OBJECTIVE: Osseous changes in the temporomandibular joint (TMJ) were evaluated using computed tomography (CT) examinations before and after TMJ injections of sodium hyaluronate or a corticosteroid in patients with osteoarthritis (OA). STUDY DESIGN: Forty patients were randomly allocated into 2 groups for 2 intra-articular injections with either sodium hyaluronate or a corticosteroid. Bilateral TMJ examinations with high resolution CT were obtained in 36 patients before and 6 months after treatment. Treated and contralateral TMJs were evaluated for the presence of osteoarthritic osseous abnormalities by 2 reviewers independently. RESULTS: Progression, regression, and no changes of osseous abnormalities were demonstrated in 13, 9, and 14 TMJs, respectively, 6 months after treatment. There was no significant difference between the groups. CONCLUSIONS: Progression/regression and no changes of osteoarthritic abnormalities were observed on CT examinations in both the treated and the contralateral TMJs after treatment with intra-articular injection with sodium hyaluronate or corticosteroid.