Abstract: 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 ?m<Ra<4.5 ?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 ?m with respect to the mean line.