Effectiveness of photobiomodulation in the treatment of primary burning mouth syndrome-a systematic review and meta-analysis

To evaluate the effectiveness of photobiomodulation (PBM) on primary burning mouth syndrome (pBMS). We searched Chinese and English studies published before February 10, 2020. The databases used include PubMed, EMBASE, the Cochrane Library, Web of Science, Wanfang Database, and China National Knowledge Infrastructure (CNKI). Randomized controlled clinical trials (RCTs) that used the PBM to treat pBMS and reported specific treatment outcomes were considered for inclusion. We eventually included 12 RCTs, and 574 samples were included in these studies. The primary outcomes investigated were pain reduction and life quality improvement. A meta-analysis performed on 9 groups in 5 trials showed that PBM was effective in reducing pain compared with placebo (MD - 1.86, 95% CI - 2.59 to - 1.13, Z = 4.99, P < 0.00001). Meta-analysis was also performed on 7 groups in 4 trials and showed that PBM was effective in improving life quality compared with placebo (MD - 3.43, 95% CI - 5.11 to - 1.75, Z = 4.00, P < 0.0001). Qualitative analysis of the included RCTs found that PBM might also play a role in the decrease of TNF-α and IL-6 in saliva. Three studies that compared PBM with medications were evaluated by descriptive analysis. None of the treatment-related adverse event was reported. Up to date, PBM appears to have an effect on pain reduction and life quality improvement in pBMS patients. However, more evidence is still required to warrant its efficacy and safety in treating pBMS.