Interfaces Between Orthodontics and Prosthodontics: Interdisciplinary Possibilities and “Innovations”

160 PRACTICE CASE REPORT

Karin Groß, Stefan Wolfart Interfaces between orthodontics and prosthodontics: interdisciplinary possibilities and “innovations”

Introduction: This article presents possibilities regarding how orthodontists and prosthodontists can cooperate together to create conditions for an esthetically pleasing and functionally oriented treatment result. When planning the prosthetic treatment of anterior gaps, the gaps can be adjusted in advance by means of orthodontic treatment so that they can subsequently be treated in the best possible esthetic and functional manner.

Material and Methods: Adhesive bridges represent a suitable treatment option in adolescents for congenitally missing lateral incisors or after anterior tooth loss due to trauma. When designed with one wing, adhesive bridges can be used before the completion of jaw bone development and, if necessary, they can be orthodontically positioned together with the abutment tooth. Prior to complex prosthetic rehabilitation in the esthetic area, malpositioned abutment teeth can be orthodontically positioned or aligned to generate space for an ideal restoration design. Moreover, orthodontic extrusion provides the possibility of achieving sufficient abutment heights in the case of deeply destroyed or fractured teeth, thus permitting the adequate treatment of these critical teeth according to prosthetic guidelines. Oftentimes, in the case of tilted, protruded or retruded teeth, an orthodontic intervention previous to tooth preparation is useful for tooth substance conservation and maintaining the vitality of abutment teeth.

Conclusion: It can be concluded that a specific combination of orthodontic and prosthetic treatment measures can achieve a better restorative treatment result in terms of function, esthetics and long-term stability. Often, this is accompanied by a reduction in treatment duration and costs.

Keywords: interdisciplinary treatments; gap management; extrusion; esthetics; adhesive bridges

Clinic for Prosthodontics, Center for Implantology, Medical Center of RWTH Aachen University: Dr. Karin Groß; Prof. Dr. Stefan Wolfart Translation from German: Christian Miron Citation: Groß K, Wolfart S: Interfaces between orthodontics and prosthodontics: interdisciplinary possibilities and “innovations”. Dtsch Zahnärztl Z Int 2020; 2: 160–167 Peer-reviewed article: submitted: 13.03.2020, revised version accepted: 07.06.2020 DOI.org/10.3238/dzz-int.2020.0160–0167

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Introduction sultation between the dentist, or- 4. Following a crowning procedure, In order to achieve esthetically pleas- thodontist and patient. approximately 15 % of teeth show ing and functionally optimized treat- 2. In the case that a dental gap is to a negative response to sensitiv- ment results in complex treatment be treated by prosthetic means, it ity testing after 10 years [12]. A cases, close cooperation between the is necessary to first check the gap remaining dentin thickness of orthodontist and prosthodontist is size and decide whether or not it is 0.5 mm should be aimed for in often advisable. In ideal circum- acceptable, as corrective orthodon- order to reduce the risk of pulp stances, this teamwork extends from tic treatment may be required be- damage [15]. Therefore, it is impor - treatment planning to joint treat- forehand for an esthetically pleas- tant to remove as little healthy ment implementation and is re- ing or functionally reasonable so - tooth structure as possible during warded by satisfied patients and lution. The same applies for the preparation. Currently, prepara- high-quality treatment results. The restoration of multiple teeth in the tion designs which preserve tooth overlap, or interface, between the esthetic zone. Often, this is only substance have gained in impor - two disciplines is multifaceted. This useful if the abutments are spaced tance. In this respect, the position article discusses 4 of these interfaces at a distance that allows esthet- and axial inclination of teeth play and presents clinical examples to ically pleasing length-width ratios a decisive role. In clinical situ- illustrate them: to be anticipated for each individ- ations where the prospective abut- 1. If individual teeth are missing, the ual restoration and between adja - ment teeth require a common in- question of which specialty domain cent anterior teeth. sertion path, but differ greatly in should have pre-eminence, and ac- 3. For the crowning of teeth, it is their axial inclinations, a conser- cordingly the responsibility, often necessary to have adequate abut- vative tooth preparation design is arises: Should an existing dental ment height and sufficient healthy not attainable. In these cases, in gap be orthodontically closed, or be tooth structure after tooth prepara- order to avoid exceedingly inva - restored by prosthetic means, such tion. If this is not the case due to sive tooth preparations, ortho- as a bridge, adhesive bridge or im- biological width considerations dontically active components can plant? Each of these approaches has and a high degree of destruction, be used in combination with inter- advantages and disadvantages; they an orthodontic extrusion can be im dentures. By combining the can best be discussed in a joint con- considered. temporary prosthetic phase with

Figure 1 Fixation of the lateral incisors – dimensioned and Figure 2 Situation after removal of the brackets; width of the shaped according to the wax-up – for attaining a harmonious gaps optimally shaped dental arch in the congenital absence of 12 and 22

Figure 3 Placement of adhesive bridges to replace teeth 12 and Figure 4 Two mesially interconnected adhesive bridges simulta- 22 neously adopt the function of a retainer.

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5) 6) 7)

Figures 5–7 Initial situation with multiple diastemas between the maxillary front teeth in the presence of a strongly abraded dentition; occlusal, frontal views and the patient’s smile

ented with the options of either an orthodontic gap closure or an implant- supported restoration. Orthodontists often favor gap closure by means of canine mesialization. Gap closure not only has functional implications, but also esthetic ones. This is because canines differ noticeably from lateral incisors, in both shape and color, as canines usually appear darker than incisors. Consequently, in the majority of cases, the treatment is not fully complete after orthodontic gap closure due to esthetic reasons; for a natural appearance, canines then require corrective treatment to imitate the appearance of lateral incisors. This impli- Figure 8 Gap closure mesially and gap opening in the area of the first premolars cates adapting the tooth’s shape and (orthodontic treatment performed by Prof. Dr. Fischer-Brandis, Kiel) color by means of applying a veneer, preparation of the enamel or whiten- ing of the enamel by bleaching [18, 20, 26]. Particularly in the case of uni- orthodontic dental alignment, a 14 and about 7 % of these front teeth lateral agenesis, asymmetrical tooth lower amount of tooth substance are lost [23]. Circa 1.5–1.8 % of people positions may lead to esthetic impair- removal can be facilitated. in Germany are affected by upper ments. For this reason, the symmetri- lateral incisor agenesis [17]. Hence, it cal alignment of the front teeth should First interface: missing teeth can be assumed that approximately always be an important objective. Anterior region gaps are most fre- 3–3.5 % of young people aged 14 years Implant-supported restorations quently caused by the congenital ab- old are missing anterior teeth [7]. A are contraindicated in adolescence. sence of teeth, especially maxillary lat- number of treatment options can then Nevertheless, even after transversal eral incisors, or traumatic loss. Around be chosen. If the lateral incisors are bone growth and canine eruption one quarter of young people experi- congenitally missing, patients, or have been completed, vertical bone ence front tooth trauma by the age of rather their parents, are often pres- growth may continue into adulthood

9) 10) 11)

Figure 9–11 Prosthetic restoration with metal-ceramic crowns and bridges in the upper jaw; occlusal, frontal views and the patient‘s smile

Figure 12 Fractured tooth 21 with Figure 13 Miniplast splint with inte- Figure 14 Abutment after successful adapted, fixed magnet grated magnet (B); magnet A fixed to extrusion; the incisal third of the abut- the abutment ment was built up with composite

Figure 15 Definitive zirconia crown half Figure 16 Forced extrusion of abutment Figure 17 Forced extrusion of the root a year after cementation 26 of tooth 11; a metal-reinforced cantilever bridge on implant 12 serves as an extrusion aid.

[21, 22]. Implants which are placed Gazette 2013, specifies that the pa- using an aligner or multiband ther- too early are often located in an infra tient should be completely informed apy. This creates sufficient space to at- position after a few years, which not regarding all possible treatment tach the wing of the bridge without only results in step formation at the options [1]. Accordingly, adhesive the need to perform any occlusal ad- incisal edges, but also in poor red- bridges must definitely be discussed as justments by grinding of antagonist white esthetics in the area of the gin- a treatment option. This necessity is teeth in the antagonist jaw. These gival line. Especially in the case of a also underlined by the fact that adhe - necessary space conditions should be high smile line, the timing for im- sive bridges are listed as a standard taken into consideration early on plant placement should be carefully care procedure in the service cata- when planning an orthodontic treat- considered. Adhesive bridges are logue of statutory health insurance ment. often overlooked, or are solely con- companies since 2016. The key advan- sidered a more or less temporary so - tages of one-wing adhesive bridges are If only one incisor is missing, the lution, until the age is reached when the minimally invasive preparation contralateral tooth in the same jaw implants can be inserted. Lately, how- design which is only confined to the determines the size and shape of the ever, very good long-term results have enamel and the fact that the restora- intended restoration. A timely con- been reported when using adhesive tion can be applied regardless of the sultation with the prosthodontist is bridges. One-wing adhesive bridges stage of jaw bone development. The helpful here. Thus, a wax-up/set-up have proven to be more reliable than requirement is the presence of a com- can be prepared at an early stage in two-wing bridges [2, 4, 10, 19, 24]. pletely erupted, caries-free neighbor- order to model a suitable tooth. A try The clinical survival rate of one-wing ing tooth which borders the gap, hav- in of the tooth wax-up can be made, adhesive bridges made of aluminum ing an adhesive surface in the enamel which is thereafter converted into or zirconium oxide ceramics is be- of at least 30 mm2, as well as, suffi- composite. The model tooth is fixed tween 95.4 and 98 % after 10 years [6, cient space relative to the antagonist in the dental arch in order to give the 9]. Thus, the survival rates of implant- jaw for the purpose of being able to orthodontist the chance to adjust the supported crowns and one-wing ad- design a connector with a height of at dental gap exactly to the desired size hesive bridges can therefore be re- least 3 mm [8]. Additionally, sufficient and position for the subsequent garded as being equivalent [11]. space should be generated for wing esthetic restoration. A similar pro- With reference to legally consis - insertion in the case of maxillary ad- cedure is useful if both lateral incisors tent patient education, the law gov- hesive bridges. For this purpose, the are missing (Fig. 1). In this case, too, erning the improvement of patients‘ corresponding abutment tooth is pro- an ideal situation can be created rights, anchored in the Federal Law truded by approximately 0.7 mm through precise prosthetic planning

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Figure 18 Extrusion of approximately 4 mm after 4 weeks Figure 19 Initial situation, distally inclined canines

before, or at the latest, during ortho- bridge is cemented, a retainer must be sirable [13]. Additionally, a harmo - dontic treatment (Fig. 2). Above all, applied, as is common for all ortho- nious anterior overjet, a length-to- the ideal width of the lateral incisors dontic treatments. The splinting to- width ratio of the central incisors cor- must be carefully considered. When gether of the two adhesive wings can responding to 75–85 %, and a cen- the width of the lateral incisors is be- take over this function (Fig. 4). tral to lateral incisor width ratio between 50 and 74 % of that of the cen- tween 50 and 74 % should be present tral incisors, they are perceived as Second interface: setting [25]. In order to achieve this, a gap being esthetic [25] (Fig. 3). However, ideal tooth spaces before closure by means of mesialization if the gaps are set-up as being too beginning with the and a gap expansion in the premolar small or too large, the dental restora- restoration region took place. Based on this tion can either Provided that several teeth in the es- orthodon-tic pre-treatment, which • then be too narrowly or too widely thetic zone must be restored with lasted about 1 year, an esthetically designed, crowns, or veneers, it is always useful pleasing and functionally appropriate • arranged in an overlapping posi- to prepare a wax-up in advance to prosthetic restoration could be cre- tion, check if the ideal length-width ratios ated (Fig. 8–11). • be fitted in, but with a remaining and proportions of the teeth with re- gap spect to each other can be achieved. Third interface: orthodontic • or orthodontic measures must be In the abrasive dentition shown here, extrusion for tooth carried out once again after the conspicuous diastemas existed be- preservation prosthetic treatment. tween all anterior teeth. Given the The extrusion of roots often makes it Directly after the removal of the tooth positions, it was not possible to possible to preserve and restore frac- multiband appliance, a retention close the spaces and make sufficient tured or deeply destroyed teeth [3, 5]: splint must be worn; it is essential to vertical bite correction, and yet, still The background behind this has to do ensure that the patient wears it con- be able to create esthetically pleasing with the planned/existing dental post tinuously until the adhesive bridge is anterior esthetics (Fig. 5–7). For this in non-vital teeth having to be sur- introduced. Otherwise, there is a risk purpose, anterior tooth lengths aver- rounded by at least 2 mm of healthy that the teeth could move in the short aging 11.7 mm for the central in- hard substance (adequate ferrule de- time it takes for the adhesive bridge to cisors, 9.5 mm for the lateral incisors sign). For vital abutment teeth, how- be finished. Directly after the adhesive and 10.8 mm for the canines are de- ever, a remaining abutment height

20) 21)

Figures 20 and 21 Interim denture with attached elastic bands at the beginning of treatment; frontal and occlusal views.

22) 23)

Figures 22 and 23 Uprighting of canines after 9 weeks of wear. A clear gap is visible between the clasp and tooth 33; frontal and occlusal views

of at least 3 mm is required. Fur- maining abutment tooth (Fig. 12). themselves. Subsequent to this pro- thermore, an adequate biological Using a 1 mm thick placeholder, a cedure, a core build-up with compos- width must be maintained around the second magnet was positioned on top ite, preparation of the abutment and abutment teeth. In the existing case, of the first magnet and fixed to a pre- fabrication of a temporary crown en- the ceramic crown on tooth 21 was viously fabricated Miniplast splint sued (Fig. 14). In order to prevent the paragingivally fractured. The remain- (Fig. 13). The supracrestal periodontal tooth from migrating again, the tem- ing abutment did not fulfill the con- fibers were additionally cut with a porary crown was fixed to the ad - ditions just described for a new crown scalpel under local anesthesia. In one jacent teeth with retainer wire for which would have a favorable long- to two weeks, the root was ortho- 4 months. After the retention period, term prognosis. The neighboring dontically extruded to the desired the definitive zirconia crown could be teeth 11 and 22 displayed adequate millimeter using magnetism. By mov- fabricated with vestibular veneering restorations. Surgical crown lengthen- ing the magnet twice inside the and adhesively bonded to the abut- ing was not an option due to esthetic splint, with a renewed adjustment of ment. Figure 15 shows the restoration reasons, as the previous gingival pro- 1 mm space between the magnets, the half a year after placement. The tooth file showed a harmonious appear- root could be extruded approximately continues to react positively to the ance. In order to preserve the tooth, 3 mm over a period of 6 weeks. The cold sensitivity test. the root was extruded with the help costs of this preliminary measure are Another method to mobilize of magnets. For this purpose, a mag- not included in the service catalogue teeth is through forced extrusion net with flowable composite was at- of the statutory health insurance using rubber bands. For this purpose, tached to the vital abutment tooth. companies, and must therefore, like if required, bars are fixed occlusally The magnet had to be reduced in size any other orthodontic treatments in to the adjacent teeth [14, 16]. The beforehand so that it matched the re- adulthood, be covered by the patients abutment itself is fitted with a dumb- bell-shaped device in the oro-vestibular direction. Elastic bands can then be hooked in with varying amounts of force (Fig. 16–18), so that the tooth root usually extrudes within a few weeks. The supracrestal sepa - ration of the gingival fibers prevents the fixed gingiva from moving with the root. When a coronal displace- ment of the soft tissue is also desired, the supracrestal fibers are not cut [16]. This applies to all extrusions, regardless of the procedure.

Fourth interface: conservative preparation by uprighting teeth before crown preparation

(Fig. 1–4, 12–23: K. Groß, Fig. 5–11: S. Wolfart, Fig. 24: L. Waltenberger) (Fig. 1–4, 12–23: K. Groß, Fig. 5–11: S. Wolfart, A well-known procedure and typical Figure 24 Appearance 3 years after cementation. example includes the classical

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uprighting of a molar that is in- Conclusion dental prostheses. J Adhes Dent 2011; clined towards a mesial gap. We In summary, a purposeful com- 13: 407–410 would like to present the case of an bination of prosthetic and orthodon- 11. Kern M, Wolfart S: Kontrovers dis- innovative, simple, and patient- tic treatment measures can achieve kutiert: Versorgung von Frontzahnlücken oriented approach for aligning two better esthetics and function in many bei Jugendlichen nach Abschluss der kie- ferorthopädischen Therapie. Dtsch canines. A 67-year-old patient with a cases. This is often accompanied by a Zahnärztl Z 2018; 73: 330–337 remaining dentition consisting of reduction in treatment duration and 33, 43, and 44 in the lower jaw costs. For optimal treatment out- 12. Kerschbaum T: Das Risiko des Vitali- tätsverlustes nach Überkronung. DGZMK required a new prosthetic restora- comes, coordinated treatment plan- Statement 1998 tion. Owing to the inclination of the ning between the orthodontist and canines, the patient could hardly in- prosthodontist is recommended be- 13. Magne P, Gallucci GO, Belser UC: Anatomic crown width/length ratios of sert and remove the existing clasp- fore beginning treatment. unworn and worn maxillary teeth in retained removable partial denture white subjects. J Prosthet Dent 2003; 89: (Fig. 19). Besides this, the patient no 453–461 longer wished for the new restora- Conflicts of Interest 14. Mörig G, Svoboda R, Podolsky L: tive treatment to have visible clasps. Forcierte Extrusion – ein Behandlungs- After a detailed consultation, he The authors declare that there is no konzept für bisher ausweglose Fälle. chose a telescopic denture. In order conflict of interest as defined by the ZMK-aktuell 2017; 33: 42–50 to have achieved a common inser- guidelines of the International Com- 15. Murray PE, Smith AJ, Windsor LJ, tion path during the preparation of mittee of Medical Journal Editors. Mjor IA: Remaining dentine thickness the 3 abutment teeth, the canines and human pulp responses. Int Endod J should have been devitalized. A 2003; 36: 33–43 treatment alternative was repre- 16. Neumeyer S: Extrusions- und Implan- References sented by the uprighting of the two tationstechniken. Grundlegende Aspekte teeth in a mesial direction. The or- 1. Gesetz zur Verbesserung der Rechte des Tissue Master Concepts (TMC) – ein von Patientinnen und Patienten. Bundes- biologisches Gewebemanagement. BZB thodontic appliance could be inte- gesetzblatt 2013; 9: 277–282 2013; November: 54–60 grated into the already existing in- 2. Botelho MG, Chan AW, Leung NC, terim denture by applying ortho- 17. Polder BJ, Van‘t Hof MA, Van der Lam WY: Long-term evaluation of canti- Linden FP, Kuijpers-Jagtman AM: A meta- dontic elements into its structure. levered versus fixed-fixed resin-bonded analysis of the prevalence of dental agen- Also, in this case, the orthodontic fixed partial dentures for missing maxil- esis of permanent teeth. Community treatment had to be privately cover- lary incisors. J Dent 2016; 45: 59–66 Dent Oral Epidemiol 2004; 32: 217–226 ed by the patient and an additional 3. Brawek P, Schley J, Wolfart S: Zahn - 18. Priest G: The treatment dilemma of private agreement for the treatment erhalt durch forcierte Magnetextrusion – missing maxillary lateral incisors-Part I: and cost plan was created, which eine Falldarstellung. Dtsch Zahnärztl Z Canine substitution and resin-bonded contained just the orthodontic 2013; 68: 456–462 fixed dental prostheses. J Esthet Restor measures. In order to use the time to 4. Djemal S, Setchell D, King P, Wickens Dent 2019; 31: 311–318 J: Long-term survival characteristics of test the new vertical bite position by 19. Saker S, El-Fallal A, Abo-Madina M, 832 resin-retained bridges and splints means of the interim denture, a Ghazy M, Ozcan M: Clinical survival of provided in a post-graduate teaching anterior metal-ceramic and all-ceramic guide groove for the elastic band was hospital between 1978 and 1993. J Oral cantilever resin-bonded fixed dental pros- prepared in cooperation with the de- Rehabil 1999; 26: 302–320 theses over a period of 60 months. Int J partment of orthodontics on the ca- 5. Harder S, Mehl C, Kern M: Behand- Prosthodont 2014; 27: 422–424 nines in the distal, lingual and ves- lungsmöglichkeiten bei tief frakturierten 20. Schneider U, Moser L, Fornasetti M, tibular areas. In addition, the den- Pfeilerzähnen. Quintessenz 2010; 61: Piattella M, Siciliani G: Esthetic evaluation 1485–1494 ture teeth 31 and 41 each received a of implants vs canine substitution in pa- knob vestibularly to avoid protru- 6. Kern M: Fifteen-year survival of ante - tients with congenitally missing maxillary sion or retrusion. In this way, the pa- rior all-ceramic cantilever resin-bonded lateral incisors: Are there any new in- tient was able to attach elastics on fixed dental prostheses. J Dent 2017; 56: sights? Am J Orthod Dentofacial Orthop 133–135 his own, which he changed daily 2016; 150: 416–424 (Fig. 20 and 21). After 3 months, the 7. Kern M: Einflügelige Adhäsivbrücken. 21. Thilander B: Dentoalveolar devel- Kieferorthopädie 2018; 32: 123–134 two canines were upright enough so opment in subjects with normal occlu- that their preparation could be suc- 8. Kern M: Adhäsivbrücken: Minimal- sion. A longitudinal study between the ages of 5 and 31 years. Eur J Orthod cessfully accomplished, while main- invasiv – ästhetisch – bewährt. Quintes- senz, Berlin 2018 2009; 31: 109–120 taining a common insertion path and the vitality of the pulp (Figs. 22 9. Kern M, Passia N, Sasse M, Yazigi C: 22. Thilander B, Odman J, Jemt T: Single Ten-year outcome of zirconia ceramic implants in the upper incisor region and and 23). The retention of the two cantilever resin-bonded fixed dental pros- their relationship to the adjacent teeth. teeth was ensured by the telescopic theses and the influence of the reasons An 8-year follow-up study. Clin Oral Im- restoration. Figure 24 shows the pa- for missing incisors. J Dent 2017; 65: plants Res 1999; 10: 346–355 51–55 tient after 3 years. The two canines 23. Tuli T, Hachl O, Rasse M, Kloss F, still respond positively to sensitivity 10. Kern M, Sasse M: Ten-year survival of Gassner R: [Dentoalveolar trauma. Analy- testing. anterior all-ceramic resin-bonded fixed sis of 4763 patients with 6237 injuries in

10 years]. Mund Kiefer Gesichtschir 2005; 9: 324–329

24. van Dalen A, Feilzer AJ, Kleverlaan CJ: A literature review of two-unit cantile - vered FPDs. Int J Prosthodont 2004; 17: 281–284

25. Wolfart S, Thormann H, Freitag S, (Photo: private, Karin Groß) Kern M: Assessment of dental appearance following changes in incisor proportions. Eur J Oral Sci 2005; 113: 159–165 DR. KARIN GROß Clinic for Prosthodontics, 26. Zachrisson BU, Rosa M, Toreskog S: Center for Implantology, Medical Congenitally missing maxillary lateral Center of RWTH Aachen University incisors: canine substitution. Point. Am Pauwelstr. 30 J Orthod Dentofacial Orthop 2011; 139: 52074 Aachen 434, 436, 438 passim [email protected]