Surface electromyography of the masticatory muscles for application in dental practice. Current evidence and future developments.

On the basis of well-founded clinical evaluations and taking into account special methodological recommendations, surface electromyography (EMG) enables the acquisition of valid and reliable quantitative data on the functional condition of the masticatory muscles as a "neuromuscular functional analysis". On the basis of a current review of the literature, surface EMG appears to be able to deliver additional diagnostic and therapy-relevant information. Meaningful EMG data can be gained regarding resting activity, maximum muscle activation, frequency spectrum under various loading conditions, as well as bilateral symmetry of the contraction behavior of the jaw muscles. With these parameters--completed by kinematic information on movements of the mandible--it appears to be possible under clinical conditions to assess (a) the neuromuscular chewing performance after prosthetic reconstructions, (b) to record the influence of pain on the neuromuscular system, and (c) to document the individual efffect of therapeutic interventions on temporomandibular disorders.