Transcutaneous Electrical Nerve Stimulation (TENS) Performed with the Myo-monitor Induced Relaxation and Relief of Pain

Pantaleo, T.,M.D., Prayer-Galletti, F. M.D., Ph.D., Pini-Prato, g., M.D., and Prayer-Galletti, S.,M.D.: "An electromyographic study in patients with myofacial pain-Dysfunction syndrome". Bull. Group. int. Rech.sc Stomat. et Odont. Vol. 26, pp. 167-179, 1983.

Summary:
An electromypgraphic (EMG) study of ipsilateral masseter and temporalis muscles was undertaken in healthy volunteers and in patients with MPD syndrome, with the aim of getting further insight into the pathophysiology of this disease.  Unlike controls, patients had abnormal MKG features and displayed involuntary sustained EMG activity at rest, chiefly in the temporalis muscles.

Transcutaneous electrical nerve stimulation (TENS) performed with the Myo-monitor induced relaxation and relief of pain: these effects were however reversed by voluntary mouth closures.

The correction of occlusal position by acrylic splints was able to induce  persistent reduction or a suppression of the abnormal EMG activity at rest and a good relief of pain: moreover, after the corretion, higher levels of EMG activity were found during maximal  biting in the intercuspal position.
Mechanisms underlying these effects were discussed and in particular it was suggested that abnormal afferenct activity from periodontium and jaw muscles may contribute to the establishment of sustained contraction leading to muscular pain, which in turn may cause reflex muscle activity in vicious circles.