An endodontic instrument includes a handle to be secured to an instrument holder and an active part to be introduced into a root canal. The active part includes a plurality of faces and at least one edge formed by the intersection of two adjacent faces. At least two of the adjacent faces have a surface with a roughness characterized by an arithmetic mean deviation with respect to the mean line Ra, chosen so that 0.5 &mu；m<；Ra<；4.5 &mu；m, so that the edge formed by the intersection of said two faces has the profile of an irregular jagged line in the space having at least one deviation greater than 0.5 &mu；m with respect to the mean line.
