Low level laser therapy for the treatment of temporomandibular disorders: a systematic review of the literature

The authors performed a review of the literature to evaluate the efficacy of low level laser therapy (LLLT) for the treatment of temporomandibular disorders (TMD). Selection criteria included: 1) human subjects, 2) articles written in English, and 3) randomized placebo-controlled trials. Evaluation was performed according to the CONSORT 2010 criteria. A total of 14 articles were included in the review. Studies varied considerably in terms of methodological design, particularly regarding the site of application of the laser beam, the number of applications performed, their duration, the laser beam features (wavelength, frequency, output, dosage), and outcome measures. The outcome of the trials was controversial and not particularly related to any features of the laser beam, to the number of laser applications, and their duration. Based on the results of this review no definitive conclusions can be drawn on the efficacy of LLLT for the treatment of TMD. Many methodological differences among the studies, especially regarding the number and duration of laser applications and characteristics of the laser beam (wavelength, frequency, output), do not allow for standardized guidelines for effective treatment with LLLT. The only indication seems to be that LLLT is probably more effective for the treatment of TMJ disorders, and less effective for the treatment of masticatory muscle disorders.