This study was designed to evaluate the efficacy of
low-level laser therapy (
LLLT) in the treatment of
temporomandibular disorders (TMDs). We searched electronic databases and references lists of relevant articles, retrieved all of the published randomised controlled trials in regard to these issues and then performed a meta-analysis. Fourteen highly qualified RCTs reporting on a total of 454 patients, which evaluated the effectiveness of
LLLT for patients suffering from TMDs were retrieved. The results indicated that
LLLT was not better than placebo in reducing chronic TMD
pain (weighted mean difference = -19·39; 95% confidence interval = -40·80-2·03; P < 0·00001; I(2) = 99%). However, the
LLLT provided significant better functional outcomes in terms of maximum active vertical opening (MAVO) (weighted mean difference = 4·18; 95% confidence interval = 0·73-7·63; P = 0·006; I(2) = 73%), maximum passive vertical opening (MPVO) (weighted mean difference = 6·73; 95% confidence interval = 01·34-12·13; P = 0·06; I(2) = 73%), protrusion excursion (PE) (weighted mean difference = 1·81; 95% confidence interval = 0·79-2·83; P = 0·59; I(2) = 0%) and right lateral excursion (RLE) (weighted mean difference = 2·86; 95% confidence interval = 1·27-4·45; P = 0·01; I(2) = 73%). The results of our meta-analysis have provided the best evidence on the efficacy of
LLLT in the treatment of TMDs. This study indicates that using
LLLT has limited efficacy in reducing
pain in patients with TMDs. However,
LLLT can significantly improve the functional outcomes of patients with TMDs.