Do NiTi instruments show defects before separation? Defects caused by torsional fatigue in hand and rotary nickel-titanium (NiTi) instruments which lead to failure during clinical use.

Aims: Visual and microscopic evaluation of defects caused by torsional fatigue in hand and rotary nickel titanium (NiTi) instruments.

Materials And Methods: Ninety-six NiTi greater taper instruments which were routinely used for root canal treatment only in anterior teeth were selected for the study. The files taken include ProTaper for hand use, ProTaper Rotary files and Endowave rotary files.