Abstract: Disclosed herein is a canal instrument for eliminating interference and achieving the widening of the opening and the contemporaneous flared reaming of the first two-thirds of the dental radicular canals, the instrument being designed in such a way that over the full length it progressively reduces in thickness towards the tip, while the cutting part that extends from the terminal part or the instrument coupling section to an endodontic drill only extends for a part of the working length.

Abstract: A stop for limiting the depth of penetration of an elongated dental instrument usable in an endodontic operation. A diametrically bifurcated disc having a central instrument-receiving bore is comprised of two disc halves disposed in use with the elongated dental instrument extending through the central bore and clamped between the disc halves. A resilient snap-ring is seated in a circumferentially grooved lateral surface of the bifurcated disc to secure the two disc halves in position with the elongated dental instrument clamped therebetween.