Abstract
Many temporomandibular dysfunction patients do not have the proper occlusal position. This can be caused by simple mechanical problems but may also be psychosomatic in origin. When treating such patients, it is important to make them recognize the stable occlusal position which agrees best with balanced muscle physiology. The present study aimed at delineating the most suitable EMG feedback technique for these patients. Both the temporal and masseter muscles were studied to determine whether subjects could learn to respond to shifts in occlusal position.
Fourteen subjects with normal occlusion were instructed to perform submaximal clenching maintaining equal activities between the right and left muscles for 30 seconds with a portable electromyographic monitoring (MBM). Then asymmetry indices (AI) were calculated for each muscle.
In this feedback training it was shown that the masseter and temporal muscles did not behave similarly. After a number of training sessions, for the masseter muscle, the mean value of AI approached zero. However interindividual variation remained despite training. On the other hand, for the temporal muscle, in addition to the mean value of AI approaching zero, intersubject variation also declined with training. Furthermore, in the case of the temporal muscle, the efficiency of feedback training increased with time. The authors concluded that this feedback training method for the temporal muscle may be the useful. It may well help patients to become more aware of stable occlusal position and assist them in learning to maintain an appropriate level of muscle tension.
