Abstract: An endodontic instrument for use in performing root canal therapy on a tooth having at least one straight flute which prevents self-threading or screwing of the instrument into a root canal during use. The instrument includes a shaft having a longitudinal central axis, a shank portion and an elongated working portion extending from the shank portion along the central axis, the elongated working portion having a proximal end, a distal end, and at least one peripheral surface and at least one straight flute formed on at least a portion of the peripheral surface of the working portion, the straight flute forming at least one cutting edge on the peripheral surface. The straight flute may be formed of a plurality of flute sections disposed on the peripheral surface of the instrument, the plurality of flute sections angularly displaced about the central axis with respect to one another. A method of manufacturing an endodontic instrument is also disclosed.

Abstract: An improved process for producing an endodontic instrument with a predetermined taper having a plurality of flutes, each with a predetermined number of spirals over a predetermined length of the instrument are provided. The process basically comprises providing a grinding wheel rotated about a first axis having a plurality of flute grinding ribs and a rolled deformed metal grinding rib extending from a periphery thereof. A rotating wire stock is fed past the plurality of flute grinding ribs and the rolled deformed metal grinding rib at a controlled rate along a second axis so that a separate flute is ground on the wire stock by each of the flute grinding ribs and rolled deformed metal is removed from the ground wire stock by the rolled deformed metal grinding rib.