In vitro evaluation of the antimicrobial efficacy of chitosan and other endodontic irrigants against Enterococcus faecalis.

The success of endodontic treatment is directly enhanced by elimination of microorganisms in infected root canals. Recently, chitosan, a natural, nontoxic biopolymer, has been introduced as an irrigant that has the capacity to remove the smear layer. The antimicrobial properties of chitosan as an endodontic irrigant have not yet been explored. The purpose of this study was to compare the antimicrobial efficacy of BioPure MTAD, 0.2% chitosan, 1% chitosan, 2% chlorhexidine gluconate, and 3% sodium hypochlorite (NaOCl) against Enterococcus faecalis, which is frequently isolated from persistent root canal infections. The agar well diffusion method was used to measure the antimicrobial activities of these irrigants. Saline was used as a negative control. The order of effectiveness was determined by the measurement of inhibition zones. Data were analyzed using 1-way analysis of variance and the Duncan multiple range test. BioPure MTAD had a significantly larger mean inhibition zone against E faecalis than the other irrigants (P < 0.001). Although 0.2% chitosan did not show any inhibition zones, 1% chitosan was as effective as 3% NaOCl (P = 0.352), and both irrigants showed significantly greater effectivity than 2% chlorhexidine (P < 0.001). Thus, 1% chitosan can be an effective natural antimicrobial substitute for synthetic irrigants.