Avaliação dos efeitos imediatos do laser de baixa potência sobre a força de mordida, amplitude de movimentos mandibulares, sensibilidade muscular à palpação e fadiga muscular quando aplicado previamente a indução de fadiga em pacientes jovens

Abstract

Introduction: Currently there is great interest in multidisciplinary care aiming to control the craniofacial muscle-skeletal disorders, in order to improve the quality and functional capacity of the masticatory muscles. Objective: The aim of the present study was to evaluate the effect of low-level laser therapy on bite force, mandibular range of motion, sensitivity to palpation and fatigue in the masseter and anterior temporal muscles of young patients when administered prior to the induction of fatigue. Methods: Fifty-two healthy volunteers aged 18 to 23 years were randomly allocated to a laser group (n=26) and sham group (n=26). Both groups were submitted to a clinical evaluation to record mandibular range of motion, bite force, muscle sensitivity to palpation and muscle fatigue. The laser group was then submitted to low-level laser therapy (780 nm, 25 J/cm2, 50 mW, 20 seconds per point) on three points of the masseter and one point of the anterior temporal muscle on each side. The sham group was submitted to the same procedure, but with the device switched off. The volunteers were then instructed to chew two pieces of gum (one on each side) for six minutes, with the pace set by a metronome calibrated to 80 bpm, followed by the reevaluation of all variables. The results were submitted to analysis of variance and then to Tukey's multiple comparisons method. For intra-group comparison the Wilcoxon and Mann-Whitney test were applied. Results: The final muscle sensitivity and muscle fatigue presented an increase in relation to the initial evaluation. No statistically significant inter-group or intra-group differences were found for the other variables analyzed. Conclusion: With the proposed protocol, low-level laser therapy administered prior to the induction of fatigue did not lead to any changes in bite force and mandibular range of motion, indicating that further studies are needed with different low-level laser dosimetric parameters.