Effectiveness of three instrumentation systems to remove Enterococcus faecalis from root canals

Abstract

Aim To assess the effectiveness of three systems of mechanical preparation to reduce Enterococcus faecalis within root canals. Methodology Twenty-four human single-rooted canine teeth were standardized to a length of 17 mm and the canal contents removed using a size 20 K-file, as the last apical file. After irrigation and sterilization, the canals were contaminated with E.similar to faecalis and incubated for 21 days at 37 degrees C with 5% CO2. Then, the teeth were divided into three groups for mechanical preparation with: ProTaper rotary system, ProTaper manual system and manual K-files. Samples of the root canal contents, before and after the debridement, were collected with sterile paper points for 1 min. Then, the samples were diluted and plated in Brain Heart Infusion (BHI) agar. The colony-forming units were counted and the percentage reduction calculated. The reduction and log CFU mL-1 were compared between groups using Wilcoxon nonparametric test and two-way analysis of variance, respectively. Results There was a significant reduction in the number of CFU/mL (P = 0.000) before and after debridement for all the systems used. However, there was no significant difference between the systems. Conclusion All the three instrumentation systems reduced E.similar to faecalis counts to a similar degree.