Abstract

ALMEIDA, Josiane de et al. Treatment of the Enterococcus faecalis root canal biofilm with nanoparticle suspensions and conventional irrigants. Arq. Odontol. [online]. 2015, vol.51, n.1, pp. 32-38. ISSN 1516-0939.

Aim: The aim of this study was to evaluate and compare the effectiveness of 1% and 5% sodium hypochlorite (NaOCl), 2% chlorexidine (CHX), 1% silver nanoparticles (Np Ag) suspension, and 26% zinc oxide nanoparticles (Np ZnO) suspension against E. faecalis biofilm. Methods: Seventy-six extracted human teeth were biomechanically prepared, mounted in a specific apparatus, and sterilized. Next, 100 μL of an E. faecalis suspension was inoculated into the root canals, and was replaced every 24 h for 7 days. Four teeth were analyzed by scanning electron microscopy (SEM) to confirm the presence of biofilm. The remaining teeth were randomly divided in 6 groups (n = 12) according to the irrigation solution: G1) 0.85% saline (control), G2) 1% NaOCl, G3) 5% NaOCl, G4) 2% CHX, G5) 1% Np Ag suspension, and G6) 26% Np ZnO suspension. After the irrigation protocol, the biofilm susceptibility to disinfecting solutions (n=10) was determined by colony-forming unit (CFU) quantification. SEM was also performed in 2 root segments to view the biofilm structure. Data, represented by the mean number of CFU for each group, were analyzed by means of the Kruskal- Wallis and Mann-Whitney post hoc tests (p < 0.05). Results: The effectiveness of 5% NaOCl and 1% Np Ag against E. faecalis biofilm was superior compared to 0.85% saline solution (p < 0.05). 5% NaOCl was able to reduce 100% of CFU when compared to the control, followed by 1% Np Ag (97.6%), 26% Np ZnO (96.1%), 1% NaOCl (94.1%), and 2% CHX (93.1%). Conclusion: Based on the methodology used, 5% NaOCl and 1% Np Ag showed excellent effectiveness against intracanal E. faecalis biofilm.

Keywords : Biofilms; Disinfection; Enterococcus faecalis; Metal nanoparticles.