CYCLIC FATIGUE RESISTANCE OF NITI INSTRUMENTS AFTERIMMERSION IN SODIUM HYPOCHLORITE, CITRIC ACID, EDTA, CHLORHEXIDINE GLUCONATE - IN VITRO STUDY

The performance and mechanical properties of nickel-titanium (NiTi) instruments are influenced by factors such as cross-section, flute design,raw material,and manufacturing processes. Many improvements have been proposed by manufacturers during the past decade to provide clinicians with safer and more efficient instruments.The mechanical performance of NiTi alloys is sensitive to their microstructure and associated thermomechanical treatment history. Heat treatment or thermal processing is one of the most fundamental approaches toward adjusting the transition temperature in NiTi alloy,which affects the fatigue resistance of NiTi endodontic files. The newly developed NiTi instruments made from controlled memory wire, M-Wire or R- phase wire represent the next generation of NiTi alloys with improved flexibility and fatigue resistance. The advantages of NiTi files for canal cleaning and shaping are decreased canal transportation and ledging,reduced risk of file fracture, and faster and more efficient instrumentation.