Purpose: The aim of this study was to measure the masseter muscles activity by electromyogram before and after arthrocentesis in patients with temporomandibular disorders.
Materials and methods: Twelve patients with unilateral painful TMJ, diagnosed by RDC/TMD as group II and indicated for unilateral TMJ arthrocentesis are considered as the study group. In this group, electromyographic analysis was performed before and four weeks following the arthrocentesis. The healthy control group included 6 volunteers without any signs and symptoms of temporomandibular disorders. Electromyographic analysis was performed and compared to that of the study group.
Results: Comparison of the electromyographic values of the affected side in the study group before and after arthrocentesis showed that only the amplitude during moderate clenching revealed significant differences after four weeks (p=0.02). Differences in all other parameters were statistically insignificant
Conclusions: TMJ arthrocentesis is an effective technique for the treatment of the disc displacements sub-types of TMDs. Following arthrocentesis, definite improvement in clinical results is achieved, but improvement in muscle function is only partial as measured by surface electromyography (SEMG). SEMG is a simple non-invasive technique for monitoring of the treatment outcomes on muscle activity in TMDs. EMG analysis for the diagnosis of TMDs is not specific, because the EMG values before and after the arthrocentesis were within the range of normal values of the control group.