COMPARISON OF CYCLICAL FADIGIC RESISTANCE OF THREE RECIPROCATING INSTRUMENTS MANUFACTURED WITH DIFFERENT NICKEL-TITANIUM ALLOYS
Cyclic fatigue; reciprocating motion; reciprocating systems; nickel-titanium alloy.
The objective of this study was to evaluate and compare the cyclic fatigue resistance of three types of single file reciprocating systems: WaveOne Gold Primary (25 / 0.07), WA1 file (25 / 0.07) and X1 Blue (25 / 0.06) with nickel-titanium alloys with different surface heat treatments. Methods: A sample of sixty instruments was divided into two groups, one using the Reciproc All Reciprocating Program and the other WaveOne All. Each group contained ten instruments from each system. Cyclic fatigue strength was tested by measuring the time and number of cycles the instrument performed in an extremely curved stainless steel artificial channel (angle of 80 ° and 6 mm radius) until the fracture was reached. The fractured surfaces of the fragments of three instruments, one from each system, randomly chosen in each group, were examined with a scanning electron microscope. The results were statistically analyzed using analysis of variance (ANOVA) and Tukey's F tests with significance levels of 5%. Results: The WA1 File instrument presented a longer fatigue life in both Reciproc All program and WaveOne All program than the other two systems tested (p <0.05). WaveOne Gold Primary presented a life in cyclic fatigue greater than the X1 Blue file in the two programs tested (p <0.05). The Reciproc All program presented better results in relation to the fatigue life of the three reciprocating systems tested when compared to the WaveOne All program (p <0.05). Conclusion: The WA1 instrument presented higher resistance to cyclic fatigue in severely curved channels when used in both Reciproc All and WaveOne All programs than WaveOne Gold Primary and X1 Blue File systems. The Reciproc All program presented better results for rotating flexion life for the three reciprocating systems tested when compared to the WaveOne All program.