US Patent 7300281 Endodontic file having bi-directional scraping edges

An endodontic file having an elongated shank with a proximal end portion, a distal end and a tapered working portion extending from the proximal portion to the distal end, the external surface of the shank working portion being defined in part by a plurality of at least two equally spaced apart continuous helical flutes formed into a central core portion of the shank working portion, the flutes having therebetween an equal number of spiraled spaced apart flanges, each flange having a semi-circular surface having a leading edge and a trailing edge, each edge being in or parallel to a plane of the shank longitudinal axis, each leading and trailing edges providing a cutting or scraping edge.