Three-dimensional bone remodelling of glenoid fossa in patients with skeletal Class III malocclusion after bimaxillary orthognathic surgery

Three-dimensional assessment of temporomandibular joint changes following maxillomandibular advancement surgery: a five-year follow-up study

This study aimed to evaluate changes of the temporomandibular joint (TMJ) following maxillomandibular advancement surgery (MMA), long-term postoperative skeletal relapse, and progressive condylar resorption (PCR) development. Preoperative and postoperative cone beam computed tomography(2 weeks, 5 years) of 50 patients (33 female, 17 male; mean age 25.6 years) were assessed three-dimensionally. Compared to the preoperative state, the largest long-term changes of the TMJ were observed in the condyles: mean volume decrease of 9.94% for the right condyle and 8.35% for the left. Condylar volume changes contributed most to the changes in condylar height (effect size right/left, η2 = 0.71/0.72) and horizontal postoperative skeletal relapse (η2 = 0.22/0.20). In contrast, glenoid fossa and joint space changes were modest and unassociated with skeletal relapse. Five female patients (10%) showed signs of PCR, with a mean reduction in condylar volume of 32%, a significant loss of condylar height and skeletal relapse. In conclusion, at 5 years following MMA, mainly condylar volume changes were observed, which had the largest effect on long-term postoperative skeletal relapse when compared to glenoid fossa and joint space changes. PCR occurred in 10% of the patients and was related to a significant loss of condylar height and skeletal relapse.

Changes in computed tomography values and morphology of the condyle and glenoid fossa before and after orthognathic surgery in female jaw deformity patients

This study aimed to investigate the computed tomography (CT) values and morphology of the temporomandibular joint (TMJ), specifically the condyle and glenoid fossa, in female patients with jaw deformities before and after orthognathic surgery. The maximum CT values were measured on the condylar and glenoid fossa surfaces. In addition, the height, length, and area of the glenoid fossa in the sagittal plane were evaluated for the bilateral TMJs, preoperatively and one year postoperatively. The ramus height, condylar square, ramus angle, and gonial angle were also measured. A total of 148 TMJs from 74 patients were analyzed. Both condylar and ramus heights decreased one year after surgery in class II and class III patients (P < 0.05). The glenoid fossa area significantly increased one year after surgery in class II (P = 0.0005). Significant postoperative increases in CT values were observed at the 0°, 135°, and 180° points on the condylar surface and at the 135° and 180° points on the glenoid fossa surface in class II patients (P < 0.05). These findings suggest that in class II patients, substantial morphological and CT value changes occurred in the condyle and glenoid fossa one year following orthognathic surgery.

Comprehensive 3-dimensional Positional and Morphological Analyses of Condyle and Glenoid Fossa in Patients with Skeletal Class II Malocclusion following Bimaxillary Orthognathic Surgery

This study aimed to comprehensively and quantitatively characterize 3-dimensional (3D) positional and morphological changes of the condyle and glenoid fossa in patients with skeletal Class II malocclusion treated with bimaxillary orthognathic surgery. Twenty eligible patients treated at our institution from January 2016 to December 2021 with more than 12 months of postoperative follow-up were retrospectively enrolled. Radiographic data of cone-beam computed tomography (CBCT) for each patient were collected at 3 stages: 1 week preoperatively (T0), immediately after surgery (T1), and at least 12 months postoperatively (T2). Positional changes, surface and volumetric alterations of condyle, and bone remodeling in glenoid fossa were measured and compared based on voxel- and surface registrations in visual 3D methods. Most patients exhibited a tendency for condyles to shift posteriorly, laterally, superiorly, and rotated outward, downward, and forward immediately after surgery. Posterior, medial, superior movement and outward, upward, and backward rotation of condyles were observed during follow-up (T1-T2). Bone resorption frequently occurred in the posterior area of condylar surfaces, while bone remodeling was more common in the anterior region of the glenoid fossa. Reduced volume of the condyle was found in most cases, which was not associated with the amount of mandibular advancement. Overall, the condyle and its corresponding glenoid fossa remained relatively stable during the follow-up. Our results reveal positional and morphological alterations in the condyle and the glenoid fossa after bimaxillary orthognathic surgery in patients with skeletal class II malocclusion. These changes predominantly fall within the spectrum of physical adaption.