Salivary Level of Glutathione Reductase, Catalase, and Free Thiol in Patients With Temporomandibular Joint Disorder: A Cross-Sectional Study.

OBJECTIVE: The role of antioxidants in temporomandibular joint dysfunction has been suggested; however, no studies have measured the saliva of patients with TMD. This study aimed to assess the concentrations of glutathione (GSH) reductase, catalase (CAT), and free thiol in the saliva of patients with TMD, compared with individuals without TMD. MATERIALS AND METHODS: In this cross-sectional study, 35 patients with TMD, who had at least one revised comprehensive diagnostic (RDC) criteria for TMD (pain in TMJ and masticatory muscles; muscle spasm or clicking), and 20 healthy individuals (without TMD) participated, and their saliva sample (5 mL) was collected in the morning. The disease severity was measured based on the Helkimo index. Salivary levels of GSH reductase (wavelength = 405 nm), CAT (wavelength = 520 nm), and free thiol (wavelength = 405 nm) were measured using enzyme-linked immunosorbent assay (ELISA). Data were statistically analyzed. RESULTS: Patients with TMD had significantly lower salivary levels of GSH reductase (253 mU/mL in the TMD group and 390 mU/mL in the control group), and CAT (159 mU/mL in the TMD group and 270 mU/mL in the control group) compared with the control group, but similar free thiol levels (60 mU/mL in the TMD group and 56 mU/mL in control group). There was a correlation between antioxidant status and the presence of click, pain, and severity of the disease; however, there was no correlation between age and sex with antioxidant contents. CONCLUSION: The results suggest that these antioxidants are affected by TMD and may be indicative of disease severity. Further studies can determine the diagnostic accuracy of these three antioxidants and their potential role to be used as diagnostic and prognostic biomarkers for monitoring and treating TMD. CLINICAL RELEVANCE: TMD is common, and oxidative stress (OS) may play a role in their development. Using saliva as a diagnostic method offers a less invasive alternative to synovial fluid or blood.