Evaluation of Cyclic Fatigue Resistance of Three Different Niti Rotary Systems-An Invitro Study

Aim: The aim of this study is to compare and evaluate the cyclic fatigue resistance of 3 different Nickel Titanium rotary file systems: Hyflex CM, Neoendo Flex files and ProTaper Gold by static method in three different curvatures, namely, 45°, 60° and 90°.

Materials and Method: Thirty Hyflex CM (25/.06), Thirty Neoendo Flex (25/.06) and Thirty Protaper Gold (25/.08) instruments were included in this study. The static cyclic fatigue test was performed using a custom-made jig. The artificial canal is made of stainless steel jig with an inner diameter of 1.5mm, a 45°, 60°, 90° angles of curvature and radii of curvature of 5 mm. All the instruments were rotated according to manufacturer’s recommendations until failure occurred. The time taken to failure was recorded in seconds for each group using a digital chronometer. The data were analyzed statistically using one way ANOVA, Post hoc test of Bonferroni was performed to identify pair-wise significance via SPSS 21.0 software (SPSS Inc, Chicago, IL). The statistical significance was set at 5%.

Result: In 45° and 60° Hyflex CM and Neoendo Flex are better than Pro Taper Gold. At 90°, Neoendo Flex is better than Hyflex CM (P<.05).

Conclusion: Within the limitation of this study, it can be concluded that, Neoendo Flex files exhibited highest cyclic fatigue resistance at 90° angle of curvature. In 45° and 60° angle of curvature Neoendo Flex files and Hyflex CM rotary instrument were more resistant to cyclic fatigue. Protaper Gold showed the least cyclic fatigue resistance than the other files tested.