Mandibular bone apposition in relation to temporomandibular joint disorders: a radiographic and MRI study

BACKGROUND: This study investigated whether mandibular angle bone apposition (MABA) observed in temporomandibular disorder (TMD) patients reflects intrinsic joint pathology or represents a skeletal response to altered biomechanical loading related to occlusal and demographic factors. METHODS: Panoramic radiographs and temporomandibular joint (TMJ) magnetic resonance imaging (MRI) scans from 282 patients with TMDss (564 TMJs) were retrospectively analyzed. Bone apposition was graded on panoramic images, while MRI findings (disc position, condylar morphology, effusion) were recorded. Demographic data and individual tooth loss patterns were evaluated. Statistical analyses included chi-square tests with Bonferroni-adjusted post hoc comparisons and ordinal logistic regression based on generalized estimating equations. RESULTS: MABA showed no significant association with MRI-detected intra-articular TMJ abnormalities (p > 0.05). In univariate analyses, higher apposition levels were associated with increasing age, male sex, and greater numbers of missing maxillary and mandibular teeth (p ≤ 0.05). Tooth-level analysis demonstrated a localized association involving the right maxillary second premolar (p = 0.037). In multivariable analysis using generalized estimating equations, male sex, right-side location, and higher grades of joint effusion remained significantly associated with bone apposition levels (p ≤ 0.05). CONCLUSIONS: Although a causal relationship cannot be confirmed in this retrospective design, the observed associations suggest that MABA may be more closely related to functional and demographic factors than to intra-articular TMJ pathology. When MABA is detected on panoramic radiographs, assessment of occlusal stability may be considered, as functional loading patterns could play a role in mandibular remodeling.