Cyclic fatigue of ProFile rotary instruments after clinical use

AIM: The purpose of this study was to evaluate cyclic fatigue of .06 ProFile Ni-Ti rotary instruments after clinical use in molar teeth. METHODOLOGY: In group 1, instruments size 40-15 were used in a crown-down technique using 2.5% NaOCl as an irrigant. Fifty-two molars were included and 13 sets of Profile Ni-Ti rotary instruments were used. Each set of instruments was used in four molars, and was steam autoclaved before each use. Group 2 (10 sets of new ProFile Ni-Ti rotary instruments) was the control group. Cyclic fatigue was tested by rotating the instruments in a 90 degrees metallic tube until they broke. RESULTS: One-way analysis of variance did not show any statistically significant differences amongst the files from both groups regarding cyclic fatigue. CONCLUSIONS: It was concluded that sterilization and clinical use in the presence of NaOCl did not lead to a decrease in the number of rotations to breakage of the files.