Efficacy of photobiomodulation in the management of oral Lichen Planus in comparison to topical corticosteroids: Systematic review, meta-analysis, and GRADE-based assessment of certainty of evidence.

Background: There is an urgent need to update the evidence available on the efficacy of photobiomodulation (PBM) in comparison to topical corticosteroids in the management of Oral Lichen Planus (OLP).

Methods: Cochrane Oral Health's Trials Register, Cochrane Central Register of Controlled Trials in the Cochrane Library, MEDLINE Pubmed, SCOPUS, Lilacs and Google Scholar were searched. Other sources included US National Institutes of Health Ongoing Trials Register, World Health Organization International Clinical Trials Registry Platform and Clinical Trial Registry - India were searched using variations of the keywords "Laser" and "Oral Lichen Planus". Randomized controlled trials comparing PBM and topical corticosteroids in the resolution of pain among OLP patients were included. The studies were assessed using the Cochrane Risk-of-Bias assessment tool. Publication bias was assessed using a funnel plot, and the certainty of evidence was evaluated according to the GRADE guidelines.

Results: Ten studies were included for qualitative assessment and of these eight were included in the meta-analysis. The included studies used laser parameters of varying strengths and duration. Meta-analysis favoured PBM (n = 274, MD =-0.48, CI -0.66- -0.30) for pain score. No adverse effects were reported for laser therapy. There was high heterogeneity and moderate certainty of evidence, and most studies had a high risk of bias.

Conclusion: There is improvement in the clinical parameters of OLP when treated with PBM in comparison to topical corticosteroids. However, the strength of the evidence for these findings in limited. It is recommended to conduct better long-term trials with large sample size.