Abstract: A screw element is brought in thread engagement with a blade-shaped piece having a first threaded hole and open at sides, and the piece and the screw element are implanted together in a jawbone. A newly grown jawbone goes into osteobond with the implanted piece and screw element, the jawbone thus defining a second threaded hole. Subsequently the screw element is removed, and a pin neck portion is threadedly fitted into position in place of the screw element. The piece is small in size and open at sides. Therefore, it has no unfavorable effect on adjacent teeth and can be steadily implanted in a narrow jawbone structure. The pin neck portion is securely fixed by both the first threaded hole of the piece and the bone-defined second threaded hole, being thus steadily implanted in position.