Efeitos imediatos da fotobiomodulação com laser de baixa intensidade e comprimentos de onda vermelho (660 nm) e infravermelho (808 nm) na fadiga eletromiográfica do músculo orbicular da boca: estudo clínico randomizado

Abstract

Purpose: To compare the immediate effects of laser photobiomodulation at wavelengths of 660 nm and 808 nm on fatigue of the orbicularis oris. Methods: This is a randomized study with 60 women aged between 19 and 43 years. The participants were divided into four groups. Group RG received photobiomodulation with a laser wavelength of 660 nm at four points of the orbicularis oris; group IRG received photobiomodulation with a laser wavelength of 808 nm at the same points; the control group did not receive light treatment; and the placebo group underwent the same procedures as RG and IRG but with the equipment switched off. The irradiation was performed with a laser of 100 mW of power, 4 J of energy per point and 133.3 J / cm2 of fluency. An electromyography evaluation was performed before and after the irradiation, concomitantly with the exercise of lip protrusion maintained until the sensation of fatigue. Fatigue was evaluated by a median frequency using the electromyographic fatigue index. The amplitude of the signal was evaluated, examining the root mean square, and the values were normalized by the peak. The difference in amplitude between the upper and lower lips was also analyzed. All variables were compared before and after irradiation. Results: No significant difference was found between the measures taken before and after irradiation. Conclusion: Photobiomodulation with the parameters investigated in this study had no immediate effect on orbicular oris fatigue.