Efficacy of Low-Level Laser Therapy in the Treatment of Temporomandibular Myofascial Pain: A Systematic Review and Meta-Analysis

Aims: To conduct a systematic review and meta-analysis to determine the efficacy of low-level laser therapy (LLLT) in treating temporomandibular myofascial pain in adults compared to laser placebo. Methods: Randomized, placebo-controlled studies were identified by a search on March 2, 2016 and updated on February 9, 2017 in the PubMed, Web of Science, and Cochrane Library databases. Three of the authors assessed the studies for risk of bias. Outcomes included pain reduction on a visual analog scale (VAS) and interincisal opening. Results: The initial search strategy yielded 142 unduplicated references assessed independently by three review authors. After evaluation, this number was reduced to eight relevant studies for inclusion in this review. Of these eight studies, four were at unclear risk of bias and four were at high risk. In a meta-analysis, pain intensity was significantly reduced after treatment in the group that received LLLT as compared to laser placebo (an average of 2.2 units on a scale of 0 to 10) (P = .005) and an average of 2.4 units 3 to 4 weeks later (P = .022). Pooled results showed a significant increase in interincisal opening at 1 month after treatment (P = .012), but not when the treatment was completed (P = .079). Conclusion: The findings from this systematic review showed that LLLT seems to be effective in reducing pain in patients with temporomandibular myofascial pain with moderate-quality evidence. However, due to the high heterogeneity, small number, and high risk of bias of the included studies, the results are not definitive, and further well-designed studies are needed. Keywords: low-level laser therapy, meta-analysis, myofascial pain, randomized controlled trials, visual analog scale