Effects of photobiomodulation therapy on secondary healing of the palatal donor site after free gingival graft harvesting: a systematic review and meta-analysis

This systematic review and meta-analysis evaluated photobiomodulation (PBM) therapy for postoperative pain and secondary wound healing at the palatal donor site after connective tissue harvesting. Following PRISMA guidelines, five databases were searched through 20 October 2025 for randomized controlled trials comparing PBM therapy with appropriate controls. Primary outcomes were postoperative pain (visual analogue scale, VAS) and epithelialization; secondary outcomes were analgesic consumption, remaining wound area, and bleeding. Random-effects meta-analysis was used, risk of bias was assessed with the Cochrane Risk of Bias 2.0 tool and certainty of evidence with GRADE. Nine randomized controlled trials with 299 participants were included. Day-1 pain could not be pooled. No statistically significant difference in postoperative pain was observed at day 3 or day 7, with reductions of approximately 1.2 and 0.4 points on a 0–10 scale. Complete epithelialization at 14 days was more than twice as frequent, with no significant difference at day 21. The remaining wound area at day 7 was smaller by approximately 22 mm². Heterogeneity was moderate for pain and low for healing outcomes. PBM therapy may increase the proportion of palatal donor sites achieving complete epithelialization at 14 days. For postoperative pain the evidence is very uncertain, and no statistically significant reduction was observed at either pooled time point. Most trials carried a high or unclear risk of bias, and treatment protocols were heterogeneous. Larger trials with standardized dosimetry are needed to establish the clinical value of PBM therapy at the palatal donor site.