Adjunctive antimicrobial photodynamic therapy versus scaling and root planing alone for stage III-IV periodontitis: a systematic review and meta-analysis

Introduction: Scaling and root planing is the cornerstone of non-surgical therapy for stage III-IV periodontitis, but its results in deep pockets are incomplete. Antimicrobial photodynamic therapy has been proposed as an adjunct, although its added benefit remains uncertain. Methods: Randomized clinical trials comparing scaling and root planing alone with scaling and root planing plus antimicrobial photodynamic therapy in adults with stage III-IV or severe periodontitis were searched in OpenAlex, PubMed and Crossref. Probing depth reduction and clinical attachment gain were pooled with a random-effects model, and risk of bias was assessed with the Cochrane RoB 2 tool. Results: Ten trials were included. At three months, adjunctive photodynamic therapy produced a greater probing depth reduction than scaling and root planing alone (mean difference 0.77 mm; 95% CI 0.46 to 1.09; I2 = 64%), whereas the gain in clinical attachment was not statistically significant (mean difference 0.72 mm; 95% CI -0.29 to 1.74; I2 = 89%). Conclusions: Adjunctive antimicrobial photodynamic therapy provides a modest additional reduction in probing depth at three months, without a demonstrable gain in clinical attachment, in stage III-IV periodontitis. The evidence is limited by small trials and marked heterogeneity.