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Title

Multidisciplinary treatment of mandibular

prognathism with multiple congenitally missing

teeth

Author(s)Nishimura, R; Nojima, K; Nishii, Y; Hanai, J;

Arataki, T; Uchiyama, T; Yamaguchi, H

Journal Bulletin of Tokyo Dental College, 47(1): 25-31

URL http://hdl.handle.net/10130/214

Right

25

Case Report

Bull Tokyo Dent Coll (2006) 47(1): 25–31

Multidisciplinary Treatment of Mandibular Prognathismwith Multiple Congenitally Missing Teeth

Ryo Nishimura, Kunihiko Nojima, Yasushi Nishii, Junichiro Hanai*,Tomohiko Arataki**, Takeshi Uchiyama* and Hideharu Yamaguchi

Department of Orthodontics, Tokyo Dental College,1-2-2 Masago, Mihama-ku, Chiba 261-8502, Japan

* Department of Oral and Maxillofacial Surgery, Tokyo Dental College,1-2-2 Masago, Mihama-ku, Chiba 261-8502, Japan

** Department of Oral and Maxillofacial Implantology, Tokyo Dental College,1-2-2 Masago, Mihama-ku, Chiba 261-8502, Japan

Received 3 April, 2006/Accepted for publication 19 May, 2006

Abstract

Surgical orthodontic treatment and dental implant therapy were performed on aman (aged 18 years 8 months) with mandibular prognathism and seven congenitallymissing teeth: upper canines, first and second premolars and lower right secondpremolar. After 17 months of preoperative orthodontic treatment at age 20 years 1month, sagittal split ramus osteotomy was performed using the remaining upperdeciduous teeth as an anchor for intermaxillary fixation. In postoperative orthodontictreatment, the remaining deciduous teeth were extracted, and fixture installation wasperformed. The entire therapy required 4 years to complete (age 22 years 8 months).After completion of orthodontic treatment, superstructures were put in place. Thispatient had many dental problems, so multidisciplinary care was performed in conjunc-tion with other departments to improve oral function and facial esthetics.

Key words: Multidisciplinary treatment—Surgical orthodontic treatment—Mandibular prognathism—Multiple congenitally missing teeth—Dental implant

Introduction

Multiple missing teeth not only cause maloc-clusion, but also make orthodontic treatmentdifficult due to poor occlusal support andstability1,3,4,9). Furthermore, Sato and Mitani7,8)

suggested that multiple missing upper teethtend to cause mandibular protrusion requir-ing orthognathic surgery due to retrusion of

the maxilla and anti-clockwise rotation of themandible12). Therefore, in order to improveoral function and facial esthetics, multidisci-plinary treatment involving orthodontists,prosthodontists and oral surgeons is impor-tant. In some surgical orthodontic treatmentcases, a removable surgical splint has been usedwhere the patient has had multiple missingteeth and severe maxillofacial deformity13,14).

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However, it is believed that, with this method,it is difficult to achieve the required level ofocclusal stability, secure an anchor for inter-maxillary fixation, and regain occlusal verticaldimension during surgery. In addition, thismethod assumes that removable dentureand bridgework are insufficient in youngerpatients where it is necessary to reconstructthe permanent occlusal function and properdental esthetics.

In this study, we performed surgical ortho-dontic treatment in conjunction with dentalimplant therapy in a patient with mandibularprognathism and missing upper canines,premolars and lower right second premolarin order to achieve favorable occlusion andproper facial proportion by effectively usingthe remaining deciduous teeth prior toorthognathic surgery.

Case Report

The patient was a man (aged 18 years 4months) who visited our department withanterior crossbite caused by mandibular prog-nathism. The patient’s family history did notreveal any relevant information. In the past,the patient had childhood asthma and feverseizure. As regards his dental history, none ofthe permanent teeth had been extracted.From the frontal view, the facial features weresymmetric, and from the lateral view, the pro-

file was concave, and mandibular protrusionwas obvious (Fig. 1). Intraorally, prolongedretention of the upper bilateral deciduouscanines, deciduous molars and lower rightdeciduous second molar was observed. Therewas an overjet and overbite of �3 mm and3 mm, respectively and the molar relation wasAngle class III. In relation to the midline,the mandible deviated 3 mm to the right. Adiastema was seen between the upper centralincisors, between the lower lateral incisor andcanine (both left and right) and between thelower right canine and first premolar (Fig. 2).A panoramic radiograph revealed that theupper canines, premolars and lower right sec-ond premolar were missing (Fig. 3). A lateralcephalogram showed the following skeletalpattern: ANB angle �3°, facial angle 92°,Y-axis 58°, and mandibular plane angle 18°.These findings indicated anti-clockwise rota-tion and anterior overgrowth of the man-dible. The U-1 to FH was 118°, and L-1 tomandibular plane was 92°, suggesting dentalcompensation of the anterior teeth (Fig. 4).Therefore, the patient was diagnosed withmandibular prognathism accompanied bymultiple congenitally missing teeth.

Sagittal split ramus osteotomy was per-formed, and seven dental implants wereplaced in place of the seven missing teeth:upper left and right canines, upper left andright premolars and lower right secondpremolar. The retained deciduous teeth were

Nishimura R et al.

Fig. 1 Pretreatment facial photographs at age 18 y 4 m

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During orthodontic treatment, 0.022-slotpreadjusted edgewise appliances were used.Starting with a 0.016 NiTi wire, the wire sizewas increased up to a 0.019�0.025 NiTi wirefor alignment and leveling. Six months afterthe start of preoperative orthodontic treat-ment, a 0.018�0.025 SS wire was used for theupper and lower dentitions. Furthermore, anedgewise bracket was attached to the remain-ing deciduous teeth (the left and right canines,first molars and second molars) using an about2-mm thick self-curing resin at the occlusalsurface (Fig. 5). After 17 months of preopera-tive orthodontic treatment (at age 20 years 1month), sagittal split ramus osteotomy wasperformed. The mandible was rotated 2mmto the left and set back approximately 7 mm.Nine months later (at age 20 years 10 months),when the screws used in orthognathic surgerywere removed, a fixture was placed in the

Case Report on Multidisciplinary Treatment

Fig. 2 Pretreatment oral photographs at age 18 y 4 m

extracted at appropriate time points. The lowerright deciduous second molar was extractedat the start of orthodontic treatment, whilethe other remaining deciduous teeth wereextracted after orthognathic surgery.

Fig. 3 Pretreatment panoramic radiograph at age18 y 4 m

28 Nishimura R et al.

Fig. 4 Tracing and measurements on pretreatment cephalometric radiograph

Measurements Mean�S.D. Pre. Treat. Post. Treat.

Facial angle (deg.) 86.1�3.3 92 89Convexity (deg.) 6.4�3.0 �7 2A-B plane (deg.) �5.2�2.5 �3 �1Mandibular plane (deg.) 24.8�5.9 18 22Y-axis (deg.) 64.0�3.1 58 60

Occlusal plane (deg.) 8.4�4.2 5 8Interincisal (deg.) 131.6�5.6 130 117L-1 to Occlusal (deg.) 21.3�5.3 16 16L-1 to Mandibular (deg.) 97.1�4.9 92 91U-1 to A-P plane (mm) 7.8�2.5 1 6

FH to SN plane (deg.) 5.4�2.4 7 7SNA (deg.) 83.4�2.6 81 81SNB (deg.) 80.0�2.5 84 82SNA-SNB diff. (deg.) 3.4�1.7 �3 �1

U-1 to FH plane (deg.) 110.8�5.6 118 130L-1 to FH plane (deg.) 61.6�5.8 70 67

Gonial angle (deg.) 117.5�8.1 118 126Ramus angle (deg.) 88.5�4.5 81 76

Fig. 5 Intraoral occlusal view of 2-mm thick self-curingresin at occlusal surface

upper left and right canines, upper left andright first premolars and second premolarsand lower right second premolar. The appli-ance was removed after four years (at age 22years 8 months) of treatment because satisfac-tory improvements in occlusion and facial fea-ture were obtained. Four months later (at age23 years 0 month), the superstructures wereput in place (Figs. 6, 7, 8). At present, thepatient is in the retention period and is beingmonitored. A wrap-around type retainer wasplaced in the upper and lower arches, and

a fixed type retainer was used between theupper lateral incisors and between uppercanines.

As for changes during active treatment,orthognathic surgery moved the mandible9 mm in the posterior direction, SNB wasdecreased by 2° and facial angle was decreasedby 3°. With maxillary superimposition, theupper first molar moved 1 mm in the mesialdirection, and the U-1 to FH of the uppercentral incisors changed from 118° to 130°,and these teeth were labially inclined by1 mm. With mandibular superimposition, thelower right first molar became upright andmoved 2 mm in the mesial direction. The L-1to FH of the lower central incisors changedfrom 70° to 67°, and these teeth were labiallyinclined by 0.5 mm. In relation to the E-line,deviation of the lower lip decreased from 4 to1 mm, and the facial features became propor-tionate (Fig. 9).

Discussion

The incidence of malocclusion accompa-nied by congenitally missing teeth is relatively

29 Case Report on Multidisciplinary Treatment

high, but that accompanied by multiplecongenitally missing teeth is rare. Oka et al.5)

studied 215 patients with congenitally missingteeth and reported that the majority (92%)had four or less missing teeth, while 8.0% had

five or more missing teeth. They also docu-mented that the incidence of congenitallymissing first and second premolars was high.Brekhus et al.2) studied 202 patients with con-genitally missing teeth and reported that only

Fig. 6 Post-treatment facial photographs at age 23 y 0 m

Fig. 7 Post-treatment oral photographs at age 23 y 0 m

30 Nishimura R et al.

Fig. 9 Composite of pretreatment and post-treatment tracingson cephalometric radiographsSolid line: pretreatment at age 18 y 4 mDashed line: post-treatment at age 22 y 8 m

Fig. 8 Post-treatment panoramic radiograph at age23 y 0 m

nine patients (4.4%) had four or more miss-ing teeth. The patient in the present study waslacking six upper teeth that were vital in deter-mining occlusal function and vertical dimen-sion. Therefore, congenital lack of teeth as afunctional matrix caused maxillary deficiency,and the collapse of occlusal vertical dimen-sion caused anti-clockwise rotation of themandible, thus leading to skeletal mandibu-lar protrusion.

As for the timing of retained deciduoustooth extraction, the lower right deciduoussecond molar was extracted at the start of

treatment so that the lower right first molarcould be moved 2 mm in the mesial directionto ensure the appropriate width for the lowerright second premolar. However, the remain-ing deciduous teeth were extracted afterorthognathic surgery as they were used asanchors for intermaxillary fixation duringorthodontic treatment and orthognathic sur-gery and were also helpful in the regaining ofocclusal vertical dimension. Until postopera-tive orthodontic treatment, the left and rightretained deciduous teeth were bound as asingle mass using self-curing resin.

For subsequent prosthesis placement, den-tal implant therapy was considered appro-priate because the width of the maxilla andbone mass were sufficient. In young patients,implant therapy must be planned after takinginto account growth and development6,10,11),but the present patient was over the age of 20years when the implants were put in place.Hence, the effects of growth and developmentwere considered minimal, and we focusedon mechanical conditions, using an implant-supported bridge to treat the upper missingteeth.

We used the remaining deciduous teeth ina patient with mandibular prognathism accom-

31 Case Report on Multidisciplinary Treatment

panied by congenitally missing teeth in orderto achieve occlusal stability, secure anchorsfor intermaxillary fixation, and regain occlusalvertical dimension prior to orthognathic sur-gery. In postoperative orthodontic treatment,these deciduous teeth were extracted, andfixtures were placed in the extracted regions.The results showed that oral function andfacial esthetics were improved in this patientwith many dental problems through multi-disciplinary care involving close collaborationwith other departments.

References

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2) Brekhus PJ, Oliver CP, Montelelius G (1941) Astudy of the patterns and combinations of con-genitally missing teeth in man. J Dent Res23:117–131.

3) Kiuchi K, Kiuchi H, Shimazaki T, Shimizu N,Noumura S (2003) A case of anterior crossbite with congenital a large number ofpremolar missing. Nihon Univ Dent J 77:151–156. (in Japanese)

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8) Sato K, Mitani H (1988) Effects of the congeni-tal teeth missing on dentofacial skeletal pat-tern—2. A large number of teeth missing—.Tohoku Univ Dent J 7:115–121. (in Japanese)

9) Shimomura T, Shouda M, Susami R (1990)Two cases of mandibular protrusion with con-genitally missing teeth. Kinki-Tokai Ortho J25:66–75. (in Japanese)

10) Thilander B, Odman J, Grondahl K (1994)Osseointegrated implants in adolescents: analternative in replacing missing teeth?. Eur JOrthod 16:84–95.

11) Thilander B, Odman J, Jemt T (1999) Singleimplants in the upper incisor region and theirrelationship to the adjacent teeth: an 8-yearfollow-up study. Clin Oral Implants Res 10:346–355.

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Reprint requests to:Dr. Ryo NishimuraDepartment of Orthodontics,Tokyo Dental College,1-2-2 Masago, Mihama-ku,Chiba 261-8502, Japan