Orthodontic-surgical treatment of Class III malocclusion with mandibular asymmetry

Class III skeletal malocclusion may present several etiologies, among which maxillary deficiency is the most frequent. Bone discrepancy may have an unfavorable impact on esthetics, which is frequently aggravated by the presence of accentuated facial asymmetries. This type of malocclusion is usually treated with association of Orthodontics and orthognathic surgery for correction of occlusion and facial esthetics. This report presents the treatment of a patient aged 15 years and 1 month with Class III skeletal malocclusion, having narrow maxilla, posterior open bite on the left side, anterior crossbite and unilateral posterior crossbite, accentuated negative dentoalveolar discrepancy in the maxillary arch, and maxillary and mandibular midline shift. Clinical examination also revealed maxillary hypoplasia, increased lower one third of the face, concave bone and facial profiles and facial asymmetry with mandibular deviation to the left side. The treatment was performed in three phases: presurgical orthodontic preparation, orthognathic surgery and orthodontic finishing. In reviewing the patient's final records, the major goals set at the beginning of treatment were successfully achieved, providing the patient with adequate masticatory function and pleasant facial esthetics.     

Treatment of a severe Class III skeletal discrepancy at an appropriate age

The 13-year-old female patient presented for correction of a severe Class III malocclusion with a Class III skeletal pattern. This was considered an appropriate age for treatment as earlier treatment may have been subject to relapse because significant facial growth may have occurred after treatment, and because treatment at a later age may have required orthognathic surgery. Initially, maxillary expansion was provided to widen the maxilla and to free the circum-maxillary sutures. Maxillary protraction headgear was worn to perform sagittal skeletal improvement. Fixed orthodontic appliances were placed to align the dentition and Class III elastics were used to improve intercuspation and stability. Patient cooperation was crucial for success. The skeletal changes provided rewards that included significantly improved facial and dental appearance, while avoiding orthognathic surgery.     

Components of adult class III malocclusion

To identify the skeletal and dental relationships of adults who have class III malocclusion, lateral cephalograms of 302 adult patients who had a class III molar and cuspid relationship were traced. Ninety-four of the patients had had presurgical orthodontic treatment and 208 had not. The tracings were digitized, and the following sets of measures were analyzed: maxillary skeletal position; maxillary dentoalveolar position; mandibular dentoalveolar position; and mandibular skeletal position. In addition, the mandibular plane angle and lower anterior facial height were measured as an indicator of vertical facial dimensions. None of these values demonstrated significant gender differences except lower anterior facial height; therefore, the subjects were treated as a group. Although there was considerable variation among patients, the most common combination of variables was a retrusive maxilla, protrusive maxillary incisors, retrusive mandibular incisors, a protrusive mandible, and a long lower facial height.     

Correction of skeletal Class III malocclusion with clockwise rotation of the maxillomandibular complex

A 19-year-old woman with skeletal Class III malocclusion, paranasal depression, and a low mandibular plane angle was treated with orthodontics and orthognathic surgery. Dental decompensation and protraction of maxillary right third molar to replace maxillary right second molar were performed before surgery. Clockwise rotation of maxillo-mandibular complex was applied by Le Fort I osteotomy and bilateral sagittal split osteotomies to achieve facial balance. The active treatment period was 12 months. The stable occlusion and skeletal relationship were observed after a 10-month follow-up period.     

Early orthognathic surgery with three-dimensional image simulation during presurgical orthodontics in adults

To correct dentofacial deformities, three-dimensional skeletal analysis and computerized orthognathic surgery simulation are used to facilitate accurate diagnoses and surgical plans. Computed tomography imaging of dental occlusion can inform three-dimensional facial analyses and orthognathic surgical simulations. Furthermore, three-dimensional laser scans of a cast model of the predetermined postoperative dental occlusion can be used to increase the accuracy of the preoperative surgical simulation. In this study, we prepared cast models of planned postoperative dental occlusions from 12 patients diagnosed with skeletal class III malocclusions with mandibular prognathism and facial asymmetry that had planned to undergo bimaxillary orthognathic surgery during preoperative orthodontic treatment. The data from three-dimensional laser scans of the cast models were used in three-dimensional surgical simulations. Early orthognathic surgeries were performed based on three-dimensional image simulations using the cast images in several presurgical orthodontic states in which teeth alignment, leveling, and space closure were incomplete. After postoperative orthodontic treatments, intraoral examinations revealed that no patient had a posterior open bite or space. The two-dimensional and three-dimensional skeletal analyses showed that no mandibular deviations occurred between the immediate and final postoperative states of orthodontic treatment. These results showed that early orthognathic surgery with three-dimensional computerized simulations based on cast models of predetermined postoperative dental occlusions could provide early correction of facial deformities and improved efficacy of preoperative orthodontic treatment. This approach can reduce the decompensation treatment period of the presurgical orthodontics and contribute to efficient postoperative orthodontic treatments.     

Effect of Orthognathic Surgery on the Posterior Airway Space in Patients Affected by Skeletal Class III Malocclusion

Introduction

Dentofacial deformity refers to deviations from normal facial proportions and dental relationships that are severe enough to be handicapping. These anomalies involve many aspects of patient’s life and are sometimes also associated with a reduction of pharyngeal air space. Through orthognathic surgery it is possible to treat dentofacial deformities: this kind of surgery has several effects on skeletal structures and it has changes, as it is demonstrated by many studies, also on the upper airways. The orthognathic surgeries commonly used to correct this deformity are the mandibular setback and the maxillary advancement procedures. This study aims to evaluate the effects of maxillary and mandibular surgery on pharyngeal airway dimensions in skeletal class III malocclusions.

Materials and methods

This study considers 76 patients, treated between 2007 and 2013 by maxillary advancement (11 patients), maxillary advancement and mandibular setback (39 patients), maxillary advancement, mandibular setback and genioplasty reduction (26 patients). Cranial latero-lateral radiography was used to compare oropharyngeal airway morphologies before and 1 year after surgery.

Conclusion

The surgeon should consider bimaxillary surgery rather than mandibular setback surgery to correct a class III deformity to prevent the development of obstructive sleep apnea syndrome; in fact, bimaxillary surgery might have less effect on reduction of the pharyngeal airway than mandibular setback surgery only.     

Improving quality of life with a team approach: a case report

An adolescent female who presented amelogenesis imperfecta with severe anterior open bite, long face, facial asymmetry, high angle, and Class III skeletal pattern was treated with an interdisciplinary (orthodontics, orthognathic surgery, and prosthodontics) treatment approach. Presurgical orthodontic treatment was followed by surgical maxillary posterior impaction with anterior advancement and mandibular setback operation with vertical chin reduction and genioplasty. After the surgery, anterior ceramic laminate veneers and posterior full ceramic onlay-crowns were performed. The results showed that function and esthetics were achieved successfully with interdisciplinary collaboration.     

Skeletal Class III and open bite treated with bilateral sagittal split osteotomy and molar intrusion using titanium screws

Two-jaw surgery has been performed for the treatment of severe skeletal open bite cases to obtain stability of occlusion after treatment. If molar intrusion with titanium screws could be performed instead of surgical superior repositioning of the maxilla, the incidence of surgical invasion would be reduced. However, there have been few reports of such a therapy. This case report describes treatment for skeletal Class III and open bite with bilateral sagittal split osteotomy and intrusion of the molars using titanium screws. The patient had a concave profile, a long lower facial height, Class III malocclusion, and excessive anterior open bite following mandibular protrusion and a high mandibular plane angle. The mandible autorotated closed 3.5° following intrusion of the upper and lower molars using titanium screws during the presurgical orthodontic treatment phase. After the autorotation of the mandible, a mandibular setback with a bilateral sagittal split osteotomy was performed. The posttreatment records showed a good facial profile and occlusion. The mandible was stable 1 year after surgery. These results demonstrate that surgical orthodontic treatment combined with bilateral sagittal split osteotomy and intrusion of the molars using titanium screws can reduce the need for surgical invasion by avoidance of maxillary surgery and was effective for correcting the facial profile and occlusion in a skeletal Class III and open bite patient.     

Is skeletal stability after bimaxillary surgery for skeletal class III deformity related to surgical occlusal contact?

A stable occlusion at the time of surgery is considered important for post-surgical stability after orthognathic surgery. The aim of this study was to determine whether skeletal stability after bimaxillary surgery using a surgery-first approach for skeletal class III deformity is related to the surgical occlusal contact or surgical change. Forty-two adult patients with a skeletal class III deformity corrected by Le Fort I osteotomy and bilateral sagittal split osteotomy with a surgery-first approach were studied. Dental models were set and used to measure the surgical occlusal contact, including contact distribution, contact number, and contact area. Cone beam computed tomography was used to measure the surgical change (amount and rotation) and post-surgical skeletal stability. The relationship between skeletal stability and surgical occlusal contact or surgical change was evaluated. No relationship was found between maxillary or mandibular stability and surgical occlusal contact. However, a significant relationship was found between maxillary and mandibular stability and the amount and rotation of surgical change. The results suggest that in the surgical-orthodontic correction of skeletal class III deformity with a surgery-first approach, the post-surgical skeletal stability is not related to the surgical occlusal contact but is related to the surgical change.     

骨性安氏Ⅲ类错下颌单颌手术后软硬组织的变化

目的:探讨正畸-正颌联合治疗成人骨性安氏Ⅲ类错,上、下颌软、硬组织的变化及其变化的相关性。方法:选取骨性安氏Ⅲ类错患者20例,手术前、后拍摄X线头颅侧位片,手术方式为双侧下颌骨矢状劈开截骨术(BSSRO)。采用SPSS13.0软件包对数据进行配对t检验。结果:治疗后SNB、B点和Pog点到Y轴的距离变小,ANB变大;软组织颏唇角、TLL点、SB点和TC点到Y轴的距离均变小,且均有显著差异(P<0.01)。SB点到Y轴的距离与B点到Y轴的距离存在线性关系,比值为1∶1,决定系数R2=0.96;TC点到Y轴的距离与Pog点到Y轴的距离比为0.84,决定系数R2=0.97。结论:单纯下颌前突患者经正畸和BSSRO治疗后,上颌软组织无明显变化,上、下唇长度不受影响。颏前点软组织与骨组织变化比值为0.84,颏唇沟点为1:1,相关强度均在0.9以上。     

An alternative for the correction of the Class II low mandibular plane angle

The traditional orthodontic and/or orthognathic surgical management of the Class II deep-bite case with a low mandibular plane angle has often been difficult; optimal esthetic results have not always been achieved, and long-term stability was often unpredictable. Many of these patients may benefit functionally and esthetically from appropriate orthodontic treatment and double-jaw surgical intervention to reorient the occlusal plane toward normal (8 degrees +/- 5 degrees to Frankfort horizontal) by moving the posterior maxilla and mandible superiorly and correcting into a Class I skeletal and occlusal relationship. As the occlusal plane angulation is increased, the upper incisor angulation decreases, the lower incisor angulation increases, the chin rotates down and backward relative to the lower incisor occlusal plane tips, and the mandibular plane angle increases. The principle of changing the occlusal plane has provided a means to improve the functional and esthetic results for the correction of this type of facial deformity, as well as many others.     

Changes in bite force and dentoskeletal morphology in prognathic patients after orthognathic surgery

OBJECTIVE: We sought to evaluate the changes in bite force and dentoskeletal morphology in prognathic patients after orthognathic surgery. STUDY DESIGN: Twenty-four patients underwent orthognathic surgery to correct Class III skeletal and dental malocclusions. Ten patients who underwent Le Fort I and bilateral sagittal split ramus osteotomy of the mandible (ie, surgical correction of 2 jaws) and 14 patients who underwent only bilateral sagittal split ramus osteotomy (ie, surgical correction of 1 jaw) were compared. Bite force was measured preoperatively and at 3, 6, and 12 months postoperatively. The dentoskeletal morphology was assessed through lateral cephalograms obtained preoperatively and 12 months postoperatively. RESULTS: Twelve months postoperatively, the bite force was significantly greater in the patients who underwent surgery on 1 jaw than in the patients who underwent surgery on 2 jaws. Significant decreases in the gonial angle, occlusal plane angle, and anterior facial height were observed postoperatively in the patients with 1 surgically corrected jaw, but not in the patients with 2 surgically corrected jaws. Patients with 2 surgically corrected jaws experienced a greater increase in the Frankfort mandibular plane angle and a greater decrease in the posterior facial height than did those with 1 surgically corrected jaw. CONCLUSION: The difference in the preoperative-to-postoperative change in dentoskeletal morphology between the 2 groups is one of the factors responsible for the significant difference in postoperative bite force between the 2 groups.     

Effects of treatment with a combined maxillary protraction and chincap appliance in skeletal Class III patients with different vertical skeletal morphologies

Several cephalometric studies and case reports have described the effects of treatment with a maxillary protraction appliance (MPA) and chincap appliance. The purpose of this investigation was to identify differences in the response to treatment with a combined MPA and chincap in skeletal Class III patients with different vertical skeletal morphologies: short- (low mandibular plane angle) and long- (high mandibular plane angle) face types. The cephalograms used in this study were of 42 Japanese girls at the beginning of treatment (T0, mean age 10.1 years) and at removal of the appliance (T1, mean age 11.5 years). The subjects were divided into two groups (short and long face) according to the inclination of the mandibular plane at T0. Total anterior face height, upper and lower face height, occlusal plane, and gonial angle were significantly larger in the long-face group at T0. In both groups, significant increases in SNA, maxillary size (A'-Ptm'), and ANB were noted during treatment. Compared with the long-face group, the short-face group showed greater forward displacement and size increment of the maxillary body, while there were no significant differences in changes in mandibular size or position between the two groups. These results indicate that the vertical dimensions of the craniofacial skeleton are important factors in the orthopaedic effects of a MPA and chincap and the prognosis for skeletal Class III patients.     

Relapse patterns of two-jaw surgical correction in patients with skeletal Class III malocclusion and different vertical facial types

The aim of this study was to evaluate postoperative relapse after the surgical correction of skeletal Class III deformities of various facial patterns as a guide to surgical planning. A retrospective cohort study of 90 consecutive patients with skeletal Class III malocclusion who underwent bimaxillary surgery was performed. The surgical outcomes and postoperative stability were compared. The primary predictor variable was vertical facial type, which was classified into three groups according to the Frankfort mandibular plane angle (FMA). The primary outcome of angular and linear measurements was obtained using serial cone beam computed tomography scans obtained at time points of preoperative, 1 week after surgery, and orthodontic debonding. No significant difference in skeletal relapse was observed in patients with the different vertical facial types. The mandible displayed a forward and upward relapse in all three groups postoperatively. The patients with a low FMA exhibited a more consistent mandibular relapse pattern than those with a normal or high FMA. These findings suggest that bimaxillary surgery is clinically stable for mandibular prognathism regardless of the vertical facial pattern. However, 1–1.5 mm of overcorrection in the mandible setback should be considered in patients with a low FMA, because of the greater facial depth and consistent forward and upward mandibular relapse pattern.     

Evaluation of long-term hard tissue remodelling after skeletal class III orthognathic surgery: a systematic review

This systematic review was performed to investigate the long-term hard tissue stability in orthognathic surgery patients with skeletal class III malocclusion. A literature search was conducted using the Embase, Cochrane Central, Web of Science, and PubMed databases, yielding 3690 articles published up to June 2018. Nine articles met the inclusion criteria; these reported skeletal changes in 886 patients with between 5 and 12.7 years of follow-up. Risk of bias was assessed according to the Cochrane Handbook. Results showed variations in stability based on age, facial pattern, surgical procedure, and fixation type. Young patients showed a greater increase in mandibular length and higher A-point stability after bimaxillary surgery than older patients. Dolichofacial patients showed skeletal relapse with a facial clockwise rotation, whereas counterclockwise rotation was observed in brachyfacial patients. Single mandibular setback surgery was linked to stability loss with decreased mandibular ramus and gonion angle; meanwhile, genioplasty fell into the highly stable surgery category. The hyoid bone relapsed significantly postero-inferiorly, which correlated with suprahyoid muscle changes but little to no mandibular position changes. Fixation with monocortical miniplates showed higher patient satisfaction and better stability compared to bicortical screw fixation. These conclusions should be regarded with caution because of the lack of current evidence from three-dimensional imaging.     

骨性Ⅱ类错牙合女性患者上颌磨牙近远中倾斜度的CBCT分析

目的:分析骨性Ⅱ类错牙合女性患者上颌磨牙近远中倾斜情况,以期为临床治疗提供参考。方法:选取骨性Ⅱ类错牙合30例及个别正常牙合10例治疗前CBCT数据,以眼耳平面、腭平面及牙合平面测量上颌磨牙倾斜度,并将患者测量项目与个别正常牙合数据进行单样本t检验。将骨性Ⅱ类高角、均角和低角间进行单因素方差分析,并把不同垂直骨面型间的测量项目与下颌平面角及牙合平面角进行Pearson相关性分析。结果:在FH平面、腭平面及牙合平面为参考平面时,骨性Ⅱ类U6较个别正常牙合更加远中倾斜。以腭平面及FH平面为参考时,骨性Ⅱ类低角组到高角组,U6有远中倾斜趋势。以牙合平面为参考时,U7在高角组到低角组有远中倾斜趋势。结论:为代偿上下颌骨矢状向关系不调,骨性Ⅱ类错牙合U6有远中倾斜。骨性Ⅱ类U6随下颌平面角的增加代偿性远中倾斜,但U7远中倾斜趋势不明显。无论何种骨性Ⅱ垂直骨面型,U6代偿性倾斜移动以维持咬合力沿牙齿长轴传递。     

Morphological evaluations in skeletal Class III malocclusion requiring maxillofacial surgery using orthognathic surgical analysis

The purpose of this study was to establish a Japanese standard norm for orthognathic surgical analysis to be used in clinical applications and to clarify maxillofacial morphological characteristics in skeletal Class III malocclusions requiring orthognathic surgery. The materials were pretreatment lateral cephalometric radiographs in the relaxed lip posture from 50 subjects with skeletal Class III malocclusions diagnosed as requiring orthognathic surgery. The control group consisted of 50 subjects with normal occlusion and well-balanced faces. Detailed cephalometric measurements were recorded and analyzed statistically. The skeletal, dental, and soft tissue measurements from the normal group did not reveal any marked differences between the sexes. The Class III group exhibited a more retrognathic maxilla and prognathic mandible, a steeper mandibular plane, a more prominent chin, and a larger lower facial height in the skeletal measurements; a significant lingual inclination of the mandibular incisor in the dental measurement; and a more concave profile with prognathic mandible, a larger lower facial height, a more acute nasolabial angle and chin in the soft tissue measurements. We suggest that this analysis can be clinically useful in diagnosis, treatment planning, and posttreatment evaluation for orthognathic surgical cases who are Class III patients.     

Moebius综合征患者牙颌面特征及正颌正畸治疗远期疗效评价

目的:评价正颌正畸联合治疗Moebius综合征患者的牙颌畸形的远期疗效。方法:Moebius综合征患者3例,经正颌正畸联合会诊制订治疗计划,按照术前正畸、正颌手术、术后正畸的联合治疗模式进行系统治疗,随访1～6a。结果:Moebius综合征患者的牙颌特征主要表现为严重的骨性开畸形。对于牙颌畸形的治疗,主要是通过正颌正畸联合治疗进行矫正,但由于升颌肌群功能障碍,开矫正的复发倾向比较明显,需要术后密切随访治疗。结论:正颌正畸联合治疗能够矫正Moebius综合征患者严重的骨性开畸形,正颌手术后的长期随访对防止开的复发具有重要意义。     

骨性Ⅱ类成年患者不同治疗方式下的侧貌审美评价

目的:评价骨性Ⅱ类上颌前突下颌后缩成年患者不同治疗方式下的侧貌美观.方法:选取1例骨性Ⅱ类上颌前突下颌后缩正畸代偿治疗后的成年女性作为研究对象,拍摄头颅侧位片和侧貌像,运用Photoshop软件模拟得到正畸代偿治疗结合不同前移程度的颏成形手术及正畸-正颌联合治疗的侧貌图共6张,由专业和非专业人员对其评分,采用SPSS22.0软件包对数据进行单因素方差分析及SNK检验.结果:正畸-正颌联合治疗最为美观,正畸代偿治疗结合颏成形手术治疗颏部前移4 mm时次之,前移8 mm时美观程度较正畸代偿治疗差.结论:正畸-正颌联合治疗仍为骨性Ⅱ类上颌前突下颌后缩患者改善侧貌美观的最佳治疗方式.颏成形手术作为一种正畸代偿治疗后的辅助治疗手段,可在一定程度上提高面部的协调及美观,但美学效果不能与正畸-正颌联合治疗相媲美.     

Increase in mandibular and chin projection with orthognathic surgery

Three groups of twelve patients, each of whom had a Class II, Division 1 malocclusion with a markedly convex facial profile and steep mandibular plane, were treated by orthodontic means and orthognathic surgery. One group had mandibular advancement, another had maxillary elevation, and the third had both surgical procedures combined, with genioplasties performed in some cases from each group. Changes were studied with the aid of lateral cephalometric headfilms taken just after surgery and from 5 to 105 months later. Horizontal changes in point B and pogonion after the follow-up period were 7.0 mm and 8.5 mm with mandibular surgery, 5.4 mm and 9.3 mm with maxillary surgery, and 10.7 mm and 16.4 mm with combined surgery. The amount of change is much larger than found with orthodontic or orthopedic treatment alone and makes possible the successful treatment of very difficult problems.