Abstract
BACKGROUND: The key element for a successful root canal treatment is proper cleaning and debridement of the canal. In recent years, antimicrobial photodynamic therapy (aPDT) has been used as an adjunct to conventional root canal treatment to reduce postoperative pain and microbial load. This systematic review investigates the effectiveness of aPDT in the reduction of postoperative pain and microbial load during root canal treatment in endodontic infection. METHODS: Five electronic databases: Medline, EMBASE, Scopus, Web of Science and Cochrane Library were searched for randomized controlled trials using aPDT as a supplement during conventional root canal treatment. Two authors independently performed study selection, data extraction and risk of bias assessment in duplicate and a third author resolved conflicts. The Risk of Bias (ROB2) tool was used to assess the quality of the studies included in the systematic review, and the certainty of evidence was evaluated using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) criteria. RESULTS: Eleven studies were included in the systematic review, of which five studies reporting postoperative pain after the use of aPDT during endodontic treatment were subjected to meta-analysis. Random-effects meta-analyses found that aPDT significantly reduced postoperative pain measured using visual analogue scale at both 24 h (Standardized mean difference: -1.21) and 72 h (Standardized mean difference: -0.63). While meta-analysis could not be conducted on the remaining six studies due to heterogeneity, the findings suggested a reduction in microbial load. Only three of the eleven studies had a low risk of bias. CONCLUSION: It can be concluded that aPDT, as an adjunct to chemo-mechanical irrigation, is effective in decreasing postoperative pain and reducing microbial load in endodontic infection. TRIAL REGISTRATION: PROSPERO (CRD42024567223). SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12903-025-07501-1.