Antibacterial effect of nano‑chlorhexidine on Enterococcus faecalis biofilm in root canal system: An in vitro study

Abstract

Background: A new method to improve the properties of the materials is nano‑encapsulation,
which improves the biological properties, antibacterial activity along with reduction of toxicity. Due
to the spread of nano‑knowledge, the present study was performed to evaluate the antibacterial
effect of nano‑chlorhexidine (CHX) on Enterococcus faecalis biofilm in the root canal system.
Materials and Methods: In this in vitro experimental study, 55 matured single‑root mandibular
premolars were decoronated and the canals were prepared by single length method up to #F3
ProTaper Universal system. Five teeth were selected as negative control. Then, the teeth were
randomly divided into three experimental groups (n = 15) and a positive control group (n = 5). The
experimental groups were irrigated with 2% nano‑ CHX gel, 2% CHX solution, and 5.25% sodium
hypochlorite (NaOCl), respectively. Finally, the number of colonies was counted. Kruskal–Wallis
test was used to compare the number of colonies among groups. The level of significance was set
at P < 0.05.
Results: The mean number of colonies in the groups of nano‑CHX, NaOCl, CHX, and positive
control were obtained as 17.73 ± 18.69, 35.53 ± 36.42, 38.8 ± 31.8, and 96.8 ± 22.52, respectively.
There was a significant decrease in the number of colonies in all the experimental groups compared
to the control group (P < 0.05). However, difference in the number of colonies among these three
groups was not significant (P > 0.05).
Conclusion: The use of nano‑CHX in removing E. faecalis biofilm from root canal is as effective
as the use of CHX and NaOCl.
Key Words: Chlorhexidine, Enterococcus faecalis, nanoparticles, sodium hypochlorite