Cyclic fatigue resistance for six types of nickel titanium instruments at artificial canals with different angles and radii of curvature

This study evaluated the cyclic fatigue resistance for six types of 25# NiTi instruments. A traditional manufacturing instrument, an M wire a gold treatment controlled memory (CM) CM instrument with electrical discharge machining (EDM), and R-phase heat were operated in different curved artificial canals. The fracture time (FT) number cycles to (NCF) instruments higher at 45° angles double-curvature canals than 60° angles. Except technology EDM technology, others showed longest FT highest NCF 8 mm radius curvature. Morphological characteristics exhibited on cross-section lateral view fragments. use M-wire, wire, CM-wire, reciprocating movement beneficial enhance files.