- Email: [email protected]
Success rate of anterior open-bite orthodontic-orthognathic surgical treatment
ORIGINAL ARTICLE
Success rate of anterior open-bite orthodontic-orthognathic surgical treatment Ute Jensena and Sabine Rufb Giessen, Germany Introduction: The aim was to evaluate the short-term success rate of combined orthodontic-orthognathic surgical correction of anterior open bite. Methods: Fifteen patients (ages, 15-28 years) with open bite treated with a combined orthodontic-surgical approach were examined. Lateral cephalograms from before treatment, after treatment, and after an average of 18 months (range, 10-26 months) of retention were evaluated. Overbite was classified as normal (2-3.5 mm), borderline (0-1.5 mm), or relapse (\0 mm), and overjet as normal (2-3.5 mm) or relapse ($4 and #1.5 mm). Results: The average overbite was –3.2 mm before treatment, 1.8 mm after treatment, and 1.3 mm after retention. During active treatment, overbite and overjet were normalized in 53.3% and 66.7% of the subjects, respectively. After the retention period, 1 patient (6.7%) showed a negative overbite, whereas a borderline overbite was found in 53.3% of the subjects. Overjet relapsed in 40% of the subjects. Only 40% of the patients had a completely successful treatment with incisal contact and normal overjet and overbite. Conclusions: Orthodontic-surgical treatment of anterior open bite improves the overbite, but an excellent treatment outcome with normal overjet and overbite and proper incisal contact was achieved in only 40% of the subjects. (Am J Orthod Dentofacial Orthop 2010;138:716-9)
S
uccessful treatment of skeletal open bite is considered a challenge. Attempts to control maxillary development and prevent eruption of the posterior teeth during growth are often counteracted by late adolescent growth changes, thus resulting in a relatively high percentage of adult open-bite treatments.1 In adult patients with milder open bites, camouflage therapy (incisor extrusion and posterior teeth intrusion) is a possible treatment option.1,2 On the other hand, in adult patients with severe open bites, combined orthodontic-orthognathic treatment3 with LeFort I impaction or bimaxillary surgery4-7 aims at correcting the jaw inclination and reducing the excessive anterior facial height to achieve good facial esthetics as well as a functional occlusion.4,8 However, relapse even after combined orthodontic-orthognathic treatment does occur.4,9-16 A functional occlusion that includes among other characteristics a correct interincisal relationship with incisal overlap and interincisal contact is a general
a
Assistant professor, Department of Orthodontics, University of Giessen, Germany. b Professor and head, Department of Orthodontics, University of Giessen, Giessen, Germany. The authors report no commercial, proprietary, or financial interest in the products or companies described in this article. Reprint requests to: Prof. Dr. Sabine Ruf; e-mail, [email protected]. uni-giessen.de. Submitted, November 2009; revised and accepted, February 2010. 0889-5406/$36.00 Copyright Ó 2010 by the American Association of Orthodontists. doi:10.1016/j.ajodo.2010.02.028
716
orthodontic treatment goal. Lack of interincisal contact despite a positive overbite (OB)—a so-called open bite with OB—was first described by Moyers.17 It was found to be an indicator for habits and a prognostic factor for open-bite stability.18 However, most open-bite studies evaluated only OB as a parameter for success and stability. Only Denison et al10 differentiated real open bites and open bites with OB at pretreatment, but whether interincisal contact could be established and maintained was unfortunately not described. Therefore, the aim of this study was to evaluate the short-term success rate of combined orthodonticorthognathic surgical correction of anterior open bite, giving special emphasis to interincisal relationship and contact. MATERIAL AND METHODS
Between 1995 and 2008, a total of 41 open-bite patients were planned for a combined orthodonticorthognathic surgical approach at the Department of Orthodontics of the University of Giessen in Germany. Twenty-six patients were excluded from the study because of no surgical treatment desired (n 5 22), syndromes (n 5 2), and incomplete documentation (n 5 2). The remaining 15 Angle Class I (n 5 1), Class II (n 5 9), and Class III (n 5 5) open-bite patients (9 male, 6 female) with a mean pretreatment age of 19.9 6 4.03 years (range, 15-28 years) were examined retrospectively. All patients had undergone presurgical and postsurgical orthodontic treatment with fixed appliances. The system used for all patients was a Tip-Edge
American Journal of Orthodontics and Dentofacial Orthopedics Volume 138, Number 6
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Fig 1. A, Cephalometric landmarks and measurements to describe the vertical jaw base relationship (ML/NSL [ ], NL/NSL [ ], and ML/NL [ ]); the inclination of the incisors (IsL/NL [ ], IiL/ML [ ], and IsL/IiL [ ]); the occlusal line (OL), the line from the distobuccal cusp of the first maxillary molar to a point that divides OB in half; and the OL perpendicular (OLp). B, Measurement of OB (mm) and OJ (mm) relative to the OL or the OLp at T1. The OL/OLp reference grid was transferred from the T1 headfilm to the subsequent headfilms after superimposition of the radiographs on the nasion-sella line at sella.24
bracket system (TP Orthodontics, LaPorte, Ind) with a 0.22-in slot. No patient received any myofunctional therapy either during or after treatment. Lateral cephalograms from before treatment (T1), after orthodonticsurgical treatment (T2), and after retention—ie, after appliance removal—(T3) were evaluated. The average length of the retention period was 18 months (range, 10-26 months). All radiographs were traced and evaluated by the same investigator (U.J.). No correction for linear enlargement (approximately 8%) was performed. Standard cephalometric parameters, overjet (OJ) and OB, were measured (Fig 1). OB was classified as normal (2-3.5 mm), borderline (0-1.5 mm), or relapse (\0 mm), and OJ as normal (2-3.5 mm) or relapse ($4 and #1.5 mm). Furthermore, interincisal contact was evaluated visually. RESULTS
Average OB values were –3.2 mm at T1, 1.8 mm at T2, and 1.3 mm at T3. During active treatment (T1-T2), OB and OJ were normalized in 53.3% and 66.7% of the subjects, respectively. At T3, 1 patient (6.7%) showed a negative OB, whereas a borderline OB was found in 53.3% of the subjects (Fig 2). OJ relapsed in 40% of the subjects. An interincisal contact was found in 53.3% (at T2) and 46.6% (at T3) of the patients, respectively.
However, only 40% of the patients had a completely successful treatment with interincisal contact and normal OJ and OB. Considering the skeletal parameters, before active orthodontic treatment, 80% of the subjects had a hyperdivergent (.38 ) vertical jaw base relationship with an average mandibular plane angle (ML/NSL) of 43.6 . During the retention period (T2-T3), the ML/NSL increased in 40% of the subjects. Half of these patients exhibited a stable OB, 33.3% were borderline, and 1 had a negative OB (16.7%). The interjawbase angle (ML/ NL) first decreased during active treatment (T1-T2) from 35.5 to 31.8 , but increased slightly to 32.9 thereafter. The maxillary plane angle (NL/NSL) was relatively stable, increasing from 8.3 to 11.1 (T1T2) and decreasing to 10.2 (T3). Patients with a borderline or relapsed OB after retention exhibited more proclined incisors than did those with a stable OB (Fig 3). Correspondingly, the interincisal angle (IsL/IiL) at T3 was greatest in patients with a stable OB (140.8 ) and smallest in those with OB relapse (84 ). The inclination of the mandibular incisors (IiL/ML) remained on average unchanged at about 87 during the entire observation period. The maxillary incisor inclination (IsL/NL) was more or less unchanged during active treatment (T1-T2) (104.3 and 104 ), but a slight proclination was seen during the retention period (106.2 ).
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American Journal of Orthodontics and Dentofacial Orthopedics December 2010
Fig 2. Number of patients with positive or negative OB at T1, T2, and T3 according to Remmers et al.25
Fig 3. Inclination of the incisors (rounded numbers) at T3 in relation to OB stability. DISCUSSION
It might be argued that our follow-up was too short. However, since most skeletal and dentoalveolar changes have been described to occur within the first 6 months after surgery, the 18-month follow-up period can be considered acceptable for the evaluation of short-term stability and success.12 The sample in our study was relatively small. However, compared with most studies in the literature, it seems acceptable because they also included only small to average numbers of subjects (10-58 patients).4,9-16,19 In addition, our subjects were a nearly consecutive sample of nonsyndromic open-bite patients; only 2 patients were excluded because of partially missing records. The patients’ ages at T1 varied between 15 and 28 years. Although it can be assumed that their growth
had terminated (complete fusion of the radial epiphysis), facial growth continues at a slow rate throughout life, and changes observed over a follow-up period might represent a continuation of growth rather than posttreatment relapse.20,21 There are several possible reasons for OB relapse after surgical-orthodontic treatment. Functional factors such as imbalanced intrinsic forces (abnormal tongue or lip position) and extrinsic forces (persistent or newly adopted habits) play an important role in both the etiology and the recurrence of open bite after treatment.1,22 Furthermore, surgical factors resulting from muscle adaptation or bone healing problems, improper positioning of the bony segments, soft-tissue tension against the mobilized segment, temporomandibular changes, or other factors can cause open-bite relapse.4 On the other hand, Denison et al10 proposed that posttreatment relapse was due to dentoalveolar changes only. An excellent treatment outcome (normal OJ, incisal overlap, and interincisal contact) was found in only 40% of the patients. About half of our subjects (53.3%) exhibited a borderline OB at T3; this cannot be called a good treatment result. Nevertheless, a true relapse with negative OB at T3 was found in only 1 subject (6.7%). In terms of true relapse, these findings contrast with the results of Swinnen et al19 and Iannetti et al,23 who reported fully stable OBs 1 to 2 years after treatment. However, the results are in line with most studies in the literature, describing anterior open bite relapse in 2% to 37% of patients.4,9-16
American Journal of Orthodontics and Dentofacial Orthopedics Volume 138, Number 6
CONCLUSIONS
Orthodontic-surgical treatment of anterior open-bite patients improves the OB, but an excellent treatment outcome with normal OJ, incisal overlap, and interincisal contact was found in only 40% of the patients. Therefore, the treatment goals for future surgical anterior open-bite patients should be adjusted accordingly. REFERENCES 1. Proffit WR, Bailey L, Phillips C, Turvey TA. Long-term stability of surgical open bite correction by Le Fort I osteotomy. Angle Orthod 2000;70:112-7. 2. Ng CS, Wong WK, Ha¨gg U. Orthodontic treatment of anterior open bite. Int J Paediatr Dent 2008;18:78-83. 3. Chang YI, Moon SC. Cephalometric evaluation of anterior open bite treatment. Am J Orthod Dentofacial Orthop 1999;115: 29-38. 4. Turvey TA, Phillips C, Zaytoun HS, Proffit WR. Simultaneous superior repositioning of the maxilla and mandibular advancement. A report on stability. Am J Orthod Dentofacial Orthop 1988;94: 372-83. 5. Bell WH, McBride KL. Correction of long face syndrome by Le Fort I osteotomy. Oral Surg 1977;44:493-520. 6. Epker BN, Fish LC. Surgical-orthodontic correction of open bite deformity. Am J Orthod 1977;71:278-99. 7. Lello GE. Skeletal open bite correction by combined Le Fort I osteotomy and bilateral sagittal split of the mandibular ramus. J Craniomaxillofac Surg 1987;15:132-6. 8. Arpornmaeklong P, Heggie AA. Anterior open bite malocclusion: stability of maxillary repositioning using rigid internal fixation. Aust Orthod J 2000;16:69-81. 9. Bailey LJ, Phillips C, Proffit WR, Turvey TA. Stability following superior repositioning of the maxilla by Le Fort I osteotomy: five year follow-up. Int J Adult Orthod Orthognath Surg 1994;9: 163-73. 10. Denison TF, Kokich VG, Shapiro PA. Stability of maxillary surgery in openbite versus nonopenbite malocclusions. Angle Orthod 1989;59:5-10. 11. Ding Y, Xu TM, Lohrmann B, Gellrich NC, Schwestka-Polly R. Stability following combined orthodontic-surgical treatment for skeletal open bite—a cephalometric 15-year follow-up study. J Orofac Orthop 2007;68:245-56.
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12. Espeland L, Dowling PA, Mobarak KA, Stenvik A. Three-year stability of open-bite correction by 1-piece maxillary osteotomy. Am J Orthod Dentofacial Orthop 2008;134:60-6. 13. Fischer K, von Konow L, Brattstro¨m V. Open bite: stability after bimaxillary surgery—2-year treatment outcomes in 58 patients. Eur J Orthod 2000;22:711-8. 14. Haymond CS, Stoelinga PJW, Blijdorp PA, Leenen RJ, Merkens NM. Surgical orthodontic treatment of anterior skeletal open bite using small plate internal fixation. J Oral Maxillofac Surg 1991;20:223-7. 15. Hoppenreijs TJ, Freihofer HP, Stoelinga PJ, Tuinzing M, Van’t Hof MA, van der Linden FP, et al. Skeletal and dento-alveolar stability of Le Fort 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. 16. Wriedt S, Buhl V, Al-Nawas B, Wehrbein H. Combined treatment of open bite—long-term evaluation and relapse factors. J Orofac Orthop 2009;70:318-26. 17. Moyers RE. Handbook of orthodontics for the student and general practitioner. 1st ed. Chicago: Yearbook; 1958. 18. Ruf S, Askeridis N. Frontal open bite with overbite—a prognostic factor for treatment success and stability? Eur J Orthod 2002;24: 441-2. 19. Swinnen K, Politis C, Willems G, De Bruyne I, Fieuws S, Heidbuchtel 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. 20. Bjo¨rk A. Variations in the growth pattern of the human mandible: a longitudinal radiographic study by the implant method. J Dent Res 1963;42:400-11. 21. Behrents RG. Growth of the aging craniofacial skeleton. Ann Arbor, Mich: Craniofacial growth series. Monograph 17. Center for human growth and development. The University of Michigan; 1985. 22. Proffit WR. Equilibrium theory revisited: factors influencing position of teeth. Angle Orthod 1978;48:175-86. 23. Iannetti G, Fadda MT, Marianetti TM, Terenzi V, Cassoni A. Longterm skeletal stability after surgical correction in Class III openbite patients: a retrospective study on 40 patients treated with mono- or bimaxillary surgery. J Craniofac Surg 2007;18:350-4. 24. Pancherz H, Hansen K. The nasion-sella reference line in cephalometry: a methodologic study. Am J Orthod 1984;86:427-34. 25. Remmers D, Van’t Hullenaar RWGJ, Bronkhorst EM, Berge´ SJ, Katsaros C. Treatment results and long-term stability of anterior open bite malocclusion. Orthod Craniofac Res 2008;11:32-42.
Success rate of anterior open-bite orthodontic-orthognathic surgical treatment Ute Jensena and Sabine Rufb Giessen, Germany Introduction: The aim was to evaluate the short-term success rate of combined orthodontic-orthognathic surgical correction of anterior open bite. Methods: Fifteen patients (ages, 15-28 years) with open bite treated with a combined orthodontic-surgical approach were examined. Lateral cephalograms from before treatment, after treatment, and after an average of 18 months (range, 10-26 months) of retention were evaluated. Overbite was classified as normal (2-3.5 mm), borderline (0-1.5 mm), or relapse (\0 mm), and overjet as normal (2-3.5 mm) or relapse ($4 and #1.5 mm). Results: The average overbite was –3.2 mm before treatment, 1.8 mm after treatment, and 1.3 mm after retention. During active treatment, overbite and overjet were normalized in 53.3% and 66.7% of the subjects, respectively. After the retention period, 1 patient (6.7%) showed a negative overbite, whereas a borderline overbite was found in 53.3% of the subjects. Overjet relapsed in 40% of the subjects. Only 40% of the patients had a completely successful treatment with incisal contact and normal overjet and overbite. Conclusions: Orthodontic-surgical treatment of anterior open bite improves the overbite, but an excellent treatment outcome with normal overjet and overbite and proper incisal contact was achieved in only 40% of the subjects. (Am J Orthod Dentofacial Orthop 2010;138:716-9)
S
uccessful treatment of skeletal open bite is considered a challenge. Attempts to control maxillary development and prevent eruption of the posterior teeth during growth are often counteracted by late adolescent growth changes, thus resulting in a relatively high percentage of adult open-bite treatments.1 In adult patients with milder open bites, camouflage therapy (incisor extrusion and posterior teeth intrusion) is a possible treatment option.1,2 On the other hand, in adult patients with severe open bites, combined orthodontic-orthognathic treatment3 with LeFort I impaction or bimaxillary surgery4-7 aims at correcting the jaw inclination and reducing the excessive anterior facial height to achieve good facial esthetics as well as a functional occlusion.4,8 However, relapse even after combined orthodontic-orthognathic treatment does occur.4,9-16 A functional occlusion that includes among other characteristics a correct interincisal relationship with incisal overlap and interincisal contact is a general
a
Assistant professor, Department of Orthodontics, University of Giessen, Germany. b Professor and head, Department of Orthodontics, University of Giessen, Giessen, Germany. The authors report no commercial, proprietary, or financial interest in the products or companies described in this article. Reprint requests to: Prof. Dr. Sabine Ruf; e-mail, [email protected]. uni-giessen.de. Submitted, November 2009; revised and accepted, February 2010. 0889-5406/$36.00 Copyright Ó 2010 by the American Association of Orthodontists. doi:10.1016/j.ajodo.2010.02.028
716
orthodontic treatment goal. Lack of interincisal contact despite a positive overbite (OB)—a so-called open bite with OB—was first described by Moyers.17 It was found to be an indicator for habits and a prognostic factor for open-bite stability.18 However, most open-bite studies evaluated only OB as a parameter for success and stability. Only Denison et al10 differentiated real open bites and open bites with OB at pretreatment, but whether interincisal contact could be established and maintained was unfortunately not described. Therefore, the aim of this study was to evaluate the short-term success rate of combined orthodonticorthognathic surgical correction of anterior open bite, giving special emphasis to interincisal relationship and contact. MATERIAL AND METHODS
Between 1995 and 2008, a total of 41 open-bite patients were planned for a combined orthodonticorthognathic surgical approach at the Department of Orthodontics of the University of Giessen in Germany. Twenty-six patients were excluded from the study because of no surgical treatment desired (n 5 22), syndromes (n 5 2), and incomplete documentation (n 5 2). The remaining 15 Angle Class I (n 5 1), Class II (n 5 9), and Class III (n 5 5) open-bite patients (9 male, 6 female) with a mean pretreatment age of 19.9 6 4.03 years (range, 15-28 years) were examined retrospectively. All patients had undergone presurgical and postsurgical orthodontic treatment with fixed appliances. The system used for all patients was a Tip-Edge
American Journal of Orthodontics and Dentofacial Orthopedics Volume 138, Number 6
Jensen and Ruf
717
Fig 1. A, Cephalometric landmarks and measurements to describe the vertical jaw base relationship (ML/NSL [ ], NL/NSL [ ], and ML/NL [ ]); the inclination of the incisors (IsL/NL [ ], IiL/ML [ ], and IsL/IiL [ ]); the occlusal line (OL), the line from the distobuccal cusp of the first maxillary molar to a point that divides OB in half; and the OL perpendicular (OLp). B, Measurement of OB (mm) and OJ (mm) relative to the OL or the OLp at T1. The OL/OLp reference grid was transferred from the T1 headfilm to the subsequent headfilms after superimposition of the radiographs on the nasion-sella line at sella.24
bracket system (TP Orthodontics, LaPorte, Ind) with a 0.22-in slot. No patient received any myofunctional therapy either during or after treatment. Lateral cephalograms from before treatment (T1), after orthodonticsurgical treatment (T2), and after retention—ie, after appliance removal—(T3) were evaluated. The average length of the retention period was 18 months (range, 10-26 months). All radiographs were traced and evaluated by the same investigator (U.J.). No correction for linear enlargement (approximately 8%) was performed. Standard cephalometric parameters, overjet (OJ) and OB, were measured (Fig 1). OB was classified as normal (2-3.5 mm), borderline (0-1.5 mm), or relapse (\0 mm), and OJ as normal (2-3.5 mm) or relapse ($4 and #1.5 mm). Furthermore, interincisal contact was evaluated visually. RESULTS
Average OB values were –3.2 mm at T1, 1.8 mm at T2, and 1.3 mm at T3. During active treatment (T1-T2), OB and OJ were normalized in 53.3% and 66.7% of the subjects, respectively. At T3, 1 patient (6.7%) showed a negative OB, whereas a borderline OB was found in 53.3% of the subjects (Fig 2). OJ relapsed in 40% of the subjects. An interincisal contact was found in 53.3% (at T2) and 46.6% (at T3) of the patients, respectively.
However, only 40% of the patients had a completely successful treatment with interincisal contact and normal OJ and OB. Considering the skeletal parameters, before active orthodontic treatment, 80% of the subjects had a hyperdivergent (.38 ) vertical jaw base relationship with an average mandibular plane angle (ML/NSL) of 43.6 . During the retention period (T2-T3), the ML/NSL increased in 40% of the subjects. Half of these patients exhibited a stable OB, 33.3% were borderline, and 1 had a negative OB (16.7%). The interjawbase angle (ML/ NL) first decreased during active treatment (T1-T2) from 35.5 to 31.8 , but increased slightly to 32.9 thereafter. The maxillary plane angle (NL/NSL) was relatively stable, increasing from 8.3 to 11.1 (T1T2) and decreasing to 10.2 (T3). Patients with a borderline or relapsed OB after retention exhibited more proclined incisors than did those with a stable OB (Fig 3). Correspondingly, the interincisal angle (IsL/IiL) at T3 was greatest in patients with a stable OB (140.8 ) and smallest in those with OB relapse (84 ). The inclination of the mandibular incisors (IiL/ML) remained on average unchanged at about 87 during the entire observation period. The maxillary incisor inclination (IsL/NL) was more or less unchanged during active treatment (T1-T2) (104.3 and 104 ), but a slight proclination was seen during the retention period (106.2 ).
718
Jensen and Ruf
American Journal of Orthodontics and Dentofacial Orthopedics December 2010
Fig 2. Number of patients with positive or negative OB at T1, T2, and T3 according to Remmers et al.25
Fig 3. Inclination of the incisors (rounded numbers) at T3 in relation to OB stability. DISCUSSION
It might be argued that our follow-up was too short. However, since most skeletal and dentoalveolar changes have been described to occur within the first 6 months after surgery, the 18-month follow-up period can be considered acceptable for the evaluation of short-term stability and success.12 The sample in our study was relatively small. However, compared with most studies in the literature, it seems acceptable because they also included only small to average numbers of subjects (10-58 patients).4,9-16,19 In addition, our subjects were a nearly consecutive sample of nonsyndromic open-bite patients; only 2 patients were excluded because of partially missing records. The patients’ ages at T1 varied between 15 and 28 years. Although it can be assumed that their growth
had terminated (complete fusion of the radial epiphysis), facial growth continues at a slow rate throughout life, and changes observed over a follow-up period might represent a continuation of growth rather than posttreatment relapse.20,21 There are several possible reasons for OB relapse after surgical-orthodontic treatment. Functional factors such as imbalanced intrinsic forces (abnormal tongue or lip position) and extrinsic forces (persistent or newly adopted habits) play an important role in both the etiology and the recurrence of open bite after treatment.1,22 Furthermore, surgical factors resulting from muscle adaptation or bone healing problems, improper positioning of the bony segments, soft-tissue tension against the mobilized segment, temporomandibular changes, or other factors can cause open-bite relapse.4 On the other hand, Denison et al10 proposed that posttreatment relapse was due to dentoalveolar changes only. An excellent treatment outcome (normal OJ, incisal overlap, and interincisal contact) was found in only 40% of the patients. About half of our subjects (53.3%) exhibited a borderline OB at T3; this cannot be called a good treatment result. Nevertheless, a true relapse with negative OB at T3 was found in only 1 subject (6.7%). In terms of true relapse, these findings contrast with the results of Swinnen et al19 and Iannetti et al,23 who reported fully stable OBs 1 to 2 years after treatment. However, the results are in line with most studies in the literature, describing anterior open bite relapse in 2% to 37% of patients.4,9-16
American Journal of Orthodontics and Dentofacial Orthopedics Volume 138, Number 6
CONCLUSIONS
Orthodontic-surgical treatment of anterior open-bite patients improves the OB, but an excellent treatment outcome with normal OJ, incisal overlap, and interincisal contact was found in only 40% of the patients. Therefore, the treatment goals for future surgical anterior open-bite patients should be adjusted accordingly. REFERENCES 1. Proffit WR, Bailey L, Phillips C, Turvey TA. Long-term stability of surgical open bite correction by Le Fort I osteotomy. Angle Orthod 2000;70:112-7. 2. Ng CS, Wong WK, Ha¨gg U. Orthodontic treatment of anterior open bite. Int J Paediatr Dent 2008;18:78-83. 3. Chang YI, Moon SC. Cephalometric evaluation of anterior open bite treatment. Am J Orthod Dentofacial Orthop 1999;115: 29-38. 4. Turvey TA, Phillips C, Zaytoun HS, Proffit WR. Simultaneous superior repositioning of the maxilla and mandibular advancement. A report on stability. Am J Orthod Dentofacial Orthop 1988;94: 372-83. 5. Bell WH, McBride KL. Correction of long face syndrome by Le Fort I osteotomy. Oral Surg 1977;44:493-520. 6. Epker BN, Fish LC. Surgical-orthodontic correction of open bite deformity. Am J Orthod 1977;71:278-99. 7. Lello GE. Skeletal open bite correction by combined Le Fort I osteotomy and bilateral sagittal split of the mandibular ramus. J Craniomaxillofac Surg 1987;15:132-6. 8. Arpornmaeklong P, Heggie AA. Anterior open bite malocclusion: stability of maxillary repositioning using rigid internal fixation. Aust Orthod J 2000;16:69-81. 9. Bailey LJ, Phillips C, Proffit WR, Turvey TA. Stability following superior repositioning of the maxilla by Le Fort I osteotomy: five year follow-up. Int J Adult Orthod Orthognath Surg 1994;9: 163-73. 10. Denison TF, Kokich VG, Shapiro PA. Stability of maxillary surgery in openbite versus nonopenbite malocclusions. Angle Orthod 1989;59:5-10. 11. Ding Y, Xu TM, Lohrmann B, Gellrich NC, Schwestka-Polly R. Stability following combined orthodontic-surgical treatment for skeletal open bite—a cephalometric 15-year follow-up study. J Orofac Orthop 2007;68:245-56.
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12. Espeland L, Dowling PA, Mobarak KA, Stenvik A. Three-year stability of open-bite correction by 1-piece maxillary osteotomy. Am J Orthod Dentofacial Orthop 2008;134:60-6. 13. Fischer K, von Konow L, Brattstro¨m V. Open bite: stability after bimaxillary surgery—2-year treatment outcomes in 58 patients. Eur J Orthod 2000;22:711-8. 14. Haymond CS, Stoelinga PJW, Blijdorp PA, Leenen RJ, Merkens NM. Surgical orthodontic treatment of anterior skeletal open bite using small plate internal fixation. J Oral Maxillofac Surg 1991;20:223-7. 15. Hoppenreijs TJ, Freihofer HP, Stoelinga PJ, Tuinzing M, Van’t Hof MA, van der Linden FP, et al. Skeletal and dento-alveolar stability of Le Fort 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. 16. Wriedt S, Buhl V, Al-Nawas B, Wehrbein H. Combined treatment of open bite—long-term evaluation and relapse factors. J Orofac Orthop 2009;70:318-26. 17. Moyers RE. Handbook of orthodontics for the student and general practitioner. 1st ed. Chicago: Yearbook; 1958. 18. Ruf S, Askeridis N. Frontal open bite with overbite—a prognostic factor for treatment success and stability? Eur J Orthod 2002;24: 441-2. 19. Swinnen K, Politis C, Willems G, De Bruyne I, Fieuws S, Heidbuchtel 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. 20. Bjo¨rk A. Variations in the growth pattern of the human mandible: a longitudinal radiographic study by the implant method. J Dent Res 1963;42:400-11. 21. Behrents RG. Growth of the aging craniofacial skeleton. Ann Arbor, Mich: Craniofacial growth series. Monograph 17. Center for human growth and development. The University of Michigan; 1985. 22. Proffit WR. Equilibrium theory revisited: factors influencing position of teeth. Angle Orthod 1978;48:175-86. 23. Iannetti G, Fadda MT, Marianetti TM, Terenzi V, Cassoni A. Longterm skeletal stability after surgical correction in Class III openbite patients: a retrospective study on 40 patients treated with mono- or bimaxillary surgery. J Craniofac Surg 2007;18:350-4. 24. Pancherz H, Hansen K. The nasion-sella reference line in cephalometry: a methodologic study. Am J Orthod 1984;86:427-34. 25. Remmers D, Van’t Hullenaar RWGJ, Bronkhorst EM, Berge´ SJ, Katsaros C. Treatment results and long-term stability of anterior open bite malocclusion. Orthod Craniofac Res 2008;11:32-42.