M-Wire

M-Wire is Dentsply Sirona's first-generation thermomechanically processed NiTi alloy. Unlike conventional NiTi that is entirely austenitic at body temperature, M-Wire contains a mixture of austenite and R-phase, which lowers elastic modulus and improves flexibility. This intermediate processing gives M-Wire approximately 400% greater cyclic fatigue resistance than conventional NiTi (manufacturer data). M-Wire files have a higher austenite finish temperature than Gold or Blue alloys, so at 37°C the alloy is predominantly in the austenite/R-phase mixture rather than the softer martensite phase. This provides a good balance of stiffness and flexibility for progressive multi-file rotary and single-file reciprocating techniques.