Comparative efficacy of sodium hypochlorite, silver nanoparticles, and chitosan nanoparticles on gutta-percha cone disinfection and topographical changes analyzed by atomic force microscopy: An in vitro study.

CONTEXT: Evaluation of newer nanoparticle-based disinfectants for the disinfection of contaminated gutta-percha cones and surface topographical changes induced by them.

AIM: To evaluate the effectiveness of sodium hypochlorite (NaOCl), silver nanoparticles (AgNPs) solution, and chitosan nanoaparticles (ChNPs) solution for the disinfection of gutta-percha cones contaminated with Bacillus subtilis (MTCC 441) and Candida albicans (MTCC 227) and the topographical changes induced by them.

METHODS

Minimum inhibitory concentration and minimum bactericidal concentration of NaOCl, AgNPs, and ChNPs against B. subtilis and C. albicans were determined by the broth microdilution method and colony-forming unit assay, respectively. Gutta-percha cones were artificially contaminated with B. subtilis and C. albicans. Contaminated cones were immersed for 1, 3, and 5 min in 2.62% NaOCl, 5.25% NaOCl, 250 µg/ml AgNP's, and 625 µg/ml ChNPs solution, and the mean colony-forming units (CFUs) were evaluated after disinfection. Topographical changes induced by these agents at different time intervals were assessed by atomic force microscopy (AFM).

STATISTICAL ANALYSIS: The data were analyzed by a two-way analysis of variance and Bonferroni post hoc test performed using licensed GraphPad Prism (v5.0).

RESULTS

NaOCl was the most effective disinfectant, eliminating both microorganisms within 1 min of immersion time. AgNPs and ChNPs showed no CFU units at 5 min of immersion time against B. subtilis but were able to eliminate C. albicans within 1 min of immersion. AFM analysis showed that, with all disinfectants on increasing time of immersion, the topographical changes become significant in comparison to the control.

CONCLUSION

NaOCl at both concentrations was the most effective disinfectant, causing minimal topographical alterations at 1 min of immersion time.