Effectiveness of Three Rotary File Systems on Enterococcus Faecalis in Single Rooted Teeth: An In Vitro Study

Objective: To evaluate the effectiveness of three rotary file systems on the elimination of Enterococcus faecalis (E. faecalis) biofilms in single-rooted teeth. Methods: A total of 70 mandibular premolars were included in this study in which 60 root canals were inoculated with E. faecalis. The positive control group (n=5) received bacterial inoculation without mechanical preparation. The negative control group (n=5) was neither infected nor mechanically prepared. The teeth were randomly assigned to 3 experimental groups (n=20 per-group) according to application of the rotary files: Group 1: XP-endo Rise Shaper (FKG, Le Crêt-du-Locle, Switzerland); Group 2: XP-endo Shaper (FKG, Le Crêt-du-Locle, Switzerland); Group 3: ProTaper Gold (Dentsply Sirona, Erlangen, Germany). Samples were collected using paper points before (S1) and after (S2) mechanical preparation. Colony-forming units (CFUs) were used to quantify bacterial loads. Results: Significant differences in bacterial counts were observed from S1 to S2 in all tested groups (p<0.001). Intergroup comparisons revealed no significant differences between the XP-endo Rise Shaper and XP-endo Shaper groups (p>0.05) and between XP-endo Shaper and ProTaper Gold groups (p>0.05). Significant differences were observed between the XP-endo Rise Shaper and ProTaper Gold groups (p<0.05). The XP-endo Rise shaper group showed the largest reduction in bacterial loads (98.2%), followed by the XP-endo Shaper (96.0%) and ProTaper Gold (93.8%) groups. Conclusion: All tested rotary files were able to reduce bacteria but the novel single-file system (XP-endo Rise shaper) was superior in reducing bacterial load compared to XP-endo Shaper and the multiple file system (ProTaper Gold).