Interdisciplinary Management of Anterior Guidance-A Case Report

Interdisciplinary Management of Anterior Guidance: A Case Report

common objective of anterior re- mandibular left second premolar, which Vincent G. Kokich, DDS, MSD Professor A storative dentistry is to establish allowed the mandibular midline to shift Department Of Orthodontics incisal guidance between the maxillary to the left. With this shift, the mandib- School of Dentistry University Of Washington and mandibular anterior teeth to dis- ular incisors also were positioned slight- Seattle, Washington clude the posterior teeth during protru- ly lingually. 1-4 sive mandibular movement. However, The patient’s gingival health was Frank M. Spear, DDS, MSD Founder and Director this goal is difficult to achieve in a pa- reasonably good and her oral hygiene Seattle Institute for Advanced tient with significant wear or abrasion was satisfactory. Sulcus depths were in Dental Education and excess anterior overjet. How does the the normal range in most areas, with Seattle, Washington restorative dentist provide for imme- no bleeding on probing. Her temporo- Affiliate Assistant Professor University of Washington diate incisal guidance when the patient mandibular joints were asymptomatic School of Dentistry has short, abraded anterior teeth and a and she only complained of mild mus- Seattle, Washington

6-mm overjet? This is a common dilem- cle aches from the protrusive bruxing Private Practice ma for the restorative dentist. However, habit. Besides missing the mandibular Seattle, Washington with the possibility of moving the anteri- left second premolar, the maxillary left or teeth orthodontically, the restorative first molar also had been extracted pre- dentist can achieve better anterior guid- viously due to caries. Sufficient space ex- ance for the patient. Achieving anterior isted for a replacement tooth in the guidance with orthodontics could in- maxillary left posterior region; howev- volve retraction of maxillary incisors, er, insufficient space existed for a re- proclination of mandibular incisors, placement for the missing mandibular extrusion of either maxillary or man- left second premolar (Figure 1). The pa- dibular incisors, jaw surgery, or a com- tient also had mild crowding and over- bination of these alternatives. This case lap of the mandibular incisors. Her goal report will describe how anterior guid- was to have better smile esthetics. ance was achieved in an adult female using an interdisciplinary approach TREATMENT OBJECTIVES The restorative objectives for this DIAGNOSIS AND ETIOLOGY patient included: This 54-year-old woman wanted to improve the esthetics of her smile. She • restoration of the maxillary and man- had abraded her maxillary central inci- dibular left edentulous spaces; sors from a protrusive bruxing habit. As • restoration of the abraded maxillary a result of the wear, the teeth had con- incisors; tinued to erupt and the gingival margins • improving posterior occlusal contacts; of the maxillary central incisors were be- • establishing adequate incisal guidance; low the gingival levels of the maxillary • correcting the maxillary anterior gin- lateral incisors (Figure 1). In addition, gival margin relationships; and the maxillary central incisors were ret- • improving anterior tooth alignment. roclined lingually. The patient had a rel- atively deep overbite and a 5-mm over- Most of these objectives could be jet. The posterior occlusion was Angle managed with conventional restorative Class I on her right side, but was Class techniques, except for the correction of II on her left side (Figure 1). Part of the gingival margin levels and the cre- the etiology of the posterior malocclu- ation of adequate incisal guidance. In sion was due to a congenitally missing addition, the edentulous space on the

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Figure 1A through Figure 1F This 54-year old woman was unhappy with the appearance of her maxillary anterior teeth. She had an Angle Class I relationship on the right side (A), and a Class II relationship on the left side (B), which produced a deviation between the maxillary and mandibular dental midlines (C). Her maxillary incisors were retroclined and abraded (D) and her mandibular incisors were mildly crowded (E). The mandibular left second premolar was congenitally absent and the space had partially closed (F) with shifting of the mandibular midline to the left. mandibular left side was too narrow achieve these aforementioned goals or mandible and move the mandibular for a proper-sized tooth. It was deter- objectives: incisors into proper contact with the mined that her edentulous spaces would maxillary incisors. However, this plan be restored with fixed bridges, because 1. Extraction of the maxillary right was rejected because the patient’s chin of the existing restorations in the abut- first premolar and mandibular right projection was acceptable before ment teeth and the lack of bone sup- first premolar and closure of all ed- treatment (Figure 2) and did not port for implants in the edentulous sites. entulous spaces. This would have need to be advanced forward. To achieve all of the restorative objec- reduced the overjet and established tives, it was decided that orthodontics adequate incisal guidance for the 3. A third alternative to reduce anteri- should be a part of the treatment plan. restorative dentist. However, the or the overjet and establish anterior The orthodontic objectives for this antero-posterior relationship of the guidance was to advance and pro- patient included: maxillary incisors to the upper lip cline the mandibular incisors in a la- was acceptable (Figure 2). Extrac- bial direction to provide contact with • reduction of the anterior overjet; tion of the teeth and closure of the the maxillary incisors. This would • reduction of anterior overbite; extraction spaces would have retrac- also allow opening of the mandibu- • establishing adequate incisal guidance; ted the maxillary incisors, thereby lar left edentulous space to create an • alignment of the anterior teeth; retracting the patient’s upper lip, adequate-sized pontic. This plan • correction of the deviated mandib- which would have produced a neg- would provide for the best profile ular midline; ative effect on her profile. There- result, avoid jaw surgery, and facili- • establishing a Class I canine rela- fore, this plan was rejected. tate all of the restorative objectives. tionship on the left side; To determine if this plan would pro- • opening space for a larger pontic in 2. A second alternative for establishing duce the correct occlusal relation- the mandibular left posterior segment; anterior guidance and reducing the ship for the restorative dentist, the and overjet was to extract the mandibu- orthodontist constructed a diagnos- • leveling of the maxillary anterior gin- lar right second premolar and close tic wax-up simulating the anticipat- gival margins. the spaces on both sides in the man- ed outcome of treatment (Figure 2). dibular arch to correct the mandi- This wax-up provided the dentist, TREATMENT ALTERNATIVES bular dental midline. Then a bilat- orthodontist, and the patient with Several orthodontic treatment alter- eral sagittal mandibular osteotomy the same vision of what could be natives could have been employed to would be performed to lengthen the accomplished. Because the wax-up

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Figure 2A through Figure 2F A diagnostic wax set-up (A, B, C) was constructed to simulate the orthodontic and restorative treatment plans. The mandibular incisors were originally positioned lingual to their desired position (D) relative the chin and lower lip. During orthodontics, the mandibular incisors were proclined nearly 3 mm at the incisal edge (E, F) to gain anterior guidance.

showed that all objectives could be canine relationship on the left side and improved with the intrusion of the achieved, this orthodontic treatment produced proclination of the mandib- maxillary central incisors and restoration plan was selected. ular incisors, which helped to establish of these previously abraded teeth (Figure maxillary and mandibular incisal con- 3). The maxillary and mandibular dental TREATMENT PROGRESS tact and anterior guidance. midlines are now coincident. The patient Before orthodontic treatment, some After all of the orthodontic objec- has canine-protected occlusion bilaterally of the patient’s questionable restora- tives had been accomplished, the patient’s with no balancing interferences. The sizes tions were temporarily reinforced to brackets were removed and orthodontic of the pontic spaces for the fixed bridges provide adequate strength to withstand retainers were placed in both arches to were improved (Figure 3). And perhaps 18 months of orthodontics. In addi- stabilize the treatment result. After about most important, adequate incisal guid- tion, she had a thorough root planing 6 months of retention, provisional res- ance in protrusive position was estab- and scaling before orthodontic banding torations were placed on those teeth that lished for this patient as a result of the and then maintenance appointments for required restoration. The provisional res- combined orthodontic and restorative tooth cleaning every 4 months during ac- torations were left in place for an addition- treatment plan. tive orthodontics. al 6 months to determine the patient’s Orthodontic brackets were placed response to her new occlusal relationship. DISCUSSION on all teeth in both arches. The brack- One year after orthodontic treatment had Establishing incisal contact in centric ets on the maxillary central incisors been completed, the final restorations occlusion and immediate incisal guidance were placed closer to the incisal edges were placed, including three-unit fixed in protrusive position are typical goals to facilitate intrusion of these teeth to bridges in the maxillary and mandibu- when restoring the maxillary anterior move their gingival margins apically lar left posterior segments (Figure 3). teeth.1-4 However, this objective is di- and allow for restoration of their in- fficult to achieve when the patient has cisal edges (Figure 3). This would re- TREATMENT RESULTS excessive overjet. Orthodontics and/or create the correct width-to-length pro- This interdisciplinary approach to orthognathic surgery can be used to portion of these teeth. After alignment managing this patient’s occlusal, gingi- reduce excessive overjet and create an- of the maxillary arch, the mandibular val, and esthetic discrepancies allowed terior guidance. As in this patient, there orthodontic brackets were placed on the team to achieve all of the restora- are several options available to correct the teeth and a spring was used to open tive and orthodontic objectives that an excessive overjet. These include re- space between the mandibular left first were established before treatment. Her traction of the maxillary incisors, pro- molar and first premolar. This move- facial profile did not change. Her max- clination of the mandibular incisors, ment helped to create an Angle Class I illary anterior dental esthetics has been eruption of either the maxillary or

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Figure 3A through Figure 3I The patient’s initial occlusion showed signs of wear and tooth drifting (A, B, C). To level the gingival margins, the maxillary incisors were intruded (D), provisionalized with composite (E), and retained in that position with brackets and archwires (F) for 6 months. One year after completion of orthodontic therapy, the final porcelain restorations were placed (G, H, I), which established an excellent, well-balanced, and healthy dentition. mandibular incisors, orthognathic sur- When mandibular incisors are pro- gingival recession is possible or likely gery, or a combination of these tech- clined labially, there are some concerns during mandibular incisor proclina- niques. The decision of which technique about stability. Posttreatment evaluation? The patient’s gingival tissue bio- to select depends on the patient’s facial tion of patients whose teeth have been type probably plays a role in providing profile, the position of the mandible proclined during orthodontics shows protection against gingival recession. If relative to the face, and the upper and that there is a tendency for these teeth a patient has a thicker biotype, as was lower lip support provided by the max- to move lingually if they are not sup- the case in our patient, the risk of re- illary and mandibular incisors. In our ported by a retainer.5 Therefore, in our cession is probably reduced.7 However, patient, her chin prominence was ac- patient, a bonded mandibular lingual with a thin tissue biotype, recession may ceptable, which eliminated jaw surgery retainer was used to help support the be more of a risk. Second would be the as an option. Her upper-lip-to-nose re- forward position of the mandibular in- amount of attached gingiva. If the amount lationship was acceptable, which elim- cisors. This retainer will need to be of gingiva labial to the mandibular in- inated retraction of the maxillary incisors maintained indefinitely to maintain the cisors is only 1 mm and the patient has as an option. The overbite was already mandibular incisor position. a 1-mm gingival sulcus, then there is no deep and needed to be reduced, which Another concern about proclining attached gingiva. This situation could eliminated tooth eruption as an op- the mandibular incisors is the possibil- provide little resistance to recession if tion. The remaining option of proclin- ity of gingival recession labial to the teeth are proclined. The third point to ing the mandibular incisors to achieve mandibular incisor roots.6 Recession did remember is that recession of the gin- incisal contact and anterior guidance not occur in our patient. What should giva cannot occur if there is no bony de- was the only logical solution. the clinician look for to determine if hiscence labial to a mandibular incisor.8

ADVANCED ESTHETICS & INTERDISCIPLINARY DENTISTRY SEPTEMBER 2007—VOLUME 3, NUMBER 3 22 If a dehiscence were present in a patient restored permanently with porcelain encourage teams to construct wax-ups with inadequate attached gingiva or a veneer or crown restorations after the for all restorative patients that are under- thin tissue biotype or both, then pro- teeth have stabilized. going orthodontic therapy. clination of the mandibular incisors is If the gingival margin discrepancies risky without considering a connective are corrected by leveling the gingival mar- CONCLUSION tissue graft to reinforce the zone of gin- gins orthodontically, these tooth posi- This case report has shown how or- giva labial to the mandibular incisors. tions should be maintained for at least thodontics and restorative dentistry Another important aspect of this 6 months to avoid relapse. As teeth are can accomplish treatment results that patient’s treatment was correcting the intruded, the orientation of the perio- would not have been possible if either gingival levels of the maxillary anterior dontal fibers changes and becomes more of these disciplines had been applied teeth during the orthodontic therapy. oblique.11 It typically takes at least 6 independently. Establishing anterior Anterior gingival margin discrepancies months for these fibers to reorient them- guidance, leveling gingival margins, re- in adults are typically due to wear or selves in a horizontal position and sta- storing edentulous spaces, and estab- abrasion of the maxillary incisal edges bilize the tooth. A method of retaining lishing a balanced occlusion were only and compensatory eruption of the in- these teeth after final restoration is to possible through the combined efforts cisors causing uneven gingival levels and have the patient wear a maxillary night- of both disciplines. Through careful unequal crown length of adjacent teeth. guard while sleeping. This type of retain- planning using diagnostic wax-ups, the The treatment for this problem could er will help to prevent further abrasion various problems with this patient’s consist of periodontal crown lengthen- and also to maintain the vertical relation- teeth could be treated effectively, effi- ing to level the gingival margins, ortho- ships of the anterior and posterior teeth. ciently, and conservatively. dontic extrusion of the longer central Another important aspect of this incisor, or intrusion and restoration of patient’s treatment was the opening of REFERENCES 9 1. Ogawa T, Koyano K, Suetsugu T. The influ- the short tooth or teeth. To diagnose space for a suitable-sized pontic in the ence of anterior guidance and condylar this problem adequately, the clinician mandibular left posterior region. This guidance on mandibular protrusive movement. J Oral Rehabil. 1997;24:303-309. must first evaluate the labial sulcular movement was accomplished using a 2. Buschang PH, Throckmorton GS, Travers KH, depth of the maxillary incisors. If the spring to push the adjacent teeth apart. Hayasaki H. Incisor and mandibular condylar movements of young adult females during sulcular depths are uniformly 1 mm, then The time necessary to create an addi- maximum protrusion and lateratrusion of the discrepancy in gingival margins may tional 3 mm to 4 mm of pontic space the jaw. Arch Oral Biol. 2001;46:39-48. 3. Peck CC, Jurray GM, Johnson CW, Klinegerg IJ. be due to uneven wear or trauma of the depends on the size of the teeth being Trajectories of condylar points during nonwork- incisal edges of the anterior teeth. In moved and also the amount of force being side and protrusive movements of the mandible. J Prosthet Dent. 1999;82:322-331. these situations, the clinician must decide ing used. In our patient, it took about 6 4. Lundeen HC, Shryock EF, Gibbs CH. An eval- if the amount of gingival discrepancy months to open this space about 3 mm. uation of mandibular border movements: Their character and significance. J Prosthet will be noticeable. If so, bracketing and So, the adjacent teeth probably moved Dent. 1978;40:442-452. alignment of these teeth must be ac- about 0.5 mm each month. An advan- 5. Little RM, Riedel RA, Stein A. Mandibular arch length increase during the mixed den- complished in a way that improves the tage to opening this space unilaterally tition: postretention evaluation of stability esthetics and restorability of the abrad- was that it allowed the midline to be cor- and relapse. Am J Orthod Dentofac Orthop. 1990;97:393-404. ed teeth. In these situations, the gingi- rected as the mandibular incisors were 6. Artun, Krogstad O. Periodontal status of man- val margins are used as a guide in tooth pushed toward the patient’s right side. dibular incisors following excessive proclination. A study in adults with surgically treated 10 positioning, not the incisal edges. As This treatment plan required inter- mandibular prognathism. Am J Orthod Den- tofac Orthop. 1987;91:225-232. the gingival margins are aligned, the disciplinary collaboration between or- 7. Yared KF, Zenobio EG, Pacheco W. Perio- discrepancy in the incisal edges be- thodontist, restorative dentist, and the dontal status of mandibular central incisors after orthodontic proclination in adults. Am J comes more apparent. These incisal patient. To determine what was possible Orthod Dentofac Orthop. 2006;130:631-638. discrepancies are restored with com- orthodontically and whether or not that 8. Lost C. Depth of alveolar bone dehiscences in relation to gingival recessions. J Clin Peri- posite restorations temporarily, and then would be acceptable to the restorative odontol. 1984;11:583-589. dentist and patient, a diagnostic wax-up 9. Kokich V. Anterior dental esthetics: An orthodontic perspective. I. Crown length. J Esthet This interdisciplinary was constructed. This step is absolutely Dent. 1993;5:19-23. vital in the management of the inter- 10. Kokich VG, Kokich VO, Spear F. Maximizing 12 anterior esthetics: An interdisciplinary approach. approach to managing disciplinary patient. However, not In: Frontiers in Dental and Facial Esthetics. many clinicians use wax-ups. This is a McNamara JA, Kelly, Jr K, eds. 2001; Need- this patient’s … ham Press, Ann Arbor, Michigan. big mistake. The diagnostic wax-up is 11. Reitan K. Clinical and histologic observations discrepancies allowed not only the vision of where the team is of tooth movement during and after orthodontic treatment. Am J Orthod. 1967;53: the team to achieve all going, it is the vehicle that gives the 721-745. patient a better idea of what the team 12. Kokich VG, Kokich VO. Interrelationship of orthodontics with periodontics and restora- of the restorative and will accomplish. Without a diagnostic tive dentistry. In: Biomechanics and Esthetic Strategies in Clinical Orthodontics. Nanda R, orthodontic objectives… wax-up in our case, it would have been ed. 2005; Elsevier Press, St. Louis, Missouri: difficult to achieve an ideal result. We 348-373.

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