Abstract
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.