Assessment of various endodontic instrumentation systems on the amount of apically extruded bacteria - An in vitro study

AIM: The objective of this in vitro study was to assess the effect of different endodontic instrumentation systems on the amount of apically extruded bacteria. MATERIALS AND METHODS: One hundred and twenty freshly extracted human mandibular premolars with single canal were collected. Endodontic access cavities were prepared and then contaminated with an Enterococcus faecalis suspension (ATCC 29212). After incubation at 37°C for 24 h, the root canals were instrumented with K flare files, F360 Single file system, K3XF files, Heroshaper files, Protaper Next files, and Hyflex EDM Single file system. During instrumentation, apically extruded bacteria were collected in the vials containing 0.9% NaCl. Samples were taken from the vials and incubated in brain–heart infusion agar medium for 24 h. STATISTICAL ANALYSIS: The number of colony-forming units was determined, and data were statistically analyzed using one-way analysis of variance and post hoc Tukey test. CONCLUSIONS: Both rotary and hand instrumentation systems extruded intracanal bacteria through the apical foramen, Group 1 (Hand K Flare files) showed maximum, whereas, Group 5 (Protaper Next) and Group 6 (Hyflex EDM) showed the least extrusion.