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 II 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.