Low-level laser therapy (
LLLT) has been commonly used for the treatment of painful musculoskeletal conditions, but the results of previous studies on this subject are controversial. The aim of this study was to evaluate the efficacy of
LLLT in the management of patients with myogenic
temporomandibular joint disorders (TMDs). In this randomized, double-blind clinical trial, 20 patients with myogenic TMD were randomly divided into
laser and placebo groups. In the
laser group, a pulsed 810-nm low-level
laser (average power 50 mW, peak power 80 W, 1,500 Hz, 120 s, 6 J, and 3.4 J/cm(2) per point) was used on painful muscles three times a week for 4 weeks. In the placebo group, the treatment was the same as that in the
laser group, but without energy output. The patients were evaluated before
laser therapy (T1), after six sessions of
laser application (T2), at the end of treatment (T3), and 1 month after the last application (T4), and the level of
pain and the amount of mouth opening were measured. There was a significant increase in mouth opening and a significant reduction of
pain symptoms in the
laser group (p < 0.05). A similar improvement was not observed in the placebo group (p > 0.05). Between-group comparisons revealed no significant difference in
pain intensity and mouth opening measurement at any of the evaluation time points (p > 0.05).
LLLT can produce a significant improvement in
pain level and mouth opening in patients affected with myogenic TMD.