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Treatment of severe anterior open bite with skeletal anchorage in adults: Comparison with orthognathic surgery outcomes
ORIGINAL ARTICLE
Treatment of severe anterior open bite with skeletal anchorage in adults: Comparison with orthognathic surgery outcomes Shingo Kuroda,a Yuichi Sakai,b Nagato Tamamura,b Toru Deguchi,c and Teruko Takano-Yamamotod Okayama, Japan Introduction: Skeletal anterior open bite is a difficult problem to correct in orthodontic treatment. In adults, treatment of severe skeletal anterior open bite consists mainly of surgically repositioning the maxilla or the mandible. Recently, molar intrusion by using skeletal anchorage has been developed as a new strategy for open-bite treatment. In this study, we compared treatment outcomes in patients with severe anterior open bite treated with molar intrusion by using skeletal anchorage and with orthognathic surgery. Methods: Twenty-three subjects with overbite less than –3.0 mm were treated with skeletal anchorage (n ⫽ 10) or with LeFort I osteotomy combined with mandibular osteotomy (n ⫽ 13). Pretreatment and posttreatment lateral cephalograms were compared. Results: Incisors were significantly elongated in the surgically treated subjects (4.6 mm, P ⬍.01). There were no significant differences in the treatment results between skeletal anchorage and surgery, with reduced facial heights of 4.0 and 3.8 mm, and increased overbites of 6.8 and 7.0 mm, respectively. Conclusions: These results suggest that molar intrusion with skeletal anchorage is simpler and more useful than 2-jaw surgery in the treatment of patients with severe anterior open bite. (Am J Orthod Dentofacial Orthop 2007;132:599-605)
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keletal anterior open bite is considered a difficult problem in orthodontic treatment. In adults, treatment of severe skeletal anterior open bite consists mainly of surgically repositioning the maxilla or the mandible. These procedures have acceptable treatment results and long-term stability.1-4 Recently, dental implants,5-7 screws,8-13 and miniplates14-19 have been used for skeletal anchorage. Even without the cooperation of patients, these materials can provide stationary anchorage for various tooth movements. We previously reported on severe skeletal anterior open-bite patients treated with molar intrusion using titanium screws for skeletal anchorage.11,13 In addition, there are several reports of molar intrusion with miniplates in anterior open-bite patients.15-18 Molar intrusion with skeletal anchorage has now become a strategy for treating these patients. From the Department of Orthodontics and Dentofacial Orthopedics, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan. a Assistant professor. b Graduate student. c Senior assistant professor. d Professor and chair. Reprint requests to: Teruko Takano-Yamamoto, Department of Orthodontics and Dentofacial Orthopedics, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-Cho, Okayama 700-8525, Japan; e-mail, [email protected]. Submitted, July 2005; revised and accepted, November 2005. 0889-5406/$32.00 Copyright © 2007 by the American Association of Orthodontists. doi:10.1016/j.ajodo.2005.11.046
However, it is unknown which method is better for treating severe anterior open bite—intrusion of molars with skeletal anchorage or orthognathic surgery. We have used skeletal anchorage to treat severe open-bite patients who would previously have required surgicalorthodontic treatment, with satisfactory improvement.11,13 In this study, we demonstrate the advantages of treatment with skeletal anchorage for molar intrusion in severe anterior open-bite patients, compared with surgical maxillary and mandibular repositioning by LeFort I osteotomy and mandibular osteotomy. MATERIAL AND METHODS
Our subjects were 23 nongrowing patients (ages, 16-46 years; mean, 21.6 years; SD 7.3 years) with anterior open bite more than 3.0 mm (mean, 5.2 mm; SD 2.3 mm) with skeletal Class I or Class II (ANB angle ⬎1.5°) jaw-based relationships (Table I).20 Ten female patients were orthodontically treated with molar impaction by using skeletal anchorage (implant group). One patient had a temporomandibular disorder (TMD) before treatment. Mean overbite at pretreatment was ⫺5.2 mm (SD 1.8 mm), and the mandibular plane angle was 38.8° (SD 6.4°). The miniplates (SAS system; Dentsply-Sankin, Tokyo, Japan) or the titanium screws (intermaxillary fixation screw, Keisei Medical Industrial, Tokyo, Japan; diameter, 2.3 mm; length, 11 mm) were placed under local anesthesia 599
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Table I.
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Comparison of pretreatment measurements between groups Implant group
Variable Angular (°) SNA SNB ANB MP-FH Go.A U1-FH L1-MP IIA Linear (mm) S-N N-Me Me/PP Ar-Go Go-Me Ar-Me OJ OB U1/PP U6/PP L1/MP L6/MP
Surgery group
Norm
SD
Mean
SD
Mean
SD
P value
80.8 77.9 2.8 30.5 122.1 112.3 93.4 123.6
3.6 4.5 2.4 3.6 5.3 8.3 6.8 10.6
78.8 72.3 6.6 38.8 127.5 117.1 96.0 109.3
4.3 5.2 3.2 6.4 7.1 8.1 7.5 8.5
80.6 76.7 4.2 39.5 131.6 113.7 86.2 120.4
4.2 4.0 3.5 6.4 6.7 6.8 10.8 10.8
.4194 .0255* .0936 .6195 .1925 .3061 .0299* .0100*
67.9 125.8 68.6 47.3 71.4 106.6 3.1 3.3 31.0 24.6 44.2 32.9
3.7 5.0 3.7 3.3 4.1 5.7 1.1 1.9 2.3 2.0 2.7 2.5
70.1 137.5 78.6 45.5 75.0 110.0 6.4 ⫺5.2 33.0 28.7 47.4 38.0
3.4 6.8 5.5 5.9 7.7 9.1 2.4 1.8 2.1 2.8 3.5 1.8
69.8 143.7 82.8 49.1 78.2 118.0 2.7 ⫺5.1 34.2 29.0 47.4 38.7
2.6 7.6 7.5 6.7 3.8 8.3 3.4 2.7 4.3 3.3 3.5 3.0
.4188 .0721 .2511 .1001 .0346* .0256* .0057* .6857 .4023 .8040 .9752 .6640
*P ⬍.05, Mann-Whitney U test.
by senior oral surgeons at the Department of Oral and Maxillofacial Surgery, Okayama University Hospital in Japan, as we previously reported.21 Miniscrews (AbsoAnchor; Dentos, Taegu, Korea; diameter, 1.3 mm; length, 6 mm) were placed without mucoperiosteal incision or flap by 1 orthodontist (S.K.).21 The orthodontic load was applied by elastic chain, estimated at 150 g, beginning 4 weeks after the placement surgery (Fig 1). In all skeletal anchorage patients, a transpalatal arch appliance or a mandibular lingual arch appliance was placed between the first molars to compensate for the crown buccal torque that would be caused by the intrusion force. Thirteen patients (4 male, 9 female) were treated with a surgical-orthodontic procedure (surgery group). Mean overbite at pretreatment was ⫺5.1 mm (SD 2.7 mm), and the mandibular plane angle was 39.5° (SD 6.4°). Orthognathic surgery was performed under general anesthesia at the same hospital. All surgical patients had LeFort I osteotomy for the maxilla; 9 of them had intraoral vertical ramus osteotomy (IVRO) and 5 had sagittal split ramus osteotomy (SSRO) for the mandible. The mean duration of hospitalization was 2 weeks. Lateral cephalograms at pretreatment and posttreatment were used for cephalometric analysis. Eight angular and 12 linear measurements were made to eval-
uate the skeletal and dental changes before and after orthodontic treatment (Figs 2 and 3). To avoid the effect of morphologic change with LeFort I osteotomy, we traced the palatal plane (PP) and the maxilla at pretreatment and superimposed them for posttreatment tracing at anterior palatal counter, and defined the PP at posttreatment. Statistical analysis
The Wilcoxon signed rank test was used to examine the difference between the pretreatment and posttreatment cephalometric analyses in the groups. The MannWhitney U test was used to compare the pretreatment cephalometric measurements and the posttreatment results between the implant and surgery groups. It was also used to compare the posttreatment results between the IVRO and SSRO surgery groups. A probability of P ⬎.05 was considered not significant. These analyses were carried out with statistical analysis software (StatView; SPSS, Chicago, Ill). RESULTS
There was a significant difference in active treatment duration between the implant and the surgery groups. Durations were 27.6 months (range, 19-36 months; SD 5.4 months) in the implant group and 33.5
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Fig 1. A, Implants used as orthodontic anchorage; B, schematic illustration of molar intrusion; C-E, intraoral photographs at start of molar intrusion, after 3 months, and postintrusion.
months (range, 20-44 months; SD 7.1 months) in the surgery group. In the comparison of the pretreatment and posttreatment cephalometric evaluations in the implant group, the mandible was significantly rotated counterclockwise as a result of molar intrusion with skeletal anchorage (Fig 4, Table II). The mandibular plane angle was decreased 3.3°, and both total and anterior lower facial heights were decreased (N-Me, ⫺4.0 mm; Me/PP, ⫺3.6 mm). Overbite was increased 6.8 mm without significant elongation of the incisors. In the comparison of the pretreatment and posttreatment evaluations in the surgery group, the total facial height was reduced by 3.8 mm after maxillary intrusion with LeFort I osteotomy (Fig 4, Table II). The maxilla was impacted 3.0 mm (SD 1.8 mm) at posterior nasal spine and 1.6 mm (SD 2.4 mm) at anterior nasal spine with reference to the Frankfort horizontal plane. However, neither the mandibular plane angle nor anterior lower facial height decreased. The size of the mandible was reduced with mandibular surgery (Ar-Me, ⫺2.6 mm). The overbite was increased 7.0 mm, but both maxillary and mandibular incisors were elongated (U1/ PP, 2.6 mm; L1/MP, 2.0 mm). There was no significant difference in treatment results between the IVRO and the SSRO groups.
There was no significant difference in vertical changes between the implant and the surgery groups. These treatments were both effective in treating anterior open bite with approximately a 4-mm decrease in total facial height and approximately a 7-mm increase in overbite (Fig 4, Table III). However, the dental measurements were significantly different. In the implant group, the molars were intruded 3.6 mm, and the incisors were not elongated. In contrast, the incisors were elongated 4.6 mm in the surgery group. DISCUSSION
In this study, we reviewed subjects with severe anterior open bite and long-face tendency to evaluate both skeletal and dental changes in the vertical dimension during treatment. Skeletal and dental characteristics of the subjects were similar between the implant and surgery groups; however, mandibular body length in the surgery group was longer than in the implant group. This caused significant differences in the anteroposterior jaw relationships between the groups. We suggest that this did not affect the differences in skeletal and dental changes in vertical dimensions between the 2 groups that we evaluated. In adults, treatment of severe skeletal anterior open bite previously had consisted mainly of surgical-orth-
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Fig 2. Angular measurements: 1, SNA angle; 2, SNB angle; 3, ANB angle; 4, mandibular plane to Frankfort horizontal (MP-FH); 5, gonial angle (Go.A); 6, maxillary central incisor to palatal plane (U1-FH); 7, mandibular central incisor to mandibular plane (L1-MP); 8, interincisal angle (IIA).
odontic treatment, because it was difficult to close the interincisal distance more than 5 mm by orthodontic tooth movement alone. Surgical correction of anterior open bite had acceptable results and long-term stability.1-4 Surgical treatment is especially effective for anterior open bite with Class III mandibular excess or long face, because it can reduce the size of the mandible. Furthermore, open-bite patients with TMD might be indicated for IVRO, because functional improvement was reported after IVRO.22,23 However, some patients do not want surgical treatment because of its risks. In addition, patients are concerned about higher medical costs, long hospitalization, postoperative discomfort, and the requirement of rehabilitation after surgery.24 In contrast, orthodontic treatment with skeletal anchorage is more comfortable for the patient than orthognathic surgery because of the minimal surgical invasion. Nevertheless, the success rate was approximately 80% to 95%, and patients complained of some pain and discomfort after implantation.21,25,26 Skeletal anchorage is useful for anterior open-bite patients, because it can provide absolute molar intrusion, which used to be impossible with traditional orthodontic mechanics such as multi-brackets combined with intraoral or extraoral anchorage. In this study, overbite was increased adequately, and total facial height was reduced in both the implant and the surgery groups. Both methods were useful for
American Journal of Orthodontics and Dentofacial Orthopedics November 2007
Fig 3. Linear measurements: 1, anterior cranial base (S-N); 2, anterior facial height (N-Me); 3, lower anterior facial height (Me/PP); 4, mandibular ramus height (Ar-Go); 5, mandibular body length (Go-Me); 6, mandibular length (Ar-Me); 7, maxillary incisal edge to palatal plane (U1/PP); 8, maxillary molar cusp to palatal plane (U6/PP); 9, mandibular incisal edge to mandibular plane (L1/MP); 10, mandibular molar cusp to mandibular plane (L6/MP); 11, vertical distance between the maxillary and mandibular incisal edges (OB); 12, horizontal distance between the maxillary and mandibular incisal edges (OJ).
Fig 4. Mean profilograms: A, implant group; B, surgery group. Solid lines are pretreatment means; dotted lines are posttreatment means.
the treatment of severe anterior open-bite patients, and implant orthodontics can be used for severe open-bite patients with less than ⫺5.0 mm overbite, which had been considered an indication for orthognathic surgery. However, the mechanism of improvement was significantly different. In the implant group, as a result of molar intrusion, the mandible rotated counterclock-
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Table II.
Comparison of pretreatment and posttreatment measurements of implant and surgery groups Implant group Pretreatement
Variable Angular (°) SNA SNB ANB MP-FH Go.A U1-FH L1-MP IIA Linear (mm) S-N N-Me Me/PP Ar-Go Go-Me Ar-Me OJ OB U1/PP U6/PP L1/MP L6/MP †
Surgery group
Posttreatement
Difference
Posttreatment
Difference
Norm
SD
Mean
SD
Mean
SD
Mean
SD
Mean
SD
Mean
SD
Mean
SD
80.8 77.9 2.8 30.5 122.1 112.3 93.4 123.6
3.6 4.5 2.4 3.6 5.3 8.3 6.8 10.6
78.8 72.3 6.6 38.8 127.5 117.1 96.0 109.3
4.3 5.2 3.2 6.4 7.1 8.1 7.5 8.5
78.6 73.7 4.9 35.5 127.3 108.3 93.7 123.4
4.5 5.6 3.3 6.9 6.7 6.4 7.8 6.7
⫺0.2 1.5† ⫺1.7† ⫺3.3† ⫺0.3 ⫺8.8† ⫺2.3 14.1†
0.3 0.8 0.6 1.5 1.2 7.6 6.1 12.1
80.6 76.7 4.2 39.5 131.6 113.7 86.2 120.4
4.2 4.0 3.5 6.4 6.7 6.8 10.8 10.8
81.7 76.7 5.0 39.2 134.0 108.0 86.5 125.4
3.5 4.0 2.5 5.1 6.7 4.2 7.7 9.8
1.1* 0.0 0.8 ⫺0.3 2.3 ⫺5.7† 0.4 5.1
1.1 2.1 2.2 2.1 4.9 6.2 9.5 11.6
67.9 125.8 68.6 47.3 71.4 106.6 3.1 3.3 31.0 24.6 44.2 32.9
3.7 5.0 3.7 3.3 4.1 5.7 1.1 1.9 2.3 2.0 2.7 2.5
70.1 137.5 78.6 45.5 75.0 110.0 6.4 ⫺5.2 33.0 28.7 47.4 38.0
3.4 6.8 5.5 5.9 7.7 9.1 2.4 1.8 2.1 2.8 3.5 1.8
70.1 133.5 75.0 46.0 74.7 110.1 2.8 1.5 33.5 26.4 47.3 36.7
3.4 6.1 4.7 5.7 7.5 9.5 0.4 0.6 2.3 2.4 3.0 1.6
0.0 ⫺4.0† ⫺3.6† 0.5 ⫺0.3 0.1 ⫺3.6† 6.8† 0.5 ⫺2.3* ⫺0.1 ⫺1.3†
0.0 1.8 1.8 1.2 0.8 1.6 2.4 1.7 1.3 2.0 1.3 1.2
69.8 143.7 82.8 49.1 78.2 118.0 2.7 ⫺5.1 34.2 29.0 47.4 38.7
2.6 7.6 7.5 6.7 3.8 8.3 3.4 2.7 4.3 3.3 3.5 3.0
69.8 139.9 81.4 47.7 76.1 115.3 3.4 1.9 36.8 29.2 49.4 38.6
2.5 6.9 6.7 6.8 4.1 7.2 0.6 0.9 4.6 3.0 2.9 2.8
0.0 ⫺3.8† ⫺1.4 ⫺1.3 ⫺2.1* ⫺2.6* 0.6 7.0† 2.6† 0.3 2.0† ⫺0.0
0.1 3.9 2.8 2.9 3.0 3.4 3.2 2.5 1.6 1.0 1.8 1.4
P ⬍.01; *P ⬍.05; Wilcoxon signed rank test.
Table III.
Comparison of pretreatment and posttreatment changes between groups Implant group
Variable Skeletal Decreased ANB angle (°) Decreased mandibular plane angle (°) Decreased facial height (mm) Decreased lower facial height (mm) Decreased mandibular length (mm) Dental Increased overbite (mm) Elongation of incisors (mm) Intrusion of molars (mm) †
Pretreatment
Surgery group
Mean
SD
Mean
SD
P value
1.7 3.3 4.0 3.6 0.1
0.6 1.5 1.8 1.8 1.6
⫺0.8 0.3 3.8 1.4 2.6
2.2 2.1 3.9 2.8 3.4
.0154 .0130 .4380 .0585 .0213
* * NS NS *
6.8 0.3 3.6
1.7 1.7 1.6
7.0 4.6 0.2
2.5 2.3 1.5
.9753 .0005 ⬍.0001
NS † †
P ⬍.01; *P ⬍.05; Mann-Whitney U test; NS, not significant.
wise, and adequate overbite was provided without elongation of the incisors. In addition, lower facial height was reduced, and the facial profile was significantly improved. These changes were effective in treating Class II patients. In contrast, the decrease in total facial height was caused by maxillary impaction in the surgery group, and the maxillary and mandibular incisors were elongated during treatment. We suggest that this incisal elongation occurred during the leveling and finishing phases. Anterior open-bite patents often
have 2 distinct occlusal planes; then anterior teeth have a tendency to elongate during leveling and alignment. In addition, intermaxillary fixation placed during and after surgical procedures can cause incisal elongation. Extrusion of anterior teeth is often undesirable in the treatment of open-bite patients, because of maxillary vertical excess and long-face tendency or the compensatory eruption of anterior teeth for esthetic reasons. Elongated incisors are considered less stable during retention.27 In addition, there was a significant differ-
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ence in the active treatment durations between the 2 groups. Therefore, we believe that treatment of anterior open bite with molar intrusion using skeletal anchorage achieves superior morphologic improvement over orthognathic surgery. We previously reported functional improvement of a patient with severe anterior open bite and TMD treated using titanium screw anchorage.13 In addition, none of the subjects without TMD at pretreatment reported a functional problem after treatment for molar intrusion, even though the mandible was significantly rotated counterclockwise. In contrast, temporary trismus cannot be avoided after an orthognathic surgical procedure.28 Furthermore, it was reported that approximately 10% of the patients who underwent mandibular surgery had neurosensory disturbance for more than 1 year.29,30 Therefore, the method of molar intrusion with skeletal anchorage might be effective for not only morphologic but also functional improvements in the treatment of severe anterior open-bite patients. Our patients having molar intrusion with skeletal anchorage had excellent retention and stability in occlusion and facial appearance more than 2 years later.11,13 In addition, they also showed functional adaptation. Therefore, we suggest that functional adaptation in the musculature might be an important factor for the stability of the occlusion during retention in anterior open-bite patients. However, the long-term stability after treatment for anterior open bite with skeletal anchorage is unknown. This is a topic for future study in implant orthodontics.
dento-alveolar stability of LeFort I intrusion osteotomies and bimaxillary osteotomies in anterior open bite deformities. A retrospective three-centre study. Int J Oral Maxillofac Surg 1997;26:161-75. Proffit WR, Bailey LJ, Phillips C, Turvey TA. Long-term stability of surgical open bite correction by LeFort I osteotomy. Angle Orthod 2000;70:112-7. Swinnen K, Politis C, Willems G, De Bruyne I, Fieuws S, Heidbuchel K, et al. Skeletal and dento-alveolar stability after surgical-orthodontic treatment of anterior open bite: a retrospective study. Eur J Orthod 2001;23:547-57. Turley PK, Kean C, Schur J, Stefanac J, Gray J, Hennes J, et al. Orthodontic force application to titanium endosseous implants. Angle Orthod 1988;58:151-62. Ödman J, Lekholm U, Jemt T, Brånemark PI, Thilander B. Osseointegrated titanium implants: a new approach in orthodontic treatment. Eur J Orthod 1988;10:98-105. Roberts WE, Helm FR, Marshall KJ, Gongloff RK. Rigid endosseous implants for orthodontic and orthopedic anchorage. Angle Orthod 1989;59:247-56. Creekmore TD, Eklund MK. The possibility of skeletal anchorage. J Clin Orthod 1983;17:266-9. Costa A, Raffaini M, Melsen B. Miniscrews as orthodontic anchorage: a preliminary report. Int J Adult Orthod Orthognath Surg 1998;13:201-9. Park HS, Bae SM, Kyung HM, Sung JH. Micro-implant anchorage for treatment of skeletal Class I bialveolar protrusion. J Clin Orthod 2001;35:417-22. Kuroda S, Katayama A, Takano-Yamamoto T. Severe anterior open-bite case treated using titanium screw anchorage. Angle Orthod 2004;74:558-67. Kuroda S, Sugawara Y, Yamashita K, Mano T, TakanoYamamoto T. Skeletal Class III oligodontia patient treated with titanium screw anchorage and orthognathic surgery. Am J Orthod Dentofacial Orthop 2005;127:730-8. Kuroda S, Sugawara Y, Tamamura N, Takano-Yamamoto T. Anterior open bite with temporomandibular disorder treated with titanium screw anchorage: evaluation of morphological and functional improvement. Am J Orthod Dentofacial Orthop 2007; 131:550-60. Jenner JD, Fitzpatrick BN. Skeletal anchorage utilizing bone plates. Aust Orthod J 1985;9:231-3. Umemori M, Sugawara J, Mitani H, Nagasaka H, Kawamura H. Skeletal anchorage system for open-bite correction. Am J Orthod Dentofacial Orthop 1999;115:166-74. Sugawara J, Baik UB, Umemori M, Takahashi I, Nagasaka H, Kawamura H, et al. Treatment and posttreatment dentoalveolar changes following intrusion of mandibular molars with application of a skeletal anchorage system (SAS) for open bite correction. Int J Adult Orthod Orthognath Surg 2002;17: 243-53. Sherwood KH, Burch JG, Thompson WJ. Closing anterior open bites by intruding molars with titanium miniplate anchorage. Am J Orthod Dentofacial Orthop 2002;122:593-600. Erverdi N, Keles A, Nanda R. The use of skeletal anchorage in open bite treatment: a cephalometric evaluation. Angle Orthod 2004;74:381-90. Fukunaga T, Kuroda S, Kurosaka H, Takano-Yamamoto T. Skeletal anchorage for orthodontic correction of maxillary protrusion with adult periodontitis. Angle Orthod 2006;76: 148-55. Wada K, Matsushita K, Shimazaki S, Miwa Y, Hasuike Y, Susami R. An evaluation of a new case analysis of a lateral
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CONCLUSIONS
Orthodontic treatment can be combined with either skeletal anchorage or orthognathic surgery to achieve acceptable results by increasing overbite and reducing total facial height in patients with severe anterior open bite. However, molar intrusion with skeletal anchorage does not require incisal elongation to increase overbite and reduce lower facial height by counterclockwise rotation of mandible. Therefore, we suggest that orthodontic treatment with skeletal anchorage is simpler and more useful than that with orthognathic surgery in the treatment of severe anterior open bite. We thank Hee-Moon Kyung, Kyungpook National University, Daegu, Korea, for his support of our research on skeletal anchorage. REFERENCES 1. Epker BN, Fish LC. Surgical-orthodontic correction of open bite deformity. Am J Orthod 1977;71:278-99. 2. Hoppenreijs TJ, Freihofer HP, Stoelinga PJ, Tuinzing DB, van’t Hof MA, van der Linden FP, et al. Skeletal and
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cephalometric roentgenogram. J Kanazawa Med Univ 1981;6:60-70. Kuroda S, Sugawara Y, Deguchi T, Kyung HM, TakanoYamamoto T. Clinical use of miniscrew implant as orthodontic anchorage: success rate and postoperative discomfort. Am J Orthod Dentofacial Orthop 2007;131:9-15. Bell WH, Yamaguchi Y, Poor MR. Treatment of temporomandibular joint dysfunction by intraoral vertical ramus osteotomy. Int J Adult Orthod Orthognath Surg 1990;5:9-27. Ueki K, Marukawa K, Nakagawa K, Yamamoto E. Condylar and temporomandibular joint disc positions after mandibular osteotomy for prognathism. J Oral Maxillofac Surg 2002;60:1424-32. Panula K, Keski-Nisula L, Keski-Nisula K, Oikarinen K, KeskiNisula S. Costs of surgical-orthodontic treatment in community hospital care: an analysis of the different phases of treatment. Int J Adult Orthod Orthognath Surg 2002;17:297-306. Deguchi T, Takano-Yamamoto T, Kanomi R, Hartsfield JK Jr, Roberts WE, Garetto LP. The use of small titanium screws for orthodontic anchorage. J Dent Res 2003;82:377-81.
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26. Cheng SJ, Tseng IY, Lee JJ, Kok SH. A prospective study of the risk factors associated with failure of mini-implants used for orthodontic anchorage. Int J Oral Maxillofac Implants 2004;19: 100-6. 27. Janson G, Valarelli FP, Henriques JFC, de Freitas MR, Cançado RH. Stability of anterior open bite nonextraction treatment in the permanent dentition. Am J Orthod Dentofacial Orthop 2003;124: 265-76. 28. Boyd SB, Karas ND, Sinn DP. Recovery of mandibular mobility following orthognathic surgery. J Oral Maxillofac Surg 1991;49: 924-31. 29. Westermark A, Bystedt H, von Konow L. Inferior alveolar nerve function after mandibular osteotomies. Br J Oral Maxillofac Surg 1998;36:425-8. 30. Al-Bishri A, Barghash Z, Rosenquist J, Sunzel B. Neurosensory disturbance after sagittal split and intraoral vertical ramus osteotomy: as reported in questionnaires and patients’ records. Int J Oral Maxillofac Surg 2005;34:247-51.
Treatment of severe anterior open bite with skeletal anchorage in adults: Comparison with orthognathic surgery outcomes Shingo Kuroda,a Yuichi Sakai,b Nagato Tamamura,b Toru Deguchi,c and Teruko Takano-Yamamotod Okayama, Japan Introduction: Skeletal anterior open bite is a difficult problem to correct in orthodontic treatment. In adults, treatment of severe skeletal anterior open bite consists mainly of surgically repositioning the maxilla or the mandible. Recently, molar intrusion by using skeletal anchorage has been developed as a new strategy for open-bite treatment. In this study, we compared treatment outcomes in patients with severe anterior open bite treated with molar intrusion by using skeletal anchorage and with orthognathic surgery. Methods: Twenty-three subjects with overbite less than –3.0 mm were treated with skeletal anchorage (n ⫽ 10) or with LeFort I osteotomy combined with mandibular osteotomy (n ⫽ 13). Pretreatment and posttreatment lateral cephalograms were compared. Results: Incisors were significantly elongated in the surgically treated subjects (4.6 mm, P ⬍.01). There were no significant differences in the treatment results between skeletal anchorage and surgery, with reduced facial heights of 4.0 and 3.8 mm, and increased overbites of 6.8 and 7.0 mm, respectively. Conclusions: These results suggest that molar intrusion with skeletal anchorage is simpler and more useful than 2-jaw surgery in the treatment of patients with severe anterior open bite. (Am J Orthod Dentofacial Orthop 2007;132:599-605)
S
keletal anterior open bite is considered a difficult problem in orthodontic treatment. In adults, treatment of severe skeletal anterior open bite consists mainly of surgically repositioning the maxilla or the mandible. These procedures have acceptable treatment results and long-term stability.1-4 Recently, dental implants,5-7 screws,8-13 and miniplates14-19 have been used for skeletal anchorage. Even without the cooperation of patients, these materials can provide stationary anchorage for various tooth movements. We previously reported on severe skeletal anterior open-bite patients treated with molar intrusion using titanium screws for skeletal anchorage.11,13 In addition, there are several reports of molar intrusion with miniplates in anterior open-bite patients.15-18 Molar intrusion with skeletal anchorage has now become a strategy for treating these patients. From the Department of Orthodontics and Dentofacial Orthopedics, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan. a Assistant professor. b Graduate student. c Senior assistant professor. d Professor and chair. Reprint requests to: Teruko Takano-Yamamoto, Department of Orthodontics and Dentofacial Orthopedics, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-Cho, Okayama 700-8525, Japan; e-mail, [email protected]. Submitted, July 2005; revised and accepted, November 2005. 0889-5406/$32.00 Copyright © 2007 by the American Association of Orthodontists. doi:10.1016/j.ajodo.2005.11.046
However, it is unknown which method is better for treating severe anterior open bite—intrusion of molars with skeletal anchorage or orthognathic surgery. We have used skeletal anchorage to treat severe open-bite patients who would previously have required surgicalorthodontic treatment, with satisfactory improvement.11,13 In this study, we demonstrate the advantages of treatment with skeletal anchorage for molar intrusion in severe anterior open-bite patients, compared with surgical maxillary and mandibular repositioning by LeFort I osteotomy and mandibular osteotomy. MATERIAL AND METHODS
Our subjects were 23 nongrowing patients (ages, 16-46 years; mean, 21.6 years; SD 7.3 years) with anterior open bite more than 3.0 mm (mean, 5.2 mm; SD 2.3 mm) with skeletal Class I or Class II (ANB angle ⬎1.5°) jaw-based relationships (Table I).20 Ten female patients were orthodontically treated with molar impaction by using skeletal anchorage (implant group). One patient had a temporomandibular disorder (TMD) before treatment. Mean overbite at pretreatment was ⫺5.2 mm (SD 1.8 mm), and the mandibular plane angle was 38.8° (SD 6.4°). The miniplates (SAS system; Dentsply-Sankin, Tokyo, Japan) or the titanium screws (intermaxillary fixation screw, Keisei Medical Industrial, Tokyo, Japan; diameter, 2.3 mm; length, 11 mm) were placed under local anesthesia 599
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Table I.
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Comparison of pretreatment measurements between groups Implant group
Variable Angular (°) SNA SNB ANB MP-FH Go.A U1-FH L1-MP IIA Linear (mm) S-N N-Me Me/PP Ar-Go Go-Me Ar-Me OJ OB U1/PP U6/PP L1/MP L6/MP
Surgery group
Norm
SD
Mean
SD
Mean
SD
P value
80.8 77.9 2.8 30.5 122.1 112.3 93.4 123.6
3.6 4.5 2.4 3.6 5.3 8.3 6.8 10.6
78.8 72.3 6.6 38.8 127.5 117.1 96.0 109.3
4.3 5.2 3.2 6.4 7.1 8.1 7.5 8.5
80.6 76.7 4.2 39.5 131.6 113.7 86.2 120.4
4.2 4.0 3.5 6.4 6.7 6.8 10.8 10.8
.4194 .0255* .0936 .6195 .1925 .3061 .0299* .0100*
67.9 125.8 68.6 47.3 71.4 106.6 3.1 3.3 31.0 24.6 44.2 32.9
3.7 5.0 3.7 3.3 4.1 5.7 1.1 1.9 2.3 2.0 2.7 2.5
70.1 137.5 78.6 45.5 75.0 110.0 6.4 ⫺5.2 33.0 28.7 47.4 38.0
3.4 6.8 5.5 5.9 7.7 9.1 2.4 1.8 2.1 2.8 3.5 1.8
69.8 143.7 82.8 49.1 78.2 118.0 2.7 ⫺5.1 34.2 29.0 47.4 38.7
2.6 7.6 7.5 6.7 3.8 8.3 3.4 2.7 4.3 3.3 3.5 3.0
.4188 .0721 .2511 .1001 .0346* .0256* .0057* .6857 .4023 .8040 .9752 .6640
*P ⬍.05, Mann-Whitney U test.
by senior oral surgeons at the Department of Oral and Maxillofacial Surgery, Okayama University Hospital in Japan, as we previously reported.21 Miniscrews (AbsoAnchor; Dentos, Taegu, Korea; diameter, 1.3 mm; length, 6 mm) were placed without mucoperiosteal incision or flap by 1 orthodontist (S.K.).21 The orthodontic load was applied by elastic chain, estimated at 150 g, beginning 4 weeks after the placement surgery (Fig 1). In all skeletal anchorage patients, a transpalatal arch appliance or a mandibular lingual arch appliance was placed between the first molars to compensate for the crown buccal torque that would be caused by the intrusion force. Thirteen patients (4 male, 9 female) were treated with a surgical-orthodontic procedure (surgery group). Mean overbite at pretreatment was ⫺5.1 mm (SD 2.7 mm), and the mandibular plane angle was 39.5° (SD 6.4°). Orthognathic surgery was performed under general anesthesia at the same hospital. All surgical patients had LeFort I osteotomy for the maxilla; 9 of them had intraoral vertical ramus osteotomy (IVRO) and 5 had sagittal split ramus osteotomy (SSRO) for the mandible. The mean duration of hospitalization was 2 weeks. Lateral cephalograms at pretreatment and posttreatment were used for cephalometric analysis. Eight angular and 12 linear measurements were made to eval-
uate the skeletal and dental changes before and after orthodontic treatment (Figs 2 and 3). To avoid the effect of morphologic change with LeFort I osteotomy, we traced the palatal plane (PP) and the maxilla at pretreatment and superimposed them for posttreatment tracing at anterior palatal counter, and defined the PP at posttreatment. Statistical analysis
The Wilcoxon signed rank test was used to examine the difference between the pretreatment and posttreatment cephalometric analyses in the groups. The MannWhitney U test was used to compare the pretreatment cephalometric measurements and the posttreatment results between the implant and surgery groups. It was also used to compare the posttreatment results between the IVRO and SSRO surgery groups. A probability of P ⬎.05 was considered not significant. These analyses were carried out with statistical analysis software (StatView; SPSS, Chicago, Ill). RESULTS
There was a significant difference in active treatment duration between the implant and the surgery groups. Durations were 27.6 months (range, 19-36 months; SD 5.4 months) in the implant group and 33.5
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Fig 1. A, Implants used as orthodontic anchorage; B, schematic illustration of molar intrusion; C-E, intraoral photographs at start of molar intrusion, after 3 months, and postintrusion.
months (range, 20-44 months; SD 7.1 months) in the surgery group. In the comparison of the pretreatment and posttreatment cephalometric evaluations in the implant group, the mandible was significantly rotated counterclockwise as a result of molar intrusion with skeletal anchorage (Fig 4, Table II). The mandibular plane angle was decreased 3.3°, and both total and anterior lower facial heights were decreased (N-Me, ⫺4.0 mm; Me/PP, ⫺3.6 mm). Overbite was increased 6.8 mm without significant elongation of the incisors. In the comparison of the pretreatment and posttreatment evaluations in the surgery group, the total facial height was reduced by 3.8 mm after maxillary intrusion with LeFort I osteotomy (Fig 4, Table II). The maxilla was impacted 3.0 mm (SD 1.8 mm) at posterior nasal spine and 1.6 mm (SD 2.4 mm) at anterior nasal spine with reference to the Frankfort horizontal plane. However, neither the mandibular plane angle nor anterior lower facial height decreased. The size of the mandible was reduced with mandibular surgery (Ar-Me, ⫺2.6 mm). The overbite was increased 7.0 mm, but both maxillary and mandibular incisors were elongated (U1/ PP, 2.6 mm; L1/MP, 2.0 mm). There was no significant difference in treatment results between the IVRO and the SSRO groups.
There was no significant difference in vertical changes between the implant and the surgery groups. These treatments were both effective in treating anterior open bite with approximately a 4-mm decrease in total facial height and approximately a 7-mm increase in overbite (Fig 4, Table III). However, the dental measurements were significantly different. In the implant group, the molars were intruded 3.6 mm, and the incisors were not elongated. In contrast, the incisors were elongated 4.6 mm in the surgery group. DISCUSSION
In this study, we reviewed subjects with severe anterior open bite and long-face tendency to evaluate both skeletal and dental changes in the vertical dimension during treatment. Skeletal and dental characteristics of the subjects were similar between the implant and surgery groups; however, mandibular body length in the surgery group was longer than in the implant group. This caused significant differences in the anteroposterior jaw relationships between the groups. We suggest that this did not affect the differences in skeletal and dental changes in vertical dimensions between the 2 groups that we evaluated. In adults, treatment of severe skeletal anterior open bite previously had consisted mainly of surgical-orth-
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Fig 2. Angular measurements: 1, SNA angle; 2, SNB angle; 3, ANB angle; 4, mandibular plane to Frankfort horizontal (MP-FH); 5, gonial angle (Go.A); 6, maxillary central incisor to palatal plane (U1-FH); 7, mandibular central incisor to mandibular plane (L1-MP); 8, interincisal angle (IIA).
odontic treatment, because it was difficult to close the interincisal distance more than 5 mm by orthodontic tooth movement alone. Surgical correction of anterior open bite had acceptable results and long-term stability.1-4 Surgical treatment is especially effective for anterior open bite with Class III mandibular excess or long face, because it can reduce the size of the mandible. Furthermore, open-bite patients with TMD might be indicated for IVRO, because functional improvement was reported after IVRO.22,23 However, some patients do not want surgical treatment because of its risks. In addition, patients are concerned about higher medical costs, long hospitalization, postoperative discomfort, and the requirement of rehabilitation after surgery.24 In contrast, orthodontic treatment with skeletal anchorage is more comfortable for the patient than orthognathic surgery because of the minimal surgical invasion. Nevertheless, the success rate was approximately 80% to 95%, and patients complained of some pain and discomfort after implantation.21,25,26 Skeletal anchorage is useful for anterior open-bite patients, because it can provide absolute molar intrusion, which used to be impossible with traditional orthodontic mechanics such as multi-brackets combined with intraoral or extraoral anchorage. In this study, overbite was increased adequately, and total facial height was reduced in both the implant and the surgery groups. Both methods were useful for
American Journal of Orthodontics and Dentofacial Orthopedics November 2007
Fig 3. Linear measurements: 1, anterior cranial base (S-N); 2, anterior facial height (N-Me); 3, lower anterior facial height (Me/PP); 4, mandibular ramus height (Ar-Go); 5, mandibular body length (Go-Me); 6, mandibular length (Ar-Me); 7, maxillary incisal edge to palatal plane (U1/PP); 8, maxillary molar cusp to palatal plane (U6/PP); 9, mandibular incisal edge to mandibular plane (L1/MP); 10, mandibular molar cusp to mandibular plane (L6/MP); 11, vertical distance between the maxillary and mandibular incisal edges (OB); 12, horizontal distance between the maxillary and mandibular incisal edges (OJ).
Fig 4. Mean profilograms: A, implant group; B, surgery group. Solid lines are pretreatment means; dotted lines are posttreatment means.
the treatment of severe anterior open-bite patients, and implant orthodontics can be used for severe open-bite patients with less than ⫺5.0 mm overbite, which had been considered an indication for orthognathic surgery. However, the mechanism of improvement was significantly different. In the implant group, as a result of molar intrusion, the mandible rotated counterclock-
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Table II.
Comparison of pretreatment and posttreatment measurements of implant and surgery groups Implant group Pretreatement
Variable Angular (°) SNA SNB ANB MP-FH Go.A U1-FH L1-MP IIA Linear (mm) S-N N-Me Me/PP Ar-Go Go-Me Ar-Me OJ OB U1/PP U6/PP L1/MP L6/MP †
Surgery group
Posttreatement
Difference
Posttreatment
Difference
Norm
SD
Mean
SD
Mean
SD
Mean
SD
Mean
SD
Mean
SD
Mean
SD
80.8 77.9 2.8 30.5 122.1 112.3 93.4 123.6
3.6 4.5 2.4 3.6 5.3 8.3 6.8 10.6
78.8 72.3 6.6 38.8 127.5 117.1 96.0 109.3
4.3 5.2 3.2 6.4 7.1 8.1 7.5 8.5
78.6 73.7 4.9 35.5 127.3 108.3 93.7 123.4
4.5 5.6 3.3 6.9 6.7 6.4 7.8 6.7
⫺0.2 1.5† ⫺1.7† ⫺3.3† ⫺0.3 ⫺8.8† ⫺2.3 14.1†
0.3 0.8 0.6 1.5 1.2 7.6 6.1 12.1
80.6 76.7 4.2 39.5 131.6 113.7 86.2 120.4
4.2 4.0 3.5 6.4 6.7 6.8 10.8 10.8
81.7 76.7 5.0 39.2 134.0 108.0 86.5 125.4
3.5 4.0 2.5 5.1 6.7 4.2 7.7 9.8
1.1* 0.0 0.8 ⫺0.3 2.3 ⫺5.7† 0.4 5.1
1.1 2.1 2.2 2.1 4.9 6.2 9.5 11.6
67.9 125.8 68.6 47.3 71.4 106.6 3.1 3.3 31.0 24.6 44.2 32.9
3.7 5.0 3.7 3.3 4.1 5.7 1.1 1.9 2.3 2.0 2.7 2.5
70.1 137.5 78.6 45.5 75.0 110.0 6.4 ⫺5.2 33.0 28.7 47.4 38.0
3.4 6.8 5.5 5.9 7.7 9.1 2.4 1.8 2.1 2.8 3.5 1.8
70.1 133.5 75.0 46.0 74.7 110.1 2.8 1.5 33.5 26.4 47.3 36.7
3.4 6.1 4.7 5.7 7.5 9.5 0.4 0.6 2.3 2.4 3.0 1.6
0.0 ⫺4.0† ⫺3.6† 0.5 ⫺0.3 0.1 ⫺3.6† 6.8† 0.5 ⫺2.3* ⫺0.1 ⫺1.3†
0.0 1.8 1.8 1.2 0.8 1.6 2.4 1.7 1.3 2.0 1.3 1.2
69.8 143.7 82.8 49.1 78.2 118.0 2.7 ⫺5.1 34.2 29.0 47.4 38.7
2.6 7.6 7.5 6.7 3.8 8.3 3.4 2.7 4.3 3.3 3.5 3.0
69.8 139.9 81.4 47.7 76.1 115.3 3.4 1.9 36.8 29.2 49.4 38.6
2.5 6.9 6.7 6.8 4.1 7.2 0.6 0.9 4.6 3.0 2.9 2.8
0.0 ⫺3.8† ⫺1.4 ⫺1.3 ⫺2.1* ⫺2.6* 0.6 7.0† 2.6† 0.3 2.0† ⫺0.0
0.1 3.9 2.8 2.9 3.0 3.4 3.2 2.5 1.6 1.0 1.8 1.4
P ⬍.01; *P ⬍.05; Wilcoxon signed rank test.
Table III.
Comparison of pretreatment and posttreatment changes between groups Implant group
Variable Skeletal Decreased ANB angle (°) Decreased mandibular plane angle (°) Decreased facial height (mm) Decreased lower facial height (mm) Decreased mandibular length (mm) Dental Increased overbite (mm) Elongation of incisors (mm) Intrusion of molars (mm) †
Pretreatment
Surgery group
Mean
SD
Mean
SD
P value
1.7 3.3 4.0 3.6 0.1
0.6 1.5 1.8 1.8 1.6
⫺0.8 0.3 3.8 1.4 2.6
2.2 2.1 3.9 2.8 3.4
.0154 .0130 .4380 .0585 .0213
* * NS NS *
6.8 0.3 3.6
1.7 1.7 1.6
7.0 4.6 0.2
2.5 2.3 1.5
.9753 .0005 ⬍.0001
NS † †
P ⬍.01; *P ⬍.05; Mann-Whitney U test; NS, not significant.
wise, and adequate overbite was provided without elongation of the incisors. In addition, lower facial height was reduced, and the facial profile was significantly improved. These changes were effective in treating Class II patients. In contrast, the decrease in total facial height was caused by maxillary impaction in the surgery group, and the maxillary and mandibular incisors were elongated during treatment. We suggest that this incisal elongation occurred during the leveling and finishing phases. Anterior open-bite patents often
have 2 distinct occlusal planes; then anterior teeth have a tendency to elongate during leveling and alignment. In addition, intermaxillary fixation placed during and after surgical procedures can cause incisal elongation. Extrusion of anterior teeth is often undesirable in the treatment of open-bite patients, because of maxillary vertical excess and long-face tendency or the compensatory eruption of anterior teeth for esthetic reasons. Elongated incisors are considered less stable during retention.27 In addition, there was a significant differ-
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ence in the active treatment durations between the 2 groups. Therefore, we believe that treatment of anterior open bite with molar intrusion using skeletal anchorage achieves superior morphologic improvement over orthognathic surgery. We previously reported functional improvement of a patient with severe anterior open bite and TMD treated using titanium screw anchorage.13 In addition, none of the subjects without TMD at pretreatment reported a functional problem after treatment for molar intrusion, even though the mandible was significantly rotated counterclockwise. In contrast, temporary trismus cannot be avoided after an orthognathic surgical procedure.28 Furthermore, it was reported that approximately 10% of the patients who underwent mandibular surgery had neurosensory disturbance for more than 1 year.29,30 Therefore, the method of molar intrusion with skeletal anchorage might be effective for not only morphologic but also functional improvements in the treatment of severe anterior open-bite patients. Our patients having molar intrusion with skeletal anchorage had excellent retention and stability in occlusion and facial appearance more than 2 years later.11,13 In addition, they also showed functional adaptation. Therefore, we suggest that functional adaptation in the musculature might be an important factor for the stability of the occlusion during retention in anterior open-bite patients. However, the long-term stability after treatment for anterior open bite with skeletal anchorage is unknown. This is a topic for future study in implant orthodontics.
dento-alveolar stability of LeFort I intrusion osteotomies and bimaxillary osteotomies in anterior open bite deformities. A retrospective three-centre study. Int J Oral Maxillofac Surg 1997;26:161-75. Proffit WR, Bailey LJ, Phillips C, Turvey TA. Long-term stability of surgical open bite correction by LeFort I osteotomy. Angle Orthod 2000;70:112-7. Swinnen K, Politis C, Willems G, De Bruyne I, Fieuws S, Heidbuchel K, et al. Skeletal and dento-alveolar stability after surgical-orthodontic treatment of anterior open bite: a retrospective study. Eur J Orthod 2001;23:547-57. Turley PK, Kean C, Schur J, Stefanac J, Gray J, Hennes J, et al. Orthodontic force application to titanium endosseous implants. Angle Orthod 1988;58:151-62. Ödman J, Lekholm U, Jemt T, Brånemark PI, Thilander B. Osseointegrated titanium implants: a new approach in orthodontic treatment. Eur J Orthod 1988;10:98-105. Roberts WE, Helm FR, Marshall KJ, Gongloff RK. Rigid endosseous implants for orthodontic and orthopedic anchorage. Angle Orthod 1989;59:247-56. Creekmore TD, Eklund MK. The possibility of skeletal anchorage. J Clin Orthod 1983;17:266-9. Costa A, Raffaini M, Melsen B. Miniscrews as orthodontic anchorage: a preliminary report. Int J Adult Orthod Orthognath Surg 1998;13:201-9. Park HS, Bae SM, Kyung HM, Sung JH. Micro-implant anchorage for treatment of skeletal Class I bialveolar protrusion. J Clin Orthod 2001;35:417-22. Kuroda S, Katayama A, Takano-Yamamoto T. Severe anterior open-bite case treated using titanium screw anchorage. Angle Orthod 2004;74:558-67. Kuroda S, Sugawara Y, Yamashita K, Mano T, TakanoYamamoto T. Skeletal Class III oligodontia patient treated with titanium screw anchorage and orthognathic surgery. Am J Orthod Dentofacial Orthop 2005;127:730-8. Kuroda S, Sugawara Y, Tamamura N, Takano-Yamamoto T. Anterior open bite with temporomandibular disorder treated with titanium screw anchorage: evaluation of morphological and functional improvement. Am J Orthod Dentofacial Orthop 2007; 131:550-60. Jenner JD, Fitzpatrick BN. Skeletal anchorage utilizing bone plates. Aust Orthod J 1985;9:231-3. Umemori M, Sugawara J, Mitani H, Nagasaka H, Kawamura H. Skeletal anchorage system for open-bite correction. Am J Orthod Dentofacial Orthop 1999;115:166-74. Sugawara J, Baik UB, Umemori M, Takahashi I, Nagasaka H, Kawamura H, et al. Treatment and posttreatment dentoalveolar changes following intrusion of mandibular molars with application of a skeletal anchorage system (SAS) for open bite correction. Int J Adult Orthod Orthognath Surg 2002;17: 243-53. Sherwood KH, Burch JG, Thompson WJ. Closing anterior open bites by intruding molars with titanium miniplate anchorage. Am J Orthod Dentofacial Orthop 2002;122:593-600. Erverdi N, Keles A, Nanda R. The use of skeletal anchorage in open bite treatment: a cephalometric evaluation. Angle Orthod 2004;74:381-90. Fukunaga T, Kuroda S, Kurosaka H, Takano-Yamamoto T. Skeletal anchorage for orthodontic correction of maxillary protrusion with adult periodontitis. Angle Orthod 2006;76: 148-55. Wada K, Matsushita K, Shimazaki S, Miwa Y, Hasuike Y, Susami R. An evaluation of a new case analysis of a lateral
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CONCLUSIONS
Orthodontic treatment can be combined with either skeletal anchorage or orthognathic surgery to achieve acceptable results by increasing overbite and reducing total facial height in patients with severe anterior open bite. However, molar intrusion with skeletal anchorage does not require incisal elongation to increase overbite and reduce lower facial height by counterclockwise rotation of mandible. Therefore, we suggest that orthodontic treatment with skeletal anchorage is simpler and more useful than that with orthognathic surgery in the treatment of severe anterior open bite. We thank Hee-Moon Kyung, Kyungpook National University, Daegu, Korea, for his support of our research on skeletal anchorage. REFERENCES 1. Epker BN, Fish LC. Surgical-orthodontic correction of open bite deformity. Am J Orthod 1977;71:278-99. 2. Hoppenreijs TJ, Freihofer HP, Stoelinga PJ, Tuinzing DB, van’t Hof MA, van der Linden FP, et al. Skeletal and
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26. Cheng SJ, Tseng IY, Lee JJ, Kok SH. A prospective study of the risk factors associated with failure of mini-implants used for orthodontic anchorage. Int J Oral Maxillofac Implants 2004;19: 100-6. 27. Janson G, Valarelli FP, Henriques JFC, de Freitas MR, Cançado RH. Stability of anterior open bite nonextraction treatment in the permanent dentition. Am J Orthod Dentofacial Orthop 2003;124: 265-76. 28. Boyd SB, Karas ND, Sinn DP. Recovery of mandibular mobility following orthognathic surgery. J Oral Maxillofac Surg 1991;49: 924-31. 29. Westermark A, Bystedt H, von Konow L. Inferior alveolar nerve function after mandibular osteotomies. Br J Oral Maxillofac Surg 1998;36:425-8. 30. Al-Bishri A, Barghash Z, Rosenquist J, Sunzel B. Neurosensory disturbance after sagittal split and intraoral vertical ramus osteotomy: as reported in questionnaires and patients’ records. Int J Oral Maxillofac Surg 2005;34:247-51.