The invention is an endodontic instrument which comprises, among other features: a handle having an elongated base with a threaded projection having a recessed distal surface capable of cupping a first terminus portion of an elongated plastic grip attached to an endodontic file; and a cap containing a channel extending through the cap with the channel being threaded for mating with the projection of the elongated base of said endodontic instrument handle, said cap possessing a side and containing an aperture through which an endodontic file can project, the diameter of the aperture being selected to be larger than the diameter of the endodontic file but smaller than the diameter of a plastic grip attached to the endodontic file, said cap further having a recessed interior surface capable of cupping a second terminus portion of an elongated plastic grip attached to an endodontic file.