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

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.

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.

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).

The use of nano‑CHX in removing E. faecalis biofilm from root canal is as effective as the use of CHX and NaOCl.