Efficacy of low-level laser as an adjunctive therapy in root canal treatment and retreatment: an umbrella review.

Abstract

This study aimed to evaluate and synthesize evidence from systematic reviews investigating the efficacy of low-level laser therapy (LLLT) as an adjunct to endodontic treatment in reducing postoperative pain, microbial load, and promoting apical healing. A comprehensive search of electronic databases (PubMed, Embase, Web of Science, Cochrane Library, Google Scholar) was conducted from February 2024 to March 2025, to retrieve systematic reviews that evaluate the efficacy of LLLT as an adjunct to endodontic treatment in reducing postoperative pain, microbial load, and promoting apical healing. Two independent authors selected the studies, extracted relevant data, and assessed the individual risk of bias and methodological quality using the ROBIS and AMSTAR-2 tools, respectively. The electronic search identified 280 records, 18 of which met the eligibility criteria and were included in the qualitative synthesis. The studies were published between 2014 and 2024. Only six reviews demonstrated a low risk of bias, and two were classified as having high methodological quality. Most systematic reviews indicated that LLLT is effective in reducing the incidence and intensity of postoperative endodontic pain and the microbial load following instrumentation. The studies also highlighted the high heterogeneity, the lack of a standardized protocol for LLLT application, and the low certainty of evidence for the outcomes. LLLT is an important adjunctive therapy in endodontic treatment; however, robust evidence regarding its application protocol is still lacking.