Nickel titanium rotary file

A nickel titanium rotary file is an engine-driven tapered and pointed endodontic instrument made of nickel titanium alloy with cutting edges used to mechanically shape and prepare the root canals during endodontic therapy or to remove the root canal obturating material while performing retreatment.

The high flexibility makes them superior to stainless steel files for the purpose of rotary root canal preparation.

The strain remains constant during this transformation until the whole NiTi mass has converted to the martensite form, which would indicate that the superelasticity phase has ended.

[citation needed] The main components of a nickel titanium rotary file are tip size, taper, flutes, helix angle and measuring stop.

Separation of nickel titanium rotary files happens due to torsional failure, cyclic fatigue, or the combination of both in clinical practice.