a top end 22 a bottom seating end surface 24 for interfacing or abutting with the implant 18 and an internal through cavity or bore 26 this cavity has a generally circular opening 28 at the top end 22 and is adapted to receive the retaining screw 14 the cavity 26 further includes an internal seating surface shoulder seat or ledge 32 that serves as a seating surface for the head of the screw 14 preferably the shoulder 32 is generally flat annular or ring like in shape but other embodiments are known to those skilled in the art the shoulder or abutting surface 32 divides or partitions the through cavity 26 into an upper generally cylindrical cavity portion or surface 34 and a lower or middle generally cylindrical cavity portion or surface 36 the cavity 34 and cavity 36 are in communication with one another with the cavity 34 having a diameter larger than that of the cavity 36 the cavity 36 is further in communication with a generally hexagonal socket portion or surface 38 at the bottom end 24 of the abutment 12 the hexagonal socket 38 permits anit rotational mating coupling or attachment between the abutment 12 and implant 16 as shown in fig2 cavity 26 includes a locking mechanism 27 formed along the interior surface of the bore preferably the locking mechanism is formed above a threaded section 29 this.