Abstract
Temporomandibular disorders (TMD) are characterized by several signs and symptoms, such as pain and changes in the electrical activity of masticatory muscles. Considering that transcutaneous electrical nerve stimulation (TENS) is a resource indicated to promote analgesia, the objective of this study was to evaluate the effect of TENS on pain and electromyographic (EMG) activity of the jaw elevator muscles in TMD patients. This study evaluated 35 female volunteers: 19 TMD patients (mean age = 23.04 +/- 3.5) and 16 normal subjects (mean age = 23.3 +/- 3.0). Transcutaneous electrical nerve stimulation (conventional mode, 150 Hz) was applied once to each group for 45 minutes. Surface electromyography (gain of 100 times and 1 kHz sampling frequency) and the visual analogue scale (VAS) were applied before and immediately after TENS application. Both VAS data and root mean square (RMS) values were analyzed using Student's t-test. The TMD group, compared to the control group, showed higher EMG activity of the jaw elevator muscles at rest. No difference was observed between the groups regarding maximum voluntary clenching (MVC). In TMD patients, TENS reduced both pain and EMG activity of the anterior portion of the temporal muscle, increasing the activity of the masseter muscles during MVC. It is possible to conclude that a single TENS application is effective in pain reduction. However, it does not act homogeneously on the features of the electric activity of the muscles evaluated.
Highlights
Temporomandibular disorders (TMD) are characterized by several symptoms and clinical signs, such as pain in the temporomandibular joint and/or masticatory muscles, and changesRodrigues D, Siriani AO, Bérzin F
Cooper et al.[2] (1991) and Lous et al.[8] (1970) stated that, among the masticatory muscles, the anterior portion of temporal muscles shows the highest electromyographic activity when the jaw is at rest position
It can be observed that EMG activity at rest is higher in the TMD group than in the control one (p ≤ 0.05)
Summary
Temporomandibular disorders (TMD) are characterized by several symptoms and clinical signs, such as pain in the temporomandibular joint and/or masticatory muscles, and changesRodrigues D, Siriani AO, Bérzin F. Some authors[11,16,19] reported that, during mastication, subjects with TMD present activity in jaw-closing muscles (masseter and temporal muscles) during the opening phase, when they should be relaxed. Cooper et al.[2] (1991) and Lous et al.[8] (1970) stated that, among the masticatory muscles, the anterior portion of temporal muscles shows the highest electromyographic activity (hyperactivity) when the jaw is at rest position. This hyperactivity of masticatory muscles at rest has been widely discussed. Some authors believe it is an exaggeration to consider muscular hyperactivity alterations from 1 to 2% of the maximum production of electrical activity of a muscle[10]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
