Antimicrobial Effect of Two Single File Systems versus One Multiple Rotary Instrumentation on Infected Root Canals

 since microorganisms play a fundamental role in the ethology of pulp and peri apical diseases, and reduction or elimination of the intra canal population, is of the main principles of a successful root canal treatment. The aim of this study was the in vitro comparison of bacterial population reduction in root canal by mechanical instrumentation, using two single file systems and multi file rotary system in root canals infected with Enterococous Faecalis

 In this experimental laboratory study, the root canals of 48 human mandibular premolar teeth were selected and were infected with a culture of E.faecalis for 30 days. Then the specimens were randomly divided into 3 groups (n=16): Reciproce, Neolix and Mtwo files. Four other teeth that were contaminated and not instrumented, were used as control group. Samples were taken before (S1) and after instrumentation (S2). Bacterial quantification was performed using quantitive PCR. Statistical analyses were performed by Mann-Whitney and Kruskal-Wallis tests

 Comparing the average number of bacteria before and after preparation, the number of bacteria increased significantly between the three groups of Reciproc, Neolix and MTO after preparation (p < 0.001). But in the control group, there was no significant difference in the number of bacteria before and after preparation (p = 0.144).

 single file canal preparation systems are as effective as multifile rotary system in reduction of the bacterial load of canals