Evaluation of cyclic fatigue resistance of nickel titanium rotary instruments: A systematic review and meta- analysis

Abstract

A number of different thermomechanical treatments of NiTi have been developed to overcome some of the drawbacks of the traditional NiTi alloy, namely, separation and distortion of instruments. The present study analyzes the data on nickel-titanium instruments and their cyclic fatigue resistance. Online electronic data base such as PubMed, Cochrane and Google scholar through 31 January 2000 to 31 January 2020 with only English language literature. Clinical study of 9 article review & stated that the Cyclic Fatigue Resistance Of Nickel Titanium Rotary Instruments tested in artificial blocks or canals ,tested with different NiTi rotary files between 200-500 rpm and accordingly torque under controled/uncntroled temperature in curved canls fracture occure. The findings of this systematic review and meta-analysis point to the possibility that the temperature at which the instruments are tested may affect the results of cyclic fatigue resistance on NiTi files with a different behavior depending on the heat treatment of the alloy and that an increase in the angle of curvature of artificial canals has a detrimental effect on the cyclic fatigue resistance. Reciprocal movement exhibited the best performance with regard to cyclic fatigue resistance. The thermal treatment of the instrument’s alloy, its cross section, and the glide path seem to influence the cyclic fatigue resistance. The cyclic fatigue resistance of instruments manufactured with the gold heat treatment is not influenced by room or intracanal temperature.