Machining efficiency of endodontic files: a new methodology.

The ability of endodontic files to effectively remove hard tissues is difficult to assess as results from published investigations often vary considerably. An analysis is presented of errors occurring during efficiency assessments. It was found that the machining property varies around the circumference of a single file as well as between various files of the same brand. A new method is proposed for the assessment of the quantity and quality of the machining properties of an endodontic file.