Cyclic Fatigue of Nickel-Titanium Rotary Instruments in Single Curvature Canals

Abstract

Aim: the aim of current research was to evaluate and compare cyclic rotations required to fracture different rotary nickel titanium (NiTi) endodontic files in single curvature canals.

Methods: Four different NiTi rotary instruments were selected for the present study: F6 SkyTaper, EndoSequence ESR, Endosequence CM, and Ordeka plex-v file of ISO 25, 0.06 instrument taper and 25 mm instrument length. All files were subjected to cyclic fatigue test inside custom-made simulated canals with 60° curvature. Time required to fracture rotary files (in seconds) while being rotated in a steel block canal was determined to calculate cyclic fatigue. Data was statistically evaluated ANOVA test at 5% level of significance. 

Results: EndoSequence ESR instrument reported the highest cyclic fatigue resistance among all other tested rotary instruments. Endosequence CM expressed the lowest fatigue resistance. One-way ANOVA test expressed a statistically significant difference between all four groups regarding number of cycles to fracture (NCF) and non-statical significant difference relating to length of fracture segment (FL). 

Conclusion: EndoSequence ESR and Ordeka plex-v files demonstrated dominance over Endosequence CM and F6 SkyTaper files in cyclic fatigue resistance.

Keywords:

NiTi rotary files, Cyclic Fatigue resistance, Single curvature canals

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