An endodontic file (10) has a handle (11) and a spiral cord (15) of helically wound metallic wire wound in a predetermined direction around a central metallic cord (13) formed between opposite ends of the central cord so as to form an integrated structure (18) of generally conical cross-section including a narrow tip end (17) and an opposite wider upper end (16) supported at the upper end by the handle. A flexible conical reinforcement (26, 31) supported by the handle covers an outermost layer of an upper portion of the spiral cord remote from the tip end, its lower end being of sufficiently low diameter to enter the root canal and dimensioned at its upper end to limit bending of the upper portion. An outer surface (20) of the spiral cord is configured for removing material from inside the root canal when the endodontic file is rotated in the predetermined direction.