Comparative effectiveness of low-level laser therapy and transcutaneous electric nerve stimulation in the treatment of pain caused by temporomandibular joint disorders: a systematic review and network meta-analysis

Abstract Background: The comparative effectiveness of low-level laser therapy (LLLT) and transcutaneous electric nerve stimulation (TENS) in the treatment of pain caused by temporomandibular joint disorders (TMD) has not been evaluated.Methods: PubMed, Cochrane Library and Embase were searched from their inception until 27 October 2019. Randomized controlled trials (RCTs) that compared the effects of LLLT or TENS or placebo group for TMD patients’ pain reduction were included. The reviewers assessed the risk of bias of individual studies with the Cochrane risk of bias tool, excluding RCTs with a high risk of bias in any domain. Then the reviewers did network meta-analysis and assessed the quality of evidence contributing to network estimate using the GRADE framework.Results: 20 RCTs with 758 patients with TMD were included. In the pair-wise meta-analysis, LLLT and TENs showed a significant pain reduction in the visual analogue scale (VAS) compared with placebo immediately after treatment [mean difference (MD)=1.99, 95% confidence interval (CI):(1.07,2.92); MD=2.16, 95%CI:(0.27,4.04), respectively]. As for pain reduction one month after treatment, LLLT performed better and there was no statistically significant difference for TENS as compared with placebo. Conclusion: The results of this meta-analysis showed the short-term efficacy of LLLT is more positive than TENS in the treatment of pain caused by temporomandibular joint disorders.