CASE REPORT
Orthodontic treatment combined with tooth transplantation for an adult patient with a missing mandibular first molar: Long-term follow-up Yohei Watanabe,a Tamaki Mohri,a Rumi Yoshida,b Masaki Yamaki,c and Isao Saitod Ibaraki and Niigata, Japan A Japanese woman, age 29 years 8 months, had a missing mandibular left first molar, bimaxillary dentoalveolar protrusion, and crowding. She had a skeletal Class II relationship and a long face with a steep mandible. She had previously undergone root canal treatment for the mandibular right second premolar, and the mandibular left third molar was impacted. The maxillary left first premolar was extracted for autotransplantation to the mandibular left first molar region. After confirmation of a favorable prognosis for the transplanted tooth, the maxillary right first premolar, the mandibular right second premolar, and the impacted mandibular left third molar were extracted for orthodontic treatment. The active orthodontic treatment period was 32 months. The patient returned for follow-up records 12 years 7 months after the active treatment, and her facial profile and occlusion were well maintained. At 13 years 9 months after transplantation, no abnormalities were observed with the transplanted tooth in the radiographic and clinical evaluations. (Am J Orthod Dentofacial Orthop 2014;145:S114-24)
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hen formulating an orthodontic treatment plan for an adult patient, several problems might be encountered that require different considerations than when treating younger patients. Problems such as dental caries, periodontal disease, prosthetically restored teeth, or missing teeth might further complicate the treatment plan.1 The treatment alternatives for missing teeth include fixed bridges, dental implants, orthodontic movement, and tooth transplantation. Tooth transplantation with complete root formation requires more time and effort compared with other treatment alternatives because root canal treatment is required after the surgery.2 However, with
regard to maintaining compatibility between the adjacent teeth and maintaining or restoring the alveolar bone volume around the missing tooth, we can consider tooth transplantation when a donor tooth can be supplied.3 Previous reports have demonstrated acceptable survival rates of autotransplanted teeth with complete root formation compared with the prognosis of other treatment alternatives.4,5 This case report describes an adult Japanese patient with a missing mandibular first molar in whom successful long-term occlusal stability was achieved by orthodontic treatment combined with tooth transplantation. DIAGNOSIS AND ETIOLOGY
a
Private practice, Ibaraki, Japan. b Research fellow, Division of Orthodontics, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan. c Lecturer, Division of Orthodontics, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan. d Professor and chair, Division of Orthodontics, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan. All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest, and none were reported. Address correspondence to: Yohei Watanabe, Mohri Orthodontic Office Tsukuba, 102, 2-7-8, Takezono, Tsukaba, Ibaraki, 302-0032, Japan; e-mail, watanabe@ mohri.jp. Submitted, June 2013; revised and accepted, July 2013. 0889-5406/$36.00 Copyright Ó 2014 by the American Association of Orthodontists. http://dx.doi.org/10.1016/j.ajodo.2013.07.018
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The patient was a Japanese woman, age 29 years 8 months, with chief complaints of maxillary protrusion and absence of the mandibular left first molar, which had been extracted approximately 2 years previously because of severe caries. She had a convex facial profile. Vertically, she had a long face with a high gonial angle. No remarkable facial asymmetry was evident. The intraoral molar relationship on the right side was Angle Class I, and the relationship could not be judged for the left side because of the missing mandibular first molar, although we speculated it to be Angle Class II. The canines exhibited a Class I relationship on the right side and a
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Fig 1. Pretreatment facial and intraoral photographs.
Fig 2. Pretreatment dental casts.
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Fig 3. Pretreatment lateral cephalogram and tracing. Table I. Cephalometric measurements at pretreat-
ment, posttreatment, and postretention Pretreatment Posttreatment Postretention Angular ( ) SNA SNB ANB Facial angle Convexity FMA Y-axis Gonial angle Op to FH U1-SN IMPA FMIA Interincisal angle Linear (mm) Overjet Overbite
79.0 72.0 7.0 84.0 15.0 44.0 75.0 134.5 11.0 101.0 86.0 50.0 117.0
79.0 72.0 7.0 84.0 15.0 44.0 75.0 134.5 16.0 90.0 82.0 54.0 132.5
79.0 72.0 7.0 84.0 15.0 44.0 75.0 134.5 16.0 91.0 83.0 53.5 130.5
4.0 3.5
2.0 1.5
2.0 2.0
Fig 4. Pretreatment panoramic radiograph showing absence of the mandibular left first molar, proclination of the adjacent second molar, and the impacted third molar.
Table II. Model analysis at pretreatment, posttreat-
ment, and postretention Pretreatment Posttreatment Postretention Maxillary arch width (mm) Intercanine 30.4 33.5 33.0 Intermolar 52.7 48.6 48.7 Mandibular arch width (mm) Intercanine 27.0 26.4 25.8 Intermolar 51.0 50.0 52.4 (second molar) Intercanine width was defined as the distance between the cusp tips of the canines. Intermolar width was defined as the distance between the mesiobuccal cusp tips of the maxillary first molars and the mandibular second molars.
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Class II relationship on the left side. Furthermore, mild maxillary and mandibular crowding was observed. The maxillary dental midline was coincident with the facial midline, and the mandibular dental midline was deviated to the left. The right and left second premolars showed buccal crossbites, and the maxillary left first molar was extruded into the edentulous space of the missing mandibular left first molar. The mandibular left edentulous space measured 7.0 mm; in addition, the mandibular left second molar had a mesial inclination. Overjet and the overbite were 4.0 and 3.5 mm, respectively (Figs 1 and 2). The functional assessment showed no remarkable discrepancy between centric occlusion and centric relation, and no apparent signs or symptoms of temporomandibular disorders. The lateral cephalometric analysis (Fig 3, Tables I and II) showed a skeletal Class
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Fig 5. Intraoral radiographs of the mandibular left first molar site: A, before treatment; B, after autotransplantation of the maxillary left first premolar to the mandibular left first molar site; C, 3 years 2 months after transplantation; root filling is compact, but the periapical region has a slightly visible lumen (arrowheads); D, at 10 years 6 months after transplantation, the visible lumen of the periapical region had disappeared; E, at 13 years 9 months after transplantation, the root filling remains compact, and the periodontal condition is good.
Fig 6. Intraoral photographs just after the onset of orthodontic treatment: maxillary and mandibular occlusal views.
II relationship with an ANB angle of 7.0 . Vertically, the patient demonstrated a high-angle tendency (FMA, 44 ) and bimaxillary dentoalveolar protrusion (interincisal angle, 117 ). Furthermore, a panoramic radiograph showed prior root canal treatment performed for the mandibular right second premolar, first molar, and second molar, and the maxillary right first molar, left central incisor, and lateral incisor. The mandibular left third molar was horizontally impacted with an axial inclination of 90 (Fig 4). No remarkable alveolar bone resorption was observed around the edentulous space of the mandibular left first molar (Fig 5, A). TREATMENT OBJECTIVES
The primary treatment objectives were as follows: (1) close the edentulous space of the missing mandibular
left first molar, (2) establish an attractive facial appearance by retracting the maxillary and mandibular incisors, (3) maintain the vertical facial height without backward rotation of the mandible because of the original longface tendency, and (4) correct the discrepancy between the facial and dental midlines. TREATMENT ALTERNATIVES
The treatment alternatives for management of the mandibular left edentulous space were a fixed bridge, dental implants, mesial orthodontic tooth movement of the second and third molars, and tooth transplantation. Even if the treatment for the mandibular left edentulous space failed, it would be necessary to ensure that the posttreatment results were not worse than the pretreatment status. Although a fixed bridge
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Fig 7. Posttreatment facial and intraoral photographs.
Fig 8. Posttreatment dental casts.
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Fig 9. Posttreatment lateral cephalogram and tracing.
left edentulous space with an extracted tooth as the donor. TREATMENT PROGRESS
Fig 10. Posttreatment panoramic radiograph.
has the advantage of a shorter treatment time, tooth preparation is required for the adjacent teeth. Furthermore, dental implants demonstrate good survival rates but require surgery, and periodontal problems might arise with marginal bone loss around the adjacent teeth and the implants. Mesial orthodontic tooth movement of the second and third molars using miniscrews would not cause the same degree of surgical trauma as that for dental implants or tooth transplantation but has the disadvantage of a longer treatment time. We therefore planned to extract the bilateral maxillary first premolars, the mandibular right second premolar, and the impacted mandibular left third molar to achieve the treatment objectives. The patient desired tooth transplantation for correction of the mandibular
The treatment objectives were explained to the patient, and informed consent was obtained. At 30 years 2 months of age, the maxillary left first premolar was transplanted to the mandibular left first molar region. The transplantation was performed according to the procedure described by Andreasen et al.2 The following were the salient features of this procedure: preservation of the periodontal membrane to the maximum extent, tight sutures, and rests for the transplanted tooth with sufficient clearance from the opposite teeth. Within 3 weeks after surgery, root canal treatment and temporary root filling with calcium hydroxide were performed for the transplanted tooth. Postoperative fixation was performed with composites, and the wire splints were removed after 3 weeks.6 When the patient was 30 years 8 months of age, 0.018 3 0.025-in standard edgewise appliances were placed in both dental arches. After we checked the prognosis of the transplanted tooth, we extracted the maxillary right first premolar, the mandibular right second premolar, and the impacted mandibular left third molar for orthodontic treatment using the standard edgewise system (Fig 6). This method of treatment required the intercanine and intermolar widths to be maintained during treatment to achieve longterm stability.7 After the leveling stage, 0.018 3 0.025-in and 0.017 3 0.025-in stainless steel wires with closing loops were used for the maxillary and
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Fig 11. Cephalometric superimpositions between the pretreatment and posttreatment stages: overall, maxilla, and mandible. The solid lines and the dotted lines show pretreatment and posttreatment, respectively.
mandibular arches, respectively, to retract both incisors and to close the extraction spaces along with high-pull headgear and Class II elastics. Vertical and Class II elastics were used during the finishing and detailing stages to obtain suitable interdigitation with ideal archwires: 0.018 3 0.025-in stainless steel for the maxillary arch and 0.017 3 0.025-in stainless steel for the mandibular arch. When the patient was 33 years 4 months of age, the active treatment was completed; this period was approximately 32 months. A circumferential type of retainer was placed in the maxillary arch, and a 0.0215-in flexibile spiral wire bonded retainer was placed in the mandibular arch. The circumferential retainer was to be worn all day for 1 year and thereafter only at night. TREATMENT RESULTS
The posttreatment facial photographs demonstrated a positive change in lip balance from retraction of both the maxillary and mandibular incisors. Suitable intraoral interdigitation was also achieved with Class I canine relationships, and the dental midline was almost coincident with the facial midline (Figs 7-10). In the lateral cephalometric analysis between the pretreatment and posttreatment stages, there were no changes in the ANB and FMA angles, and no increase
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in facial height because appropriate vertical control was applied to both the maxillary and mandibular molars (Fig 11). Furthermore, both the maxillary and mandibular incisors showed lingual inclinations with an increase of 15.5 in the interincisal angle (Table I). Moreover, the maxillary intercanine width increased by 3.1 mm between the cusp tips as a result of the corrected lingual inclination of the maxillary canines, whereas the mandibular intercanine width decreased by 0.6 mm (Table II). During the postretention phase at 12 years 7 months after the active treatment, there were no significant changes in the facial profile and the occlusion (Figs 12-15). Comparison of the posttreatment and postretention lateral cephalograms showed only minor changes in U1-SN, IMPA, and the interincisal angle (Fig 14, Table I). The maxillary and mandibular intercanine widths decreased by 0.5 and 0.6 mm, respectively. The maxillary intermolar width increased by 0.1 mm, and the mandibular intermolar width increased by 2.4 mm (Table II). At 3 years 2 months after transplantation, the periapical radiolucent finding showed a slightly visible lumen (Fig 5, C), although the transplanted tooth had a favorable clinical prognosis. At 10 years 6 months after transplantation, the visible lumen of the periapical radiolucent finding had disappeared (Fig 4, D).
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Fig 12. Postretention facial and intraoral photographs.
Thereafter, at 13 years 9 months after transplantation, radiographs indicated that the periodontal condition remained good, and no abnormalities were observed on clinical evaluation (Fig 5, E). DISCUSSION
When we determine an orthodontic treatment plan for an adult, several problems must be considered.1 The following were the limitations in our patient: root canal treatment performed for 6 teeth, 4 prosthetically restored teeth, an impacted mandibular third molar, and the edentulous space of the missing mandibular left first molar (Fig 4). Furthermore, 3 premolars and the impacted mandibular third molar were extracted to achieve the treatment objectives. In consideration of the long-term prognosis, we judged it better to retain the mandibular right first premolar rather than the second premolar because the second premolar was a nonvital, prosthetically restored tooth.
Minimal alteration of the mandibular arch form might be important for stability, and there are certain situations in which the maxillary arch form is purposely changed with orthodontic treatment.8 In particular, the original mandibular arch form and intercanine width should serve as guides to shape the treated arch form during the orthodontic treatment.9 Furthermore, previous studies have reported that dental arch length and width physiologically diminish by mesial inclinations of the teeth and abrasion of adjacent crown surfaces with age.10,11 Satisfactory mandibular alignment is maintained for 10 years after retention in less than 30% of patients, with approximately 20% of patients demonstrating marked crowding several years after removal of the retainers.10 In this patient, during the postretention phase at 12 years 7 months after active treatment, there were no significant changes in her dental arch forms and occlusion. However, we must consider the possibility that arch length and arch width might decrease as crowding increases.
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Fig 13. Postretention dental casts.
Fig 14. Lateral cephalogram after retention and cephalometric superimpositions between the posttreatment and postretention stages. The solid line and the dotted line show posttreatment and postretention, respectively.
Occlusal establishment for missing teeth includes the use of fixed bridges and implants, orthodontic tooth movement, and tooth transplantation. The survival rates of fixed bridges have been reported to be 80% at 10
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years and 70% at 20 years.12 However, the tooth preparation that is required for the adjacent teeth could damage or injure the pulp and periodontal tissues. Nevertheless, the survival rate of implants has been
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Fig 15. Postretention panoramic radiograph.
reported to be as high as 91% at 20 years,13 whereas the survival rates of autotransplanted teeth with complete root formation have been reported as 84% at 5 years5 and 86.8% at 9.2 years.4 Although the survival rates of implants appear superior compared with those of tooth transplantation, with regard to the relationship to the adjacent teeth in the long term, incompatibility between the levels of the gingival margin and the incisal edge has been reported in adjacent teeth in adults.14,15 As for implants, periodontal problems might result from marginal bone loss around the adjacent teeth along with bone loss around the buccal aspect of the implants.14,15 Even if the treatment for a missing tooth fails, it was necessary to ensure that the posttreatment results are not worse than the pretreatment status. Therefore, with regard to maintaining compatibility between the adjacent teeth and maintaining or restoring the alveolar bone volume around the missing tooth, transplantation is probably more desirable than implants.3 The transplanted tooth had a minor periapical radiolucent finding at 3 years 2 months after the surgery, but this condition was resolved at 10 years 6 months. The reason for this was unclear, but it might be better to observe this finding without treatment for a while, as long as there are no clinical indications such as replacement resorption or inflammatory resorption. There have been no abnormal findings, and the compatibility between the adjacent teeth and the alveolar bone volume has been maintained until the present time (Fig 5, E). When a tooth with complete root formation is transplanted, preservation of the periodontal membrane and the quality of the root canal filling influence the long-term prognosis.4,5 In this patient, the favorable prognosis could be attributed to an appropriate surgical technique as well as a compact root filling.
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Recent case reports have reported mesial movement of the mandibular second molars using miniscrews to close the missing mandibular first molar spaces.16-18 This patient had a 7.0-mm mandibular edentulous space, and closure by orthodontic tooth movement with temporary anchorage was possible. However, when the third molar, which must be occluded, is impacted, uprighting and alignment might require a longer treatment time. Furthermore, in this patient, the extracted maxillary left premolar was available as a donor tooth. For these reasons, it seemed that tooth transplantation was more efficient than orthodontic tooth movement in consideration of the treatment time. When a treatment plan incorporates tooth transplantation, long-term follow-up is a prerequisite for both the orthodontic treatment and the transplants. CONCLUSIONS
Orthodontic treatment combined with tooth transplantation contributed to successful long-term stability for an adult patient with a missing mandibular first molar, bimaxillary dentoalveolar protrusion, and crowding. Tooth transplantation is a viable option to avoid prosthetic rehabilitation or to maintain a good alveolar bone condition when a donor tooth is available. ACKNOWLEDGMENTS
We thank Dr. Yoshioki Hamamoto for performing the surgical procedure in this patient. REFERENCES 1. Proffit WR. Special considerations in treatment for adults. In: Proffit WR, Fields HW, Sarver DM, editors. Contemporary orthodontics. 4th ed. St Louis: Mosby; 2004. p. 635-85. 2. Andreasen JO, Paulsen HU, Yu Z, Ahiquist R, Bayer T, Schwartz O. A long-term study of 370 autotransplanted premolars. Parts I-IV. Eur J Orthod 1990;12:3-50. 3. Kristerson L, Lagerstrom L. Autotransplantation of teeth in cases with agenesis or traumatic loss of maxillary incisors. Eur J Orthod 1991;13:486-92. 4. Watanabe Y, Mohri T, Takeyama M, Yamaki M, Okiji T, Saito C, et al. Long-term observation of autotransplanted teeth with complete root formation in orthodontic patients. Am J Orthod Dentofacial Orthop 2010;138:720-6. 5. Sugai T, Yoshizawa M, Kobayashi T, Ono K, Takagi R, Kitamura N, et al. Clinical study on prognostic factors for autotransplantation of teeth with complete root formation. Int J Oral Maxillofac Surg 2010;39:1193-203. 6. Hamamoto Y, Hamamoto N, Izumi K, Kobayashi T, Nakajima T, Mohri T, et al. Relationship between recipient condition and periodontal healing of autotransplanted teeth. J Oral Maxillofac Surg 1997;43:733-8. 7. Kanayama K, Watanabe N, Takeyama M, Yamaki M, Ishii K, Saito I. Long-term changes in the occlusion post-retention on Japanese. Orthod Waves 2011;70:89-94.
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8. Zachrisson BU. Important aspects of long-term stability. J Clin Orthod 1997;31:562-83. 9. Felton JM, Sinclair PM, Jones DL, Alexander RG. A computerized analysis of the shape and stability of mandibular arch form. Am J Orthod Dentofacial Orthop 1987;92:478-83. 10. Little RM, Riedel RA, Artun J. An evaluation of changes in mandibular anterior alignment from 10 to 20 years postretention. Am J Orthod Dentofacial Orthop 1988;93:423-8. 11. Little RM. Stability and relapse of dental arch alignment. In: Nanda R, Burstone CJ, editors. Retention and stability in orthodontics. Philadelphia: W. B. Saunders; 1993. p. 97-106. 12. Valderhaug J, Jokstad A, Ambjornsen E, Norheim PW. Assessment of the periapical and clinical status of crowned teeth over 25 years. J Dent 1997;25:97-105. 13. Lekholm U, Gr€ ondahl K, Jemt T. Outcome of oral implant treatment in partially edentulous jaws followed 20 years in clinical function. Clin Implant Dent Relat Res 2006;8:178-86.
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14. Thilander B, Odman J, Lekholm U. Orthodontic aspects of the use of oral implants in adolescents: a 10-year follow-up study. Eur J Orthod 2001;23:715-31. 15. Thilander B, Odman J, Jent T. Single implants in the upper incisor region and their relationship to the adjacent teeth. An 8-year follow-up study. Clin Oral Implants Res 1999;10:346-55. 16. Kyung SH, Choi JH, Park YC. Miniscrew anchorage to protract lower second molars into first molar extraction sites. J Clin Orthod 2003;37:575-9. 17. Nagaraj K, Upadhyay M, Yadav S. Titanum screw anchorage for protraction of mandibular second molars into first molar extraction sites. Am J Orthod Dentofacial Orthop 2008;134: 583-91. 18. Baik UB, Chun YS, Jung MH, Sugawara J. Protraction of mandibular second and third molars into missing first molar spaces for a patient with an anterior open bite and anterior spacing. Am J Orthod Dentofacial Orthop 2012;141:783-95.
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Orthodontic treatment combined with tooth transplantation for an adult patient with a missing mandibular first molar: Long-term follow-up Yohei Watanabe,a Tamaki Mohri,a Rumi Yoshida,b Masaki Yamaki,c and Isao Saitod Ibaraki and Niigata, Japan A Japanese woman, age 29 years 8 months, had a missing mandibular left first molar, bimaxillary dentoalveolar protrusion, and crowding. She had a skeletal Class II relationship and a long face with a steep mandible. She had previously undergone root canal treatment for the mandibular right second premolar, and the mandibular left third molar was impacted. The maxillary left first premolar was extracted for autotransplantation to the mandibular left first molar region. After confirmation of a favorable prognosis for the transplanted tooth, the maxillary right first premolar, the mandibular right second premolar, and the impacted mandibular left third molar were extracted for orthodontic treatment. The active orthodontic treatment period was 32 months. The patient returned for follow-up records 12 years 7 months after the active treatment, and her facial profile and occlusion were well maintained. At 13 years 9 months after transplantation, no abnormalities were observed with the transplanted tooth in the radiographic and clinical evaluations. (Am J Orthod Dentofacial Orthop 2014;145:S114-24)
W
hen formulating an orthodontic treatment plan for an adult patient, several problems might be encountered that require different considerations than when treating younger patients. Problems such as dental caries, periodontal disease, prosthetically restored teeth, or missing teeth might further complicate the treatment plan.1 The treatment alternatives for missing teeth include fixed bridges, dental implants, orthodontic movement, and tooth transplantation. Tooth transplantation with complete root formation requires more time and effort compared with other treatment alternatives because root canal treatment is required after the surgery.2 However, with
regard to maintaining compatibility between the adjacent teeth and maintaining or restoring the alveolar bone volume around the missing tooth, we can consider tooth transplantation when a donor tooth can be supplied.3 Previous reports have demonstrated acceptable survival rates of autotransplanted teeth with complete root formation compared with the prognosis of other treatment alternatives.4,5 This case report describes an adult Japanese patient with a missing mandibular first molar in whom successful long-term occlusal stability was achieved by orthodontic treatment combined with tooth transplantation. DIAGNOSIS AND ETIOLOGY
a
Private practice, Ibaraki, Japan. b Research fellow, Division of Orthodontics, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan. c Lecturer, Division of Orthodontics, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan. d Professor and chair, Division of Orthodontics, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan. All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest, and none were reported. Address correspondence to: Yohei Watanabe, Mohri Orthodontic Office Tsukuba, 102, 2-7-8, Takezono, Tsukaba, Ibaraki, 302-0032, Japan; e-mail, watanabe@ mohri.jp. Submitted, June 2013; revised and accepted, July 2013. 0889-5406/$36.00 Copyright Ó 2014 by the American Association of Orthodontists. http://dx.doi.org/10.1016/j.ajodo.2013.07.018
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The patient was a Japanese woman, age 29 years 8 months, with chief complaints of maxillary protrusion and absence of the mandibular left first molar, which had been extracted approximately 2 years previously because of severe caries. She had a convex facial profile. Vertically, she had a long face with a high gonial angle. No remarkable facial asymmetry was evident. The intraoral molar relationship on the right side was Angle Class I, and the relationship could not be judged for the left side because of the missing mandibular first molar, although we speculated it to be Angle Class II. The canines exhibited a Class I relationship on the right side and a
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Fig 1. Pretreatment facial and intraoral photographs.
Fig 2. Pretreatment dental casts.
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Fig 3. Pretreatment lateral cephalogram and tracing. Table I. Cephalometric measurements at pretreat-
ment, posttreatment, and postretention Pretreatment Posttreatment Postretention Angular ( ) SNA SNB ANB Facial angle Convexity FMA Y-axis Gonial angle Op to FH U1-SN IMPA FMIA Interincisal angle Linear (mm) Overjet Overbite
79.0 72.0 7.0 84.0 15.0 44.0 75.0 134.5 11.0 101.0 86.0 50.0 117.0
79.0 72.0 7.0 84.0 15.0 44.0 75.0 134.5 16.0 90.0 82.0 54.0 132.5
79.0 72.0 7.0 84.0 15.0 44.0 75.0 134.5 16.0 91.0 83.0 53.5 130.5
4.0 3.5
2.0 1.5
2.0 2.0
Fig 4. Pretreatment panoramic radiograph showing absence of the mandibular left first molar, proclination of the adjacent second molar, and the impacted third molar.
Table II. Model analysis at pretreatment, posttreat-
ment, and postretention Pretreatment Posttreatment Postretention Maxillary arch width (mm) Intercanine 30.4 33.5 33.0 Intermolar 52.7 48.6 48.7 Mandibular arch width (mm) Intercanine 27.0 26.4 25.8 Intermolar 51.0 50.0 52.4 (second molar) Intercanine width was defined as the distance between the cusp tips of the canines. Intermolar width was defined as the distance between the mesiobuccal cusp tips of the maxillary first molars and the mandibular second molars.
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Class II relationship on the left side. Furthermore, mild maxillary and mandibular crowding was observed. The maxillary dental midline was coincident with the facial midline, and the mandibular dental midline was deviated to the left. The right and left second premolars showed buccal crossbites, and the maxillary left first molar was extruded into the edentulous space of the missing mandibular left first molar. The mandibular left edentulous space measured 7.0 mm; in addition, the mandibular left second molar had a mesial inclination. Overjet and the overbite were 4.0 and 3.5 mm, respectively (Figs 1 and 2). The functional assessment showed no remarkable discrepancy between centric occlusion and centric relation, and no apparent signs or symptoms of temporomandibular disorders. The lateral cephalometric analysis (Fig 3, Tables I and II) showed a skeletal Class
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Fig 5. Intraoral radiographs of the mandibular left first molar site: A, before treatment; B, after autotransplantation of the maxillary left first premolar to the mandibular left first molar site; C, 3 years 2 months after transplantation; root filling is compact, but the periapical region has a slightly visible lumen (arrowheads); D, at 10 years 6 months after transplantation, the visible lumen of the periapical region had disappeared; E, at 13 years 9 months after transplantation, the root filling remains compact, and the periodontal condition is good.
Fig 6. Intraoral photographs just after the onset of orthodontic treatment: maxillary and mandibular occlusal views.
II relationship with an ANB angle of 7.0 . Vertically, the patient demonstrated a high-angle tendency (FMA, 44 ) and bimaxillary dentoalveolar protrusion (interincisal angle, 117 ). Furthermore, a panoramic radiograph showed prior root canal treatment performed for the mandibular right second premolar, first molar, and second molar, and the maxillary right first molar, left central incisor, and lateral incisor. The mandibular left third molar was horizontally impacted with an axial inclination of 90 (Fig 4). No remarkable alveolar bone resorption was observed around the edentulous space of the mandibular left first molar (Fig 5, A). TREATMENT OBJECTIVES
The primary treatment objectives were as follows: (1) close the edentulous space of the missing mandibular
left first molar, (2) establish an attractive facial appearance by retracting the maxillary and mandibular incisors, (3) maintain the vertical facial height without backward rotation of the mandible because of the original longface tendency, and (4) correct the discrepancy between the facial and dental midlines. TREATMENT ALTERNATIVES
The treatment alternatives for management of the mandibular left edentulous space were a fixed bridge, dental implants, mesial orthodontic tooth movement of the second and third molars, and tooth transplantation. Even if the treatment for the mandibular left edentulous space failed, it would be necessary to ensure that the posttreatment results were not worse than the pretreatment status. Although a fixed bridge
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Fig 7. Posttreatment facial and intraoral photographs.
Fig 8. Posttreatment dental casts.
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Fig 9. Posttreatment lateral cephalogram and tracing.
left edentulous space with an extracted tooth as the donor. TREATMENT PROGRESS
Fig 10. Posttreatment panoramic radiograph.
has the advantage of a shorter treatment time, tooth preparation is required for the adjacent teeth. Furthermore, dental implants demonstrate good survival rates but require surgery, and periodontal problems might arise with marginal bone loss around the adjacent teeth and the implants. Mesial orthodontic tooth movement of the second and third molars using miniscrews would not cause the same degree of surgical trauma as that for dental implants or tooth transplantation but has the disadvantage of a longer treatment time. We therefore planned to extract the bilateral maxillary first premolars, the mandibular right second premolar, and the impacted mandibular left third molar to achieve the treatment objectives. The patient desired tooth transplantation for correction of the mandibular
The treatment objectives were explained to the patient, and informed consent was obtained. At 30 years 2 months of age, the maxillary left first premolar was transplanted to the mandibular left first molar region. The transplantation was performed according to the procedure described by Andreasen et al.2 The following were the salient features of this procedure: preservation of the periodontal membrane to the maximum extent, tight sutures, and rests for the transplanted tooth with sufficient clearance from the opposite teeth. Within 3 weeks after surgery, root canal treatment and temporary root filling with calcium hydroxide were performed for the transplanted tooth. Postoperative fixation was performed with composites, and the wire splints were removed after 3 weeks.6 When the patient was 30 years 8 months of age, 0.018 3 0.025-in standard edgewise appliances were placed in both dental arches. After we checked the prognosis of the transplanted tooth, we extracted the maxillary right first premolar, the mandibular right second premolar, and the impacted mandibular left third molar for orthodontic treatment using the standard edgewise system (Fig 6). This method of treatment required the intercanine and intermolar widths to be maintained during treatment to achieve longterm stability.7 After the leveling stage, 0.018 3 0.025-in and 0.017 3 0.025-in stainless steel wires with closing loops were used for the maxillary and
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Fig 11. Cephalometric superimpositions between the pretreatment and posttreatment stages: overall, maxilla, and mandible. The solid lines and the dotted lines show pretreatment and posttreatment, respectively.
mandibular arches, respectively, to retract both incisors and to close the extraction spaces along with high-pull headgear and Class II elastics. Vertical and Class II elastics were used during the finishing and detailing stages to obtain suitable interdigitation with ideal archwires: 0.018 3 0.025-in stainless steel for the maxillary arch and 0.017 3 0.025-in stainless steel for the mandibular arch. When the patient was 33 years 4 months of age, the active treatment was completed; this period was approximately 32 months. A circumferential type of retainer was placed in the maxillary arch, and a 0.0215-in flexibile spiral wire bonded retainer was placed in the mandibular arch. The circumferential retainer was to be worn all day for 1 year and thereafter only at night. TREATMENT RESULTS
The posttreatment facial photographs demonstrated a positive change in lip balance from retraction of both the maxillary and mandibular incisors. Suitable intraoral interdigitation was also achieved with Class I canine relationships, and the dental midline was almost coincident with the facial midline (Figs 7-10). In the lateral cephalometric analysis between the pretreatment and posttreatment stages, there were no changes in the ANB and FMA angles, and no increase
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in facial height because appropriate vertical control was applied to both the maxillary and mandibular molars (Fig 11). Furthermore, both the maxillary and mandibular incisors showed lingual inclinations with an increase of 15.5 in the interincisal angle (Table I). Moreover, the maxillary intercanine width increased by 3.1 mm between the cusp tips as a result of the corrected lingual inclination of the maxillary canines, whereas the mandibular intercanine width decreased by 0.6 mm (Table II). During the postretention phase at 12 years 7 months after the active treatment, there were no significant changes in the facial profile and the occlusion (Figs 12-15). Comparison of the posttreatment and postretention lateral cephalograms showed only minor changes in U1-SN, IMPA, and the interincisal angle (Fig 14, Table I). The maxillary and mandibular intercanine widths decreased by 0.5 and 0.6 mm, respectively. The maxillary intermolar width increased by 0.1 mm, and the mandibular intermolar width increased by 2.4 mm (Table II). At 3 years 2 months after transplantation, the periapical radiolucent finding showed a slightly visible lumen (Fig 5, C), although the transplanted tooth had a favorable clinical prognosis. At 10 years 6 months after transplantation, the visible lumen of the periapical radiolucent finding had disappeared (Fig 4, D).
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Fig 12. Postretention facial and intraoral photographs.
Thereafter, at 13 years 9 months after transplantation, radiographs indicated that the periodontal condition remained good, and no abnormalities were observed on clinical evaluation (Fig 5, E). DISCUSSION
When we determine an orthodontic treatment plan for an adult, several problems must be considered.1 The following were the limitations in our patient: root canal treatment performed for 6 teeth, 4 prosthetically restored teeth, an impacted mandibular third molar, and the edentulous space of the missing mandibular left first molar (Fig 4). Furthermore, 3 premolars and the impacted mandibular third molar were extracted to achieve the treatment objectives. In consideration of the long-term prognosis, we judged it better to retain the mandibular right first premolar rather than the second premolar because the second premolar was a nonvital, prosthetically restored tooth.
Minimal alteration of the mandibular arch form might be important for stability, and there are certain situations in which the maxillary arch form is purposely changed with orthodontic treatment.8 In particular, the original mandibular arch form and intercanine width should serve as guides to shape the treated arch form during the orthodontic treatment.9 Furthermore, previous studies have reported that dental arch length and width physiologically diminish by mesial inclinations of the teeth and abrasion of adjacent crown surfaces with age.10,11 Satisfactory mandibular alignment is maintained for 10 years after retention in less than 30% of patients, with approximately 20% of patients demonstrating marked crowding several years after removal of the retainers.10 In this patient, during the postretention phase at 12 years 7 months after active treatment, there were no significant changes in her dental arch forms and occlusion. However, we must consider the possibility that arch length and arch width might decrease as crowding increases.
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Fig 13. Postretention dental casts.
Fig 14. Lateral cephalogram after retention and cephalometric superimpositions between the posttreatment and postretention stages. The solid line and the dotted line show posttreatment and postretention, respectively.
Occlusal establishment for missing teeth includes the use of fixed bridges and implants, orthodontic tooth movement, and tooth transplantation. The survival rates of fixed bridges have been reported to be 80% at 10
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years and 70% at 20 years.12 However, the tooth preparation that is required for the adjacent teeth could damage or injure the pulp and periodontal tissues. Nevertheless, the survival rate of implants has been
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Fig 15. Postretention panoramic radiograph.
reported to be as high as 91% at 20 years,13 whereas the survival rates of autotransplanted teeth with complete root formation have been reported as 84% at 5 years5 and 86.8% at 9.2 years.4 Although the survival rates of implants appear superior compared with those of tooth transplantation, with regard to the relationship to the adjacent teeth in the long term, incompatibility between the levels of the gingival margin and the incisal edge has been reported in adjacent teeth in adults.14,15 As for implants, periodontal problems might result from marginal bone loss around the adjacent teeth along with bone loss around the buccal aspect of the implants.14,15 Even if the treatment for a missing tooth fails, it was necessary to ensure that the posttreatment results are not worse than the pretreatment status. Therefore, with regard to maintaining compatibility between the adjacent teeth and maintaining or restoring the alveolar bone volume around the missing tooth, transplantation is probably more desirable than implants.3 The transplanted tooth had a minor periapical radiolucent finding at 3 years 2 months after the surgery, but this condition was resolved at 10 years 6 months. The reason for this was unclear, but it might be better to observe this finding without treatment for a while, as long as there are no clinical indications such as replacement resorption or inflammatory resorption. There have been no abnormal findings, and the compatibility between the adjacent teeth and the alveolar bone volume has been maintained until the present time (Fig 5, E). When a tooth with complete root formation is transplanted, preservation of the periodontal membrane and the quality of the root canal filling influence the long-term prognosis.4,5 In this patient, the favorable prognosis could be attributed to an appropriate surgical technique as well as a compact root filling.
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Recent case reports have reported mesial movement of the mandibular second molars using miniscrews to close the missing mandibular first molar spaces.16-18 This patient had a 7.0-mm mandibular edentulous space, and closure by orthodontic tooth movement with temporary anchorage was possible. However, when the third molar, which must be occluded, is impacted, uprighting and alignment might require a longer treatment time. Furthermore, in this patient, the extracted maxillary left premolar was available as a donor tooth. For these reasons, it seemed that tooth transplantation was more efficient than orthodontic tooth movement in consideration of the treatment time. When a treatment plan incorporates tooth transplantation, long-term follow-up is a prerequisite for both the orthodontic treatment and the transplants. CONCLUSIONS
Orthodontic treatment combined with tooth transplantation contributed to successful long-term stability for an adult patient with a missing mandibular first molar, bimaxillary dentoalveolar protrusion, and crowding. Tooth transplantation is a viable option to avoid prosthetic rehabilitation or to maintain a good alveolar bone condition when a donor tooth is available. ACKNOWLEDGMENTS
We thank Dr. Yoshioki Hamamoto for performing the surgical procedure in this patient. REFERENCES 1. Proffit WR. Special considerations in treatment for adults. In: Proffit WR, Fields HW, Sarver DM, editors. Contemporary orthodontics. 4th ed. St Louis: Mosby; 2004. p. 635-85. 2. Andreasen JO, Paulsen HU, Yu Z, Ahiquist R, Bayer T, Schwartz O. A long-term study of 370 autotransplanted premolars. Parts I-IV. Eur J Orthod 1990;12:3-50. 3. Kristerson L, Lagerstrom L. Autotransplantation of teeth in cases with agenesis or traumatic loss of maxillary incisors. Eur J Orthod 1991;13:486-92. 4. Watanabe Y, Mohri T, Takeyama M, Yamaki M, Okiji T, Saito C, et al. Long-term observation of autotransplanted teeth with complete root formation in orthodontic patients. Am J Orthod Dentofacial Orthop 2010;138:720-6. 5. Sugai T, Yoshizawa M, Kobayashi T, Ono K, Takagi R, Kitamura N, et al. Clinical study on prognostic factors for autotransplantation of teeth with complete root formation. Int J Oral Maxillofac Surg 2010;39:1193-203. 6. Hamamoto Y, Hamamoto N, Izumi K, Kobayashi T, Nakajima T, Mohri T, et al. Relationship between recipient condition and periodontal healing of autotransplanted teeth. J Oral Maxillofac Surg 1997;43:733-8. 7. Kanayama K, Watanabe N, Takeyama M, Yamaki M, Ishii K, Saito I. Long-term changes in the occlusion post-retention on Japanese. Orthod Waves 2011;70:89-94.
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8. Zachrisson BU. Important aspects of long-term stability. J Clin Orthod 1997;31:562-83. 9. Felton JM, Sinclair PM, Jones DL, Alexander RG. A computerized analysis of the shape and stability of mandibular arch form. Am J Orthod Dentofacial Orthop 1987;92:478-83. 10. Little RM, Riedel RA, Artun J. An evaluation of changes in mandibular anterior alignment from 10 to 20 years postretention. Am J Orthod Dentofacial Orthop 1988;93:423-8. 11. Little RM. Stability and relapse of dental arch alignment. In: Nanda R, Burstone CJ, editors. Retention and stability in orthodontics. Philadelphia: W. B. Saunders; 1993. p. 97-106. 12. Valderhaug J, Jokstad A, Ambjornsen E, Norheim PW. Assessment of the periapical and clinical status of crowned teeth over 25 years. J Dent 1997;25:97-105. 13. Lekholm U, Gr€ ondahl K, Jemt T. Outcome of oral implant treatment in partially edentulous jaws followed 20 years in clinical function. Clin Implant Dent Relat Res 2006;8:178-86.
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14. Thilander B, Odman J, Lekholm U. Orthodontic aspects of the use of oral implants in adolescents: a 10-year follow-up study. Eur J Orthod 2001;23:715-31. 15. Thilander B, Odman J, Jent T. Single implants in the upper incisor region and their relationship to the adjacent teeth. An 8-year follow-up study. Clin Oral Implants Res 1999;10:346-55. 16. Kyung SH, Choi JH, Park YC. Miniscrew anchorage to protract lower second molars into first molar extraction sites. J Clin Orthod 2003;37:575-9. 17. Nagaraj K, Upadhyay M, Yadav S. Titanum screw anchorage for protraction of mandibular second molars into first molar extraction sites. Am J Orthod Dentofacial Orthop 2008;134: 583-91. 18. Baik UB, Chun YS, Jung MH, Sugawara J. Protraction of mandibular second and third molars into missing first molar spaces for a patient with an anterior open bite and anterior spacing. Am J Orthod Dentofacial Orthop 2012;141:783-95.
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