A rotatable endodontic file (10) for cleaning / shaping a tooth root canal, comprising an elongated shaft having a proximal end portion (14), a distal end (16) and a tapered working portion (18) having a rotational axis, the working portion (18) extending from the proximal portion (14) to the distal end (16), the external surface of the shaft working portion having a plurality of at least two spiraled, spaced apart continuous helical flutes (22), the flutes having therebetween an equal number of spiraled, spaced apart flanges (26), each flange having in a plane perpendicular the rotational axis an outer end surface forming a continuous spiraled scraping/cutting edge (30) extending the length of the shaft working portion (18), the flutes having helical angles relative to the rotational axis of between 10° and 30° and wherein the helical angles vary at selected longitudinal locations.
