Abstract: A set of endodontic instruments for use in performing root canal therapy on a tooth each comprise a shaft, a cutting head on the shaft having a frusto-conical cutting surface tapering inwardly of a shaft from a base end to a second end of the cutting head, and a follower extending from the second end of the cutting head to the distal end of the instrument. The cutting surfaces of a set of the endodontic instruments have different lengths and different tapers between the base and second ends thereof. A pair of retaining spring wires are helically wound in opposite directions about the shaft and are connected to the shaft and to the cutting head to preclude total separation of the cutting head and shaft in the event of breakage of the shaft.