564 Theories and techniques of oral implantology

plant was fabricated with two horizontally placed transfixation pins to stabilize the implant.

To make the bone impression, infiltration anesthesia was given labially and palatally. An incision was made along the edentulous ridge crest from the mesial surface of the left central incisor to the mesial surface of the right cuspid. The incision became continuous labially and lingually with the gingival tissue that was attached at the neck lines of neighboring teeth. The tissues were reflected to expose a good portion of the labial and palatal plate of bone (Fig. 12-86) .

With a special twist drill the same diameter as the

Fig. 12-88. Both pins remained transfixed through the bone prior to the elastic impression.

Fig. 12-90. The master stone model was poured into the impression with the pins horizontally fixed inside.

Fig. 12-89. The pins were first removed from the mouth after the elastic impression hardened and were then slipped back into the impression after it was removed.

Fig. 12-91. A, The unilateral subperiosteal implant with specially cast cobalt-chrome pins is seen on the master model. B, The labial ends of the transfixation pins were fabricated with a wider head to prevent them from slipping through the holes in the substructure framework.