Correlation of Facial Form with Temporomandibular Joint-Space Dimensions: A CBCT-Based Cross-Sectional Study

Introduction: The relationship between facial form and temporomandibular joint (TMJ) joint-space dimensions remains unclear, particularly regarding variation across different facial shapes. Cone-beam computed tomography (CBCT) provides accurate three-dimensional evaluation of TMJ structures and allows precise assessment of joint-space dimensions. This study aimed to evaluate the association between facial form and TMJ joint-space dimensions (anterior, superior, and posterior) using CBCT. Materials and Methods: This cross-sectional study included 69 adults aged 18-50 years with complete permanent dentition and no signs of temporomandibular disorders based on the Fonseca Index. Facial form was classified as round, oval, or square using standardized two-dimensional photography and an algorithm-based facial classification method (Fisherface-based analysis). CBCT images were obtained using a standardized TMJ protocol, and anterior, superior, and posterior joint spaces were measured bilaterally. Statistical comparisons were performed using ANOVA or Kruskal-Wallis tests (p < 0.05). Results: Most joint-space dimensions showed no significant differences among facial forms. A significant variation was observed only in the left posterior joint space (p = 0.002), where round-faced individuals exhibited the smallest mean value (2.39 ± 1.64 mm) compared with oval (3.77 ± 2.01 mm) and square (6.01 ± 3.12 mm) facial types. Conclusions: Facial form demonstrated minimal influence on temporomandibular joint joint-space dimensions, with differences observed only in the left posterior compartment. These findings suggest that facial-shape assessment may have limited but potentially complementary value in TMJ evaluation. However, the clinical implications should be interpreted cautiously given the predominantly non-significant findings.