Comparison of the Antimicrobial Efficacy of Sodium Hypochlorite, Silver Nanoparticles, Chitosan-Capped Silver Nanoparticles, and Chlorhexidine-Loaded Silver Nanoparticles as Endodontic Irrigants Against Enterococcus faecalis: An In Vitro Study

Introduction Persistent endodontic infections are frequently associated with Enterococcus faecalis, a microorganism capable of surviving harsh intracanal conditions and penetrating dentinal tubules. Although sodium hypochlorite remains the gold-standard irrigant, nanoparticle-based irrigants have emerged as promising alternatives due to their enhanced antimicrobial properties. Aim The aim of the study is to compare and evaluate the antimicrobial efficacy of sodium hypochlorite, silver nanoparticles, chitosan-capped silver nanoparticles, and chlorhexidine-loaded silver nanoparticles against E. faecalis in an in vitro model. Materials and methods Forty-five extracted mandibular premolars were divided into five groups (n = 9). Following standardization of root length and biomechanical preparation, canals were inoculated with E. faecalis (ATCC 29212) and incubated for 14 days. The specimens were irrigated with the respective test solutions and subjected to passive ultrasonic agitation. Microbial samples were collected using sterile paper points, and colony-forming units (CFU) were determined. Data were analyzed using one-way analysis of variance (ANOVA) and Tukey’s post hoc test with significance set at p < 0.05. Results A statistically significant difference was observed among the groups (p < 0.001). Silver nanoparticles demonstrated the greatest antimicrobial efficacy, followed by sodium hypochlorite, chitosan-capped silver nanoparticles, and chlorhexidine-loaded silver nanoparticles. The control group exhibited the highest bacterial counts. Conclusion Silver nanoparticles exhibited superior antimicrobial activity against E. faecalis compared with the other irrigants tested and may represent a promising alternative intracanal irrigant. This study highlights the potential of nanoparticle-based irrigants as a future alternative to conventional endodontic irrigation protocols.