Clinical Outcome of Sodium Hyaluronate Injection into the Superior and Inferior Joint Space for Osteoarthritis of the Temporomandibular Joint Evaluated by Cone-Beam Computed Tomography: A Retrospective Study of 51 Patients and 56 Joints

BACKGROUND: The aim of this study was to determine the clinical effects of sodium hyaluronate injection into the superior and inferior joint space for osteoarthritis of the temporomandibular joint (TMJ) and to evaluate the joint changes using cone-beam computed tomography (CBCT). MATERIAL/METHODS: A retrospective observational clinical study included 51 patients and 56 TMJs, with a diagnosis of osteoarthritis. All patients received sodium hyaluronate injections into the superior and inferior TMJ joint spaces (articular cavities). At baseline and post-treatment the condylar bony changes were evaluated by CBCT. To evaluate TMJ function, maximum mouth opening (MMO), and Helkimo’s index was used, which included an anamnestic index (Ai) and a clinical dysfunction index (Di). Patients were divided into short-term (<one year) and long-term (>one year) follow-up groups. RESULTS: In both patient follow-up groups, sodium hyaluronate injection of the superior and inferior TMJ space significantly improved MMO, the Ai, and the Di (P<0.05). There were no significant differences between the two groups in condylar bony changes of the TMJ seen by CBCT (sclerosis, erosion, hyperplasia, and flattening) (P>0.05). CBCT showed a good predictive ability on post-treatment symptom relief following sodium hyaluronate injection into the superior and inferior TMJ space in patients with osteoarthritis of the TMJ (P=0.024). CONCLUSIONS: The findings of this clinical and CBCT imaging study showed that sodium hyaluronate injection into the superior and inferior TMJ space in patients with osteoarthritis improved clinical symptoms, but did not control the progression of osteoarthritic joint destruction.