Correlation between facial asymmetry of skeletal class III jaw relationship and morphology of the temporomandibular joint: A cone beam computed tomography study.

Background/purpose: Facial asymmetry is a common dentofacial deformity especially in skeletal Class III jaw relation. The purpose of this study was to evaluate the condylefossa relationship of Taiwanese people in skeletal Class III jaw relation with or without facial asymmetry by CBCT image. Materials and methods: CBCT images were collected from Kaohsiung Medical University Hospital and then divided into symmetric Class III group (Menton [Mn] deviation ≦ 4 mm) and asymmetric Class III group (Menton [Mn] deviation > 4 mm). Maxilla deviation, upper and lower dental midline deviation, joint space, condylar axial angle and condylar volume was measured. Independent t test was used for comparison between groups, and paired t test was applied for comparison between both condyles within each group. The Pearson correlation coefficient was used to analyze the correlation between skeletal midline deviations and joint morphology. Results: No significant difference was found in joint space between groups or between sides within each group, but we can find a significant difference in axial condylar angle easurement which was greater on the non-deviation side of condyle. Significant lesser condylar volume was also found on the deviation side in asymmetric group. There had a significant positive correlation between Mn point deviation, geometric center difference and condylar volume ratio. Conclusion: These results demonstrated that in the side with greater mandibular growth potential, the axis rotation in axial plane would be greater. In the side with lesser mandibular growth potential, the total condyle volume would be lesser, even though with large variation.