The Effect of Photobiomodulation Therapy in the Treatment of Postoperative Pain After Impacted Third Lower Molar Extraction: A Systematic Review with Meta-Analysis.

Background/Objectives: Postoperative pain following impacted mandibular third molar extraction is a common complication that negatively affects patients' quality of life. Photobiomodulation (PBM) therapy has been proposed as a non-pharmacological adjunctive approach to reduce postoperative pain. This study aimed to evaluate the effectiveness of intraoral PBM in reducing postoperative pain after impacted mandibular third molar extraction compared with placebo, sham treatment, or standard postoperative care. Methods: A systematic review was conducted according to the PRISMA 2020 guidelines. PubMed and Embase were searched through January 2025 for randomized controlled trials (RCTs) investigating intraoral PBM after impacted mandibular third molar extraction. Only studies reporting postoperative pain using the Visual Analog Scale (VAS) were included. Risk of bias was assessed using the Cochrane RoB 2 tool, and the certainty of evidence was evaluated using the GRADE approach. Random-effects meta-analyses were performed at 24, 48, and 72 h postoperatively using standardized mean differences (SMDs). Results: Eight RCTs met the inclusion criteria for qualitative synthesis, whereas only two provided extractable data for quantitative analysis. Meta-analysis demonstrated a significant reduction in postoperative pain in the PBM group at 24 h (SMD = -0.64; 95% CI: -0.90 to -0.38; p < 0.001), 48 h (SMD = -0.82; 95% CI: -1.64 to -0.01; p = 0.047), and 72 h (SMD = -1.11; 95% CI: -1.38 to -0.84; p < 0.001). Conclusions: Intraoral PBM appears to reduce postoperative pain during the first 72 h. However, the available evidence is limited by the small number of studies included in the meta-analysis, heterogeneity in PBM protocols, and inconsistent outcome reporting. Additional well-designed RCTs are needed to strengthen the current evidence.