Efeitos de 8 semanas de exercícios isométricos de resistência muscular à fadiga no tratamento da disfunção temporomandibular em mulheres por meio de biofeedback: ensaio clínico randomizado

Abstract

BACKGROUND: Changes in the temporomandibular joint, muscles and bones characterize the so-called temporomadibular disorders (TMD), being pointed out as the second most frequent cause of orofacial pain in the world. The pathophysiology and multifactorial etiology (functional, structural and psychological factors) are still unknown, affecting frequently women and presenting as the most common symptoms limitation or mandibular asymmetry, joint sounds, ear, head or neck pain. Patients with these symptoms have decreased muscle oxygen extraction, early fatigue and less effective masticatory muscles. To treat such disorders, exercises were used in combination with other modalities of treatment. However there were no studies that standardized a protocol solely on fatigue resistance exercises. OBJETIVE: To assess the efficacy of 8-week protocol of endurance exercises on muscle excitation, force response, perceived pain and over muscle efficiency. METHODS: Randomized clinical trial with 46 women diagnosed by RDC/TMD with TMD miogenic were divided into experimental group (n = 23) and control group (n = 23). The experimental group received a protocol of endurance exercises controlled by biofeedback. The control group received placebo by laser therapy with device turned off. Evaluations were on baseline, at 4 weeks and at the end of the eighth week, which measured the pressure pain threshold and visual analog scale of pain, muscle activity by surface electromyographic and bite force by a load cell synchronized with electromyograph of the anterior temporal and masseter muscles, bilaterally. The general linear multivariate analysis of variance (MANOVA) model with repeated measures was used to classify within- and between subjects variables, with significance set at p <0.05 RESULTS: The experimental group had longer time until fatigue, more efficiency within- and between groups and greater anterior temporal arousal at week 8 compared to the baseline evaluation, but without differences between groups. Bite force increased in control group between the 4th and 8th weeks, but no difference between groups. There was a decrease in pain for both groups, with lower scores in the experimental group at the end of week 8. There was no significant difference in pressure pain threshold, although increased in both groups over time. CONCLUSION: An 8-week endurance exercise protocol improve time until fatigue and muscle efficiency, as well as relieving the pain in TMD subjects.