Association Between Articular Eminence Structure and Joint Spaces in Temporomandibular Joints with Anterior Disc Displacement

Background and Aims: The association among the joint spaces, articular eminence morphology, and disc displacement is not well documented in the literature. This study aims to evaluate and compare the joint spaces and the articular eminence structure (eminence height [E-h] and inclination [E-i]) using cone-beam computed tomography (CBCT) of temporomandibular joints (TMJs) with anterior disc displacements and joints with normal disc position. Methods: The study groups consisted of 75 TMJs of 39 patients. The disc status of TMJs was diagnosed with magnetic resonance imaging, and the measurements were performed on CBCT. Three groups, that is, normal disc position (NDP) group, anterior disc displacement with reduction (ADDWR) group, and anterior disc displacement without reduction (ADDWoR) group, were established. Anterior, superior, posterior joint spaces (AJS, SJS, and PJS, respectively), articular E-h, and articular E-i were measured. Statistical Package for the Social Sciences version 22 was used for statistical analysis. Shapiro-Wilk test was used to check the normality of data. Intergroup comparisons of categorical variables were assessed with Fisher-Freeman-Halton test. For comparison of continuous variables parameters, Mann-Whitney U test and Kruskal-Wallis test were used. Statistical significance level was determined as P < 0.05. Results: Significant differences were not found in intergroup comparisons for PJS. However, the difference between groups was found to be significant for AJS, SJS, E-h, and E-i. Intergroup comparisons were performed for these parameters. No significant difference was found between the NDP group and the ADDWR group for AJS, SJS, E-h, and E-I. The mean AJS, SJS, E-h, and E-i values in ADDWoR were found to be significantly lower compared to the corresponding values in both NDP and ADDWR groups. Conclusion: Decreased AJS and SJS when TMJ is evaluated with CBCT may be an indicator of ADDWoR. Authors suggest that narrowed articular E-i and reduced articular E-h can be one of the predisposing factors for anterior disc displacement.