Cone-Beam Computed Tomography as a Diagnostic Tool for TMJ Morphological Alterations in Disc Displacement.

Introduction And Aims: Cone beam computed tomography (CBCT) is widely utilized tool in routine clinical practice for TMJ assessment. This retrospective study investigated the presence of changes associated with disc displacement (DD) detected in CBCT and to correlate it with gender and condylar morphology.

Methods: A retrospective study was conducted on 294 joints from 147 patients (105 females, 42 males) aged 18 to 41 years. Based on TMD clinical diagnosis and magnetic resonance imaging (MRI) findings, joints were categorized into three groups: control (with normal discs), disc displacement with reduction (DDR), and disc displacement without reduction DDWR. CBCT images were evaluated for joint spaces, glenoid fossa characteristics, condylar inclination, and condyle morphology. Kruskal-Wallis, Mann-Whitney U tests, and Pearson Chi-Square tests were performed to identify differences among groups, and assess correlations of DD with condylar morphology, Multinomial logistic regression (MLR) was performed to assess and predict the influence of CBCT-derived morphological variables on TMJ DD, with the control group as the reference.

Results: DDR and DDWR groups showed significantly smaller superior (SS) and larger anterior spaces (AS) versus controls. Reduced anterior eminence inclination (AEI) and fossa height (HF) were observed in DD groups, with distal condylar inclination in DDR. Flat condyles predominated in DDWR. Females exhibited more pronounced DD-associated changes. MLR identified key predictors: reduced medial space, AEI and increased eminence height predicted DD (χ² = 192.92, P < .001; pseudo-R² 31-55%); DDWR was additionally associated with wider PS and reduced HF.

Conclusion: CBCT can effectively detect TMJ morphological changes associated with DD. These findings provide valuable insights into the progression of DD and its demographic correlations, emphasizing the importance of CBCT in clinical diagnostics.

Clinical Relevance: The current study identified specific CBCT-derived radiographic features that offer insights into the condition of the TMJ articular disc, thereby enhancing the practitioner's ability to diagnose, assess, and prognosticate TMD.