Dental implant

A device for securing a dental prothesis to a base implanted into body tissue of a patient has a stud which is secured to the base and has a cylindrical body and a threaded free end. A tubular spacer surrounds the stud, is supported on the base, and terminates short of the free stud end. A tubular cup is supported on the spacer and has a through hole defining a first hole section of a first diameter about equal to an inner diameter of the tubular spacer and a second hole section of a diameter larger than the inner diameter of the tubular spacer. An annular ledge is positioned between the first and second hole sections, extends radially inwardly to proximate the threaded free end of the stud, and defines a bearing surface facing away from the tubular space. A retaining nut is threaded onto the threaded free end of the stud and has an under side in engagement with the bearing surface which, upon tightening of the nut on the stud, firmly presses the cup against the tubular spacer. The nut can be turned relative to the stud to increase the force with which the cup and the spacer are pressed against the base. The nut and the bearing surface and/or the threaded free end of the stud are constructed to inhibit relative rotation of the nut, and a resulting loosening of the dental prosthesis on the base, by increasing friction between them.