Mandibular endosseous implant interventions 367

(Fig. 9-108). The extensions were fabricated distoproximally on the lower right lateral and lower left cuspid copings, while the extension on the molar coping was fabricated on the mesioproximal surface.

The copings were tried over the three prepared abutments for proper fit. They were left in position

Fig. 9-107. A preoperative photograph shows a lower re-movable appliance with a six-unit anterior splint with a posterior removable partial denture.

Fig. 9-108. A, Only three teeth remained. B, Copings with atypical extensions were made for the three remaining teeth.

while the implants were being inserted. To insert the implants, No. 6 round burs were drilled through the fibromucosa (Fig. 9-109). Helical burs were then used until the sites were wide enough to accommodate the taps (Fig. 9-110). Implants with hollow-threaded shafts were set deep enough so that the shafts were almost flush with the fibromucosa (Fig. 9-111) .

An accurate wax or stone bite, including both arches, was taken. Round copper rods were placed inside the hollow shafts. These extended about 5 mm. above the shafts and were used merely to emphasize the implant sites, thus facilitating the lab-oratory technique.

A full upper alginate impression was taken. With the proper size tray, a full lower plaster index was allowed to set in the mouth and then removed. Du-plicate, hollow-threaded shafts were then placed in their proper positions in the plaster index. (The

Fig. 9-109. Burs were then drilled into the bone to create the sockets for the implants.

Fig. 9-110. Taps were then used to widen the holes.