Effect of tens on the activation pattern of the masticatory muscles in TMD patients

Temporomandibular disorder (TMD) is characterized by several signs and symptoms, such as pain and changes in the activation pattern of the masticatory muscles. Thus, the objective of this study was to evaluate the effect of transcutaneous electrical nerve stimulation (TENS) of the electromyographic pattern of the masticatory muscles in individuals with myogenic TMD. This study evaluated 40 female volunteers: 20 with myogenic TMD (x=23.04 ± 3.5) and 20 normal individuals (x=23.3 ± 3). TENS (conventional mode, 150Hz) was applied once to each group for 45 minutes. The electromyographic (EMG) signal (gain of 100 times and 1KHz sampling frequency) and visual analogue scale (VAS) were applied before and immediately after TENS application. The VAS data were analyzed using paired t-test. The EMG signals were analyzed using the normalized linear envelopes. The results showed that individuals with TMD have an alteration in the activation pattern of the masticatory muscles, when compared to the control group, and the TENS reversed this pattern. TENS reduced the pain intensity in the TDM group. We conclude that a single TENS application is effective in pain reduction and promotes betterments in the activation pattern of the masticatory muscles in individuals with TMD.

Keywords
temporomandibular disorders, electromyography, masticatory muscles, transcutaneous electrical nerve stimulation, pain.