• Logo
  • SBMUJournals

Cyclic fatigue resistance and fractographic analysis of RaCe and ProTaper rotary NiTi instruments

Shahram Azimi, Parisa Delvari, Hamid Cyrus Hajarian, Mohammad Ali Saghiri, Kasra Karamifar, Mehrdad Lotfi




INTRODUCTION: This study investigated the fatigue and fracture modes of RaCe and ProTaper rotary instruments.

MATERIALS & METHODS: Fatigue resistance was evaluated by rotating the files 30° or 60° and with 2 or 5mm radius of curvature. RaCe taper 06 size 25 and ProTaper F1 files (n=40) were used. The number of rotations to failure was analyzed by two-way ANOVA and independent sample    t-test. Fracture surfaces were examined under a scanning electron microscope.

RESULTS: Both files exhibited significantly more resistance to fracture when angle severity was reduced and increase in curvature radius (P=0.000). ProTaper demonstrated higher number of cycle of failure (P=0.0029) in one group (r=5mm, 60º). SEM observation revealed fatigue mark/features in 17 specimens, shear characteristics in 37 samples, and tensile overload in 26 samples.

CONCLUSION: Radius of curvature was the main factor in torsional and fatigue failures.


Fractographic analysis, cyclic fatigue, torsional failure, rotary NiTi instrument.

DOI: https://doi.org/10.22037/iej.v6i2.2095


  • There are currently no refbacks.