Antimicrobial activity of root canal irrigants associated with cetrimide against biofilm and planktonic Enterococcus faecalis

Abstract

AIM: To evaluate the antibacterial activity of sodium hypochlorite (NaOCl) and chlorhexidine (CHX) alone or associated with cetrimide (CTR), and QMiX against biofilm and planktonic Enterococcus faecalis (E. faecalis) [American type culture collection (ATCC) 29212]. MATERIALS AND METHODS: The solutions 2.5% NaOCl, 2.5% NaOCl + 0.2% CTR, 2% CHX, 2% CHX + 0.2% CTR, 0.2% CTR, and QMiX were evaluated. E. faecalis biofilms were induced for 14 days on bovine dentin blocks. The irrigants were evaluated after contact with E. faecalis suspension and biofilm for 1 and 3 minutes. After that, serial decimal dilutions were made and plated on tryptic soy agar (TSA) medium. Plates were incubated for 24 hours at 37°C and the colony-forming unit (CFU) 1 ml was determined. Data were subjected to ANOVA and Tukey's tests at 5% significance. RESULTS: All microorganisms were eliminated by direct contact of the irrigants with planktonic cells. Only NaOCl and NaOCl + CTR were able to completely eliminate the microorganisms by direct contact with E. faecalis biofilm. CHX presented effectiveness similar to CHX + CTR CTR, and QMiX after 1 minute of contact and similar to NaOCl and NaOCl + CTR after 3 minutes (p > 0.05), but was unable to completely eliminate the microorganisms. CTR and QMiX did not differ from each other. CONCLUSION: CTR addition to CHX and NaOCl solutions did not improve the antimicrobial activity against biofilm. All evaluated irrigants and associations presented activity against planktonic E. faecalis. Only NaOCl and NaOCl + CTR eliminated biofilm after 1 and 3 minutes of direct contact.