Variations in cyclic fatigue resistance among ProTaper Gold, ProTaper Next and ProTaper Universal instruments at different levels

AimTo compare the cyclic fatigue resistance of ProTaper Gold (PTG, Dentsply Tulsa Dental Specialities, Tulsa, OK, USA), ProTaper Next (PTN, Dentsply Tulsa Dental Specialities) and ProTaper Universal (PTU, Dentsply Tulsa Dental Specialities) instruments at different levels. MethodologyA total of 72 files were used to evaluate the cyclic fatigue of PTU (F2), PTN (X2) and PTG (F2) at 5mm (n=12) and 8mm (n=12) from the tip in 3-mm-radius steel canals with a 60 degrees angle of curvature. The time to fracture was recorded. The Kolmogorov-Smirnov test was used to assess the normality of the samples distribution, and the statistical analysis was performed using the independent sample t-test (P<0.01). ResultsSignificant differences were found amongst the instruments 5mm from the tip (P<0.01). The PTG files had the highest CF resistance, and the PTN files displayed greater CF resistance than the PTU files. No significant differences were found between the PTG and PTN files 8mm from the tip (P>0.01). The PTG and PTN files demonstrated greater CF resistance than the PTU files (P<0.01). ConclusionsThe PTG instruments were the most resistant 5 and 8mm from the tip; however, at 8mm, there was no difference between the PTG and PTN instruments. The PTU files had the lowest CF resistance at all levels.