Effectiveness of Photobiomodulation in Temporomandibular Disorder-Related Pain Using a 635 nm Diode Laser: A Randomized, Blinded, and Placebo-Controlled Clinical Trial.

We aimed to evaluate the efficacy of photobiomodulation (PBM), using an 635 nm diode laser, to provide pain relief for temporomandibular disorder (TMD). TMD involves a set of multiple clinical manifestations where pain is prevalent. Treatment ideally should be noninvasive and innocuous such as PBM. A randomized, placebo-controlled, clinically blinded trial was performed on 42 patients with painful TMD diagnosed according the Research Diagnostic Criteria for Temporomandibular Disorders. They were randomly placed into two groups: an intervention group ( = 22) subjected to the application of a 635 nm wavelength diode laser (using a 8-mm diameter handpiece in contact mode, delivering 8 J/cm over a period of 20 sec applied over the sensitive points where the pain was reported by the participants) and a placebo group ( = 20) following the same protocol but without laser activation. All patients received four sessions of treatment over 4 weeks. Personal pain perception, nonassisted pain-free maximum mouth opening and tenderness elicited during palpation of muscles were used as primary outcomes, evaluated at baseline and at follow-up 1 month later by blinded, calibrated evaluators. There was a significant reduction in the degree of pain recorded in the laser group after treatment (0.63 ± 0.36) compared with the baseline evaluation (4.59 ± 2.36;  < 0.001), which was not observed in the placebo group. Reduction of pain during palpation of most masticatory muscles was significant following treatment in the intervention group. A significant increase in the nonassisted painless mouth opening was observed after treatment (42.14 ± 5.8 mm) compared with baseline values (36.73 ± 9.91 mm) only among the laser group ( = 0.007). There were no reported adverse events or side effects among the patients in the intervention group. Our results suggest that PBM using a 635 nm laser was effective on the remission of painful TMD, without complications.