Conservative treatment of mandibular dysfunction. Clinical, experimental and electromyographic studies of biofeedback and occlusal appliances.
Two modes of treatment for mandibular dysfunction, electromyographic biofeedback and occlusal appliances, were studied. Thirty patients were randomly assigned to treatment with biofeedback or splints and it was shown that both therapies reduced signs and symptoms of mandibular dysfunction in the short and long-term perspective. An analysis of potentially useful clinical predictors of the treatment outcome indicated that laboratory diurnal biofeedback may be a useful alternative to splint therapy in cases where night-time bruxing is not the dominating feature. During biofeedback training, from the masseter or frontal muscle, the EMG activity in both muscle areas in 20 patients with acute or chronic mandibular dysfunction decreased within but not between six sessions, progressively more often for the masseter area. The results were valid irrespective of feedback or symptom duration. A simplistic neuromuscular learning model could not alone explain the positive effects on symptoms. It was shown that motivation was important. The EMG activity in the masseter area was greater during experimentally induced stress than under baseline or resting conditions, and greater in the patients than in matched controls. There was no difference between the pain side and the non-pain side. After the biofeedback training, the EMG activity during stress in the patients under identical conditions was lower and at the same level as in the controls, whose responsiveness had not changed. The anxiety level, expressed in TMAS scores, was greater in patients than in controls before but not after treatment. The influence on the integrated EMG activity in the masseter and temporal muscles after night-time use of appliances with different occlusal design was studied in 17 healthy subjects. After use of stabilisation splints, the activity in the temporal muscle was lower in the rest position and lower than after use of bite plates. The activity during gentle and maximal biting had not changed. The mean activity in a control group of 8 subjects had not changed at any functional level. A positive correlation between clinical signs and level of EMG activity in the temporal muscle in the rest position was observed in 19 patients with mandibular dysfunction. The patients also had less activity in the masseter and temporal muscles during maximal biting compared to healthy subjects. No change in EMG activity could be observed after night-time use of stabilisation splints or bite plates for six weeks, although the symptoms improved.(ABSTRACT TRUNCATED AT 400 WORDS)
D000293:Adolescent; D000328:Adult; D001676:Biofeedback, Psychology; D003766:Dental Occlusion; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008334:Mandible / Q000503:physiopathology; D008406:Masseter Muscle / Q000502:physiology; D008875:Middle Aged; D011626:Pterygoid Muscles / Q000503:physiopathology; D012064:Relaxation Therapy; D013165:Splints; D013312:Stress, Physiological / Q000503:physiopathology; D013703:Temporal Muscle / Q000502:physiology; D013706:Temporomandibular Joint Dysfunction Syndrome / Q000503:physiopathology / Q000628:therapy*