Antimicrobial Efficacy of Chitosan vs. Sodium Hypochlorite Against Enterococcus faecalis: A Systematic Review and Meta-Analysis.

Background and Objectives: This study compared the antimicrobial effects of chitosan and sodium hypochlorite against Enterococcus faecalis (E. faecalis) at different irrigation solution concentrations. E. faecalis is a persistent pathogen frequently surviving root canal treatment, while sodium hypochlorite remains the current gold-standard irrigation material. Materials and Methods: A systematic review and meta-analysis of in vitro studies was conducted using Cochrane Library, EMBASE, and PubMed. Evidence certainty was assessed with GRADE. Two outcomes were analyzed: colony-forming units (CFU/mL) and the inhibition rate (IR). Two reviewers independently screened studies and extracted data. Results: Of 889 identified records, 10 studies met the inclusion criteria. For CFU/mL, the overall effect was -0.28 (95% CI: -1.54 to 0.97). For IR, chitosan concentrations < 1% showed an effect of -7.35 (95% CI: -27.27 to 12.56), while concentrations ≥ 1% showed an effect of -0.90 (95% CI: -19.24 to 17.45). Conclusions: Chitosan demonstrated antimicrobial activity comparable to sodium hypochlorite in vitro, with concentrations above 1% showing enhanced antibacterial effects. However, methodological heterogeneity limits direct comparison, and clinical equivalence cannot be concluded.