Sodium hypochlorite (NaOCl) is considered the most effective solution for irrigating root canals due to its powerful disinfecting properties, including its ability to dissolve tissue, disrupt microorganisms, and eliminate bacterial biofilms in endodontic treatments. Typically, NaOCl is used at concentrations ranging from 0.5% to 5.25% during procedures. The objective of this research was to evaluate the bactericidal effects of different concentrations of NaOCl on biofilms and their influence on the outcomes of root canal treatment. This review compiles studies published between 2000 and 2023, utilizing databases like Medline, PubMed, and ScienceDirect. A total of 10 studies were included to assess how varying NaOCl concentrations impact root canal disinfection and patient outcomes. While higher concentrations were more successful in reducing bacterial counts, they did not significantly affect healing rates or patient discomfort. NaOCl exhibited strong antibacterial effects against several bacterial species, including Enterococcus faecalis, Candida albicans, Actinomyces naeslundii, and Streptococcus aureus. The findings suggest that NaOCl's efficacy is dependent on using appropriate irrigation protocols and adequate solution exchange. Further research is needed to better understand how different concentrations of NaOCl and its combination with other irrigants influence root canal treatment outcomes.
