Differential outcomes of jaw bone position after surgical-orthodontic treatment in three types of skeletal Class III asymmetry patients.

BACKGROUND/PURPOSE: Facial asymmetry is common in Class III patients requiring orthognathic surgery. This study aimed to analyze jaw bone position after surgical-orthodontic treatment in three types of skeletal Class III asymmetry patients. METHODS: The retrospective study included 30 Class III patients who underwent surgical-orthodontic treatment comprising LeFort I osteotomy and bilateral sagittal split osteotomy (BSSO) without genioplasty. Cone-beam computed tomography (CBCT) images obtained before surgery (T1) and after post-surgical orthodontic treatment (T2) were superimposed with voxel-based registration. Patients were classified into three groups based on T1 CBCT scans. Groups 1 and 2 exhibited menton and ramus deviated to the same side. Menton deviation was larger than ramus width asymmetry in group 1, while the reverse was true for group 2. Group 3 had menton deviation contralateral to the side with greater ramus width. RESULTS: Menton deviation after treatment was improved in all groups. Ramus width asymmetry and coronal ramus angle difference decreased in groups 1 and 2. Neither improvement nor deterioration of ramus width asymmetry was noted for group 3. Comparing to groups 1 and 2, group 3 had greater roll and yaw rotations of distal segment, more upward pitch of proximal segment on chin deviation side, and largest inward yaw as well as backward translation of proximal segment on non-deviation side. CONCLUSION: The positional changes of osteotomy segments differed among three types of mandibular asymmetry. Special attention should be given to the atypical mandibular asymmetry with mandibular body and ramus deviating to opposite directions during surgical correction of jaw deflection.

Correction of Severe Skeletal Class II High Angle with Mandibular Retrusion and Gummy Smile by Double-Jaw Surgery.

This report describes the treatment of severe skeletal Class II malocclusion in a young woman with a gummy smile and pronounced lower anterior facial height. Overjet and overbite were +12.0 mm and -1.0 mm, respectively. Cephalometric analysis revealed inferior positioning of the maxilla and severe mandibular retrusion with clockwise rotation. Both the upper and lower anterior teeth showed labial inclination. Based on a diagnosis of a skeletal Class II high angle with mandibular retrusion and a gummy smile, double-jaw orthognathic surgeries for upper and lower premolar extraction were chosen to gain ideal occlusion and an improvement in the esthetic facial profile. Le Fort I osteotomy was performed to move the anterior and posterior teeth upward by 4.0 mm and achieve mandibular counterclockwise rotation. Short lingual sagittal split ramus osteotomy was performed to move the mandible forward by 3.0 mm. As a result, normal overjet and overbite were achieved together with a straight profile and a good smile. After surgery, electromyographic evaluation of anterior temporal muscle activity showed an improvement in the percentage overlapping coefficient value (a symmetric index of bilateral muscle activity) from 28.1% to 63.2% compared to at pre-treatment. The pattern of jaw movement also showed an improvement. These results suggest that orthognathic surgery in skeletal Class II cases can improve not only malocclusion and the skeletal relationship of the jaws, but also masticatory function and jaw movement.

The relationship between fixation method and early central condylar sagging after bilateral sagittal split ramus osteotomy in orthognathic surgery.

PURPOSE: There is no consensus about the ideal fixation methods and their effects on the condyle after the sagittal split ramus osteotomy (SSRO) procedure. The aim of this study was to compare the incidence, clinical presentation, and treatment of condylar sagging between different fixation methods following SSRO. METHODS: Patients who underwent double jaw surgery between 2007 and 2017 were evaluated retrospectively. Mandibular fixation was maintained using one of three different options: a miniplate and a single bicortical screw, three bicortical screws, or a single bicortical screw. Some patients had malocclusion relapse in the early postoperative period due to condylar sagging, and needed reoperation. The reoperated condylar sagging patients were analysed statistically with respect to their fixation methods. RESULTS: 233 patients (134 females, 99 males) with a mean age of 23.3 years were enrolled in the study. The patients fixated with a single bicortical screw had lower revision surgery rates than those with three bicortical screws or with miniplate with a single bicortical screw (p = 0.034 and p = 0.032, respectively). These differences in central condylar sagging with a need for revision were statistically significant. CONCLUSION: Although a miniplate and a single bicortical screw and three bicortical screws are widely used after SSRO, if the priority is to avoid sagging then it seems that a single screw should be preferred for osteosynthesis.

Double jaw surgery – a modified surgical approach to treat skeletal class II

@#Patients with mandibular deficiency and skeletal class II malocclusions exhibit a wide spectrum of esthetic, cephalometric, and occlusal characteristics. The structure of chin determines facial attractiveness and is directly linked to a quality of life. Correction of dentoalveolar protrusion of maxilla is done by anterior maxillary subapical osteotomy by which anterior segment can be moved superiorly or inferiorly and posteriorly as indicated. Augmentation genioplasty is advocated to improve the overall facial esthetics of patient with mandibular deficiency. In skeletal class II malocclusions cases best results are obtained with double jaw surgery combined with the orthodontic treatment. This is a case report of skeletal class II malocclusion with mandibular deficiency and protruded maxilla in 22 year old female patient who was treated surgically by anterior maxillary subapical osteotomy and augmentation genioplasty along with the orthodontic treatment

A Study on the preoperative prediction values versus the postoperative actual values in class III two jaw surgery patients

Soft tissue changes after double jaw surgery in skeletal Class III malocclusion / 대한치과교정학회지

The purpose of this study was to evaluate the amount and interrelationship of the soft and hard tissue changes after simultaneous maxillary advancement and mandibular setback surgery in skeletal Class III malocclusion. The sample consisted of 25 adult patients(13 males and 12 females) who had severe anteroposterior skeletal discrepancy. These patients had received presurgical orthodontic treatment and surgical treatment which consisted of simultaneous Le Fort I or Le Fort II osteotomy and bilateral sagittal split ramus osteotomy. The presurgical and postsurgical lateral cephalograms were evaluated. The computerized statistical analysis was carried out with SPSS/PC+ program. The results were as follows: 1. The correlation of maxillary hard and soft tissue horizontal changes were high and the ratios for soft tissue to A point were 71% at Sn, 67% at SLS and 37% at LS. 2. The correlation of mandibular hard and soft tissue horizontal changes were very high and the ratios were 84% at LI, 107% at ILS, 96% at Pog' and 97% at Gn'. 3. The correlation of mandibular hard tissue horizontal changes and soft tissue vertical changes were moderate. 4. The upper to lower lip length were increased(P<0.001). 5. The soft tissue thickness were decreased in upper lip and increased in lower lip(P<0.001). The postsurgical changes were reversely correlated with initial thickness in upper lip.