Consecutive digital infrared thermography in patients with temporomandibular joint arthralgia

Abstract

The objective of this study was to investigate the changes of skin temperatures over the temporomandibular joint (TMJ) and clinical findings consecutively during conservative treatments in unilateral TMJ arthralgia patients. The study enrolled 31 patients with unilateral TMJ arthralgia and 26 healthy control subjects based on the Research Diagnostic Criteria for Temporomandibuar Disorders. The measurements of skin temperatures over the TMJ and clinical examinations were performed in all subjects at baseline, 2 and 4 weeks later, and patients were given conservative treatments. Thermographic examinations were performed before and after chewing activity for 5 minutes in each session. The data were analyzed by repeated-measures ANOVA. In affected TMJ, the change in temperature between before and after chewing activity was significantly high in TMJ arthralgia group and decreased after 2 and 4 weeks. Thermal asymmetry measured before chewing activity showed insignificant difference between groups. However, those measured after chewing activity were significantly high in TMJ arthralgia group and reduced to the similar level of control group after 2 and 4 weeks. After chewing activity, both skin temperature over painful TMJ and the extent of thermal asymmetry in TMJ arthralgia patients were higher than those of control group. These thermal indices of TMJ arthralgia patients were reduced in accordance with clinical improvements by conservative treatments. Consecutive thermography accompanying chewing activity which may increase TMJ pain temporarily can be a useful adjunctive technique to diagnose TMJ arthralgia and evaluate its clinical progression including level of pain.