxillary advancement were analyzed pre-surgery, within 4 weeks post-surgery and 6 months post-surgery. Analyses was made using 3D cone beam computed tomography fully automated superimposition based on the cranial base and all measurement were done by projection on Frankfort horizontal. RESULTS: There was no significant difference between the test and control groups for point A, ANS, PNS, AFH and SNA angle. CONCLUSION: There was excellent post-operative stability of Le Fort I maxillary advancement in skeletal Class III, with maxillary deficiency. The twin force bite corrector appliance had no statistical significance on stability at 6 months post-operative to Le Fort I maxillary advancement. Fixation plates and light vertical elastic were sufficient to stabilize the Le Fort I maxillary advancement. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021

391 EVALUATION OF THE SIZES OF THE REMAINING DENTITION IN PATIENTS WITH HYPODONTIA AGED 12 TO 16 YEARS A Reshitaj1, M Sejdini1, S Krasniqi1, X Mulo2, Department of Orthodontics, 1University of Pristina, Kosovo and 2University of Tirana, Albania

AIM: To evaluate the mesiodistal crown sizes of the remaining dentition in patients with hypodontia compared with a control group with a complete dentition. MATERIALS AND METHOD: Intraoral photographs of treated patients were reviewed to select a sample of 22 cases with agenesis of one or more permanent teeth except third molars (hypodontia group). The control group included 22 consecutive patients with a complete dentition. The patients ranged in age from 12 to 16 years. Statistical calculation was performed using SPSS 15.0. A paired samples t-test was used to detect statistical differences in tooth width measurements between the two groups. The significance level was predetermined at α = 0.05. RESULTS: The mean age of patients in the hypodontia group was 14.55 ± 1.57 years and in the control group 14.23 ± 1.11 years. The most common congenitally missing teeth were the upper lateral incisors (46.16%) followed by the upper first premolars (11.54%). Significant between group differences were found for the maxillary central incisors and right maxillary molar quadrant, while in the left quadrant differences were observed for the central incisor (P < 0.05). No significant differences between the groups were found for tooth size in the lower jaw. CONCLUSION: A reduced tooth size was evident except for the right posterior molar in the hypodontia group. This should be considered during treatment planning when deciding on treatment mechanics in order to achieve a functional occlusion and an aesthetic dentition at the end of orthodontic treatment.

392 PRELIMINARY DATA OF A TRANSPLANTATION SURVEY IN A UNIVERSITY ENVIRONMENT: A RETROSPECTIVE STUDY M F Ronchetti1, S Valec2, M Locher2, H van Waes1, 1Department of Orthodontics and Pediatric Dentistry and 2Clinic of Cranio-Maxillofacial and Oral Surgery, Center of Dental Medicine, University of Zurich, Switzerland

AIMS: To determine survival and failure rates one year after tooth transplantation and to evaluate the reasons for early failures. Moreover differences between molars and premolars were analysed as well as the potential benefit of enamel matrix proteins (Emdogain®) applied on the root surface immediately before transplantation. SUBJECTS AND METHOD: Twenty nine patients who had had a tooth transplanted. A total of 36 teeth, namely 28 premolars and eight molars, were transplanted by three different paediatric dentists and one oral surgeon. Statistical analyses of survival and success rates after one year, the latter being defined as survival with no

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periodontal, ankylotic or resorptive issue, were calculated. Moreover the influence of factors such as endodontic treatment, apex width at transplantation, transplantation site and use of Emdogain® were analysed using a Chi2-test. RESULTS: The overall survival rate after one year was 91.7 per cent, the success rate being 80.6 per cent. Premolars showed a higher survival (96.4%) as well as success (96.4%) rate than molars (75%/25%), but only the success rate showed a statistically significant difference between the two groups (P < 0.000) contrary to the one year survival rate (P = 0.053). Three teeth were lost during the first year: two for periodontal reasons and one because of ankylosis. Seven teeth could not be regarded as successfully transplanted as two showed ankylosis, four periodontal breakdown and one root resorption. None of the measured factors such as endodontic treatment (P = 0.468), use of Emdogain® (P = 0.217), apex width at transplantation (P = 0.096) or transplantation site (P = 0.297) had an impact on one year success rate. CONCLUSION: The data confirms, as already shown in previous studies, the transplantation of premolars to be a Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 reliable and well predictable procedure. However the results do not support the same statement for transplantations of permanent molars. No beneficial effect of Emdogain® could be shown.

393 DOES CLINICAL EXPERIENCE AFFECT THE REPRODUCIBILITY OF THE CERVICAL VERTEBRAE MATURATION METHOD? R Rongo, R Bucci, A Manfredonia, R Valletta, V D'Antò, Section of Orthodontics, University of Naples ‘Federico II’, Italy

AIM: The cervical vertebrae maturation method (CVMM) has been advocated as a predictor of peak mandibular growth. The aim of this study was to assess intra- and interobserver reproducibility of CVMM among three panels with different levels of orthodontic experience. MATERIALS AND METHOD: Fifty individual lateral cephalograms of good quality, of 25 male and 25 female subjects, representing all six CVMM stages, with complete visualization of the cervical vertebrae 1 through to 4, were selected. Thirty practising orthodontists, equally divided according experience (EX) Junior Group (JU): EX≤1 year; Postgraduate Group (PG): 2≤EX≤4 years, Specialist Group (SP): EX>7 years, evaluated the cephalograms in two sessions three weeks apart (T1 and T2). Statistical analysis was conducted to evaluate Kendall’s W coefficient for interobserver agreement and weighted Cohen’s kappa (κ) coefficient for the intraobserver agreement. The percentage of intra- and interobserver disagreement for each judge was calculated. RESULTS: For interobserver agreement Kendall’s W varied from 0.61 to 0.87 with the best results in JU. Cohen’s κ was found to be between 0.24 and 0.81; again the best performances were achieved by JU. The percentage of intraobserver disagreement was 45.8 per cent but in 75.8 per cent the errors on cervical staging were just one stage apart. The percentage of interobserver agreement was of 42.3 per cent at T1 and 46.3 per cent at T2. CONCLUSION: The reproducibility of the method was not influenced by clinical experience. The CVMM was identified as a reliable instrument for the evaluation of skeletal maturation.

394 IDENTIFICATION OF A NOVEL MUTATION IN THE EDA GENE ASSOCIATED WITH NON-SYNDROMIC OLIGODONTIA G Ruiz Heiland1, S Jabir1, N Bock1, D Nolte2, S Ruf1, Departments of 1Orthodontics and 2Human Genetics, Justus- Liebig University, Gießen, Germany

AIM: Mutations in the EDA gene are commonly associated with X-linked hypohydrotic ectodermal dysplasia. Recently, mutations in this gene have been associated with non-syndromic tooth agenesis. In the present study a novel EDA mutation in two brothers presenting oligodontia is described. SUBJECTS AND METHOD: Two brothers suffering from oligodontia without clear syndromic features as well as their available relatives were analyzed. A total of eight family members (Patients A-H) were evaluated. e198

Genomic DNA of all subjects was isolated from saliva. Genetic screening was performed by means of direct sequencing of polymerase chain reaction (PCR) fragments covering the entire coding regions and the intron exon junctions of the EDA gene, as well as the WNT10a gene. Mutation analysis was performed using the Mutations Surveyor Software. RESULTS: A novel G to A mutation located in exon 7 at nucleotide position 866 (c.866G>A) was identified in the EDA gene. The nucleotide change resulted in the substitution of an arginine by a histidine (P.R289H). This mutation was inherited maternally. The two brothers (Patients A and B) presented few signs of skin abnormalities and wiry hair. Patient A had six missing teeth with a tooth agenesis code (TAC) sum of 10 (TAC quadrant values 2, 2, 3, 3) while his younger brother (Patient B) had agenesis of 23 permanent teeth. The TAC sum of this subject was 66 (TAC quadrant values 14, 14, 19, 19). The pedigree evaluation indicated that the mother (Patient C) of both individuals presented no dental abnormalities or agenesis whereas her deceased father had suffered from oligodontia. The mother has two more children with a second partner: a son Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 presenting a normal dentition (Patient D) and a daughter with hypodontia (Patient E). The mother has one sister (Patient F) who did not show any tooth agenesis like her two daughters (Patients G and H). CONCLUSION: The EDA signalling pathway plays a key role during tooth formation. Here, a novel EDA gene mutation concomitant with Oligodontia is shown.

395 MOST USED RETENTIONS AMONG ORTHODONTISTS IN SPAIN - A SURVEY D Sànchez, J Mendes, J M Ustrell, Department of Orthodontics, University of Barcelona, Spain

AIM: To identify the most used methods of retention among orthodontists in Spain given their years of professional experience, genre, usage time, treated arch and trends over the past 5 years. MATERIALS AND METHOD: The research was conducted via an electronic survey. Nine hundred and eighty five surveys were sent to practicing members of the Spanish Society of Orthodontists and to several University Masters of Orthodontics in Spain. All statistical analysis was made using SPSS software. RESULTS: A total of 310 surveys were answered. Clear thermoplastic was the most used retainer in the upper arch (72%). In the lower arch a bonded lingual retention was mostly used (76%) usually from canine to canine. Seventy eight per cent of orthodontists stated not to have changed their retainer choice during the last five years. CONCLUSION: Orthodontists with >20 years of experience use more Hawley retainers than new graduates. Clear thermoplastic removable retainers are mostly used in the upper arch. A lingual bonded, canine-to-canine, braided steel wire retainer is used, in most cases, for the lower arch. Retention is prescribed for >2 years. Those who changed their retainer preferences during the past five years shifted away from Hawley towards clear thermoplastic retainers.

396 BUTOXAMINE, A SELECTIVE ß2-ADRENOCEPTOR ANTAGONIST, PREVENTS ORTHODONTIC TOOTH MOVEMENT VIA THE SYMPATHETIC NERVOUS SYSTEM T Sato1, K Miyazawa1, Y Suzuki1, A Togari2, S Goto1, Departments of 1Orthodontics and 2Pharmacology, Aichi- Gakuin University, Nagoya, Japan

AIM: Recently, involvement of the sympathetic nervous system in bone metabolism has attracted attention. ß2-adrenergic receptor (ß2-AR) is present on osteoblastic and osteoclastic cells. It has previously been demonstrated that ß-AR blockers, at low dose, improve osteoporosis with hyperactivity of the sympathetic nervous system via ß2-AR blocking. In this study, the effects of butoxamine (BUT), a specific ß2-AR antagonist, on tooth movement were examined in spontaneously hypertensive rats (SHR) showing osteoporosis with hyperactivity of the sympathetic nervous system.

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MATERIALS AND METHOD: Groups of SHR and Wistar-Kyoto rats (WKY) were administered BUT at a dose of 1 mg/kg (P.o.). SHR and WKY controls were administered saline in the same way. After sacrifice, the distance of tooth movement, trabecular microarchitecture, and histomorphometry analysis were calculated. RESULTS: The distance in the SHR control was longer than that in the WKY control. No significant difference was found in the SHR treated with BUT compared with the WKY. Analysis of bone volume per tissue volume, trabecular number, and osteoclast surface per bone surface in the alveolar bone showed clear bone loss by an increase of bone resorption in SHR. In addition, BUT treatment resulted in a recovery of alveolar bone loss. Furthermore, tyrosine hydroxylase (TH)-immunoreactive nerves in the periodontal ligament were increased by tooth movement, and BUT administration decreased TH-immunoreactive nerves. CONCLUSION: These results suggest that the sympathetic nervous system is involved in tooth movement, and prevents alveolar bone loss and orthodontic tooth movement. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 397 PATIENTS’ AND THEIR GUARDIANS’ PERSONALITIES AS RELIABLE PREDICTORS OF OBJECTIVELY VERIFIED COMPLIANCE DURING TREATMENT WITH REMOVABLE APPLIANCES M Sarul1, B Jarco-Lewandowska2, A Kozanecka1, B Kawala1, J Antoszewska1, 1Department of Orofacialorthopaedics and orthodontics, Medical University of Wroclaw and 2Department of Psychology, University of Wroclaw, Poland

AIM: Patient compliance is a key factor contributing to the effectiveness of treatment with removable appliances. Electronic systems verifying true wear time of the devices allow an objective assessment of the patient’s cooperation. The level of the latter may be influenced by many factors, one of the most important of which is the patient’s and/or their guardian’s character. The aim of the study was to evaluate the effect of selected personality characteristics on the level of cooperation during treatment with removable appliances, measured objectively with Thera Mon sensors. SUBJECTS AND METHOD: Forty patients treated with removable appliances. The Thera Mon sensors mounted in the appliances were to measure the true wear time. A psychologist assessed patient’s and/or their guardians characteristics using personality tests (NEO-FFI, the GSEs, EAS-C). Pearson’s correlation coefficient and regression analysis, the level of statistic significance at P < 0.05 enabled the relationship between the assessed variables and the patient’s cooperation to be determined. RESULTS: There was a positive relationship between the guardians’ personality traits, such as conscientiousness, self-effectiveness, acceptance and high expectations from the child, and wear time of the appliance. The child’s sense of perseverance, as well as shyness also positively influenced compliance. In turn, high levels of neuroticism and guardians’ inconsistency, along with the child’s high activity had a negative impact on the level of cooperation. CONCLUSION: Assessment of the character of patients and, particularly, their guardians may allow prediction of the level of cooperation in terms of using removable orthodontic devices. Further studies will allow accurate assessment, the psychological predictors of cooperation and development of a programme supporting patients and their guardians whose cooperation is necessary for effective treatment with removable appliances. Thera Mon sensors are valuable tools for research since they allow objective control of a patient’s compliance.

398 QUALITATIVE REVIEW OF THE LAST 10 YEARS OF IN VITRO STUDIES ON SLIDING RESISTANCE IN ORTHODONTICS F Savoldi, D Dalessandri, C Paganelli, Department of Orthodontics, Dental School, University of Brescia, Italy

AIM: The literature on low friction is extensive, but primarily aimed at comparing materials available on the market and not their different properties. The aim of this review was to compare the last 10 years of literature

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on resistance to sliding. Different types of materials on the market were not investigated; the aim was to identify the quality of the studies in finding the variables that actually contribute to friction. MATERIALS AND METHOD: The data were collected from computer sources and from references in the articles. Only in vitro studies with tests on the friction between the wire and bracket, published after 2003, were selected. Each study was analyzed, filling in a table of evaluation criteria and a table of variables, to compare the methods used and the variables investigated in the 20 selected studies. RESULTS: Thirty per cent of articles did not state the P value used in statistical analysis, 50 per cent the method used to align the slots of the brackets, 70 per cent the parameter used to evaluate static friction, 75 per cent the parameter used to evaluate dynamic friction and 25 per cent the material used to fix the bracket on the support. Many variables that might contribute to the resistance to sliding, were ignored: 30 per cent did not state the width of the wire, 63 per cent the distance between two or more brackets, 65 per cent the temperature of the room where the experiment was undertaken, 45 per cent the length of the test, 50 per cent the amount of Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 misalignment, 45 per cent the angulation of the bracket slot in the third order, 45 per cent the type of ligatures used, 85 per cent the frequency of data acquisition, 95 per cent analysis of the bracket shape and 80 per cent analysis of the bracket surface. CONCLUSION: Under the term ‘friction’, authors sometimes researched very different aspects, using protocols more suitable for other characteristics. The quality of the studies did not allow a quantitative analysis. Variables must be selected more carefully, avoiding the overlap of too many contributing factors. A stricter and more detailed protocol would be useful in clarifying this complex topic.

399 RADIOLOGICAL ASSESSMENT OF THE POSITION OF IMPACTED MAXILLARY CANINES AND PREMOLARS WITH CASE PRESENTATION OF SPONTANEOUS ERUPTION OF IMPACTED TEETH M Sawicka, A Wojtaszek-Słomińska, Department of Orthodontics, Medical University of Gdansk, Poland

AIM: Eruption disturbances of the maxillary canines and premolars are a frequent clinical problem that often requires an interdisciplinary approach. In some cases self-eruption occurs after extraction of the primary tooth, providing sufficient space. The aim of this study was to investigate the radiographic position of impacted canines and premolars of patients with eruption problems in the lateral arch segments. MATERIALS AND METHOD: Panoramic radiographs of 31 patients with 37 impacted upper canines and 10 premolars were analyzed. The eruptive position of the impacted maxillary canines and first or second premolars were assessed according to the following radiographic parameters: inclination of the long axis of the impacted canines (α angle) and premolars (π angle) to the upper mIdline and to the long axis of the adjacent permanent maxillary lateral incisors (β angle), the mesiodistal position of the canine crown in sectors 1 to 5 and the height of the impacted canines. Three panoramic radiographs and measurements of impacted canines and premolars that erupted spontaneously are presented. The radiographic variables were measured twice, with a 2 week interval, by a single operator on all radiographs. RESULTS: Thirty five per cent of canines (13 canines) were impacted in sector 4 and 29.7 per cent (11 canines) in sector 3, only two canines were positioned in sector 5. The mean α angle was 36.79 degrees, β angle was 41.17 and the mean distance from the occlusal plane to the canine tip equalled 17.95. The mean π angle was equal to 36.3 degrees to the upper midline and all examined premolars erupted without surgical intervention. CONCLUSION: Panoramic radiography is a good tool for assessment of the positions of canines and premolars. More research is needed to establish if radiographic parameters can be prognostic indicators of spontaneous eruption of impacted teeth in the lateral arch segments.

400 FLOATING NORMS FOR CEPHALOMETRIC INDICES OF SAGITTAL DISCREPANCY A Scalia, M Ceschi, G Perinetti, L Contardo, Department of Medical, Surgical and Health Sciences, University of Trieste, Italy

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AIM: To evaluate whether indices of sagittal discrepancy are correlated with facial divergence and subsequently to elaborate floating norms related to individual skeletal patterns. SUBJECTS AND METHOD: One hundred and nineteen subjects (74 females, 45 males) with an ideal occlusion (mean age, 11.2 ± 1.5 years; range, 8.2-14.0 years). A multiple regression analysis was run to associate vertical and sagittal craniofacial measurements (SNA, SN/PP, SN/MP and NS-Ba angles) with ANB angle, beta angle and MMBP Wits. RESULTS: ANB angle was significantly associated with all the explanatory variables. On the contrary, both beta angle and MMBP-Wits were significantly associated only with SNA and SN/MP angles. Floating norms were derived for beta angle and MMBP-Wits according to the variations of SNA and SN/MP. CONCLUSION: Indices of sagittal discrepancy are, in different ways, influenced by craniofacial variability. Floating norms may be a reliable procedure to obtain individual cephalometric norms that consider variations of the craniofacial complex. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021

401 A FIVE-YEAR FOLLOW-UP STUDY OF ORAL HEALTH-RELATED QUALITY OF LIFE AND ORTHODONTIC TREATMENT WITH CLEAR ALIGNERS I Schaefer1, J Schwarze2, B Braumann1, 1Department of Orthodontics, University of Cologne, and 2Private Practice, Cologne, Germany

AIM: There is little evidence about long-term patient-based outcomes of orthodontic treatment. This longitudinal follow-up study examined the oral health-related quality of life (OHRQoL) among adults who started orthodontic treatment with the Invisalign® system in 2008. Furthermore, patients´ self-report of their oral health and their satisfaction with the orthodontic treatment was evaluated five years after the start of treatment. SUBJECTS AND METHOD: A prospective longitudinal study was adopted in 2008. Thirty one patients (7 males, 24 females; mean age: 36 years) with good periodontal health initially participated. Patients answered a questionnaire prior to (T0) as well as during their active orthodontic treatment (T1; on average 3.5 months after T0). As a part of this follow-up study, the patients were asked to complete the questionnaire once more, five years after T0 (T2; on average 3.6 years after finishing active orthodontic treatment). The questionnaires contained previously validated questions extracted from the German short form of the Oral Health Impact Profile (OHIP-G 14) as well as questions regarding patient-reported oral health status extracted from questionnaires of the Forth German Oral Health Study (DMS IV). In addition to that, patients were asked to rate their satisfaction with the treatment outcome. Descriptive statistics were used to analyze the findings. RESULTS: A response rate of 94 per cent was obtained in this follow-up study. OHRQoL improved from 2008 (T0) to 2013 (T2). Initial impairment of OHRQoL (T0-T1) was mainly due to pronunciation issues and perceived pain. At T2 no impairment on OHRQoL was found. Parameters of self-reported oral health status such as oral hygiene habits were good at T0, improved throughout the treatment (T1) and remained excellent at T2. All patients reported a greater satisfaction with their dental condition at T2 compared with T0 and T1. At T2 86 per cent of the patients were `very satisfied´ and 14 per cent were `satisfied´ with the long-term treatment outcome. CONCLUSION: This study shows that OHRQoL, patient-reported oral health status as well as long-term satisfaction seem to be at a high level five years after the start of orthodontic treatment with the Invisalign® system.

402 INFLUENCE OF RAPID MAXILLARY EXPANSION ON THE POST-PUBERTAL MIDPALATAL SUTURE: A COMPARATIVE LOW-DOSE COMPUTED TOMOGRAPHIC STUDY ON RETENTION TIME M Schauseil1, B Ludwig2, B Zorkun3, H Korbmacher-Steiner1, 1University of Marburg, 2Private Practice, Traben- Trarbach, Germany and 3Sivas Merkez, Turkey

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AIM: Rapid maxillary expansion (RME) is a common technique to improve the dental and skeletal transverse width in subjects with constricted maxillary arches. Although retention after RME has been widely examined there is still no clear statement about the minimal retention time in post-pubertal patients and many practitioners have retention concepts varying between 3 and 6 months. SUBJECTS AND METHOD: This retrospective study comprised 14 patients who were either treated with a Haas- type RME (6 patients) or a hybrid-RME (8 patients). The mean age was 15.8 years (minimum 13.5 years, maximum 23.0 years). Low-dose computed tomographic (CT) scans were taken before placement of the RME (T0), directly after maximal activation (T1) and (in 6 cases) also in retention after 6 months (T2). Analyses of the data sets was performed blinded using a free trial of the software ‘OnDemand3D’ in analogy to the method published by Franchi et al. (2010). All values were measured twice with an interval of 1 month to assess the method error and intraoperator reliability. Statistical analysis was performed using SPSS 21 for Mac. Possible Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 influences of RME type were assessed using univariate ANOVA. Changes in the sutural density between the different time points were examined using paired t-tests. RESULTS: The density of the suture decreased significantly after expansion (T0-T1) with both types of RME (P = 0.000). In the retention period there was a significant increase of sutural density (P = 0.007) although it did not achieve the initial level (P = 0.002). CONCLUSION: 1. In post-pubertal subjects RME leads to an initial decrease of sutural density. 2. Although patients were older, the hybrid-RME was able to open the suture and to decrease the density to a similar level as the conventional RME in the younger patients. 3. Particularly in post-pubertal patients a retention time of more than six months seems to be beneficial to prevent relapse.

Franchi L, Baccetti T, Lione R, Fanucci E, Cozza P 2010 Modifications of midpalatal sutural density induced by rapid maxillary expansion: A low-dose computed-tomography evaluation. American Journal of Orthodontics and Dentofacial Orthopedics 137: 486-688

403 THE INFLUENCE OF LIGHT INTENSITY AND EXPOSURE TIME OF DIFFERENT LIGHT CURING UNITS ON THE SHEAR BOND STRENGTH OF ORTHODONTIC BRACKETS J Schumacher1, S Soika1, F-J Faber2, B Braumann1, 1Department of Orthodontics and 2Center of Dental Medicine, University of Cologne, Germany

AIM: To investigate the shear bond strength (SBS) of compounds made of tooth enamel, adhesive and brackets for certain polymerisation modes of light curing units (LCUs) of different light intensity in order to test the efficacy of maximum intensity light emitting diode (LED) LCU with reduced polymerisation times for clinical use. MATERIALS AND METHOD: The SBS of orthodontic brackets on permanent bovine incisors, achieved by polymerisation with two maximum intensity LCUs was examined. The polymerisation modes were 3 seconds with 4000-5000 mW/cm² (Flashmax P3 light pen®, RMO, Denver, Colorado, USA) and 6 seconds with 3200 mW/cm² (Valo®, Ultradent, South Jordan, Utah, USA). The maximum intensity LCUs were compared with an established high intensity LCU as reference, using as polymerisation mode 20 seconds with 800 mW/cm² (Bluephase® G2, Ivoclar Vivadent, Schaan, Liechtenstein). Transbond XT™ (3M Unitek, Monrovia, California, USA) was chosen as the adhesive and Discovery® brackets (Dentaurum, Ispringen, Germany) were used as attachment. According to the DIN 13990-2 standard, the teeth were embedded, adhesive and bracket were applied and then put into storage. This was followed by shear tests in a material testing machine (Zwick ZMART.PRO; Zwick, Ulm, Germany) with the shear force acting directly on the bracket base in the occlusal gingival direction. Finally the Adhesive Remnant Index was determined. Statistical significance was tested by one-way ANOVA and Duncan's post-hoc test (P < 0.05).

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RESULTS: The greatest SBS was observed after polymerisation with the reference LCU Bluephase® C8 (42.24 ± 16.27 N/mm²) and lowest after polymerisation with Flashmax P3® (13.95 ± 4.84 N/mm²). The values for Valo® were in between (20.12 ± 5.70 N/mm²). The differences in SBS values were significant. CONCLUSION: The SBS achieved by certain polymerisation modes of LCUs of different light intensity showed great variability. According to the current opinion in the literature, a SBS of 5-10 N/mm² is regarded as clinically sufficient. The SBS of maximum intensity LCUs, investigated in this study according to DIN standard 13990-2, provided a satisfactory result for clinical use inspite of very short polymerisation times.

404 ORTHODONTIC TREATMENT OF PATIENTS WITH DIABETES MELLITUS L Sergienko, J Lendengolds, E Karton, L Persin, A Seleznev, Moscow State University of Medicine and Dentistry, Russia Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 AIM: To consider the possibility to treat diabetic patients orthodontically with minimal complications from periodontal tissue. SUBJECTS AND METHOD: Thirty patients (13 females, 17 males aged 20-30 years) with crowding and diabetes mellitus type 1 treated with self-ligating brackets. Bone densitometry and periapical radiographs were evaluated before and after treatment. The patients were examined to check their metabolic status. The results were compared with a control group of 15 patients with crowding (9 females, 6 males aged 20-30 years) without diabetes mellitus. RESULTS: After orthodontic treatment, densitometry showed normal parameters of optical density in all patients in the examined groups. The rate of bone loss was higher in diabetic patients but not significantly. CONCLUSION: Patients with diabetes mellitus type 1 with a stable metabolic status can be treated orthodontically with minimal bone tissue complications.

405 GROWTH AND DEVELOPMENT OF THE MANDIBULAR CANAL USING CONE BEAM COMPUTED TOMOGRAPHY Y Sezaki, N Shiba, K Oketa, T Suzuki, Y Okumura, Meikai University, Sakado, Japan

AIM: To analyze and investigate the spatial relationship and changes in the mandibular bone during each stage of growth using cone beam computed tomography. MATERIALS AND METHOD: One hundred Indian dried mandibular bones with a tooth age between 1A to 5A were taken. Radiographic data was reconstructed to be vertical to the lingual and buccal side of the mandibular at intervals of 1 mm from the mandibular foramen to mental foramen and tomographic images were then obtained of the forehead. The following were then measured: 1. The distance of line from the centre of the mandibular canal to the inside of the lingual and buccal cortical bone, which was parallel an acrylic plate. 2. The distance of a line vertical to the lingual and buccal cortical bone from the centre of the mandibular canal to inside of the lingual cortical bone. 3. The distance of a line from the centre of mandibular canal to the acrylic plate vertically. RESULTS: 1. The thickness of the buccal cortical bone was about 1.266 mm (±0.489) for the measurement from the centre of the mandibular canal to the inside of the lingual cortical bone parallel to the acrylic plate. 2. The thickness of the inferior marginal cortical bone was about 1.363 mm (±0.832), then became thicker to the mental foramen for the measurement from the centre of mandibular canal to the acrylic plate vertically. 3. The thickness of the lingual cortical bone was approximately 1.18 mm (±0.419); the thickness of the mandibular bone on 1A and 1C tends to be thinner for the measurement parallel to the acrylic plate from the centre of the mandibular canal to the lingual cortical bone. CONCLUSION: 1. The mandibular canal starts from the centre of the mandibular ramus and runs to the inner lingual side of the mandibular ramus. In the molar part, the mandibular canal runs in the middle of the

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mandibular bone, then to the buccal side from the premolar part. 2. The development of the mandibular foramen and mental foramen vertically correlates with the general type of the Hellman's dental ages.

406 A SURVEY OF PATIENT SATISFACTION WITH ORTHOGNATHIC TREATMENT R Shah1, L Barreto1, R Williams2, 1Birmingham Dental Hospital and 2Queen Elizabeth Hospital, Birmingham, U.K.

AIM: To assess patient satisfaction with orthognathic treatment. SUBJECTS AND METHOD: Seventy two patients, who had received orthognathic treatment between 2006 and 2013, were asked to complete a questionnaire six months after surgery. This was based on the validated orthognathic patient satisfaction questionnaire, which forms part of the British Orthodontic Society/British Association of Oral Maxillofacial Surgeons minimum data set. The surgery was performed by one maxillofacial consultant. The questionnaire comprised 39 questions, which assessed reasons for seeking orthognathic Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 treatment, factors affecting overall patient experience and patient satisfaction, and perceived benefits. RESULTS: The main reasons for seeking treatment were to improve facial appearance (72%), to improve the smile (76%) and to straighten the teeth (88%). Following treatment, 29 per cent of patients experienced residual problems, such as difficulty eating, numbness, dental problems, jaw clicking and trismus. The perceived benefits of treatment were improved facial appearance (90%), improved smile (92%) and straighter teeth (92%). The majority of patients felt well-informed regarding orthodontic treatment, surgery and outcome (77, 97 and 93%, respectively). However, 53 per cent of patients felt that the duration of orthodontic treatment was longer than expected. Ninety per cent of patients said that they would have the same treatment again. CONCLUSION: The level of patient satisfaction with orthognathic treatment provided at Birmingham Dental Hospital and the Queen Elizabeth Hospital, Birmingham was high. The study highlights the need for more accurate information regarding the duration of orthodontic treatment. This will be addressed by improving verbal and written information given to patients during the consent process.

407 UNIVERSAL THREE-DIMENSIONAL REFERENCE LANDMARKS S Shahen1, F Fahim2, 1Department of Orthodontics, Faculty of Medicine and Surgery Second University of Naples, Italy and Private Practice, 2Cairo, Egypt

AIM: Construction of a universal reliable three-dimensional (3D) reference system not affected by craniofacial deformities - the Shahen triangle. MATERIALS AND METHOD: From 23 patient, 10 unilateral cleft palate (CP), 10 with different skeletal classifications, one with hemifacial microsomia and two with impacted canines without any skeletal deviation, cone beam computed tomographic scans were obtained with an iCAT machine. Traditional reference structures were checked as hypophyseal fossa, crista galli, foramen ceacum, auditory meatus, orbits and frontonasal suture related to N point to determine how deformity affects reference structures and which of them is the most stable. Twisting of the hypophyseal fossa was measured around a 3D sella axis. Crista galli highest point deviation from its basal centroid was measured, as was the distance from foramen ceacum to right and left Porion. RESULTS: Twisting of the hypophyseal fossa was between 5 to 25 degrees around the fossa axis in CP subjects. Crista galli leaning by 3 to 6 degrees towards the side of cleft was observed in CP subjects. There was undeniable displacement of Porion in the hemifacial microsomia subject. The foramen ceacum distance to the right porion was equal to that on left in each case. In hemifacial microsomia there is a groove which ends at original location of porion point and has same relationship as the other side. CONCLUSION: There is a stable relationship between foramen ceacum and two porion points in all cases and a substitute of Porion in hemifacial microsomia a universal reference can be constructed based on this stable triangle. Sella and Cresta galli cannot be used as a reference in CP cases

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408 A COMPARISON OF DISCOLOURATION BETWEEN HARD AND SOFT CLEAR ORTHODONTIC ALIGNERS M Shakib Pour, M Shakib Pour, G T Szabo, M Shakib Pour, A Kirova, Department of Dentistry, Oral and Maxillofacial Surgery, University of Pecs Medical School, Hungary

AIM: To investigate the discolouration of hard and soft clear orthodontic aligners, to determine if there is a specific colour change after use and if the changes are perceivable to the human eye. MATERIALS AND METHOD: One hundred and four aligners were randomly selected; 52 hard and 52 soft splints, which had been used for three weeks, 22 hours per day. Two reference aligners were used. Digital photographs were taken and the images were analyzed in Adobe, Photoshop, version 7.0. A reference point located on the first premolar of the aligners was selected by utilizing the eyedropper tool and the red, green, blue values (L* a* and b*) for each aligner was determined. All measurements were done in the internationally standardized Commission internationale de l'éclairage (CIE) Lab (Lightness a b) (CIELAB) colour space. Total colour change Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 (ΔE*ab) and specific changes in individual colour components were tested separately and comparisons were made to examine the difference between the values obtained. RESULTS: Data demonstrated discolouration regardless of the type of aligner; however the colour change in the soft aligners were significantly greater than in the hard aligners (mean ΔE*ab values: soft: 38.568 and hard: 32.082). Specific colour changes were observed towards the yellow side of the colour continuum (mean values: soft: 38.49, hard: 4.04). Changes in Δa*values were not significant and therefore excluded from the results. CONCLUSION: The experimental design involved both hard and soft aligners, enabling multiple comparisons to be performed in order to detect the degree of discolouration and specific colour changes. Intraoral use of clear aligners causes yellow discolouration which is visible to the human eye. The degree of discolouration varied; the soft splints demonstrated more discolouration in comparison with the hard splints.

409 INCIDENCE AND CAUSE OF OPEN GINGIVAL EMBRASURE SPACE BETWEEN CENTRAL INCISORS AFTER ORTHODONTIC TREATMENT C H Shin, C Chung, H Kwon, K-H Kim, Y J Choi, Department of Orthodontics, Gangnam Severance Dental Hospital, Seoul, Korea South

AIM: To evaluate the incidence and cause of open gingival embrasure space after orthodontic treatment in Koreans. MATERIALS AND METHOD: The occurrence and the severity of open gingival embrasure space were classified according to the Jemt index using intraoral photographs. Age, treatment duration, and orthodontic tooth movement, measured on lateral cephalograms, periapical radiographs, and study model, were compared between the occurrence and the non-occurrence groups. RESULTS AND CONCLUSION: The prevalence of an open gingival embrasure space between the central incisors after orthodontic treatment was 34.3 per cent in the maxilla and 42.6 per cent in the mandible. The major causal factors of open gingival embrasure space seem to be the distance from contact point to alveolar bone crest after treatment in the maxilla (P < 0.05), and the amount of intrusive movement of the incisal edge in the mandible (P < 0.05).

410 MECHANICAL CHARACTERIZATION OF ORTHODONTIC ARCHWIRES EMPLOYING INSTRUMENTED INDENTATION TESTING I Sifakakis1, S Zinelis1, T Eliades2, 1Department of Biomaterials, School of Dentistry, University of Athens, Greece and 2Department of Orthodontics and Paediatric Dentistry, Center of Dental Medicine, University of Zurich, Switzerland

AIM: To characterize the mechanical properties of orthodontic archwires employing Instrumented Indentation testing (IIT). e206

MATERIALS AND METHOD: Segments from the central part were cut from six commercially available orthodontic archwires A J Wilcock (G & B Wire Company), Superelastic Regular Force NiTi (Highland Metals Inc.), 018 inch SuperElastic Regular Force NiTi (Highland Metals Inc.), BetaBlue (Highland Metals Inc.), Ortho Technology True Force (Tampa, Florida) and (Highland Metals Inc.) and embedded in epoxy resin. The specimens were then ground with water coolant SiC papers from 220 to 2000 grit, and polished with 1 μm alumina slurry. The indentation modulus (EIT), the ratio of elastic to total work (ηIT) and Vickers hardness were then measured according to ISO 14577-1 specification by IIT employing a Vickers indenter. The results were statistically analyzed by one way ANOVA and Student-Newman-Keuls multiple comparison test at α = 0.05. RESULTS: The mean values and standard deviations for EIT, ηIT, and HV0.5 are presented. The results of hardness were comparable to the values found in the orthodontic literature but modulus of elasticity for all materials tested was significantly underestimated. An explanation for this outcome might be the intense residual strain developed during the cold drawing of wires in the manufacturing process. The residual strain Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 increased the hardness and the fracture strength but decreased the . The latter was indirectly presented by the elastic to total work ratio, as higher ratios indicated a less ductile material as typical values for ductile alloys were below 20 per cent. CONCLUSION: The material tested illustrated significant differences in their mechanical properties although it seems that IIT is not the appropriate method to determine the modulus of elasticity of orthodontic archwires.

411 A RETROSPECTIVE CLINICAL STUDY ON TREATMENT EFFECTIVENESS USING THE CLEAR ALIGNER SYSTEM M Simon1, J Schwarze2, B A Jung1, L Keilig3, C Bourauel3, 1Department of Orthodontics, University of Freiburg, 2Private Orthodontic Practice, Cologne and 4Department of Oral Technology, University of Bonn, Germany

AIM: To investigate the effectiveness of orthodontic treatment using the Invisalign® system. Additionally, the influence of auxiliaries (attachment/power ridge) as well as staging (movement/aligner) and patients’ compliance in terms of treatment effectiveness were analysed. SUBJECTS AND METHOD: Thirty patients were divided into three groups according to the investigated tooth movement: incisor torque >10 degrees, premolar derotation >10 degrees and molar distalization >1.5 mm. To investigate the influence of attachments, the groups were subdivided: in the first subgroup tooth movement was supported with an attachment, whereas in the other subgroup, tooth movement was performed without auxiliaries (except incisors torque, where power ridges were used). Allocation of the teeth to the subgroups with/without an auxiliary was randomized. To analyze clinical effectiveness, pre-treatment and final plaster cast models were scanned with the Micromeasure 70 laser scanner and the achieved tooth movement was determined via a surface/surface matching algorithm. The results were compared with the amount of tooth movement predicted by ClinCheck®. RESULTS: The overall mean effectiveness was 59 per cent. Distalization of an upper molar was the most effective movement at around 87 per cent. The mean accuracy for upper central incisor torque was 42 per cent. The lowest effectiveness was in the premolar derotation group at approximately 40 per cent. CONCLUSION: Other than patient compliance and tooth shape, the staging (movement/aligner) and the total amount of planned movement have an impact on treatment effectiveness.

412 EFFECT OF PRECURING THE ADHESIVE PRIMER ON SHEAR BOND STRENGTH WHEN BONDING METAL ORTHODONTIC BRACKETS S Sirabanchongkran1, S Sumranrom2, S Meema2, A Surapattanaporn3, A Kumpichai2, 1Department of Orthodontics and Pediatric Dentistry, Chiangmai University and Private Practices, 2Bangkok and 3Phayao, Thailand

AIM: To evaluate the efficiency of precuring the adhesive primer on the shear bond strength (SBS) between metal brackets and the tooth surface. e207

MATERIALS AND METHOD: Fifty human upper premolar teeth were divided into two groups. The enamel surface was cleaned and prepared conventionally. One layer of adhesive primer was applied. In the control group, the precoated bracket was placed on the buccal surface and cured with light emitting diodes for 20 seconds on each side of the bracket. In the experimental group, the same method was used, except that the primer was precured for 10 seconds before bracket placement. Thermocycling was operated between 5°C and 55°C for 1,000 cycles. After the samples had been stored in water at 37°C for 24 hours, SBS was measured with an Instron® machine and the adhesive remnant index scores were recorded. Comparative analysis was done with the SPSS program. RESULTS: There was no statistically significant difference in SBS between the groups with or without precuring primer (12.39 ± 4.75 MPa and 10.58 ± 4.27 MPa, respectively). More adhesive remaining on the enamel was noted when the primer was precured. CONCLUSION: Precuring the adhesive primer would be an unnecessary step in bonding brackets. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021

413 CONSTITUTIONAL AND TYPOLOGICAL FEATURES OF BODY STRUCTURE IN PATIENTS WITH MALOCCLUSION L Smaglyuk, D Sheshukov, A Bilous, Higher Medical Educational Institution of Ukraine 'Ukrainian Medical Stomatological Academy', Poltava, Ukraine

AIM: Somatotype, as a morphological expression of the constitution, is one of the integral characteristics of the human body. In the past two decades interest in the study issues such as the relationship between total and local constitutional rights has increased. However, research that defines the interdependence between global and local structural features of the body and malocclusion are not available. SUBJECTS AND METHOD: Two hundred and one orthodontic patients (96 males, 105 females) aged 18-24 years. Somatotyping performed using the method of Reese-Eisenk (1948) and pathology of the occlusion was determined according to the classification of Angle (1889). Statistical analysis was carried out using a Student- Fischer test. RESULTS: A normosthenic type was identified in 62.18 per cent of patients (59 males, 66 females). An asthenic type was determined in 24.88 per cent (20 males, 30 females) and a hypersthenic type in 12.94 per cent (17 males, 9 females). A Class I malocclusion diagnosed in 122 patients, a Class II division 1 in 30 patients, a Class II division 2 in 28 patients, and a Class III in 21 patients. A definite pattern between somatotype and malocclusion was observed, so most patients diagnosed as Class I had a normosthenic type of body structure (90 subjects, 73.7%), with a Class II an asthenic type of body structure (29 subjects, 50.0%) and with a Class III a normosthenic type of body structure (18 subjects, 85.7%). CONCLUSION: Determining the type of structure of the human body shows that most orthodontic patients with Class I and III malocclusions have a normosthenic somatotype. Class II patients are principally asthenic somatotypes. The type of structure of the human body has great scientific and practical importance and should be an integral element in the diagnosis of orthodontic patients.

414 MANDIBULAR SAGITTAL SPLIT OSTEOTOMY VERSUS MANDIBULAR DISTRACTION OSTEOGENESIS IN THE TREATMENT OF NON-SYNDROMIC SKELETAL CLASS II PATIENTS A Smalec1, K Miśków2, K Dowgierd3, 1University Children's Hospital in Olsztyn and 2Department of Orthodontics and 3Cranio-Facial Centre, University Children's Hospital in Olsztyn, Poland

AIM: To show the clinical outcome of treatment of patients with a skeletal Class II malocclusion. Mandibular retrognathia is a common skeletal congenital dysgnathia. Many skeletal Class II patients require surgery. Orthognathic surgery offers mandibular sagittal split osteotomy to advance the mandible. However, a new technique, mandibular distraction osteogenesis is beneficial in particular cases. It is based on different

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mechanism – an active histogenesis of hard and soft tissues in the region of the osteotomy site. This presentation will show details of treatment planning and management of treatment pre- and post-surgery regarding bilateral sagittal split osteotomy (BSSO) and mandibular distraction osteogenesis (MDO) as well as use of the distraction device. SUBJECTS AND METHOD: Twenty patients, who had undergone either MDO (8 patients) or BSSO (12 patients) between 2011 and 2013; performed by the same surgeon. All patients were prepared orthodontically before surgery. In both groups any concomitant procedures, including maxillary osteotomy or genioplasty, were undertaken if indicated. Seventy four lateral cephalometric radiographs were investigated. The mean age of the patients was 17.9 years (MDO 17.14; BSSO 19.85). The criteria for cephalometric comparison were angular and linear cephalometric variables (Steiner analysis with modifications). The criteria for inclusion into this study were: males and females with a skeletal Class II pattern plus dentofacial and dental abnormalities such as a skeletal open bite. A reliability test was performed. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 RESULTS: There was no statistically significant difference between BSSO post-operatively and MDO post- distraction. CONCLUSION: MDO may offer another option for treatment of skeletal Class II malocclusions in children after the pubertal growth spurt. However, there is a need for long-term data on the stability of both methods.

415 COHORT STUDY OF CLEFT LIP AND PALATE EPIDEMIOLOGY CARRIED OUT ON 135 PATIENTS FROM SPECIALIST CHILDREN’S HOSPITAL IN OLSZTYN A Smalec1, K Miśków1, K Dowgierd2, 1Department of Orthodontics and 2Cranio-Facial Centre, University Children’s Hospital in Olsztyn, Poland

AIM: To assess the environmental factors causing a cleft lip and palate (CLP). SUBJECTS AND METHOD: The retrospective cohort study analysis of 135 non-syndromic patients with CLP; aged between 1 month and 22 years, who had undergone treatment from 2008 to 2013. RESULTS: Eighteen per cent of the babies’ mothers had experienced disturbances during pregnancy (such as severe infections) and 0.7 per cent had higher rates of alcohol consumption. The research showed that the educational status of the parents was 64 per cent secondary, 22 per cent higher and 14 per cent primary. CONCLUSION: Complications during pregnancy such as illness of the mother before and/or during pregnancy; the medicament intake during pregnancy; alcohol consumption; cigarette use and the occupation of parents as well as the sector of their work may have an impact on the presence of a CLP in selected group of patients.

416 DIAGNOSIS OF SKELETAL DEFORMITIES AND EARLY ASSESSMENT OF THE COMPLEXITY OF ORTHODONTIC TREATMENT BASED ON THE WHEEL OF COLOURS P Smolka1, M Greinke2, 1Gabinet Stomatologiczny Piotr Smolka, Wroclaw and 2Gabinet stomatologiczny, Kościerzyna, Poland

AIM: An indispensable part of clinical practice consists of the classification of a skeletal problem based on the sagittal and vertical relationships. These parameters allow for a precise diagnosis and determination of the extent of a skeletal discrepancy. This presentation introduces the wheel of colours, a novel method of interpretation of the most widely consulted cephalometric results, the Wits appraisal and the ML-NL angle values (Anderson et al., 2006; Sadat-Khonsari et al., 2009). The wheel of colours represents these two values by a single colour, whose intensity instructs the clinician about the estimated complexity of an orthodontic treatment. MATERIALS AND METHOD: A modified wheel of colours was employed in the Ortodoncja 7 software to create a pictorial representation of the selected cephalometric results plotted on a coordinate plane. The X axis included the Wits values from 13 mm to –13 mm, and in the Y axis the ML-NL values from 0 to 40 degrees, so the

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averages of both parameters defined the exact centre of the chart. A modified wheel of colours was superimposed on the chart, consisting of six hues passing fluently into one another. The colour intensity changes gradually from white in the centre to black on the perimeter. As a result, the correct relationship between Wits and ML-NL shows as white and the more pronounced a discrepancy, the darker it will appear on the diagram. The crossing point of the two lines corresponding to each value determines the hue associated with a given disorder and its respective severity. RESULTS: The wheel of colours brings a distinct advantage in the early assessment of a skeletal problem, because it allows the clinician to gain a preliminary understanding of the nature of a malocclusion just by looking at a colour generated by the computer. CONCLUSION: The wheel of colours will prove particularly useful for inexperienced orthodontists, who need to gradually increase the complexity of their treated cases. The wheel of colours gives them a clear sign of warning when it is the time to send a patient to a more experienced practitioner. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021

417 NORMATIVE VALUES OF JAW MOVEMENT CAPACITY IN HEALTHY INDIVIDUALS 4-17 YEARS OF AGE P Stoustrup1, K Dahl Kristensen1, A Küseler1,2, T Herlin3, T K Pedersen1,2, 1Section of Orthodontics Aarhus University and Departments of 2Maxillofacial Surgery and 3Paediatrics, Aarhus University Hospital, Denmark

AIM: Clinical assessment of mandibular movement capacity is an important part of pre-orthodontic evaluation as well as the routine clinical dental examination. The aim of this study was to establish age-related normative values for maximal mouth opening capacity and mandibular laterotrusion capacity in healthy individuals. SUBJECTS AND METHOD: The material of this cross-sectional population-based study consisted of 1114 healthy Danish consecutive individuals between the ages of 4-17 years. During a routine dental examination maximal mouth opening capacity and laterotrusion capacity were assessed in each individual according to a standardized measurement protocol with calibrated metallic rulers. The measurements were adjusted for overbite and midline deviations. Exclusion criteria: temporomandibular diagnosis, previous orofacial complaints, jaw fractures, general hypermobility. RESULTS: The mean maximal mouth opening gradually increased from 38 mm, SD 6.1 mm, at 4 years of age to 54.5 mm, SD 6.8 mm, at age 17. A minor non-significant inter-gender difference of 0.6 mm in maximal mouth opening capacity was observed (P < 0.15, male > female). The mean total laterotrusion capacity (right excursion + left excursion) gradually increased from 15.4 mm, SD 3.1 mm, at 4 years of age to a mean value of 20.1 mm, SD 3.7 mm, at age 17. A statistically significant inter-gender difference of 0.8 mm, SD 0.4 mm (P < 0.01, male >female) was observed in relation to total laterotrusion capacity; however, the clinical relevance of this significant difference is questionable. CONCLUSION: Normative values of maximal mouth opening capacity and laterotrusion capacity in individuals between 4 and 17 years of age were established. The findings oppose the use of a single universal cut-off value for ‘normal’• range of motion in children and adolescent patients. Instead it is recommended to include the specific age-related normative values of mandibular range of motion in the assessment of orthodontic patients.

418 THREE-DIMENSIONAL EVALUATION OF DENTAL ABNORMALITIES OBSERVED IN CLEIDOCRANIAL DYSPLASIA A Strzecki, J Jablońska-Zrobek, E Pawłowska, Department of Orthodontics, Medical University of Lodz, Poland

AIM: Cleidocranial dysplasia (CCD) is an autosomal dominant inherited disorder affecting the entire skeleton with symptoms being most notably visible within the chest and dentofacial complex . Dental abnormalities such as the presence of numerous unerupted supernumerary teeth, dental impaction and displacement, retention of the primary dentition, delayed eruption of the permanent teeth, and elongated and dilacerated dental roots are associated with CCD. The aim of this study was to perform a three-dimensional (3D) quantitative and qualitative

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analysis of dental abnormalities encountered in CCD by means of cone beam computed tomography (CBCT) and 3D mesh modelling of anatomic reconstructions. SUBJECTS AND METHOD: Five CCD patients (3 females, 2 males, mean age: 22 ± 9 years). All patients had undergone a CBCT scan of the maxillary and mandibular region and subsequently 3D anatomic reconstructions were created on the basis of the obtained Dicom files. RESULTS: A total of 62 either impacted or displaced teeth were detected in all patients; 33 impactions were diagnosed in the maxilla and 29 in lower dental arch, with premolars being the most often (39%) impacted teeth. Supernumerary teeth were observed in all patients varying in number from 1 to 16 (total number of supernumerary teeth: 38; 7.6 ± 3.5 teeth per patient). The majority of supernumerary teeth were impacted and detected in either the incisor (47.4%) or premolar (44.7%) region. Other commonly encountered dental abnormalities were root dilacerations, retained primary teeth dentition and hypodontia. One case of dental transposition was observed. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 CONCLUSION: Symptoms of CCD in the study group manifested significant diversity especially in terms of the total number of teeth, although if the supernumerary teeth were present they would most often be detected in either the incisor or premolar region. Adversely, canines could be considered the tooth group most prone to impaction. Root dilacerations proved to be a relatively common finding which could possibly impair the course of orthodontic treatment. Numerous dental abnormalities regarding both the number of teeth and their morphology require complex 3D evaluation on the basis of anatomic reconstructions which significantly improve treatment planning.

419 AGE RELATED CHANGES IN THE MEDIAN PALATAL SUTURE – A CONE BEAM COMPUTED TOMOGRAPHY STUDY A Strzecki, J Jablońska-Zrobek, E Pawłowska, Department of Orthodontics, Medical University of Lodz, Poland

AIM: Rapid palatal expansion (RPE) is a widely accepted method of correcting maxillary deficiencies. The success of expansion is largely related to patients’ skeletal growth and age. The purpose of this study was to evaluate the palatal suture characteristic on the basis of a cone-beam computed tomography (CBCT) scan in various age groups. SUBJECTS AND METHOD: Eighty seven (41 male; mean age: 24 ±19 years) patients with no history of rapid palatal expansion/surgically assisted palatal expansion (RPE/SPE) or maxillary distraction who underwent CBCT examination of the maxillary region. The patients were divided into four groups (I - <14 years, II - 15-20 years, III - 21-30 years, IV - >30 years) and four frontal projections of the median palatal suture were recorded (A-at the level of anterior margin of the incisive foramen, B-at the level of posterior margin of the incisive foramen, C and D, 10 and 20 mm distally from the posterior margin of the incisive foramen). Subsequently, the images underwent identical contrast and sharpness adjustment and in all projections the suture was classified into one of four categories on the basis of the shape of the maxillary connection and the amount of calcified tissue forming the suture. RESULTS: Most significant anatomic changes in suture anatomy were observed in A, B and D points with the amount of calcified tissue increasing with age. Point C remained relatively stable in terms of shape and the amount of calcified tissue (66.3% versus 68% versus 75.1% versus 75% in groups I-IV, respectively). Patients from groups I and II showed similar suture anatomy with the exception of point B where the suture could be described as more serrated in group II. However the amount of calcified tissue in patients <14 and 15-20 year old showed no significant differences. CONCLUSION: Although the borderline age for RPE resulting in desired skeletal expansion remains controversial, the results of this study suggest that patients younger than 21 years show similar maxillary suture anatomy. Skeletal factors other than the architecture of the palatal suture may prove more significant determinants of RPE success.

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420 ORTHODONTIC FORCES INDUCE HEME OXYGENASE-1 EXPRESSION – IMPLICATIONS FOR TOOTH MOVEMENT? M Suttorp, D Lundvig, F Wagener, J Maltha, A M Kuijpers-Jagtman, Department of Orthodontics and Craniofacial Biology, Radboud UMC, Nijmegen, Netherlands

AIM: To correct malocclusions orthodontic forces are applied to the tooth by orthodontic appliances. The orthodontic force disturbs the microenvironment of the periodontal ligament (PDL), and induces bone remodelling, which is necessary for tooth movement. The reduced blood flow in the compressed PDL generates ischaemic injury and leads to cell death (hyalinization) and root resorption. Protection against hyalinization and root resorption would strongly ameliorate orthodontic treatment. Heme oxygenase-1 (HO-1) is a cytoprotective enzyme that can be activated by a variety of stresses and protects against oxidative and inflammatory insults. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 Therefore, the aim of this study was to investigate whether the expression of the cytoprotective enzyme HO-1 in the PDL is induced during orthodontic tooth movement in rats. MATERIALS AND METHOD: Twenty-five 6-week-old male Wistar rats were used. The upper three molars on one side were moved mesially using a nickel titanium coil spring of 10 cN. The contralateral side served as the control. After 6, 12, 72, 96 and 120 hours the rats were euthanized. On parasagittal sections immunohistochemical staining using HO-1 antibodies was performed for analysis and quantification of HO-1 expression. RESULTS: A significant time-dependent induction of HO-1 expression was demonstrated at both the apposition and resorption side in mononuclear cells within the PDL. Shortly after appliance placement HO-1 was induced in specified mononuclear cells but returned to control levels within 72 hours. Osteoclasts were found to switch from the mesial to the distal side after 120 hours of force application. A majority of these osteoclasts were positively stained for HO-1 but this induction was shown to be independent of the orthodontic force. CONCLUSION: A time-dependent induction of HO-1 following a constant mechanical stress was observed within the PDL. HO-1 expression was differentially induced in the different cell populations. In the future, HO-1 induction may form a novel strategy to further reduce unwanted side effects in orthodontics.

421 CEPHALOMETRIC MARKERS FOR TREATMENT SUCCESS WITH A MANDIBULAR ADVANCEMENT APPLIANCE IN PATIENTS WITH OBSTRUCTIVE SLEEP APNOEA P Svanholt1, N Petri2, L Sonnesen1, 1Department of Orthodontics, University of Copenhagen and 2Ear Nose Throat Department, Nykøbing Falster, Denmark

AIM: To find cephalometric markers to predict treatment success with a mandibular advancement appliance used for patients with obstructive sleep apnoea (OSA). SUBJECTS AND METHOD: Twenty three males and four females aged 28-65 years (mean 50 years) diagnosed with OSA by sleep studies using overnight polysomnography. The apnoea-hypopnea index (AHI) 10.6-111.7 (mean 39.1) and body mass index (BMI) 24-43 (mean 30.7) was measured before intervention. Lateral cephalograms in a standardized head posture were taken and cephalometric analyses of the craniofacial and pharyngeal morphology were performed. After four weeks of continuous use of a mandibular advancement appliance, AHI was measured at 0.9-101.1 (mean 25.0). The success criteria of treatment was a reduction of AHI >50 per cent and AHI <5. Cephalometric markers for success were assessed by t-test and Fishers exact tests. RESULTS: Eight patients (30%) met the success criteria of treatment. The cephalometric markers for success were mandibular and maxillary retrognathia (P < 0.05; P < 0.01), small SNB (P < 0.01) and a narrow space behind the soft palate (P < 0.01). Furthermore, patients with treatment success had a smaller BMI than those with no success (P < 0.05).

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CONCLUSION: It was possible to identify cephalometric markers for treatment success with a mandibular advancement appliance in OSA patients. This knowledge is important for the information to the OSA patients and for the selection of OSA patients with regards to mandibular advancement appliance treatment.

422 IS OBJECTIVE ASSESSMENT WITH OCCLUSAL INDICES RELATED TO PATIENTS’ QUALITY OF LIFE? A-L Svedström-Oristo1,2, O Alanko2,3, T Peltomäki4, M T Tuomisto3,5, 1Department of Oral Development and Orthodontics, University of Turku and 2Department of Oral and Maxillofacial Diseases, Turku University Central Hospital, 3School of Social Sciences and Humanities (Psychology), University of Tampere, 4Oral and Maxillofacial Unit, Tampere University Hospital and 5Department of Psychiatry, Tampere University Hospital, Finland

AIM: To analyse the capability of the Peer Assessment Rating (PAR) and Index of Complexity, Outcome and Need (ICON)-scores to reflect the Orthognathic Quality of Life (OQoL) of prospective patients referred to two Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 hospital clinics for assessment of surgical-orthodontic treatment. SUBJECTS AND METHOD: Sixty patients (16 males, 44 females, age range 17-61 years). The OQoL-questionnaire was mailed to them together with the appointment details and they were requested to fill in the questionnaire in advance. An orthodontist assessed their study models using the PAR and the ICON indices. Spearman correlation coefficients were calculated between patients’ ICON and OQoL scores and PAR and OQoL scores. RESULTS: The patients’ OQoL scores ranged from 3 to 82 (mean 32.35), the weighted PAR scores from 6 to 43 (mean 26.46) and the ICON scores from 13 to 94 (mean 62.46). No statistically significant associations were found between the OQoL sum score and ICON scores or between the OQoL sum score and PAR scores. Nor were there significant associations between any of the four subscales (oral function, facial aesthetics, awareness of facial aesthetics, social aspects of dentofacial deformity) of the OQoL and the ICON or PAR scores. CONCLUSION: Objective assessment methods used to analyse occlusal traits and patients’ OQoL describe different views on morphological deviations and their impact on the patients’ lives.

423 SWEDISH ORTHODONTISTS’ OPINIONS AND EXPERIENCES REGARDING MINISCREW IMPLANTS D Svensk, L-I Norevall, Department of Orthodontics, The Center for Orthodontics and Pediatric Dentistry, Linköping, Sweden

AIM: Anchorage control is a key issue in orthodontic treatment. Several studies have described the use of miniscrew implants (MSI) which enable absolute anchorage and direct orthodontic force application. The aim of this study is to describe the opinions and experiences of MIS among orthodontists currently practising in Sweden. MATERIALS AND METHOD: A web-based anonymous questionnaire (Publech® Survey 5.7) was sent to 218 listed members of the Swedish Orthodontists Society during fall 2012. In a total of 147 (67%) respondents 80 were women, 62 were men and five did not specify gender. The questionnaire contained 17 multiple choice questions. Descriptive statistics were used for analysing the collected data set. RESULTS: 1. MSI had been used in orthodontic treatment by 78 (53%) respondents. 2. The majority of the respondents, 53 (70%), had used 1-10 MSI. 3. Placement of MSI was made by 48 (84%) orthodontists personally while 18 (9%) referred the procedure to an oral surgeon. 4. The most common indications for MSI were space closure, intrusion and bodily movements. 5. The use of MSI enabled 61 (81%) of the respondents to set higher treatment objectives. 6. The success frequency of the MSI was perceived as satisfactory by 48 (65%) of the respondents. CONCLUSION: The response rate shows an interest in MSI among Swedish orthodontists. Anchorage control in the form of MSI was used by half of the respondents. The experience of MSI varies widely but the opinions are mostly positive. Space closure, intrusion and bodily movements are the most common treatment indications for MSI.

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424 FAILURE OF PERMANENT MOLAR ERUPTION A Swirski1, A Sekowska1, I Mitura2, M Rudzki1, I Dunin-Wilczynska1, 1Medical University, Lublin and 2Dental Clinical Centre, Lublin, Poland

AIM: To assess the relationship between failure of eruption of the first or second molars and other types of dental anomalies or general disorders. MATERIALS AND METHOD: The medical records of nine patients (3 males, 6 females) aged 7-23 years, with failure of permanent molar eruption. Failure of tooth eruption was defined as retention of the tooth in the alveolar bone partial or completely covered by oral mucosa in the presence of fully erupted teeth in the dental arches. RESULTS: In seven patients failure of eruption affected individual teeth, five of which were the first permanent molars, in the remaining subjects only the second permanent molars were unerupted. In the remaining patients Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 there was retention of more than one tooth. In one patient impaction was seen in the first and second molar in one quadrant and second molar in the second quadrant. In the second case the first, second and third molars were retained in one quadrant and the second molar in the other quadrant. Arrest occurred in three patients in the upper dental arch, in the other four in the lower dental arch, and in the other two cases, the teeth were retained in both dental arches. In three cases, arrest concerned the right side, and six - left. Angle Class: Class I in 3 cases, Class II in 3 cases and Class III in one case was observed. Associated dental anomalies: In one case, failure of first permanent molar eruption coexisted: impacted upper canine, root dilacerations of premolar and molar and odontoma which caused the arrest of a premolar. Two patients experienced infraocclusion in one case the primary second molar and in the other the first and second permanent premolar. One patient had a unilateral crossbite. In two patients vitamin D deficiency was detected. The patient with the highest number of impacted teeth was treated for thyroid insufficiency (Hashimoto’s thyroiditis). CONCLUSION: Failure of permanent molar eruption may coexist with other dental anomalies. Disorders of mineral, vitamin D and thyroid hormone metabolism co-occur with failure of permanent molar eruption.

425 THREE-DIMENSIONAL EVALUATION OF FACIAL MORPHOLOGY CHARACTERISTICS IN THE ROMANIAN POPULATION C Szuhanek, O David, N Riham, University of Medicine and Pharmacy Victor Babes Timisoara, Romania

AIM: To evaluate the facial parameters of a group of patients from Timisoara, Romania using a comprehensive three-dimensional (3D) photographic analysis. SUBJECTS AND METHOD: One hundred and thirty five adult patients aged 18-35 years. The 3D photographs were recorded using the ProFace™ option from Planmeca ProMax 3D. Soft tissue parameters were recorded, including head width, middle face length, upper face width, nasolabial angle, labiomental angle, interlabial angle, and upper and lower lip distance to profile line. The results were statistically analysed. RESULTS: The subjects from the study group frequently had special morphological characteristics. Among these, large faces, convex profiles, Class II profiles and retrusive mandibles were recorded CONCLUSION: 3D facial scanning allows more accurate representation of facial morphology and the attainment of more predictable results.

426 EVALUATION OF HEALTH-RELATED QUALITY OF LIFE IN CHILDREN UNDERGOING FACEMASK THERAPY B Tagrikulu1, O Capan1, K Peker2, E F Erbay1, M Sarac1, Departments of 1Orthodontics and 2Dental Public Health, Faculty of Dentistry, Istanbul University, Turkey

AIM: There is a growing interest in assessing the impact of treatment on patients’ satisfaction and subjective well-being in orthodontic practice. The aim of this study was to compare treatment satisfaction and health-

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related quality of life (HRQoL) in children with a unilateral cleft lip and palate (UCLP) and skeletal Class III malocclusion. MATERIALS AND METHOD: The Turkish version of Pediatric Quality of Life Inventory (PedsQL) for 8-12 year old children was used to evaluate HRQoL; treatment satisfaction was measured with the cleft lip evaluation profile (CLEP). The sample comprised 10 patients with UCLP (5 boys, 5 girls; mean age: 11.3 ±0.67 years) and 10 patients with a skeletal Class III malocclusion due to maxillary retrognathia (5 boys, 5 girls; mean age: 11.5 ± 0.97 years). Maxillary expansion and facemask therapy was required in all patients. The HRQoL assessments were made prior to and 1 month after the end of facemask therapy. Data were analyzed via SPSS 15 software using descriptive statistics, Student's t, paired-t, Fisher's exact tests and Pearson correlation coefficients. RESULTS: There were no statistically significant differences in demographic variables. Cronbach’s alpha coefficients were higher than 0.70 for the PedsQL and CLEP. In children with a UCLP, significant differences were found between pre- and post-facemask therapy in physical and social functioning, psychosocial health Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 summary score and total scale score of PedsQL. There were no significant differences in the non-cleft group. While children with a UCLP showed more satisfaction with speech, hearing, appearance of teeth/lips and nose, profile of face and bite; those with a Class III malocclusion reported more satisfaction with the teeth, lips, profile of face, and bite after treatment in CLEP. Before facemask treatment, significant differences were found between the two groups in speech and appearance of the nose score of CLEP. After treatment the only difference was in the appearance of the nose scores. CONCLUSION: In UCLP patients, facemask therapy improves their quality of life and satisfaction. In this study the general HRQoL questionnaire was used. Further research exploring the relationship between oral and general HRQoL in these patient groups is needed. This pilot study may provide valuable information to develop a patient-centred, multidisciplinary care model for routine clinical practice.

427 EXAMINATION OF CRANIOFACIAL MORPHOLOGY IN TOOTH AGENESIS PATIENTS Y Takahashi, N Higashihori, Y Komazaki, J-i Takada, K Moriyama, Department of Maxillofacial Orthognathics, Tokyo Medical and Dental University, Japan

AIM: The prevalence of permanent tooth agenesis is relatively high among orthodontic patients. It has been reported that tooth agenesis patients have altered craniofacial morphology, with retarded maxillary growth, and protrusion and anti-clockwise rotation of the mandible. Clinically, however, the craniofacial morphology and skeletal pattern are highly variable in tooth agenesis patients. In this study, to elucidate the relationship between variations in tooth agenesis and craniofacial morphology, tooth agenesis patients were classified using the anteroposterior and vertical maxillary and mandibular relationships and subsequently their characteristics were analyzed. MATERIALS AND METHOD: Lateral cephalograms of a hypodontia group (1-5 congenitally missing teeth, n = 56, mean age 17.7 ± 7.8 years), an oligodontia group (6 or more congenitally missing teeth, n = 30, mean age 15.0 ± 6.5 years) and a control group (no congenitally missing teeth, n = 150, mean age 19.2 ± 7.5 years) were used for angular and linear analysis. Z-scores were formulated according to age and gender, matched to the Japanese norm. The A-B plane angle and mandibular plane angle were used as reference parameters. Each parameter was sub-divided according to Z-score (low: <-1SD; moderate: -1SD–+1SD; high: >+1SD; giving nine classifications in total) and the percentage in each classification was assessed. RESULTS: The percentage of patients with a low mandibular score (<-1SD) was increased in the hypodontia and oligodontia groups, while the number of patients with a high A-B plane angle (>1SD) was increased in the oligodontia group compared with the others due to the retarded maxillary growth in this group. Most patients in the oligodontia group had a low mandibular plane angle and a high A-B plane angle, a significant difference compared with the control and hypodontia groups. A deep overbite was common in hypodontia and oligodontia.

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CONCLUSION: Tooth agenesis affects the skeletal pattern and the skeletal patterns seen in oligodontia are more severe. However, craniofacial morphology is less closely related, especially in some of the oligodontia patients, suggesting that orthodontic treatment planning should be carefully tailored to the individual’s craniofacial morphology.

428 THE IMPACT OF FORCE MAGNITUDE ON THE MAXILLARY SECOND MOLARS IN CERVICAL HEADGEAR THERAPY T Talvitie1, M Helminen2, S Karsila3, L Signorelli4, T Peltomäki1, 1Oral and Maxillofacial Unit, Tampere University Hospital, 2Science Center, Pirkanmaa Hospital District and School of Health Sciences, University of Tampere and 3Dental Teaching Unit, Turku Municipal Health Care Services, Finland and 4Clinic for Orthodontics and Pediatric Dentistry, Center for Dental Medicine, University of Zurich, Switzerland Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 AIM: To study the effect of force magnitude on the maxillary second molars inclination in cervical headgear therapy. SUBJECTS AND METHOD: Subjects with Class II or end-to-end molar relationship, mixed dentition and moderate crowning to be treated with cervical headgear (HG) were recruited. They were randomly allocated to light (L, 300 g) or heavy (H, 500 g) force in the headgear measured and monitored by Smartgear (Swissorthodontics, Switzerland) module. The inner bow of the HG was expanded (3-4 mm) and a long outer bow bent upwards horizontal 10-20 degrees in relation to the inner bow. Patients were asked to wear the HG for 9-10 hours in the evening and at night. They were seen and the force magnitude controlled every 6-8 weeks until end of the study at 10 months. The angle between the long axis of first and second maxillary molars was measured on dental pantomograms obtained before and after treatment. Wilcoxon’s signed test was used to study difference between the right and left side before treatment and Student’s t-test between the groups after treatment. This preliminary study was based on the analysis of 36 children (mean age 9.66 years ±0.57, n = 20 in the L group, n = 16 in the H group). RESULTS: During treatment median change in angle on the right and left side were –2.8 (25th% –4.8,75th% 2.4), –0.5 (–6.5, 3.4) and 3.8 (–4.25, 9.6), 2.0 (–0.25, 8.3), in the L and H groups, respectively. There were no statistically significant differences between the right and left sides. CONCLUSION: Preliminary results of this randomized, prospective study indicate no statistically significant differences in the inclination of the second maxillary molars after HG therapy with different forces.

429 EFFECTS OF A MODIFIED HERBST APPLIANCE IN THE TREATMENT OF ANGLE CLASS II MANDIBULAR RETRUSION*** C Tazumi1, S Tazumi1, T Tazumi2, N Matsumoto1, 1Department of Orthodontics, Osaka Dental University, Osaka and 2Tazumi Orthodontic Clinic, Hyogo, Japan

AIM: To examine functional muscular adaptation through analysis of short-term morphological and functional changes induced with the use of a modified Herbst appliance which was expected to promote condylar cartilage growth and thereby induce forward reremodelling of the glenoid fossa. SUBJECTS AND METHOD: Ten patients aged between 15 and 25 years with Angle Class II malocclusions. Treatment time with this appliance was 8 to 10 months. Lateral cephalometric radiographs and computed tomography (CT) images were taken to evaluate morphological changes. Electromyographic (EMG) activity of the masseter, temporalis and anterior belly of the digastric muscles was recorded with surface electrodes. Lateral cephalograms and CT images were acquired before treatment, at the start of treatment (at Herbst appliance placement), during treatment (12 to 16 weeks after appliance placement), after treatment (at Herbst appliance removal), and 4 months after appliance removal.

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RESULTS: All subjects were treated to a Class I or overcorrected Class I dental arch relationship with significant (P < 0.01) forward mandibular positioning. Cephalometric analysis revealed increases in SNB, SNP, N-Me, S-Me, and Cd-Gn. Morphological changes in the glenoid fossa and the condyle were also observed on the CT images. CONCLUSION: Class II treatment with a modified Herbst appliance was accompanied by both skeletal and dental changes. The results suggest that forward and downward movement of the condyles in the glenoid fossae with Herbst treatment led to a combination of condylar growth and fossa reremodelling.

430 INFLUENCE OF AGE AND BODY MASS INDEX ON THE EFFICACY OF MANDIBULAR ADVANCEMENT DEVICES IN OBSTRUCTIVE SLEEP APNOEA TREATMENT M Thier1, D Ohlendorf1, J Rey2, J Langenhan1, S Kopp1, Departments of 1Orthodontics and 2Biostatistics and Mathematical Modeling, Goethe-University, Frankfurt/Main, Germany Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 AIM: For many years oral appliances - also known as mandibular advancement devices (MAD) - have been used as an alternative to continuous positive airway pressure therapy (CPAP) in obstructive sleep apnoea (OSA) treatment. This study aimed to identify the influence of the parameters of age and body mass index (BMI) on patient’s response to oral appliance treatment. SUBJECTS AND METHOD: Eighty eight patients who were pre-diagnosed with OSA and had received oral appliance treatment at a dental practice (Idstein/Germany. The mean age of the group was 51.8 (SD ±10.8) years and the mean BMI was 27.5 (SD ±4.9). A good response, defined as an apnoea-hypopnoea index (AHI) lower than five events per hour following insertion of the MAD, could be achieved in 52.3 per cent of the cases. Treatment data of the patients were analyzed using the BiAS for Windows™ statistical software (version 10.0 epsilon-Verlag, Frankfurt/M., Germany). Age being a normally distributed parameter was statistically examined using the two-sample t-test. BMI as a parameter not following normal distribution was examined using the Mann-Whitney-U-test RESULTS: Mean age significantly differed in the patients with a good response compared with the group with moderate or no response (P < 0.001); the good responders were of a younger age. The patient group with a good treatment response showed a significantly lower BMI than the moderate or no response group (P < 0.001). CONCLUSION: Age and BMI of subjects can have a significant impact on the effectiveness of a MAD. These parameters could also be of significant prognostic value in future patient treatment. Younger patients with a lower BMI seem to have a better prognosis with oral appliance therapy.

431 CEPHALOMETRIC DETERMINANTS FOR SUCCESS OR FAILURE IN CLASS III CAMOUFLAGE TREATMENT U Thongudomporn, O Henprom, Department of Preventive Dentistry, Prince of Songkla University, Hatyai, Songkhla, Thailand

AIM: To determine cephalometric parameters contributing to the success or failure in Class III camouflage treatment based on occlusion and aesthetic perspective. MATERIALS AND METHOD: Pre- and post-treatment study models of 45 Class III malocclusion patients who underwent camouflage orthodontic treatment were examined by seven experienced orthodontists. Each case was categorized as ‘successful’• or ‘unsuccessful’• according to the Peer Assessment Rating Index (PAR) and Profile Assessment Score (PAS). Treatment was considered to be successful if PAR improved >30 per cent and PAS improved >0.5. Pre-treatment cephalometric parameters of the successful and unsuccessful groups were compared using independent t-tests at the level of significance of P < 0.05. RESULTS: Thirty-two patients (71.1%) gained more than 30 per cent PAR and 0.5 PAS improvement. Five parameters which were statistically significantly different between the successful and unsuccessful groups were U lip-E plane, L lip-E plane, H angle, L lip-H line, and facial contour angle. Patients in the unsuccessful group had more retruded upper and lower lips and a higher tendency toward a concave profile than those in the successful group. e217

CONCLUSION: Class III patients with more retruded upper and lower lips and a more decreased facial contour angle may not be successfully treated with camouflage orthodontic treatment from the occlusal and aesthetic viewpoints.

432 A METHOD FOR CALCULATION OF THE VOLUME OF FACIAL ASYMMETRY AND ITS LOCALISATION IN ORTHODONTIC TREATMENT PLANNING A Thurzo1, A Nádaždyová2, 1Čeľustnej ortopédie Department, Klinika stomatologie a maxilofacialnej chirurgie LFUK a OUSA, Bratislava and 2Department of Orthodontics, Clinic of Dentistry and Maxillofacial Surgery of Medical Faculty - Comenius University, Bratislava, Slovakia

AIM: To define an exact method to evaluate facial asymmetry, its localisation and its exact volume, which could be used in orthognathic surgery treatment planning as well as the fat-grafting and other procedures concerned Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 in facial soft tissue proportions. MATERIALS AND METHOD: One hundred random facial scans were chosen from 1273 scans made on a Di3D scanner. All subjects were chosen randomly and evaluated by six clinicians who were given the same instructions for evaluation of facial asymmetry and its volume. Intra- and interobserver errors were evaluated. Only non-smiling facial expressions were considered. Intraclass correlation coefficients (ICC) were used for detecting intra- and interobserver agreement for each particular scan/asymmetry. The basic steps followed were: 1. Face scan export to OBJ format; 2. Flip the mesh according the A axis (freeze Matrix); 3. Invert faces Orientation and export mirrored mesh to OBJ; 4. Match the meshes in Di3D view software according to a facial region (forehead); 5. Evaluate asymmetry - mesh-difference map up to 0.5 mm difference; 6. Measure the volume of the most prominent asymmetry region RESULTS: Each operator was consistent in the repeated measurements; all ICC were greater than or equal to 0.90 and none of the 95 per cent confidence limits on these ICC had a lower boundary less than 0.84. Interobserver agreement also showed correlation coefficients greater than 0.75. The differences occurred only in very small asymmetrical regions which were difficult to measure due to their small volumes. CONCLUSION: The use of the described method can be carried out with good inter and intraobserver reliability. It is important to appreciate the true volume of soft tissue asymmetry in treatment planning, particularly if treatment can result a change of the soft-tissues. There is a demand for a reliable and simple volumetric method for asymmetry evaluation and the method demonstrated showed future potential.

433 DISTRACTION OSTEOGENESIS IN YOUNG PATIENTS C Tian, F Paiocchi, L Svanetti, F Savoldi, S Bonetti, Department of Orthodontics, University of Brescia, Italy

AIM: Distraction osteogenesis (DO) is a surgical technique, based on the slow and progressive separation of two bone segments by means of a distractor that allows to increase bone and soft tissues volumes, and to change their shape. The aim of this study was to test the use of DO for correcting Class II and Class III skeletal patterns in growing patients. SUBJECTS AND METHOD: Seven non-syndromic patients, aged between 12 and 16 years: four skeletal Class III and three skeletal Class II. All received orthodontic therapy for dental decompensation and underwent DO to lengthen the maxilla (skeletal Class III) or for mandibular elongation (skeletal Class II). The patients were evaluated by a lateral cephalogram and a cone beam computed tomographic based stereolitographic model immediately before and after surgery (t1 and t2). Stereolithographic models were used to select and prepare the distractors before surgery. RESULTS: In Class III patients the average maxillary advancement, measured from the anterior nasal spine, was 6.4 mm after distraction, with a reduction of 0.7 mm in the consolidation phase. The direction of distraction was parallel to the maxillary occlusal plane with a mean change of 2.4 degrees. The average reduction of negative

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overjet was 5.7 mm. The opening of the facial angle remained within 5 degrees in all cases. In Class II patients the average mandibular advancement, measured from pogonion, was 5.7 mm immediately after distraction, with a reduction of 2.3 mm after the consolidation phase. The gonial angle opened on average 6.3 degrees, with an average rotation of the occlusal plane of less than 4.2 degrees. The overjet decreased by 4.9 mm on average during the consolidation phase, although the changes related to the orthodontic treatment finishing phase also have to be considered. Cutaneous pogonion advanced 3.8 mm on average after the consolidation phase. CONCLUSION: DO has proven to be a reliable technique in jaw advancement in growing adolescent patients. Relapse after surgical distraction was minimal, with a greater stability in the maxilla.

434 ASSOCIATION BETWEEN ATLANTO-OCCIPITAL LIGAMENT CALCIFICATION AND CONGENITALLY MISSING TEETH IN BOSNIAN ORTHODONTIC PATIENTS A Tiro1, V Dzemidzic1, L Redzepagic Vrazalica1, A Fetahovic2, E Nakas1, Departments of Orthodontics, 1School of Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 Dental Medicine, University of Sarajevo and 2Health Centre of Vitez, Bosnia and Herzegovina

AIM: To investigate association between presence of cervical spine anomalies (atlanto-occipital ligament calcification and congenital missing teeth in Bosnian orthodontic patients. Tooth development is under the genetic control, which determines tooth position, number, size, and shape. The familial and sporadic forms of tooth agenesis have been associated with mutations in MSX1 and PAX9. Skull and face skeletal development as well as neck and shoulder skeletal development, are influenced by neuro crestal cells (NCCs). It indicates the possibility of links between tooth agenesis and atlanto-occipital ligament calcification. MATERIALS AND METHOD: Lateral cephalograms and dental pantomograms of 30 subjects between 12 and 18 years old with congenital missing teeth collected and evaluated retrospectively. An inclusion criterion was good- quality panoramic radiographs and lateral cephalometric radiographs with the cervical spine clearly visible. The anomalies recorded for each case included, atlanto-occipital ligament calcification on lateral cephalogram, and congenital missing teeth on DPT. A control group consisted of 60 subjects between 12 and 18 years, without congenital missing teeth or the other morphological and structural dental anomalies. Each radiograph was carefully inspected for the presence of complete or partial calcification of the atlanto occipital ligament. Direct visual method of examination was used. RESULTS: In congenital missing teeth group 7 of the 30 subjects (23.3%), showed some degree of a atlanto- occipital ligament calcification (ponticulus posticus). In control group, 8 of the 60 subjects (13.3%) showed presence of some degree of cervical spine anomalies. The value of t-test was 1.440, P = 0.230. CONCLUSION: These findings indicate an association between anomalies of the cervical vertebral column and tooth agenesis. Tooth development as a part of face skeletal development as well as neck skeletal development, are influenced by NCCs.

435 EVALUATION OF THE ASSOCIATION OF THIRD MOLARS WITH ANTERIOR MANDIBULAR AND MAXILLARY CROWDING. A SYSTEMATIC REVIEW I Toulia1, I Doulis1, D Kloukos2, A Souliotis1, Departments of Orthodontics and Dentofacial Orthopedics, 1251 Hellenic Air Force V.A. General Hospital, Athens, Greece and 2University of Bern, Switzerland

AIM: To systematically search the literature and assess the available evidence for the influence of, impacted or not, extracted or retained third molars on anterior mandibular and maxillary crowding. MATERIALS AND METHOD: Electronic database searches of published and unpublished literature were performed. The following electronic databases, with no language and publication date restrictions, were searched: Medline (via Ovid and PubMed), Embase (via Ovid), the Cochrane Oral Health Group’s Trials Register and Central. Unpublished literature was searched on ClinicalTrials.gov, the National Research Register, and Pro- Quest Dissertation Abstracts and Thesis database. The reference lists of all eligible studies were hand-searched for additional studies. Two review authors performed data extraction independently and in duplicate using e219

individualised data collection forms. Disagreements on data extraction and quality assessment were resolved by discussion or the involvement of an arbiter. RESULTS: From the 581 articles identified by the search, after application of the specific inclusion and exclusion criteria and removal of the duplicates, 32 papers were considered eligible for inclusion in the review. After further selection following the full text reading stage, 18 studies qualified for the final review analysis. Among them only one randomised clinical trial (RCT) was identified. All studies were assessed for their quality and graded eventually from a low to moderate level of evidence. The RCT compared the removal of impacted mandibular third molars with retention and examined the effect on late lower incisor crowding. This study was evaluated as at high risk of bias and provided no evidence that extraction of third molars had an effect on lower incisor crowding over 5 years. All other studies, except three, found no association between third molars and anterior maxillary or mandibular crowding. CONCLUSION: The available evidence supports that although the third molar influences the lateral segments, no Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 obvious relationship between the third molar and anterior crowding can be observed. Continuous changes of the dental arches occur from the primary until the adult period, with individual variations. This change could be interpreted as a biological migration of the dentition, resulting in anterior crowding especially in the mandible, even in subjects with congenitally missing third molars.

436 A COMPARATIVE STUDY OF THE OCCLUSAL SUCCESS RATE IN TWO AND FOUR PREMOLAR EXTRACTION TREATMENT E Toy, E Cakir, B Altuntas, Department of Orthodontics, Faculty of Dentistry, Inonu University, Malatya, Turkey

AIM: Malocclusions can be treated by several means, according to the problem, and the treatment plan might include extractions. The purpose of this study was to compare the occlusal success rate of orthodontic treatment results between two or four first premolar extraction protocols using two different indexes, the Treatment Priority Index (TPI) and American Board of Orthodontics Objective Grading System (ABO-OGS). MATERIALS AND METHOD: In this retrospective study, the samples were selected from the files of over 200 treated patients’ records. The initial and final records of 32 patients with Class I and Class II malocclusions were divided into two groups according to extraction protocols. Group 1 consisted of 17 patients (7 males, 10 females) treated with two maxillary first premolar extractions at an initial mean age of 15.02 years (range: 11.33-17.5 years). Group 2 consisted of 15 patients (3 males, 12 females) treated with four first premolar extractions at an initial mean age of 15.92 years (range: 10.83-32.91 years). The TPI and ABO-OGS indices were calculated on the pre- (T1) and post- (T2) treatment dental study models of each patient. (NPar, Mann-Whitney U, Wilcoxon Signed Ranks and Chi-Square tests). The means and standard deviations for each variable were calculated to enable characterization of both groups. Significance was defined as P < 0.05. RESULTS: Values of TPI and ABO-OGS scores in group 1 showed no statistically significant differences (P < 0.05) compared with group 2 except for dental displacement. Treatment success was also found to be statistically significant for both groups. The final overjet, overbite and crossbite were significantly smaller in both groups. ABO-OGS scores, when coded as successful (≤ 30) and unsuccessful (>30), were found to be significant for both groups. There were no statistically significant differences between groups 1 and 2 according to ABO-OGS scores. CONCLUSION: Treatment of Class II malocclusions with both two maxillary or four premolar extractions had similar occlusal success rates in these patients. There was no significant difference in final TPI values and ABO- OGS scores between two groups.

437 PATIENTS’ EVALUATION OF QUALITY OF LIFE DURING ORTHODONTIC TREATMENT V Tsarik1, L Andreeva2, V Gurgurieva2, 1Premier Stomatology, Moscow, Russia and 2Orthodontic Department, Medical University, Sofia, Bulgaria

AIM: To examine patients’ evaluation of quality of life during their orthodontic treatment. e220

SUBJECTS AND METHOD: The survey was conducted among 122 patients aged 5 to 53 in years attending two private orthodontic clinics. The patients were selected according to the following criteria: group I, mixed dentition patients aged 5 to 11 years. Interceptive treatment with removable appliances was undertaken. The orthodontic treatment decision was made by the parents. Group II, patients in the permanent dentition aged 11 to 18 years were treated with fixed appliances. The treatment decision was made by the patients’ parents. Group III, aged over 18 years treatment was performed with fixed appliances. All patients completed identical questionnaires each containing 10 questions. The patients in group I were assisted by their parents while answering. The data was statistically processed. RESULTS AND CONCLUSIONS: In group I the attitude to treatment was determined by the patient’s age. The patients’ attitude towards aesthetics was highest in group III. The assessment that orthodontic treatment improves dental health had the lowest rate in group III. 1. The patients were divided into three groups according to their attitude to orthodontic treatment: Group I children, being most disengaged in treatment, Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 were either very satisfied for a short period of time or indifferent to their treatment. Group II teenagers’ attitude was rather negative, but they followed parental decisions. Group III adults had the highest percentage of positive attitudes. 2. Generally patients considered orthodontic treatment as a way to obtain ‘beautiful teeth and a Hollywood smile’. 3. Some patients were aware that treatment of orthodontic anomalies improves dental health and prevents periodontal disease. 4. Most patients disapproved of extended orthodontic treatment. 5. The majority of patients accepted the temporary inconveniences of having orthodontic appliances in order to achieve positive treatment results.

438 LONGITUDINAL EVALUATION OF HYOID BONE POSITION IN DIFFERENT MALOCCLUSIONS A Tsaous Chasan, M O Akçam, G Yüksel, Department of Orthodontics, Faculty of Dentistry, Ankara University, Turkey

AIM: To investigate hyoid bone position in different malocclusions longitudinally to reveal possible differences between malocclusions and to determine positional differences. MATERIALS AND METHOD: One hundred and seventy four lateral cephalometric radiographs of 58 individuals having different malocclusions (mean age: females: 10.6 years, males: 10.1 years) which were randomly selected from the orthodontic department archives. Dimensional and angular measurements of the reference points marked on radiographs were obtained by the PORDIOS, computer software. Statistical analysis of the parameters according to year (3 years) and Class (3 different groups) factors were analyzed by the repeated measurement variance analysis technique and statistically different year and/or Class groups were identified by Duncan’s multiple range test. RESULTS: The vertical position of the hyoid bone was relocated downwards during the 3 year follow-up period in all groups. The vertical position of the hyoid bone showed statistically significant differences between malocclusion groups. The lowest increase in the vertical position of the hyoid bone was in the Class II group and the greatest increase in the Class III group. The change in the vertical position of the hyoid bone might possibly be related to vertical development of face. Sagittal position of the hyoid bone showed forward linear increase during the 3 year period in all groups. The sagittal position of the hyoid bone did not show a statistically significant difference between malocclusion groups. In the sagittal direction; the distance between hyoid bone and atlas/CVT was lowest in the Class II group and highest in the Class III group. According to cranial base, the hyoid bone was positioned more backward in the Class II group. It was determined that the position of the hyoid bone was related to mandibular position and dimensions. When considering the efficacy of functional treatment utilized in the growth and development period, it is suggested to consider the changes in the position of hyoid bone during the normal growth and development period. CONCLUSION: The vertical position of the hyoid bone showed statistically significant differences between malocclusion groups during growth which might be related to the vertical development of the face.

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439 HISTOMORPHOLOGICAL FINDINGS IN AREAS ADJACENT TO AND REMOTE FROM A LOADED TOOTH A Tsolakis1, L Khaldi2, M Makou1, P Stanko3, I Dontas4, 1Orthodontic Department, School of Dentistry, 2General Hospital 'Agios Savvas', 4Laboratory for Research of the Musculoskeletal System, School of Medicine, Athens, Greece and 3Maxillofacial Surgery Department, School of Dentistry, Bratislava, Slovakia

AIM: To investigate the effect of orthodontic tooth force on the alveolar and basal bone adjacent to and remote from the loaded teeth, in ovariectomized (OVX) female rats. MATERIALS AND METHOD: Twenty-four 6-month-old female Wistar rats. The animals were divided into two equal groups: group A (control group) the rats were subjected to orthodontic movement of the upper right first molars; group Brats underwent orthodontic movement of the upper right first molar following bilateral ovariectomy. Ovariectomy was performed on the first experimental day and the upper right first molars were subjected to orthodontic forces 60 days post-ovariectomy. The orthodontic force lasted for 14 days. Histology Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 of the basal bone ahead of the loaded tooth and of the alveolar bone of the adjacent and distal teeth to the loaded molar as well as of the contralateral side, was performed following euthanasia. RESULTS: In non-OVX rats, in areas ahead of the orthodontic force application, distortion of the bone structure and woven bone formation were observed compared with lamellar and well orientated bone of the contralateral unaffected side. In contrast, in OVX rats, on the side ahead of application of orthodontic forces, distinct cement lines and extensive remodelling were apparent. In the non-OVX rats, extensive resorption was noticed in the direction of the orthodontic movement in the second and third molar interdental space, whereas the respective contralateral interdental space did not show any remodelling activity. OVX rats displayed reduced osseous tissue in the interdental alveolar space on both sides. The alveolar bone in the interradicular area of the second molar revealed anterior resorption, whereas, the alveolar interradicular alveolar bone of the contralateral second molar showed internal resorption. CONCLUSION: Orthodontic forces applied to the dentoalveolar complex of OVX rats affect bone remodelling, even in areas ahead and distal to the site of force application and may produce distal and remote alveolar bone responses, regional acceleratory phenomena and distraction like phenomena.

440 PREVALENCE OF LOWER INCISOR AGENESIS T Turk1, F Çelebi2, M Turkal3, H Aydemir Turkal4, E Canlı1, 1Department of Orthodontics, Ondokuz Mayıs University, Samsun and Departments of 2Orthodontics, 3Prosthodontics and 4Periodontics, Gazi Osman Paşa University, Tokat, Turkey

AIM: To retrospectively evaluate the prevalence and sexual distribution of lower incisor agenesis. MATERIALS AND METHOD: One thousand four hundred and sixty nine panoramic radiographs taken from patients who applied for treatment. The radiographs were examined in order to determine whether there was lower incisor agenesis. Patients were in both the mixed and permanent dentitions with an age range from 10 to 60 years. RESULTS: The prevalence of lower incisor agenesis was found to be 1.49 per cent for this patient population. Lower incisor agenesis was observed in 22 patients (12 females, 10 males). CONCLUSION: For this patient population, the prevalence of lower incisor agenesis was 1.49 per cent. The number of female and male patients with lower incisor agenesis was almost equal.

441 INDIVIDUAL SKELETAL MATURITY ASSESSMENT IN ORTHODONTIC PATIENTS M Tymczyna-Sobotka, Department of Jaw Orthopaedics, Medical University, Lublin, Poland

AIM: Treatment timing should be determined according to individual skeletal maturity. Assessment of future growth, periods of accelerated growth and correct growth management on the basis of the patient’s age and

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gender is insufficient considering heterogeneous individual development with different growth rates. The aim of this study was to assess skeletal maturity in randomly selected subjects. MATERIALS AND METHOD: Lateral cephalograms of 1000 individuals were analyzed. According to the inclusion criteria, 274 (27.4%) of subjects were excluded. Finally 726 subjects were investigated (417 females, 309 males) with an age range between 5 and 33.9 years. Visual analysis using the cervical vertebral maturation (CVM) method according to Baccetti et al. (2005) was performed. Descriptive statistical analysis including Spearman’s rank correlation was performed. The correlation between chronological and skeletal age at every stage of skeletal maturity, the duration of the pubertal growth spurt, chronological age with the greatest diversity of skeletal maturity and the mean chronological age when the growth was complete was evaluated RESULTS: 1. Due to the wide range of chronological age in different stages of skeletal maturity, bone age should be individually assessed, especially among girls aged 10 years and boys aged 12 and 14 years. 2. Differentiation of chronological age during the pubertal growth spurt precludes the use of chronological age as the sole Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 indicator to determine the degree of development. 3. The CVM method allows clinical use of the cervical vertebrae to assess the level of skeletal maturity and prediction of the subsequent stages of bone growth. 4. Determination of skeletal maturity from cervical vertebrae is only possible on the basis of good quality images of the head.

442 MAXILLOFACIAL AND INTRAORAL CHARACTERISTICS OF NOONAN SYNDROME T Ueno1, K Kataoka1, E Issareeya1, Y Baba2, K Moriyama1, 1Department of Maxillofacial Orthognathics, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo and 2Division of Dentistry, Department of Surgical Specialties, National Center for Child Health and Development, Setagaya-ku, Tokyo, Japan

AIM: Noonan syndrome (NS) is a multiple congenital malformation characterized by short stature, congenital heart defect and a typical facial appearance. The maxillofacial morphology of NS has been reported previously as a part of systemic features; however, only a few clinical reports have described maxillofacial and intraoral characteristics. Therefore, this study evaluated these characteristics systematically in terms of orthodontics. MATERIALS AND METHOD: Data were compiled to include lateral cephalograms, panoramic radiographs, intraoral photographs, and dental models at the initial visit before orthodontic treatment from eight Japanese NS patients (mean age 12.1 ± 2.5 years) and seven age-matched control subjects (mean age 11.5 ± 2.1 years), apart from one subject who was not part of the analysis target. Cephalometric measurements were performed and compared with normal Japanese standards. Intraoral characteristics were examined using dental models and intraoral photographs. Among them, dental arch width was compared with the normal Japanese standard. After three-dimensional scanning of dental casts, the height of the palatal arch was measured and compared with normal Japanese data. Root formation and apical closure timing were observed on panoramic radiographs according to Moorrees’s method and compared statistically between NS and control subjects using Mann Whitney U-tests (P < 0.05). RESULTS: In NS patients: 1) cephalometric analysis revealed skeletal characteristics of mild mandibular retrusion and mandibular clockwise rotation, and occlusal characteristics of proclined lower anterior teeth were noted; 2) The anterior teeth had a tendency to a shallow bite; 3) Five out of eight subjects had high canines; five an open bite or edge-to-edge bite; and two an anterior crossbite; 4) There was no tendency to deviated maxillary and mandibular dental arch widths; 5) The values for the height of the palatal arch were quite variable; 6) Mandibular premolar root formation and apical closure timing were significantly delayed in NS when compared with control subjects. CONCLUSION: NS patients present specific maxillofacial and intraoral characteristics. As a delay in dental root formation and apical closure were observed, careful consideration with regard to the timing of the start of orthodontic treatment using multibracket appliances is required.

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443 ORTHODONTIC CORRECTION OF INCISOR POSITION IN UNILATERAL CLEFT LIP AND PALATE PATIENTS: COMPARISON OF DIFFERENT TREATMENT MODALITIES R Uomo, V D'Antó, L Chianella, T Gentile, A Galeotti, Department of Pediatric Surgery, Division of Dentistry, ‘Bambino Gesù’ Children Hospital, Roma, Italy

AIM: Abnormalities in incisor position, including altered rotation and angulation, are reported to occur in more than 45 per cent of unilateral cleft lip and palate (UCLP) patients. Affected anterior teeth position may play a key role in determining mandibular shift, promoting the development of anterior and lateral crossbites. Moreover, orthodontic correction of the malpositioned upper incisors, before bone grafting, is reported to make surgery easier. The aim of this study was to compare the efficiency of different orthodontic systems in the correction of incisor position in UCLP patients. SUBJECTS AND METHOD: Fifteen patients were selected to meet the following inclusion criteria: non-syndromic Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 UCLP, mixed dentition, meso- or hypodivergent growth pattern, incisor rotation ≥90 degrees, incisor angulation ≥20 degrees. The subjects were randomly divided into three groups, and treated with palatal expansion alone, palatal expansion and a 0.017 × 0.025 inch beta titanium utility arch (UA) connecting banded molars to the central incisors bonded with 0.022 × 0.028 inch brackets (UA), or palatal expansion and UA with V-bends applied with an occlusal apex on the side of the cleft and with a gingival apex on the opposite side. Data regarding tooth rotation were evaluated before and after treatment (mean duration time 10.3 ±2.2 months) on dental casts, while incisor angulations were digitally measured on posteroanterior cephalograms at the same timepoints. Measurements were analyzed by descriptive statistics, and the Mann-Whitney U test was used to evaluate intergroup differences. RESULTS: Palatal expansion had only a minor effect on incisor position and angulation. Compared with the first group, the use of a straight UA was helpful in the correction of incisor rotation (P < 0.05), but not in improving tooth angulation (P = 0.15). Regardless of the initial severity of rotation or altered angulation, a V-bent UA showed the highest degree of incisor position correction among groups (P < 0.05). CONCLUSION: UA with correct V-bends are a useful tool in correcting incisor position and angulation in UCLP patients.

444 UPPER RESPIRATORY TRACT AND CRANIOFACIAL MORPHOLOGY IN PATIENTS WITH MILD ADENOID HYPERTROPHY QUALIFIED FOR ORTHODONTIC TREATMENT A Urbaniak, A Wojtaszek-Słomińska, A Przedpełska, Department of Orthodontics, Medical University of Gdansk, Poland

AIM: To assess the upper respiratory tract obstruction and craniofacial morphology in patients with mild adenoid hypertrophy requiring orthodontic treatment. SUBJECTS AND METHOD: One hundred and nineteen children, aged 8-12 years, who qualified for orthodontic treatment were classified into two groups. The study group included 81 children with mild adenoid hypertrophy (patients did not qualify for adenoidectomy). The control group included 38 children without significant airway obstruction. An interview regarding breathing disorders was conducted. Craniofacial morphology and the anteroposterior width of the upper respiratory tract were evaluated on the lateral cephalograms. The results were subjected to statistical analysis. RESULTS: Children with upper respiratory tract narrowing showed an increased prevalence of oral breathing and respiratory disorders during sleep. Cephalometric analysis of the study group revealed disrupted morphology of the craniofacial skeleton. In the anteroposterior dimension, there was mandibular retrusion with a correct position of the maxilla, and increased prevalence of a skeletal Class II malocclusion. In the vertical dimension, there was mandibular posterior rotation due to a considerable increase of its angle and of the NS/ML and NL/ML angles. These changes resulted in an increased anterior face height.

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CONCLUSION: Adenoid hypertrophy and abnormal respiratory function may negatively affect growth and development of craniofacial morphology and the occurrence of malocclusions in a child. Restoration of correct breathing patterns should become the primary aim of paediatric, laryngological and orthodontic treatment of a growing patient.

445 MICROBIAL COLONIZATION OF THE CLEFT BEFORE ALVEOLAR BONE GRAFTING W Urbanová1, M Koťová2, E Leamerová2, J Dvořáková2, 1Department of Orthodontics and Cleft Anomalies and 2Clinic of Plastic Surgery, 3rd Medical Faculty Charles University FHRV Prague, Czech Republic

AIM: To determine microbial colonization of the alveolar cleft in patients before alveolar bone grafting and its impact on pre- and post-operative C-reactive protein (CRP) level and white blood cell (WBC) count. SUBJECTS AND METHOD: In 27 consecutive patients (♂17, ♀10); scheduled for alveolar cleft repair (18 Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 unilateral cleft lip and palate, four bilateral cleft lip and palate, five cleft lip and alveolus) swabs from the alveolar cleft or oronasal fistulae, nose and throat were taken before surgery. The average age of the patients was 9 years 11 months. If pathogenic bacteria were identified in the swab the result was evaluated as positive, negative swabs contained opportunistic pathogens and microbiota of normal flora. The CRP level and WBC count were monitored 1) before, 2) during the first three days after the surgery, 3) from the fourth to sixth day after the surgery. The dependence of the levels of the inflammatory markers and positive or negative swab results was evaluated using a two-sample Wilcoxon test. RESULTS: In 13 patients in at least one of the three swabs pathogenic microorganisms were detected, inside the alveolar cleft pathogens were found in 11 cases. Candida albicans was identified in five more cleft swabs. Four examined patients had a positive swab only from the cleft; no pathogens were isolated from the nose or throat mucosa. Among the bacteria found in the cleft were Staphylococcus aureus, Streptococcus pyogenes, Proteus mirabilis, Pseudomonas aeruginosa and others. A statistically significant difference was found before surgery in CRP levels between patients with positive and negative cleft swabs (P = 0.03), however no significant differences in CRP levels or WBC counts were found in the first post-operative week. CONCLUSION: As pathogenic bacteria were identified in the alveolar cleft, additional swabs from the cleft were used to estimate optimal antibiotic prophylaxis for the alveolar bone grafting. The CRP levels before surgery differed between patients with positive or negative cleft swabs, however no differences were found between patients with positive or negative cleft, nose or throat swabs in the inflammatory markers levels in the first post- operative week. Further research is necessary to identify the clinical impact of latent infection and occurrence of potential pathogens inside the cleft on healing and on the incidence of post-operative complications.

446 GRADUATE ORTHODONTIC EDUCATION IN TURKEY: THE RESIDENT’ PERSPECTIVE S Usumez1, J Noble2, A Yagci3, T Uysal4, W Wiltshire2, Departments of Orthodontics, 1Bezmialem Vakif University, Istanbul, Turkey, 2University of Manitoba, Winnipeg, Canada, 3Erciyes University, Kayseri, Turkey and 4Izmir Katip Celebi University, Izmir, Turkey

AIM: To explore residents’ perceptions of their educational and clinical treatment experiences, including the number of clinical cases undertaken, patient completion rates, techniques utilised and the scientific component of Turkish graduate orthodontic programmes. SUBJECTS AND METHOD: Residents recorded in the list of Turkish Orthodontic Society were sent an e-mail to participate in a survey containing 46 multiple-choice questions and 10 one-line answers. An e-mail with a personalised online link was sent to a total of 227 residents throughout Turkey. Data were categorised, and basic statistics, including chi-square comparative analyses, were performed. RESULTS: A total of 136 (response rate of 59.91%) residents completed the survey. The majority of residents (58.08%) were either ‘very satisfied’ or ‘satisfied’ with their programme. Respondents said they have just the right amount of formal didactic teaching sessions or dedicated and protected academic time. Most residents e225

(69.11%) indicated their programme offered training in numerous philosophies; whilst 97.79 per cent said they had sufficient clinically based training and 42.64 per cent said they have sufficient research-based training. Overall, residents in Turkey were satisfied with their orthodontic programme. They received comprehensive training with the opportunity to start and complete a significant number of their patients. CONCLUSION: The survey findings suggest that orthodontic programmes in Turkey are deficient in providing care to underserviced populations and disabled patients. Programmes could improve the opportunity for residents to treat patients requiring interdisciplinary treatment.

447 COMPARISON OF HAND TRACING AND CEPHALOMETRIC SOFTWARE: A RETROSPECTIVE STUDY L Vahdettin1, K Orhan2, O Rusu3, 1Department of Orthodontics, Faculty of Dentistry, Near East University, Nicosia, Cyprus, 2Department of Dentomaxillofacial Radiology, Ankara University, Turkey and 3Department of General and Dental Radiology, University of General Medicine and Pharmacy ‘Gr. T. Popa', Iasi, Romania Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021

AIM: To compare the measurements obtained from the various two-dimensional digital software programs with those of hand tracing. MATERIALS AND METHOD: Pre-treatment cephalometric radiographs of 121 patients were retrospectively evaluated using Vistadent OC (GAC International, Inc., Bohemia, New York, USA), TotalCeph (Torc Software Ltd., Istanbul, Turkey), Planmeca Romexis (Romexis 3.2.0., Helsinki, Finland) software and hand tracing method. A total of 18 cephalometric measurements (11 angular and 7 linear) commonly used to assess dentofacial relationships were selected. Differences in measurements between the four groups were evaluated using the Kruskal Wallis H test (P < 0.05) and multiple group comparisons using the Mann-Whitney U test (P < 0.017). To evaluate the method error, all of the radiographs were retraced and the differences between the two groups were evaluated using Wilcoxon’s signed rank test (P < 0.05). RESULTS: More statistically significant differences were detected for repeated measurements performed with the digital method, especially for TotalCeph and Planmeca Romexis software. The mean AB/NPg measurement was significantly lower for the Planmeca Romexis than for the other groups. The mean Nperp-A measurement was significantly lower for the hand tracing method than for the TotalCeph and Planmeca Romexis groups, and the mean measurement for the same parameter was significantly lower for the Vistadent OC than for the Romexis group. The mean U1-NA measurement was significantly higher for the TotalCeph than for the Vistadent and Planmeca Romexis groups. The mean Oc/SN measurement for the hand tracing method was significantly lower than for the other groups and the mean measurement for the same parameter was significantly higher for the Vistadent OC than for the Planmeca Romexis group. CONCLUSION: Cephalometric analysis was highly reproducible for hand tracing and Vistadent OC software. Although some measurements made using TotalCeph and Planmeca Romexis showed statistically significant differences, the differences were rarely above 1 mm or 1 degree. Statistically significant differences in measurements were identified between the groups; therefore these parameters should be examined more carefully when making orthodontic diagnoses, drawing up treatment plans, and when assessing treatment outcomes.

448 CORRELATION OF 2D:4D DIGIT RATIO AND CRANIOFACIAL SHAPE IN PREPUBERTAL CHILDREN K Valla, D Halazonetis, Department of Orthodontics, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece

AIM: The 2D:4D ratio is sexually dimorphic and is considered a proxy of prenatal androgen levels, or, according to recent evidence, is related to genes involved in ocular and palate development. The aim of this research was to investigate the correlation between the 2D:4D ratio and the shape of the craniofacial skeleton in a population of prepubertal children.

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SUBJECTS AND METHOD: A cross-sectional study was conducted of 58 male and 59 female prepubertal children aged 7 to 12 years. Craniofacial shape was evaluated using 15 skeletal landmarks on lateral cephalometric radiographs and fingers were measured with a computer-assisted procedure that involved tracing the finger outline. Geometric morphometric analysis was applied to the craniofacial landmarks and multivariate regression between digit ratios and craniofacial shape was computed in shape space and form space. RESULTS: The male 2D:4D ratio was smaller than the female ratio (Cohen’s d: 0.275 left hand, 0.126 right hand), but the difference was not statistically significant. Craniofacial shape did not show sexual dimorphism, but males were larger than females. No correlation was found between digit ratio and craniofacial shape in prepubertal children, either for the whole sample or for any of the two gender groups. CONCLUSION: As several factors might be involved in the development and growth of both the craniofacial complex and fingers, 2D:4D ratio, a potential proxy for foetal sex-hormone levels, is probably unable to impose a measurable effect within the variation of a normal population. Future research needs to examine an adult Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 sample for potential covariation arising after the pubertal growth spurt.

449 NASAL SEPTUM DEVIATION IN PATIENTS WITH DIFFERENT VERTICAL GROWTH PATTERNS ASSESSED WITH CONE-BEAM COMPUTED TOMOGRAPHY İ Veli1, M Orhan2, M A Öztürk1, A E Şekerci3, T Uysal1, Departments of Orthodontics, 1Izmir Katip Celebi University, Izmir and 2Gazi University, Ankara and 3Department of Oral and Maxillofacial Radiology, Erciyes University, Kayseri, Turkey

AIM: To evaluate the correlation between vertical growth patterns and nasal septum deviation using three- dimensional images. MATERIALS AND METHOD: A total of 45 cone beam computed tomographic (CBCT) scans of good quality. Septum deviation was assessed at four different points in a coronal view: (1) at the choanae, (2) at half the distance from the piriform aperture to the choanae through the cartilaginous bony septum (3) the piriform aperture, (4) at half the distance from the tip of the nose to the piriform aperture. Tortuosity ratio of the septum was evaluated by dividing the length of the septum by the ‘ideal’ length. To assess correlation between vertical skeletal pattern and the degree of septum deviation, SNGoMe angle of each patient was measured on the lateral cephalograms derived from CBCT scans. Pearson's correlation coefficients were calculated to determine relationship between tortuosity ratio and Sn-GoMe angle. RESULTS: According to Pearson’s correlation, positive (r = 0.237) but not statistically significant correlation (P = 0.117) was found between tortuosity ratio and SN-GoMe angle. CONCLUSION: There is a positive relationship between vertical growth patterns and nasal septum deviation. However, this relationship seems clinically not important.

450 MOLAR HEIGHT AND DENTOALVEOLAR GROWTH CHANGES IN MALES WITH A DEEP BITE MALOCCLUSION: A LONGITUDINAL STUDY İ Veli, M A Öztürk T Uysal, Department of Orthodontics, Izmir Katip Celebi University, Izmir, Turkey

AIM: To evaluate, in a retrospective longitudinal study, molar height and dentoalveolar growth changes in untreated male subjects with a deep bite malocclusion, and to correlate a deep bite with these components. MATERIALS AND METHOD: Dentoalveolar and skeletal changes at three intervals, defined by the cervical vertebral maturation method (T1: prepubertal-mean: 11.6 ± 1.7 years; T2: pubertal-mean: 14.1 ± 1.5 years; T3: post-pubertal-mean: 16.7 ± 0.9 years) were digitized and analyzed on longitudinal lateral cephalograms of 26 male subjects with a deep bite malocclusion. A total of five angular and 10 linear variables were evaluated. Friedman test and analysis of variance with repeated measures were used to determine the changes. In all statistical analyses, a significance level of 5 per cent was considered.

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RESULTS: Statistically significant decreases (P < 0.001) were found for gonial angle at all time periods. Upper molar height, lower incisor length and the width of lower anterior alveolar process exhibited significant increases at T1-T2 and T1-T3 time periods. Lower molar height, upper incisor length (measured on the long axis of the alveolar process), the width of upper anterior alveolar process and mandibular ramus length were statistically significantly increased at all time periods. Significant positive correlations were also determined between overbite and the inclination of the lower incisors to the mandibular plane (r = 0.515, P = 0.007) at T2-T3 and between overbite and NS-ML angle (r = 0.464, P = 0.017) at T1-T3. CONCLUSION: Incisor length and increased molar height play a significant role in deep bite malocclusions in growing male subjects.

451 THE CURVE OF SPEE AND DENTOFACIAL MORPHOLOGY: A POPULATION STUDY İ Veli, M A Öztürk, B Yüksel, T Uysal, Department of Orthodontics, Izmir Katip Celebi University, Izmir, Turkey Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021

AIM: To determine the relationship between the curve of Spee and dentofacial morphology in a Turkish population. MATERIALS AND METHOD: Three-dimensional (3D) digital models and lateral cephalograms of 60 patients (30 boys, 30 girls; age range, 14-20 years). The depth of the mandibular curve of Spee was determined on 3D digital models and angular and linear cephalometric measurements were analyzed on digital lateral cephalograms to determine dentofacial morphology. Correlation coefficients between the depth of the curve of Spee and dentofacial measurements were calculated and multiple linear regression analysis was performed. RESULTS: The curve of Spee was deepest at the mesiobuccal cusp of the mandibular first molar. The results did not show any statistically significant differences between genders. No statistically significant differences were found between the right and left depth of the curve of Spee. The correlation coefficients between dentofacial measurements and the curve of Spee revealed that the curve of Spee had significant correlations with SNB and FMA. CONCLUSION: The curve of Spee is influenced by the anteroposterior position of the mandible but not by gender.

452 THE QUALITY OF ONLINE ORAL HYGIENE INSTRUCTIONS FOR PATIENTS WITH FIXED ORTHODONTIC APPLIANCES. W Verhoef, C Livas, Y Ren, Department of Orthodontics, University of Groningen, University Medical Centre Groningen, Netherlands

AIM: To evaluate the standards of available Internet information on oral hygiene instructions for patients undergoing fixed appliances treatment. MATERIALS AND METHOD: A systematic electronic search was performed with search terms of ‘brushing braces’, ‘cleaning braces’, ‘oral hygiene instructions and braces’ in combination with ‘orthodontics’ using Google™, Bing™, and Yahoo® search engines. The first 20 results from each search term-engine alternative were examined for eligibility. After excluding websites requiring a fee or password, non-English language domains, links to books and articles, video feeds, and duplicates, 47 Web pages were evaluated in terms of readability, accessibility, usability, and reliability by means of the Flesch Reading Ease Score (FRES), and the LIDA instrument. Authorship information was also recorded. RESULTS: In general, the results revealed a variable quality of informational material. With an average FRES of 70 per cent, the Web sites displayed acceptable readability. However, LIDA scores for accessibility (88%), usability (66%), and reliability (31%) pointed to medium or low quality. CONCLUSION: The quality of information about oral hygiene instructions for patients with fixed appliances presents high variability. Further improvement of the infrastructure of the respective Web sources should be

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attempted. Well-organized e-education material may prove beneficial for both potential and current orthodontic patients.

453 PAIN DURING ORTHODONTIC TREATMENT WITH FIXED APPLIANCES AFTER INSERTION OF DIFFERENT INITIAL ARCHWIRES J Volk, M Mikac-Cankar, Community Health Centre Ljubljana, Slovenia

AIM: To evaluate and compare the initial time at which pain occurs, the pain level and duration, the medication need and the effect of the pain on daily life after insertion of two different initial archwires. SUBJECTS AND METHOD: Roth 0.022 inch fixed appliances were bonded in 22 subjects (16 females, 6 males, mean age 15.8 ± 2 years). Eleven subjects were randomly selected for the insertion of the 0.015 inch Dentaflex six-strand twisted archwires (8 females, 3 males, mean age 16.6 ± 1.9 years; D-group) and in another 11 subjects Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 the 0.012 inch BioStarter Straight-Arch-Form were inserted (8 females, 3 males, mean 14.9 ± 1.9 years; B-group). The subjects were given a questionnaire with questions about the time of initial pain, spontaneous pain and pain during chewing, eventual medication need and the impact of the pain on daily life at 6 hours and the following 7 days. A combination of ‘yes’ and ‘no’ answers and the 100-mm horizontal visual analogue scales (VAS) on which the subjects marked the degree of pain at the indicated time periods was used in the questionnaire. Chi-square and Mann-Whitney U-tests were applied and the level of significance was set at P < 0.05. RESULTS: The initial pain peaked at 6 hours (mean VAS D-group 42, B-group 37) and decreased after 3 days, when also no more medication use was reported in either groups. Thirty six per cent of subjects in D-group and 45 per cent in B-group reported the effect of the pain on daily life. No significant differences were found between the two groups in the time of initial pain, spontaneous pain, medication need or the impact of the pain on daily life at 6 hours and the following 7 days. During chewing, at 6 hours the pain was significantly higher in D-group (VAS 66, B-group VAS 34, P = 0.005). CONCLUSION: The spontaneous pain level and duration, the medication need and the impact of pain on daily life was not related to the type of initial archwire. However, there was significantly more pain during chewing at 6 hours when using 0.015 inch Dentaflex archwire.

454 CLEANING PERFORMANCE OF DISHWASHERS FOR PMMA-SPECIMENS K von Wallis, S Engel, P-G Jost-Brinkmann, Abteilung für Kieferorthopädie, Charité - Universitätsmedizin Berlin, Germany

AIM: In this in vitro study the performance of dishwashers for cleaning removable orthodontic appliances was evaluated. MATERIALS AND METHOD: One hundred and forty acrylic resin specimens (Orthocryl®) were manufactured according to manufacturer’s instructions: 20 for the pre-tests, 10 stained and 10 unstained for each dishwashing detergent (K Classic Geschirr-Reiniger-Pulver® and Sodasan Maschinenspülmittel® with corresponding rinse agent and dishwasher salt, Somat 10 Spülmaschinentabs®) and each cleaning programme (short programme, 40°C; intensive programme, 75°C). Subsequent to sanding and polishing the specimens to a thickness of 1 ± 0.1 mm, they were stained in accordance to the method of Jagger et al. (2002) with a combination of black-tea solution, 0.2 per cent chlorhexidine and saliva as a plaque-substitute. The optical density of each specimen was determined before and after staining and after cleaning in the dishwasher. All measurements were undertaken using a spectrophotometer at 380 nm, the absorption maximum of the stains. In addition, in each series 10 unstained specimens were used in order to determine the average opacity caused by the cleaning process itself, the values of which were subsequently subtracted from the values measured for the stained specimens. The cleaning performance was expressed as a percentage of removed tea-chlorhexidine-salvia-stains (absorption) in

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relation to the total stain (absorption). The results were analysed for significant differences, using the Kruskal- Wallis and Mann-Whitney tests. RESULTS: All specimens showed less tea-chlorhexidine-saliva-stains after cleaning. The cleaning performance was always significantly higher using the intensive programme. Only the short programme yielded significant differences for the tested detergents with K Classic Geschirr-Reiniger-Pulver® being the most effective (median: 97.65%). Sodasan Maschinenspülmittel® was the least effective product (median: 33.11%). No significant dimensional changes were measured after cleaning for all cases. CONCLUSION: Cleaning of acrylic resin specimens in a dishwasher leads to very good results, in particular using the intensive programme. However, before recommending this method, it should be explored whether there are unfavourable effects such as corrosion of wires.

455 SECULAR TRENDS OF DENTAL DEVELOPMENT IN DUTCH CHILDREN Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 S Vucic1, E de Vries2, P Eilers3, E Wolvius1, E Ongkosuwito1, Departments of 1Oral & Maxillofacial Surgery, Special Dental Care and Orthodontics, 2Public Health and 3Biostatistics. Erasmus University Medical Centre, Rotterdam, Netherlands

AIM: To analyze secular changes in dental development in a large group of Dutch children born between 1961 and 1994. Additionally, the observed trend for the year 2003 was extrapolated and this prediction was validated with data from 9-10 year old children born between 2002 and 2004 from the Generation R study. MATERIALS AND METHOD: Two thousand six hundred and fifty five dental panoramic radiographs of 2-16 year old Dutch children from studies performed in three major cities in the Netherlands were used to assess dental maturity using Demirijan’s method. RESULTS: A trend was observed in children born between 1961 and 1994, showing that a child of a certain age and gender achieved the same dental maturity on average 13.9 days sooner than a child of the same age born one year earlier. The observed trend from 1961-1994 was extrapolated to 9-10 year old children born in 2002- 2004, and validation with the other samples of children with the same characteristics showed that 95.9-96.8 per cent of the children had dental maturity within 95 per cent of the predicted range. CONCLUSION: Dental maturity score was significantly and positively associated with the year of birth, gender, and age in Dutch children, indicating a trend in earlier dental development during the observation period, 1961- 2004. These findings highlight the necessity for considering the year of birth in population-representative databases to correct for secular changes in dental maturity and to periodically update dental age standards.

456 CYTOKINE INTERLEUKIN 1 IN GINGIVAL CREVICULAR FLUID AND IN GINGIVAL TISSUE DURING ORTHODONTIC TREATMENT A Vujacic1, V Todorovic2, J Pavlovic1, V Vukicevic1, N Milosevic-Jovcic3, 1Department of Orthodontics, University of Priština, Medical Faculty, Kosovska Mitrovica, 2Dental Faculty of Pančevo and3Institute for Medical Research, University of Belgrade, Serbia

AIM: To examine changes in the level of expression of Interleukin (IL)-1 in the gingival crevicular fluid (GCF) and its tissue expression in different histological elements during orthodontic tooth movement . SUBJECTS AND METHOD: Twenty patients (15-20 years of age) undergoing orthodontic movement of a single tooth, with the untreated antagonistic tooth used as the control. GCF and gingival tissue (needle biopsy) was sampled at the control and treatment sites before and 24, 72, and 168 hours after initiation of orthodontic treatment. Cytokine levels in GCF were determined using enzyme-linked immunosorbent assay kits. Tissue samples were immunochemically coloured. The degree of cytokine expression was determined on the basis of immunochemical staining intensity and the number of stained tissue structure . RESULTS: GCF levels of IL-1 for the treated teeth were higher than for the control teeth, with marked fluctuations throughout the period examined. On the free gingival tissue samples of treated orthodontic teeth, e230

ranging from 24 up to 168 hours, there were weak to stronger signs of inflammation of the mucosa, which manifested in vasodilatation or infiltration of inflammatory cells. The most pronounced inflammation existed at 168 hours. CONCLUSION: IL-1 was increasingly expressed during the initial phase of orthodontic treatment both in GFC and in the tissue of the free gingival epithelial cells, mucosal fibroblasts, infiltrates of inflammatory cells and vascular endothelial cells. 457 HEAD POSTURE AND CRANIOFACIAL MORPHOLOGY IN CHILDREN WITH ORAL BREATHING V Vukicevic1, D Petrovic2, J Pavlovic1, A Vujacic1, S Simic1, Departments of Dentistry, Medical Faculties, 1Kosovska mitrovica and 2Novi Sad, Serbia

AIM: To analyze the position of the head and craniofacial morphology of children who breathe through the mouth, and to compare the values obtained with those of the same parameters in children who breathe through Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 the nose. SUBJECTS AND METHOD: Group 1 contained 30 children aged 8-14 years, in whom mouth breathing was confirmed by clinical examination. For these children, there was condensation of exhaled air at the surface of a mirror, placed in front of the mouth. In addition, these children could not retain a sip of water in the mouth for longer than 10 seconds without swallowing. Group 2 comprised children of the same age, who had a variety of orthodontic problems, but did not show clinical signs of mouth breathing. For each patient, a lateral cephalometric radiograph was obtained under standardized conditions of recording. The following parameters were analyzed: craniocervical angle (NS/OPT), SNA, SNB, ANB angles, anterior face height (N-Me), posterior face height (S-Go), ratio of posterior to anterior face height (SGo:NMe), angle of facial convexity (NA/APg) and maxillomandibular angle (SpP/MP). All data were statistically analyzed and determined by the mean, standard deviation, maximum and minimum values. A Student’s t-test was used to determine the significance of differences in the studied parameters in both groups. Statistical significance was set at P = 0.05. RESULTS: There was a significantly higher value for craniocervical angle (P < 0.0001) in group 1, suggesting an increased extension of the head in relation to the cervical spine. There was also an increase in anterior face height and ANB angle in group 1 compared with group 2. The dominant type of growth in group 1 was backward mandibular rotation. CONCLUSION: Long-term mouth breathing due to obstruction of the upper airway, especially if it occurs during the period of growth, can lead to disturbances in growth of the craniofacial complex.

458 ORAL HEALTH RELATED QUALITY OF LIFE OF ORTHODONTIC PATIENTS B Walawska1, K Lewkowicz2, 1Private practice Ortomix, Lublin and 2Private practice Stomed, Zamosc, Poland

AIM: Malocclusions is an important issue in public health and subjects’ well-being. The aim of this study was to evaluate oral health related quality of life (OHRQoL) of orthodontic patients of different ages, by comparing the psycho-social needs with functional limitations and physical disability. SUBJECTS AND METHOD: Two hundred and sixty three patients aged between 10.6 and 56.0 years (20.4 ± 8.3 years), 184 females and 79 males. Taking into account the psycho-social aspects, they were divided into groups < 13 years (primary school), 13-16 years (secondary school), 16-19 years (high school), 19-35 years and >35 years. All patients were treated in two orthodontic practices. Anonymous self-administered Oral Health Impact Profile (OHIP) questionnaires were used for the estimation of OHRQoL that consisted of 14 questions in seven domains such as functional limitation, physical pain, psychological discomfort, physical disability, psychological disability, social disability and handicap. The Likert psychometric scale was used to collect the qualitative range of patients’ answers. Statistica 10PL and χ2 tests were used for statistical analysis. Receiver operator characteristic curves were used to set cut-off points for the patient’s age associated with configuration of particular problems to achieve the highest sensitivity.

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RESULTS: Except for a speech defect, other physical complaints or functional limitation as well as psychological and social problems were more frequently reported by patients between 19 and 35 years of age. A speech defect associated with malocclusion was reported mainly by children before the age of 13 years. Females significantly more frequently reported psychological and social problems associated with malocclusion. Male patients significantly often reported problems in domains such as physical disability. Patients who reported one psychological/social problem significantly more often reported another problem in these domains. Patients who reported particular physical problems more frequently confirmed another physical dysfunction. CONCLUSION: Malocclusions have an important influence on the quality of life, especially in psychological and social aspects. Psycho-social conditions are more important during adulthood compared with school years. The OHIP-14 survey is the useful tool to evaluate OHRQoL.

459 EFFICACY OF EARLY OROFACIAL ORTHOPAEDICS APPLIED TO PATIENTS WITH CLEFT LIP AND PALATE: A Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 SYSTEMATIC REVIEW C Wang-Merkelbach, N Daratsianos, A Jäger, Department of Orthodontics, University of Bonn, Germany

AIM: Orofacial clefts are common congenital malformations. The treatment of patients with a cleft lip and palate (CLP) remains a subject of considerable controversy. Early orofacial orthopaedics are techniques that contribute to the surgical treatment of the cleft patients by forming the tissues before or shortly after primary surgery. A number of active and passive appliances have been reported in the literature. The objective of this review is to provide reliable evidence regarding the middle-term effectiveness of early orofacial orthopaedics to improve the treatment outcomes of patients with non syndromic cleft lip and cleft palate. MATERIALS AND METHOD: Randomized controlled trials and controlled clinical trials with a follow-up period of a minimum of 4 years were included, except for the studies evaluating parental satisfaction and feeding. This systematic review was conducted following a pre-defined protocol including a search strategy, eligibility criteria for study inclusion, screening methods, data extraction and quality control, which was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. Articles were obtained through an electronic search of databases and bibliographic reference listings, and through a hand search. Assessment of the risk of bias was undertaken independently by two review authors. RESULTS: Eleven studies were included in this review. Not sufficient evidence was found to support that treatment with early orofacial orthopaedics with intraoral-only devices before and after primary surgery improve the treatment outcomes of patients with a CLP. Some evidence was found for improvement of treatment outcomes when using combinations of intra- and extraoral devices i.e. nasoalveolar moulding (NAM) devices. CONCLUSION: There is limited evidence for improvement of treatment outcomes when using infant orthopaedics in CLP patients before and after primary surgery. Future clinical trials should investigate the efficacy of NAM devices.

460 A COMPARATIVE STUDY OF UPPER ANTERIOR TOOTH INCLINATION IN RELATION TO THE SN LINE AND TO THE MAXILLARY PLANE B Wendl1, P Muchitsch1, H Winsauer2, M Pichelmayer1, T Wendl3, 1Department of Orthodontics and Dentofacial Orthopedics, University of Graz, 2Private Practice, Bregenz and 3Institute of Biomedical Engineering, Technical University of Graz, Austria

AIM: To analyze the relationship between the inclination of the upper incisors to SN line and to the maxillary plane of untreated adult Class II division 1 patients, and the dependence on the skeletal parameter.

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SUBJECTS AND METHOD: Fifty four untreated Class II division 1 patients were investigated using pre-treatment lateral cephalograms. The average age of the patients was 21.5 years. The relevant dental and skeletal parameters were analyzed, statistically evaluated and compared with international data. RESULTS: The inclinations with reference to the SN line and the maxillary plane showed similar deviation in comparison with the Class II division 1 average value. Compared with the Class I average value, there was a smaller range of incisor protrusion while using the maxillary plane, mean 2.1 degrees. When using the SN line as a reference, this value had a range of –6.9 to +7 degrees, in contrast with the mean value of Class I patients, by application of the maxillary plane, –6.9 to +4.9 degrees. With an increase of the S-Ar-Go angle, the inclination angle became lower. Patients with a vertical growth tendency had less upper incisor protrusion. The higher the SNA angle the more the inclination of the upper anterior teeth with reference to the SN line increased. The inclination of the upper anterior teeth increased 3 degrees with age (from 15 to 21.5 years) in the male group and decreased in the female group by about 1 degree when using the maxillary plane. The same tendency was Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 shown when using the SN line, a 4 degree increase of upper anterior tooth inclination for males and 2 degree decrease for females. Male and female Class II division 1 patients had a lower SNB-angle (especially females), SNA angle remained constant while articulare angle clearly showed a positive deviation from standard values. There was also a significant difference in the value of face height in males and females. CONCLUSION: Both SN and the maxillary plane can be used as a reference line for incisor positioning. Compared with standard Class I values, a smaller amount of incisor protrusion could be detected when using the maxillary plane. A change of inclination, depending on age and growth pattern, should also be considered.

461 HIGH MOBILITY GROUP BOX PROTEIN 1 – A POSSIBLE TARGET IN THE BIOLOGY OF TOOTH MOVEMENT? ɫɫ M Wolf1, S Lossdörfer1, K Küpper2, S Memmert1, A Jäger1, Departments of Orthodontics, 1University of Bonn and 2Cologne University, Germany

AIM: High mobility group box protein 1 (HMGB1) is released into the extracellular milieu by damaged periodontal ligament (PDL) cells and functions as an alarm to mediate the inflammatory host response. Recent studies have demonstrated that HMGB1 also provides anabolic traits. Therefore the aim of the present investigation was to evaluate the isolated effect of HMGB1 within the periodontal remodelling process following tooth movement. It was hypothesized, that besides its immunological function, HMGB1 is able to induce PDL cell differentiation and will support tissue remodelling within the late phase of periodontal repair. MATERIALS AND METHOD: The expression of HMGB1 from PDL cells in vitro and of orthodontically treated rats (in vivo) was analyzed via immunocytochemistry and ELISA. The influence of HMGB1 by human PDL cells on macrophage physiology was investigated by migration and osteoclastic differentiation assays. To investigate the effect of HMGB1 on PDL cell differentiation, cells were cultured in the presence of HMGB1 and analyzed for cell differentiation capacity towards an osteogenic phenotype at the transcriptional and translational level. Furthermore the effect of HMGB1 to modify PDL cell migration and proliferation was investigated. RESULTS: Induction of mechanical stress in vivo and in vitro resulted in enhanced HMGB1 protein expression and an intracellular translocation of HMGB1 in the initial phase of tissue repair. Exposure of human macrophages to HMGB1 influenced migration and osteoclastic differentiation only in combination with proinflammatory factors. Supplementation of PDL cell cultures with HMGB1 induced expression of ostegenic markers, PDL cell migration and proliferation. CONCLUSION: These data clearly point to the distinguished role of HMGB1 in periodontal tissue repair of having an immune modulatory role when acting with other cytokines in the initial phase of tissue remodelling and providing important anabolic functions on PDL cells the phase of periodontal reconstruction. These findings extend the basis for possible therapeutic intervention and prevention strategies for the tissue remodelling process following orthodontic treatment.

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ɫɫ Winner of an EOS poster award.

462 MAXILLARY INCISOR ROOT RESORPTION INDUCED BY ECTOPIC MAXILLARY CANINES: A LITERATURE REVIEW OF THE PREVALENCE RATES AND INCISOR LONGEVITY OUTCOMES L Wong1, S Khan2, Departments of 1Oral and Maxillofacial Surgery and 2Orthodontics, John Radcliffe Hospital, Oxford, U.K.

AIM: To carry out a systematic and comprehensive review of the literature to determine the prevalence and long-term prognosis of resorbed maxillary incisors as a result of ectopic maxillary canines. MATERIALS AND METHOD: The search strategy for this review followed guidelines from the National Health Service Centre for reviews and Dissemination (2011). A computerized search was performed using the Medline Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 database (Entrez PubMed) and the Cochrane Library electronic databases. Non-electronic journals were also hand searched. The terms used in the search were: canine, tooth, root, impaction, ectopic, incisors, root resorption, radiographs and cone beam computed tomography (CBCT). RESULTS: A total of 62 papers were identified within the search as being of relevance to this study. There were no prospective studies on this subject and the available literature consisted mainly of case series and retrospective reports. Lateral incisors were more commonly affected by resorption induced by ectopic buccal canines than palatal canines, and lateral incisors were also more commonly resorbed than central incisors. Consolidation of the available published literature revealed the prevalence of incisor resorption to widely range between 0.3 to 77.8 per cent due to varying methods of two-dimensional (2D) and three-dimensional (3D) imaging. Conventional 2D imaging was deemed to be less diagnostically accurate in detecting the extent of resorption in comparison with 3D imaging, particularly with CBCT. CONCLUSION: Contrary to the widely held belief that resorbed incisors have a poor long-term prognosis, this study revealed minimal loss of resorbed incisors from follow-up studies ranging between 1 to 28 years.

463 SCUBE3 IS EXPRESSED IN MULTIPLE TISSUES DURING DEVELOPMENT BUT IS DISPENSABLE FOR EMBRYONIC SURVIVAL IN THE MOUSE G Xavier1 L Panousopoulos2, M Cobourne1, Departments of 1Orthodontics and 2Craniofacial Development and Stem Cell Biology, King’s College London, U.K.

AIM: The vertebrate Scube family consists of three independent members, Scube1-3; which encode secreted cell surface-associated membrane glycoproteins that share a domain organization of at least five recognizable motifs and the ability to both homo- and heterodimerize. There is recent biochemical evidence to suggest that Scube2 is directly involved in Hedgehog signalling, acting co-operatively with Dispatched to mediate the release in soluble form of cholesterol and palmitate-modified Hedgehog ligand during long-range activity. In an attempt to further elucidate the role of Scube genes during development, the first murine model for a loss of Scube3 function was generated. MATERIALS AND METHOD: Different techniques were employed to analyse in depth the phenotype of Scube3-/- mice including radioactive in situ hybridization, Western blot analysis, LacZ staining and Skeletal preparation. RESULTS: Despite a dynamic developmental expression pattern, particularly within the craniofacial region, an absence of Scube3 function results in no overt embryonic phenotype in the mouse. Mutant mice are born at expected Mendelian ratios, are both viable and fertile, and seemingly retain normal Hedgehog signalling activity in craniofacial tissues. These findings suggest that in the mouse, Scube3 is dispensable for normal development; however, they do not exclude the possibility of a co-operative role for Scube3 with other Scube members during embryogenesis or a potential role in adult tissue homeostasis over the long-term. CONCLUSION: Scube3 exhibits a dynamic expression pattern in the developing mouse embryo, particularly in ectodermal-derivatives of the early craniofacial region. Here, mice lacking Scube3 function were generated ad it

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was found that they remain viable and fertile, demonstrating no overt embryonic phenotype. Therefore, it is concluded that Scube3 is not essential for gross embryonic development and survival. These findings might indicate redundancy with other Scube family members during development and do not discount a potential role in adult tissue homeostasis over the long-term.

464 HEAD AND NECK CHARACTERISTICS OF NOONAN SYNDROME T Yabunaka1, J J Miyamoto1, M Sato2, Y Baba2, K Moriyama1, 1Department of Maxillofacial Orthognathics, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo and 2Division of Dentistry, Department of Surgical Specialties, National Center for Child Health and Development, Setagaya-ku, Tokyo, Japan

AIM: Noonan syndrome (NS) is a multiple congenital malformation characterized by short stature, congenital heart defect, and a typical facial appearance. It is proposed that new characteristics, which are seldom Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 reported, including basilar impressions, are included into the syndrome; these are frequently observed in NS patients using lateral cephalograms (Miyamoto et al., 2013). This presentation reports other new findings regarding the head and neck characteristics of NS. MATERIALS AND METHOD: Lateral cephalograms and facial photographs were taken at first visit of 10 NS patients (mean age 12.1 ± 2.3 years) and 10 age-matched control subjects (mean age 12.0 ± 2.2 years). 1) Cranial base, 2) morphology of cervical vertebrae, 3) positioning of the cervical vertebrae and hyoid bones relative to the cranium; and 4) degree of basilar impressions were examined. Cranial base morphology was compared with normal Japanese standards and the other parameters were statistically evaluated between NS and control subjects using Mann Whitney U-tests (P < 0.05). RESULTS: 1) In the NS group, shortening of the anterior and posterior cranial base and flattening of the cranial base were found; 2) There were no significant differences in the actual height of the third, fourth, and fifth cervical vertebrae between the two groups. Conversely, the actual length of the cervical spine from the odontoid tip to the bottom of the fifth cervical vertebra in the NS group was significantly shorter than in the controls; 3) The positions of the third and fourth cervical vertebrae relative to the cranium in the NS group were located vertically higher than in the control group, which were significantly different. However, the position of the hyoid bone showed no significant difference between the two groups; 4) Compared with the control group, the odontoid process of the NS group was significantly invaginated into the cranial base. CONCLUSION: A flat cranial base, high positioning of cervical vertebrae relative to the cranium, and shortening of the cervical spine are specific head and neck characteristics of NS, and are useful in diagnosis using lateral cephalograms.

465 VISUAL PERCEPTION OF FACES WITH DIFFERENT VERTICAL DIMENSIONS: AN EYE-TRACKING STUDY A Yalçin1, B N Türkan2, F Dindaroğlu1, S Doğan1, Departments of 1Orthodontics and 2Experimental Psychology, Ege University, Izmir, Turkey

AIM: To observe how faces with different vertical growth patterns are perceived by laypersons objectively using an eye-tracking method. SUBJECTS AND METHOD: Fifty participants aged between 20 and 40 years were enrolled. In total 45 facial images with different lower vertical dimensions (hyperdivergent, normodivergent and hypodivergent) were viewed intricately. Fifteen images of patients with a normal lower vertical dimension were used as the control group. An eye-tracking technique was used to measure the viewers’ eye movements when they were viewing images of the faces. All faces were divided into four areas of interest (AOI): eyes, nose, mouth and chin. The location of the first fixation, the maximum fixation duration and the maximum number of fixations were measured and compared between image groups.

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RESULTS: Most frequently participants looked longer and firstly into the eyes of the control group. Although the first fixation was on the eyes in hypodivergent photographs, the participants looked at the eyes longer than the other AOI. When hyperdivergent photographs were viewed, the chin was viewed first and most frequently compared with other AOI. CONCLUSION: A vertical growth pattern is shown to be efficient when perceiving facial attractiveness. Especially the increased focusing to the lower third of the face emphasizes the importance of orthognathic surgery to enhance facial attractiveness in severe hyperdivergent patients.

466 RELIABILITY OF TWO DIFFERENT METHODS TO CONSTRUCT AVERAGE FACES A Yazici1, H Turkkahraman2, H Ademoglu2, S Malkoc3, 1Department of Computer Engineering, Bogazici University, Istanbul, 2Department of Orthodontics, Faculty of Dentistry, Suleyman Demirel University, Isparta and 3Department of Orthodontics, Faculty of Dentistry, Inonu University, Malatya, Turkey Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021

AIM: To construct average faces in Cartesian and cylindrical coordinate systems and compare their reliabilities according to manually prepared ground truth data. SUBJECTS AND METHOD: White children selected from two comprehensive schools in the East Anatolian area in Turkey. Thirty five male images were obtained with a three-dimensional imaging device, ‘3dMD Face’• (3dMD Ltd., London, UK). The facial images were processed and aligned with Rapidform XOV before constructing average faces such that they were registered on top of a reference image with best fit algorithm. The reference image was picked randomly. The origin of the reference image was translated to the point location which was 3 mm posterior from the centre of inner left and right canthi. For evaluation purpose, nine pre-defined points were marked on each of the faces (Inner and outer canthus of eyes and tip of the nose, right and left cheilions, right and left alare of the nose) and their averages were calculated manually. Average faces were constructed using planar and cylindrical projections. The former approach averages the z values of corresponding points on aligned faces. The latter, first transforms points into a cylindrical coordinate system and calculates averages over the radial distance of corresponding points. After obtaining the average, it transforms points back to Cartesian coordinates. Predefined points were also located on planar and cylindrical average faces. The distance between the manually averaged points and correspondences on averaged faces were calculated. Statistical analyses were performed using SPSS (version 17). An independent samples t-test was applied on the results to statistically compare the reliability of the two methods. RESULTS: Except for one point, cylindrical average faces showed closer location to manually averaged points. The independent samples t-test showed that cylindrical average faces are more reliable than planar average faces. CONCLUSION: Constructing average faces in a cylindrical coordinate system can be a preferential method and the constructed average faces can be useful templates to analyse facial morphology three dimensionally.

467 EVALUATION OF DENTAL ARCH WIDTHS AND RATIOS IN DIFFERENT MALOCCLUSIONS USING THREE- DIMENSIONAL MODELS K G Yazıcı, Y Lena, A Paşaoğlu, S Doğan, Department of Orthodontics, Faculty of Dentistry, Ege University, Izmir , Turkey

AIM: To evaluate the relationships between dental arch widths and ratios in different malocclusions using three-dimensional (3D) digital models. MATERIALS AND METHOD: The 3D digital dental models of 80 patients (28 males, 52 females; 15-17 years of age, Class I: 20 patients, Class II division 1: 20 patients, Class II division 2:20 patients and Class III: 20 patients). All had a normal vertical growth pattern. The Orthomodel software program was used to measure the dimensions. Corresponding distances (intercanine and intermolar widths) and the ratio between these

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measurements were calculated for both jaws. Correlations between the objective values of arches were statistically tested by one-way ANOVA. RESULTS: There were no statistically significant correlations between the malocclusions in intercanine and intermolar widths and intercanine/intermolar ratios in both arches. However, when using one-way ANOVA, the mean value of intercanine widths in Class II division 2 patients were higher in both arches, compared with the other malocclusion types. CONCLUSION: The size and shape of the arches have significant implications in orthodontic diagnosis and treatment planning which affects dental aesthetics, and the stability of the dentition. However, in this study, it was found that dental arch widths and ratios were no different in different malocclusions. It is important to evaluate dental arch widths and forms at the beginning of orthodontic treatment to obtain stable results.

468 AUDIT OF COMPLIANCE OF ORTHODONTIC TRAINEES UPLOADING PATIENT IMAGES ONTO A MEDICAL Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 IMAGE MANAGER Y Yeung, D Bister, Department of Orthodontics, King’s College London Dental Institute and Guy’s Hospital, U.K.

AIMS: Storing patient images securely forms an important part of good clinical practice. This audit monitored the compliance of orthodontic trainees uploading patient images, after introduction of a medical image manager system (WABA). The aims were 1. To monitor the total number of patient images uploaded by orthodontic trainees at Guy’s Hospital generally; 2. Five final year orthodontic trainees were specifically monitored for uploading patient images; 3. To determine the number of all new patient images uploaded onto WABA; 4. To compare the total number of patient images uploaded onto WABA with a previous database. MATERIALS AND METHOD: 1. The total number of patient images uploaded onto WABA was recorded weekly for 52 weeks. 2. The patients’ identifications (ID) who had images uploaded onto WABA and a patient list containing those who had been treated by the five final year students were compared. 3. All patients undergoing active orthodontic treatment had study models taken pre-treatment and stored on a database containing three-dimensional virtual models (3Shape). The patient's ID from 3Shape was compared with WABA’s patient ID to assess the compliance of uploading new patient photographs. RESULTS: One thousand three hundred and eighteen patient images were uploaded, exceeding a previous database of 432 patients. An increase of 1089 patient images were uploaded onto WABA within 52 weeks. Thirty seven per cent of patient images were uploaded onto WABA by the five final year trainees. Fifty three per cent new patient images were uploaded onto WABA. CONCLUSION: The increase in the total number of patients images uploaded onto WABA exceeded the previous database. There was an Increase in the percentage of patient images uploaded by the five final year students and an increase in the number of new patients uploaded onto WABA. WABA allows re-audits and future audits to be carried out easily. It allows the auditor to filter patient information into different categories. There was noticeable behavioural improvement leading to better acceptance of an image upload over time. The percentage of patient images uploaded to a database should ideally be 100 per cent and it is anticipated that this will be achieved in the near future: All patients undergoing treatment should have images taken as recommended in the British Orthodontic Society guidelines.

469 CONDYLAR RESPONSE TO FUNCTIONAL THERAPY WITH TWIN-BLOCKS: A STUDY WITH CONE-BEAM COMPUTED TOMOGRAPHY E Yildirim, S Karacay, M Erkan, Dental Service, Gulhane Military Medical Academy, Istanbul, Turkey

AIM: To evaluate condylar changes, on cone beam computed tomographic (CBCT) images, of patients treated with the Twin-block functional appliance. MATERIALS AND METHOD: In this retrospective study, CBCT images of 30 patients treated with Twin-block appliance were used. The mandible was segmented and pre- and post-treatment (T0 and T1) condylar volume e237

was compared. SNA, SNB, ANB, midfacial length (Co-A), mandibular length (Co-Gn), and the distances from right condylion to left condylion (CoR-CoL) were also measured on three-dimensional images. Differences were analyzed with Wilcoxon signed-rank tests, and Mann-Whitney U tests were used to compare the scores of male and female participants. Significance was set at P < 0.05. RESULTS: A decrease in SNA and ANB (P < 0.05 and P < 0.01, respectively), and an increase in SNB (P < 0.01) were found. Additionally, CoR-CoL, Co-Gn and condylar volume increased on both the left and right sides (P < 0.01). However, the increase at Co-A was not statistically significant (P > 0.05). Comparison of gender differences was insignificant for all measurements (P > 0.05). CONCLUSION: CBCT can be successfully used to evaluate the condylar response to functional orthopaedic treatment. The Twin-block appliance increases condylar volume, mandibular length, and inter-condylar distance by stimulating growth of the condyle in upward and backward direction. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 470 ORTHODONTIC DEFORMATION–DENTAL TRANSPOSITION G Yordanova, Department of Orthodontics, Faculty of Dental Medicine, Medical University of Sofia, Bulgaria

AIM: Dental transposition is a deviation that is clinically manifested by replacing the locations of two adjacent teeth, which changes the natural order in the dental arch. Manifestation of the problem can be observed in clinically erupted or impacted teeth. The purpose of this study was to determine the frequency and specificity of this type tooth ectopia as well as the clinical approaches used in this deformation. SUBJECTS AND METHOD: The study was undertaken on 1440 patients treated for a period of 8 years, at age 8 to 15 years. The analyses were carried out on radiographs or cone beam computed tomographs and intraoral digital photographs. RESULTS: An incidence of dental transposition was found of 0.48. For females it was 57 per cent and for males 43 per cent. More commonly this deformation was observed unilaterally (86%), bilaterally (14%). The deformation was more common in the maxilla (725) than in the mandible (28%). The most common transposition was between the canine and first premolar (50%) followed by the maxillary canine and lateral incisor (25%) and by the mandibular canine and lateral incisor (25%). The aetiology of this deformation is not known. Most often this is an early loss of the same primary tooth, tooth migration due to a bone obstacle during odonthogenesis and heredity. The treated patients had transposition and related problems such as odontoma collection and retention of the tooth in transposition; hypodontia of the lateral incisors; fully unresorbed root of the primary lateral incisor; retention of the opposite canine. Treatment was conducted with good alignment and aesthetic restoration of the transposed teeth in 62.5 per cent, for 25 per cent canine extraction was required and in 12.5 per cent the correct canine location in the dental arch was achieved. CONCLUSION: Transposition is a rare condition that often requires complicated orthodontic treatment and subsequent aesthetic restoration.

471 LONG-TERM POSITIONAL CHANGES OF THE MANDIBULAR PROXIMAL SEGMENT AFTER INTRAORAL VERTICAL RAMUS OSTEOTOMY USING THREE-DIMENSIONAL COMPUTED TOMOGRAPHY IN FACIAL ASYMMETRY PATIENTS H-S Yu, H-S Yeon, S-J Kim, D-H Lee, J-H Moon, Department of Orthodontics, College of Dentistry, Yonsei University, Seoul, Korea South

AIM: To evaluate, using three-dimensional computed tomography (3D CT), the long-term positional changes of the mandibular proximal segment, including the condyle, after two-jaw orthognathic surgery [Le Fort I osteotomy and intraoral vertical ramus osteotomy (IVRO)]. SUBJECTS AND METHOD: Seventeen skeletal Class III patients with facial asymmetry. CT images were taken at pre-surgery (T1), 1 year post-surgery (T2), and 4 years post-surgery (T3). Reconstructed 3D CT images were used to measure the horizontal condylar angle (HCA), coronal condylar long axis angle (CCLA), coronal condylar e238

vertical axis angle (CCVA), sagittal condylar angle (SCA), and temporomandibular joint space distances (A-B and C-D) on the deviated and non-deviated sides. RESULTS: HCA, CCLA, CCVA, and SCA showed significant bilateral differences (P < 0.05) at T1, while most measurements did not significantly differ at T2 and T3. Most measurements significantly changed during T1-T2 (P < 0.0167), but not during T2-T3. HCA increased significantly on both sides during T1-T2, indicating post-IVRO outward condyle rotation (P < 0.0167). The non-deviated side CCLA and deviated side CCVA each decreased significantly during T1-T2 (P < 0.0167). During T1-T2, SCA decreased significantly at both sides and A-B and C-D increased significantly, indicating post-IVRO anterior-inferior condyle movement (P < 0.0167). CONCLUSION: In skeletal Class III asymmetry patients, mandibular asymmetry improved post-IVRO. These improvements were stable during the 4-year follow-up. The mandibular proximal segments moved to a more stable position during post-operative recovery of mandibular function. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 472 EPIDEMIOLOGY AND GENETICS OF MICRODONTIA AND HYPODONTIA IN THE GENERAL POPULATION: A KOREAN TWIN FAMILY STUDY Y Yun1, K H Jeong1, D Kim2, Y H Kim1, 1Department of Orthodontics, The Institute of Oral Health Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul and 2Department of Epidemiology, School of Public Health, Seoul National University, Korea South

AIM: To investigate the epidemiology and genetics of microdontia and hypodontia in the permanent dentitions of Koreans, and to identify genetic and environmental factors contributing to the dental anomalies using Korean twin family data. SUBJECTS AND METHOD: A total of 1267 individuals including 282 families, 180 monozygotic (MZ) twin pairs, and 43 dizygotic (DZ) twin pairs from the Healthy Twin Study in Korea. Dental anomalies ‘microdontia and hypodontia’ were diagnosed using radiographs and clinical examinations. In order to reveal the genetic relevance of dental anomalies, pairwise concordance, recurrence risk ratio, and heritability estimates were investigated. RESULTS: Prevalence of microdontia and hypodontia was 3.00 and 3.55 per cent, respectively. Pairwise concordance and recurrence risk ratio of microdontia and hypodontia in MZ and DZ twins are much higher than those of siblings, parent-offsprings and spouses. Heritability estimates showed both an additive genetic effect and twin common environmental effect in dental anomalies. There are more twin common environmental effects in hypodontia than in microdontia or pooled with microdontia and hypodontia. CONCLUSION: This twin-family study revealed that formation of dental anomalies is both affected by genetic and environmental factors. An early developmental stage may significantly contribute to the formation of dental anomalies.

473 THREE-DIMENSIONAL ANALYSIS OF FACIAL SOFT TISSUES: CORRESPONDENCE TO TRADITIONAL CEPHALOMETRICS AND PROPOSAL OF NORMAL STANDARDS P A Zecca, R Fastuca, A Caprioglio, A Macchi, University of Insubria, Varese, Italy

AIM: The relationships among facial soft tissues should be considered as an essential aspect in orthodontic diagnosis and treatment planning as the assessment of skeletal and dental measurements. Unfortunately three- dimensional (3D) soft tissue analysis has not yet become routine, mostly due to the cost related to the tools usually employed and the absence of mean normal standard values. The aim of this study was therefore to develop a reliable 3D analysis of facial soft tissues with a commercially available infrared scanner that could be useful and minimally invasive in supporting radiographs in orthodontic diagnosis and provide mean values for principal relevant measurements. SUBJECTS AND METHOD: Three hundred and twelve Caucasian subjects. Exclusion criteria were all craniofacial anomalies. A cephalometric analysis was developed employing 13 soft tissue landmarks, 17 sagittal and 14 e239

vertical angular measurements corresponding to routinely used skeletal cephalometric variables. The parameters were analyzed in terms of their reliability and gender-age specific differences. The 3D soft tissue values were further analyzed for any correlations with two-dimensional (2D) cephalometric values using Pearson’s correlation coefficient analysis. RESULTS: Medium and high correlations were found for sagittal parameters and vertical parameters. Means and standard deviations were calculated for each 3D soft tissue cephalometric variable to establish norms. CONCLUSION: Sagittal parameters seem to be more reliable in providing a soft tissue diagnosis close to the skeletal commonly used cephalometric variables. Vertical soft tissue measurements meanwhile showed less correlation with the corresponding cephalometric 2D values, perhaps due to the difficulty of reproducing the cranial reference system to soft tissue landmarks used for the vertical evaluations. Normal standard mean values were collected and proposed for the present cephalometric 3D soft tissue analysis. Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 474 ORTHODONTIC TREATMENT NEED AND DEMAND IN AZERBAIJAN AND THE UKRAINE*** Z Zeynalov1, S Richmond2, M Drohomyretska3, A Yakimets3, 1Department of Orthodontics, Children's Dental Centre of Health Ministry of Azerbaijan Republic, Baku, Azerbaijan, 2Department of Applied Clinical Research and Public Health, Cardiff University, Wales, U.K. and 3Department of Orthodontics, Shupik National Medical Academy of Postgraduate Education, Kiev, Ukraine

AIM: To organize an orthodontic service it is necessary to obtain reliable information regarding the prevalence of malocclusions within the child population as well as demand and suitability for orthodontic care. Treatment need estimates can range from 27.5 to 76.7 per cent in a population. Demand for orthodontic treatment varies widely from 2 to 47 per cent. There are many factors that affect the uptake of treatment, and family income is considered as a major factor. The assessment of orthodontic treatment in different countries can provide useful information on the social/cultural and ethnic influences on orthodontic treatment need and demand. Azerbaijan and the Ukraine are different geographically and socially but were both republics of the USSR until August 1991. So economically there was similarity between them with the mean salary around $300 per month. Since independence the orthodontic services in Azerbaijan and the Ukraine have developed differently. There are 1.3 specialists per 100,000 in the Ukraine as against 0.35 orthodontist per 100,000 in Azerbaijan. The aim of this study was to determine the level of orthodontic treatment need and demand for orthodontic care taking into account the differing resources in Azerbaijan and the Ukraine. MATERIALS AND METHOD: The Index of Complexity Outcome and Need (ICON) was used to assess orthodontic treatment need in high schools in three cities in Azerbaijan and five cities in the Ukraine. One thousand four hundred and ninety one children aged from 14 to 17 were examined (898 Azerbaijan; 593 Ukraine). RESULTS: The ICON scores were statistically significant between Azerbaijan and the Ukraine (P < 0.001). With regard to the number of children needing orthodontic treatment, the prevalence was 55.7 and 63.2 per cent for Azerbaijan and the Ukraine, respectively. There was considerable variation in the number of children who had received orthodontic treatment in the various cities (5 to 39.4%). Of the Ukrainian children, 28.8 per cent received orthodontic treatment compared with only 8.2 per cent of Azerbaijan children (P < 0.009). CONCLUSION: The treatment need difference between the two countries did not correlate with the greater difference in treatment demand. Taking into account the similar economic situations in these countries, the conclusion was that social/cultural factors influence treatment demand no less than financial possibilities.

Funded by an EOS Research Grant.

475 EVALUATION OF MALOCCLUSION IMPACT ON QUALITY OF LIFE IN THE YOUNG POPULATION OF ROMANIA I Zetu1, S Rosu1, M Jacob1, A Ionescu1, L Zetu2, Depatments of 1Orthodontics and 2Periodontics, UMF‘Gr. T. Popa’, Iasi, Romania e240

AIMS: To study the relationships between different aspects of orthodontic care to predict and to assess the impact of malocclusion on quality of life, using the psychometric properties of the Psychosocial Impact of Dental Aesthetics Questionnaire (PIDAQ). SUBJECTS AND METHOD: A cross-sectional study was conducted on 1,126 subjects WHO COMPLETED the self- administered PIDAQ. Statistical analysis was performed using SPSS17 for Windows. RESULTS: Of the respondents, 40.16 per cent were ‘very dissatisfied’ about the alignment of their teeth but were uncertain about the need for orthodontic treatment. Aesthetic perception analysis (P = 0.30) showed that it did not significantly influence the ‘demand for care’ and ‘perceived need’. Assessment of patients concerning their level of satisfaction about their tooth alignment showed that 80 per cent were ‘dissatisfied’•. All subjects in the study ‘thought’• or ‘were sure’ (45 %) that their tooth alignment required orthodontic treatment. CONCLUSION: The PIDAQ proved to be a reliable instrument specifically for orthodontics, for assessment of the Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 relationship between malocclusions and quality of life.

476 THE RACE FOR THE SURFACE BETWEEN HUMAN BONE CELLS AND SUB-GINGIVAL ORAL BACTERIA ON DENTAL IMPLANT SURFACES IN A POST-OPERATIVE MODEL B Zhao1, H C Van der Mei2, M Rustema-Abbing2, H J Busscher2, Y Ren1, Departments of 1Orthodontics and 2Biomedical Engineering, University of Groningen and University Medical Centre, Netherlands

AIM: To identify surface properties of implant materials significant for the outcome of the race for the surface between human osteoblast cells and different sub-gingival oral bacterial strains for different dental implant surfaces in a co-culture model, simulating post-operative bacterial contamination of implantation. MATERIALS AND METHOD: Titanium, titanium-zirconium alloy and zirconium oxide implant materials were used after different surface modifications, ranging from polished (P), machined (M), acid-etched (A) and machined, acid-etched and protectively packaged (modMA). Surfaces were characterized by their hydrophobicity (water contact angle), roughness (atomic force microscopy), morphology (scanning electronic microscopy) and elemental composition (X-ray photoelectron spectroscopy). In order to simulate post-operative bacterial contamination of the implant surface, two bacterial strains (Prevotella intermedia, Porphyromonas gingivalis) were adhered to an implant surface after the adhesion of U2-OS osteosarcoma cells, subsequently they were allowed to grow together. After 72 hours co-culturing, the total surface coverage by U2-OS cells was measured and the reduction in surface coverage due to the presence of bacteria was taken as a comparative measure for the outcome of the race for the surface on the different implant materials through backward multiple linear regression analysis. RESULTS: U2-OS cells were losing the race for the surface on all implant material after challenges by sub-gingival bacteria, with the exception of TiZr-modMA. On TiZr-modMA, the total surface coverage by adhering U2-OS cells was not significantly affected by a challenge with sub-gingival strains. Regression analysis showed that the major implant surface properties determining the outcome of the race for the surface were hydrophobicity and chemical composition. CONCLUSION: The degree to which adhering osteoblasts can withstand a challenge by sub-gingival bacteria depends on the hydrophobicity and chemical composition of the implant surface.

477 MECHANICAL PROPERTIES OF THERMOPLASTIC ORTHODONTIC MATERIALS S Zinelis1, S Hersche2, I Sifakakis3, T G Bradley4, T Eliades2, Departments of 1Biomaterials and 3Orthodontics, University of Athens, Greece, 2Department of Orthodontics and Paediatric Dentistry, Centre of Dental Medicine, University of Zurich, Switzerland and 4Department of Developmental Sciences, Marquette University, Milwaukee, USA

AIM: To determine the mechanical properties of thermoplastic orthodontic materials. e241

MATERIALS AND METHOD: Three thermoplastic materials were included in the study: Clear Aligner Soft (Scheu- Dental), ACE30 and A+80 Essix plastic (Dentsply). Two samples were prepared for each material by pressing the thermoplastic material over a stone rectangular model. The level central part was cut from the rest of the material and used for Instrumented Indentation Testing (IIT). Force to indentation depth curves were monitored employing a Vickers indenter and 5 N force according to ISO 14577-1 specification. The mechanical properties tested were indentation modulus (EIT), and Vickers hardness. The results were statistically analyzed by one way ANOVA and Student-Newman-Keuls multiple comparison test at a = 0.05. RESULTS: The mean values and standard deviations for EIT and HV are shown below. Brand name: EIT (GPa) and HV0.5 (N/mm2); Clear Aligner (Soft): 2.2 ± 0.3 and 105 ± 2; ACE30: 1.8 ± 0.1 and 98 ± 1; A+80: 2.2 ± 0.1 and 115 ± 3. ACE 30 showed a lower modulus of elasticity compared with A+80, the lowest hardness but the highest elastic to total work ratio. Materials with a lower modulus of elasticity exerted lower forces under the same strain and thus might prolong treatment time. Higher hardness is also desirable to increase wear resistance Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 under clinical conditions. CONCLUSION: Aligners show significant variations in their mechanical properties and this might affect their clinical performance, load exerted, and resultant discomfort levels.

478 MICROSTRUCTURAL AND MECHANICAL CHARACTERIZATION OF CONTEMPORARY LINGUAL ORTHODONTIC BRACKETS S Zinelis1, I Sifakakis1, C Katsaros2, T Eliades3, 1Department of Biomaterials, School of Dentistry, University of Athens, Greece, 2Department of Orthodontics and Dentofacial Orthopedics, School of Dentistry, University of Bern, Switzerland, 3Department of Orthodontics and Paediatric Dentistry, Center of Dental Medicine, University of Zurich, Switzerland

AIM: To investigate the composition and the microstructural and mechanical characterization of three different types of lingual brackets. MATERIALS AND METHOD: Incognito™ (3M Unitek), In-Ovation L (Dentsply GAC) and STb™ (Light Lingual System, Ormco) lingual brackets were studied under the scanning electron microscope employing backscattered electron imaging, and their elemental composition was analysed by energy-dispersive X-ray microanalysis. Additionally, Vickers hardness was assessed using a universal hardness-testing machine and the indentation modulus was measured according to instrumented indentation test. Two-way analysis of variance was conducted employing bracket type and location (base and wing) as discriminating variable. Significant differences among groups were allocated by post hoc Student-Newman-Keuls multiple comparison analysis at the 95 per cent level of significance. RESULTS: Three different phases were identified for Incognito and In-Ovation L brackets based on the mean atomic number contrast. On the contrary, STb did not show mean atomic contrast areas and thus was recognized as a single phase. Incognito is a one-piece bracket with the same structure in wing and base regions. Incognito consists mainly of noble metals while In-Ovation L and STb show similar formulations of ferrous alloys in wing and base regions. No significant differences were found between ferrous brackets in hardness and modulus values, but there were significant differences between wing and base regions. Incognito illustrated intermediate values with significant differences from base and wing values of ferrous brackets. CONCLUSION: Significant differences exist in microstructure, elemental composition, and mechanical properties of the brackets tested, and thus differences in their clinical performance are anticipated.

479 EVALUATION OF THE INFLUENCE OF CHINCUP TREATMENT ON THE TEMPOROMANDIBULAR JOINT. A SYSTEMATIC REVIEW M Zurfluh1, D Kloukos2, T Eliades1, 1Department of Orthodontics and Paediatric Dentistry, Centre of Dental Medicine, University of Zurich and 2Department of Orthodontics and Dentofacial Orthopedics, Medical School, University of Bern, Switzerland e242

AIM: To systematically search the literature and assess the available evidence for the influence of chincup therapy on the temporomandibular joint regarding morphological adaptation and the appearance of temporomandibular disorders (TMD). MATERIALS AND METHOD: Electronic database searches of published and unpublished literature were performed. The following electronic databases with no language and publication date restrictions were searched: Medline (via Ovid and Pubmed), EMBASE (via Ovid), the Cochrane Oral Health Group’s Trials Register and Central. Unpublished literature was searched on ClinicalTrials.gov, the National Research Register, and Pro- Quest Dissertation Abstracts and Thesis database. The reference lists of all eligible studies were checked for additional studies. Two review authors performed data extraction independently and in duplicate using data collection forms. Disagreements were resolved by discussion or the involvement of a mediator. RESULTS: From the 152 articles identified by the search, after application of the specific inclusion and exclusion Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 criteria and removal of duplicates, 53 papers were considered eligible for inclusion in the review. After further selection following the full text reading stage, 10 studies qualified for the final review analysis. No randomised clinical trial was identified. Nine of the included studies were of a prospective and one of a retrospective design. All studies were assessed for their quality and graded eventually from low to moderate level of evidence. The results showed that chincup therapy affects the condylar growth pattern. However, two studies reported no significant changes in disc position and arthrosis configuration. Concerning the incidence of TMD, it can be concluded from the available evidence, that chincup therapy is neither a risk factor for nor a prevention of TMD. CONCLUSION: The available evidence supports that there are craniofacial adaptations induced by chincup therapy for Class III orthodontic anomalies. Nevertheless, there is insufficient or low quality data in the orthodontic literature to allow the formulation of clear statements regarding the influence of chincup treatment on the temporomandibular joints based on solid scientific evidence.

480 CLINICAL EFFECTIVENESS OF THE TWIN BLOCK: A SYSTEMATIC REVIEW AND META-ANALYSIS V Zymperdikas1, V Koretsi2, S Papageorgiou3, M Papadopoulos4, 171st Airmobile Medical Company, Dental Unit, 71st Airmobile Brigade, Nea Santa, Greece, 2Department of Orthodontics, School of Dentistry, University Medical Centre Regensburg, Germany, 3Departments of Oral Technology and of Orthodontics, School of Dentistry, University of Bonn, Germany and 4Department of Orthodontics, School of Health Sciences, Faculty of Dentistry, Aristotle University of Thessaloniki, Greece,

AIM: To assess the effectiveness of the Twin Block (TB) appliance in the correction of Class II malocclusions through comparison of treated versus untreated patients by means of lateral cephalometric radiographs. MATERIALS AND METHOD: An unrestricted search of 18 electronic databases and additional manual searches was performed up to October 2013. Only prospective controlled randomized or non-randomized trials fulfilling all of the a priori established inclusion criteria were included. The Cochrane Risk of Bias Tool and a modified checklist of that originally proposed by Downs and Black were used for evaluation of methodological limitations. RESULTS: Eleven studies were finally included in the analysis with most of them reporting cephalometric results immediately after appliance removal. According to random-effects meta-analyses, TB treatment was found to induce a minimal increase of SNB angle (8 studies, MD = 1.30, 95% CI: 0.99 to 1.60), slight reduction of SNA angle (8 studies, MD = –0.79, 95% CI: –1.10 to –0.49), moderate decrease of ANB angle (9 studies, MD = –1.94, 95% CI: –2.31 to –1.56) and substantial reduction in the 1s-NL angle (2 studies, MD = –9.20, 95% CI: –12.70 to - 5.69), when compared with untreated Class II individuals. Specific patient- or appliance-related factors seem to affect treatment outcome, but additional studies are required for the evaluation of these factors. It was not possible to assess the long-term effectiveness of the TB due to the limited evidence. CONCLUSION: Based on the existing evidence, TB treatment seems to be effective in Class II correction in the short-term, partly through growth modification of the skeletal components and partly through dental changes.

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481 CLINICAL EFFECTIVENESS OF AN ACTIVATOR: A SYSTEMATIC REVIEW AND META-ANALYSIS V Zymperdikas1, V Koretsi2, S Papageorgiou3, M Papadopoulos4, 1Dental Unit, 71st Airmobile Medical Company, 71st Airmobile Brigade, Nea Santa, Greece, 2Department of Orthodontics, School of Dentistry, University Medical Centre Regensburg, Germany, 3Department of Oral Technology and Department of Orthodontics, School of Dentistry, University of Bonn, Germany and 4Department of Orthodontics, School of Health Sciences, Faculty of Dentistry, Aristotle University of Thessaloniki, Greece

AIM: Assessment of the effectiveness of an in the correction of Class II malocclusion through comparison of treated versus untreated patients by means of lateral cephalometric radiographs. MATERIALS AND METHOD: Eighteen electronic databases and complementary manual searches were performed up to October 2013. Only prospective controlled randomized or non-randomized trials fulfilling all of the pre-specified criteria were included. Possible methodological limitations were evaluated with the Cochrane Downloaded from https://academic.oup.com/ejo/article/36/5/e1/405724 by guest on 30 September 2021 Risk of Bias Tool and a modified checklist of that initially proposed by Downs and Black. RESULTS: Ten studies were included in the analysis, the majority of which presented cephalometric data after appliance removal. Based on random-effects meta-analyses, activator treatment was found to induce a minimal increase of SNB angle (8 studies, MD = 1.06, 95% CI: 0.55 to 1.57), a slight decrease of SNA angle (8 studies, MD = –1.07, 95% CI: –1.62 to –0.52), moderate reduction of ANB angle (6 studies, MD = –2.19, 95% CI: –3.03 to – 1.34) and substantial reduction of 1s-NL angle (4 studies, MD = –9.07, 95% CI: –11.46 to –6.69) compared with untreated Class II patients. Various appliance- and patient-related factors may influence the effectiveness of the activator, yet further studies are needed for complete assessment of these factors. Current evidence was deemed inadequate for the proper evaluation of the long-term effects of activator treatment. CONCLUSION: According to currently available evidence the activator was found to be effective in Class II correction, partly through slight modification of skeletal components and partly through changes in dental components.

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