Survival of Enterococcus faecalis in root canals after conventional and experimental intracanal medications

Abstract

Background: The aim of this study was to evaluate the antimicrobial effect of different experimental boric acid gels in comparison with calcium hydroxide [Ca(OH)2] and chlorhexidine (Chx) gels on Enterococcus faecalis. Methods: Crowns of sixty extracted single-rooted human teeth were removed and root canals were instrumented using ProTaper instruments to the size of F3 file. After removal of smear layer, the specimens were sterilized and divided into groups of ten samples in each. All samples were inoculated with E. faecalis for 21 days. The following medicaments were used in test groups: Ca(OH)2 paste, 2% Chx gel, methyl cellulose/boric acid combination (MCBA), chitosan/boric acid combination (CBA), 2% Chx/chitosan/boric acid combination (CthBA). One group was kept infected and served as control. After days of incubation, the medicaments were removed and the dentin chips were collected from inner canal walls with gates glidden burs into vials containing phosphate buffered saline, vortexed, serially diluted and seeded on tryptic soy agar plates and incubated at 37 °C for 48h before colony-forming units (CFLI) were counted. Results were statistically analysed by using Kruskal-Wallis test and Mann--Whitney (.l-test, respectively (p=0.05). Results: All the CFLl values of tested medicaments were significantly lower than the control group (P 0.05). Only Ca(OH)2 and CthBA groups totally eliminated all E. faecalis cells (CF(_l=O). E. faecalis microorganisms were more susceptible to Chx than the CBA and MCBA groups (P 0.05). Conclusions: Within the limitations of this in vitro study, it has been shown that CthBA combination may effectively remove all planktonic E. faecalis microorganisms from the canal.