Volumetric differences in temporomandibular joint components in patients with facial asymmetry: A 3D tomographic segmentation study

Purpose

To determine if there are differences in condylar volume, glenoid cavity and joint space between patients diagnosed with facial asymmetry (FA), between affected and contralateral sides and with respect to subjects without FA.

Methods

Cross-sectional, retrospective study comparing CT/CBCT images from patients with FA diagnosis referred to a private clinic, versus a control group, age and sex matched, of patients requiring orthodontic treatment without FA. The 3D Slicer software was used for the analysis. Bivariate analysis was performed to compare qualitative variables using Chi-square or Fisher tests, and for normal distribution quantitative variables, the t-student test was used. The level of significance was p < 0.05.

Results

The FA group (n = 138) included: Hemimandibular Elongation (HE) (n = 64), Hemimandibular Hyperplasia (HH) (n = 12), Hybrid Form (HF) (n = 20), Asymmetric Mandibular Prognathism (AMP) (n = 25), Glenoid Cavity Asymmetry (GCA) (n = 9) and Functional Laterognathism (FL) (n = 8). The control group (n = 20) had no FA and no signs or symptoms of temporomandibular dysfunction. The right condylar and glenoid cavity volumes were significantly larger in FA cases. The volumes of the right and left joint space had significant differences only in HE patients.

Conclusion

Condylar volumes are higher in almost all FA subgroups compared to matched controls. The glenoid cavity volume is larger in FA patients, except for the GCA right and FL left sides. Regarding articular spaces, HE was the only entity with less volume on the contralateral side. The evaluation of structural volume by 3D-CT images helps to diagnose and differentiate FA subgroups.