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Objective: This study aimed to evaluate the association between temporomandibular joint (TMJ) structure and occlusal support status using computed tomography (CT) images.Methods: In this cross-sectional study, the computed tomography (CT) scans of 90 patients were categorized into six groups based on the number of posterior and anterior occlusal support areas (Eichner classification). In CT images, the articular eminence inclination, and glenoid fossa depth and angle were measured. Furthermore, condylar shape and position, and the presence of condyle-flattering or other pathologic changes were recorded. The TMJ variables were compared between different Eichner classification groups. The data were analyzed by paired samples T-tests, one-way ANOVA, and chi-square test (α=0.05).Results: The loss of posterior occlusal support was associated with TMJ flattening and a posterior condylar position (P<0.001). No significant difference was found in the inclination of the articular eminence and depth of the glenoid fossa between different Eichner groups (P>0.05). In patients with unilateral occlusal support, the TMJ on the edentulous side had a significantly lower articular eminence inclination, a greater angle of the glenoid fossa, and a decreased glenoid fossa depth (P<0.001).Conclusions: Loss of posterior occlusal support may lead to changes in the structure of the glenoid fossa, joint space, and condylar position and cause flattening of the condyle. These changes may predispose the joint to degenerative changes.