Cyclic fatigue testing of Three NiTi files at different temperatures and their corresponding phase transformations (In vitro study)

Abstract

o overcome the inconveniences of manual filing systems, nickel-titanium (NiTi) rotary shaping techniques were developed. This study was conducted to compare three types of rotary systems of different microstructure (superelastic, M-wire alloy and Controlled memory wire) through the following: 1) Instrument cyclic fatigue Twenty files of each system were used. Ten of them were tested in room temperature and ten in Intracanal temperature. Cyclic fatigue testing of instruments at room and intracanal temperature was performed with dynamic cyclic fatigue testing device which will allow the instruments to rotate freely inside a Stainless Steel artificial canal while providing an axial movement with amplitude of 3mm up and down movement. The number of cycles to failure (NCF) was calculated by the following equation: