HyFlex <scp>EDM</scp>: superficial features, metallurgical analysis and fatigue resistance of innovative electro discharge machined NiTi rotary instruments

Abstract

Spark-machined peculiar surface is the main feature of HyFlex EDM. Low degradation was observed after multiple canal instrumentations. Prototypes exhibited surprising high values of cyclic fatigue resistance and a safe in vitro use in severely curved canals.