THESIS – SYNOPSIS
DR. CHIDANANDESWARA G POST GRADUATE STUDENT
DEPARTMENT OF ORTHODONTICS AND DENTOFACIAL ORTHOPAEDICS
K.V.G. DENTAL COLLEGE & HOSPITAL KURUNJIBAGH, SULLIA – 574327 DAKSHINA KANNADA RAJIV GANDHI UNIVERSITY OF HEALTH SCIENCES BANGALORE, KARNATAKA ANNEXURE II
PROFORMA FOR REGISTRATION OF SUBJECT FOR DISSERTATION
1. NAME OF THE CANDIDATE : DR. CHIDANANDESWARA G AND ADDRESS POST GRADUATE STUDENT, DEPT OF ORTHODONTICS AND DENTOFACIAL ORTHOPAEDICS, K.V.G DENTAL COLLEGE & HOSPITAL, KURUNJIBAGH, SULLIA – 574 327
2. NAME OF THE INSTITUTION : K.V.G. DENTAL COLLEGE & HOSPITAL, KURUNJIBAGH, SULLIA – 574 327.
3. COURSE OF THE STUDY AND : MASTER OF DENTAL SURGERY SUBJECT ORTHODONTICS, BRANCH –V
4. DATE OF ADMISSION TO : 27/05/2011 COURSE A RADIOGRAPHIC EVALUATION OF 5. TITLE OF THE TOPIC : “SAFE ZONES” OF ALVEOLAR BONE FOR ORTHODONTIC MINISCREW IMPLANT PLACEMENT IN DIFFERENT DENTOSKELETAL PATTERN IN DAKSHINA KANNADA POPULATION. 6 BRIEF RESUME OF THE INTENDED STUDY 6.1 NEED FOR THE STUDY Anchorage control is critical in orthodontics. Multiple strategies have been developed to enhance anchorage.1 Recently, the use of miniscrew implant has become an accepted and reliable method for providing orthodontic anchorage.2 Mini-implants are a new anchorage paradigm if compared with traditional procedures; they offer many advantages over conventional implants: placement without special preparation, stable and solid anchorage, lower cost, easy placement, and immediate loading.3 In addition , the small size of miniscrew allows its placement into interradicular space. The interradicular alveolar ridge has been a favourable placement site, since direct application of force from the miniscrew head is possible even without flap surgery.4
Several studies have been performed to assess the safe location in the interradicular space for miniscrew placement, the so called safe zone. A minimal clearance of 1mm of alveolar bone around the screw has been recommended to preserve the periodontal health. Therefore, when the diameter of the miniscrew and the minimum clearance of alveolar bone are considered, interradicular space larger than 3mm is needed for safe miniscrew placement.2
Dentoalveolar compensation is a common adaptive feature observed in subject with different skeletal patterns. Therefore, it is hypothesized that such characteristic dentoalveolar compensation observed in different skeletal discrepancies might affect the availability of interradicular spaces. 2,5
Several factors that would potentially affect the availability of interradicular spaces such as severity of crowding, tooth anatomy, larger sinuses, ethnic variability, and path of eruption of the third molars.2
Considering ethnic group variability, the study will be conducted on different dentoskeletal pattern of Dakshina kannada population . 6.2 REVIEW OF THE LITERATURE A study was conducted using panoramic radiographs to determine if sufficient interradicular divergence for miniscrew placement exists at the level of the buccal mucogingival junction. Sixty panoramic radiographs (30 pretreatment, 30 post treatment) of orthodontic patient were obtained and interradicular site was examined with digital caliper. They found that sites with sufficient bone stock for miniscrew placement existed at 9 of 14 sites they investigated around the mouth . They stated that sufficient bone stock for miniscrew placement existed mesial to the maxillary 1st molars and mesial and distal to the mandibular 1st molars. 1
A study was conducted to investigate optimal locations for miniscrew placement in the maxilla, and concluded that the safest interradicular sites for miniscrew insertion were the buccal and palatal locations between the canine and lateral incisors, maxillary second bicuspid and first molar, and maxillary first and second molars. However, they recommended caution in inserting miniscrews too high in the vestibule in this area because of the presence of the maxillary sinus. 6
A study was aimed to provide an anatomical map to assist the clinician in miniscrew placement in a safe location between dental roots. Volumetric tomographic images of 25 maxillae and 25 mandibles taken with the NewTom System were examined. For each interradicular space, the mesiodistal and the buccolingual distances was measured at two, five, eight, and 11 mm from the alveolar crest. In this article, measurements distal to the canines are presented. In the maxilla, the greatest amount of mesiodistal bone was on the palatal side between the second premolar and the first molar. The least amount of bone was in the tuberosity. The greatest thickness of bone in the buccopalatal dimension was between the first and second molars, whereas the least was found in the tuberosity. In the mandible, the greatest amount of mesiodistal dimension was between first and second premolar. The least amount of bone was between the first premolar and the canine. In the buccolingual dimension, the greatest thickness was between first and second molars. The least amount of bone was between first premolar and the canine. 7
A study was conducted to elucidate relationship between the dental roots and surrounding tissue from 20 human mandible and maxilla with 200 section each, 9 items measured for orthodontic miniscrew installation. According to their study the interroot distance increased from anterior to posterior teeth and from cervical line to apex in both the maxilla and the mandible. The study concluded that the safest zone for placement of a miniscrew in the maxilla was between the second premolar and the first molar, from 6 to 8 mm from the cervical line. The safest zone for placement of a miniscrew in the mandible was between the first and second molars, less than 5mm from the cervical line. 8
A study was conducted to determine the ideal sites for placement of orthodontic mini- implants in mandibular interradicular spaces by using computed tomography (CT) and to suggest length, diameter, and angulation of the mini-implants on 15 dry human mandibles with 1-mm tomography slices. Measurements were made at 3, 5, 7, 9, and 11 mm heights from the bone crest. The study concluded that the most convenient site for implant placement in a mandible was between the first and second molars, with a 10° to 20° inclination, but orthodontic mini-implants should not exceed 1.5 mm in diameter and 6 mm in length.3
A study was designed to quantify the periradicular space in the tooth bearing area to provide practical guideline for miniscrew placement using computerized tomographs.CT of 30 maxillae and mandible were taken from non-orthodontic adult with normal occlusion. Both mesiodistal interradicular distance and bone thickness over the narrowest interradicular space were measured at 2,4,6 and 8mm from cementoenamel junction. The study concluded that placement is advocated in the anterior segment. Premolar areas appear reliable in both arches. Angulated placement in the intermolar area is suggested to use the sufficient safety depth in this area.4
A study aimed to determine the optimal interradicular spaces for miniscrew placement in the mandible and maxilla using CT images from 12 adult patients, mean interradicular distance and standard deviation values were obtained at heights of 2, 5, 8 and 11 mm from the alveolar bone crest. The means was compared with mean data from the literature. The study concluded that the safest interradicular site for miniscrew insertion in the mandible was found to be between the first and second molars, whereas in the maxilla, this site was between the canines and first premolars.9
A study was conducted to assess the influence of different dentoskeletal patterns on the availability of interradicular spaces and to determine the safe zones for miniscrew implant placement. Periapical radiographs of 60 subjects with skeletal Class I, II, or III patterns were examined. For each interradicular site, the areas and distances at 3, 5, 7, 9, and 11 mm from the alveolar crest was measured. The study concluded that For all skeletal patterns, the safest zones were the spaces between the second premolar and the first molar in the maxilla, and between the first and second premolars and between the first and second molars in the mandible.2
OBJECTIVES OF THE STUDY 1. To determine safe zone between root of posterior teeth for miniscrew placement in different dentoskeletal pattern.
2. To assess the influence of different dentoskeletal pattern on the availability of 7. interradicular space.
MATERIAL & METHODS
7.1 SOURCE OF THE DATA Subjects native to Dakshina kannada population visiting to the Department of Orthodontics, K V G Dental College & Hospital, Sullia.
Materials Required: Standardized Lateral Cephalogram
Radiovisiography
Software Nemotec.
7.2 METHODOLOGY A total of 81 Subject will be divided into three groups class I, class II and class III Skeletal pattern comprising 27 in each group on the basis of ANB angle measured on lateral cephalograph.
Digital Dental Lateral Cephalometric radiographs will be obtained and analysis will be done using software(Nemotec). Periapical radiograph will be taken using radiovisiography and measurement of interradicular space will be obtained.
Inclusion criteria
All subjects should be in the age group of 18-28 years.
1. Acceptable radiographic quality, 2. A full complement of erupted teeth from second molar to second molar, and 3. No history of previous orthodontic or prosthodontic treatment. Exclusion criteria
1. Dental arches with severe crowding or rotation in the posterior region, 2. Missing teeth, 3. Radiographic signs of periodontal disease will be excluded.
Measurements Lateral Cephalometric Measurements . Lateral cephalometric measurements will be obtained using software that was designed for this study. The cephalometric measurements are as follows : SNA angle: angle formed by the SN line and the NA line; SNB angle: angle formed by the SN line and the NB line; ANB angle: angle formed by the NA line and the NB line; U1–PP: angle formed by the maxillary central incisor axis and the palatal plane (ANS- PNS); and L1–MP: angle formed by the mandibular central incisor axis and the mandibular plane (Me-Go). Interradicular space measurements . A total of 12 posterior tooth interradicular sites will be examined in each subject. All Periapical radiographs will be taken using RVG using paralleling technique. Li near and area measurements are as follows Interradicular distances (mesiodistal dimension): The horizontal measurements between the lamina dura of adjacent tooth roots, at 3, 5, 7, 9, and 11-mm depths from the alveolar crest. This measurement will be made perpendicularly to a vertical line extended from the alveolar crest.
Interradicular area: The area between the lamina dura of adjacent tooth roots will be calculated using the reference landmarks at the alveolar crest and at 3, 5, 7, 9, and 11-mm depths from the alveolar crest.
STATISTICAL ANALYSIS. The statistical analyses will be performed using the SPSS software package. One-factor analysis of variance (ANOVA) will be used to compare means of measurements between different skeletal patterns.
7.3 DOES THE STUDY REQUIRE ANY INVESTIGATIONS OR INTERVENTIONS TO BE CONDUCTED IN PATIENTS OR OTHER HUMANS? Yes. The study requires lateral cephalometric radiograph and intra oral Periapical radiographs for investigation on subjects.
74. HAS ETHICAL CLEARANCE BEEN OBTAINED FROM YOUR INSTITUTION? HAS BEEN OBTAINED.
LIST OF REFERENCES 1. Schnelle MA, Beck FM, Jaynes RM, Huja SS. A radiographic evaluation of the availability of bone for placement of miniscrews. Angle Orthod. 2004;74:832–837.
2. Chaimanee P,Suzuki B,Suzuki EY.”Safe zones” for miniscrew implant placement in different dentoskeletal patterns. Angle Orthod. 2011;81:397-403.
3. Monnerat C, Restle L, Muchab JN.Tomographic mapping of mandibular interradicular spaces for placement of orthodontic mini-implants. Am J Orthod Dentofacial Orthop. 135:428.e1–428.e9.
4. Lee KJ, Joo E, Kim KD, Lee JS, Park YC, Yu HS. Computed tomographic analysis of tooth-bearing alveolar bone for orthodontic miniscrew placement. Am J Orthod Dentofacial Orthop. 2009;135:486–494.
5. Ishikawa H, Nakamura S, Iwasaki H, Kitazawa S, Tsukada H, Sato Y. Dentoalveolar compensation related to variations in sagittal jaw relationships. Angle Orthod. 1999;69:534–538.
6. Carano A, Velo S, Incorvati C, Poggio P. Clinical applications of the Mini-Screw- Anchorage-System (M.A.S.) in the maxillary alveolar bone. Prog Orthod. 2004;5: 212–235.
7. Poggio PM, Incorvati C, Velo S, Carano A. ‘‘Safe zones’’: a guide for miniscrew positioning in the maxillary and mandibular arch. Angle Orthod. 2006;76:191–197.
8. Hu SK, Kang KM, Kim WT, Kim HK, Kim JH. Relationship between dental roots and surrounding tissues for orthodontic miniscrew installation.Angle Orthod. 2009;79:37-45
9. Bittencourt LP, Raymundo MV ,Mucha JN. The optimal position for insertion of miniscrews. Rev Odonto Cienc 2011;26(2):133-138. 9. SIGNATURE OF CANDIDATE
10. REMARKS OF THE GUIDE
11. NAME AND DESIGNATION OF
11.1 GUIDE DR. JACOB JOHN, M.D.S., M Orth RCS PROFESSOR DEPARTMENT OF ORTHODONTICS AND DENTOFACIAL ORTHOPAEDICS, K.V.G DENTAL COLLEGE AND HOSPITAL, KURUNJIBAGH, SULLIA, D.K -574327
11.2 SIGNATURE
11.3 REMARKS OF HOD
11.4 HEAD OF THE DEPARTMENT DR. SHARATH KUMAR SHETTY, M.D.S. DIRECTOR OF PG STUDIES, PROFESSOR AND HOD, DEPARTMENT OF ORTHODONTICS AND DENTOFACIAL ORTHOPAEDICS, K.V.G DENTAL COLLEGE AND HOSPITAL, KURUNJIBAGH, SULLIA, D.K -574327 11.4 SIGNATURE
12. REMARKS OF THE PRINCIPAL
DR. MOKSHA NAYAK, M.D.S. PRINCIPAL, K.V.G. DENTAL COLLEGE AND HOSPITAL, KURUNJIBAGH, SULLIA. 12.1 SIGNATURE