Maxillary endosseous implant interventions 417

the copings are then removed, exposing the duplicate shafts onto which new castings are made. Or the gold copings may be used as a base for the wax-ups of properly contoured crowns that will be double-cast to the copings. A case in point shows a prefabricated maxillary, full arch denture with some of its vent-plants and triplants (Fig. 10-113). The scalloped template is distal to the upper right first bicuspid (Fig. 10-114).

The bridge was seated in the mouth and all necessary adjustments accomplished. To determine the final location of the implants, periapical radiographs of the entire maxilla were taken with the bridge in place. Indelible pencil was used on the tissue-bearing surfaces of the pontics intended to house the implants (Fig. 10-115). The marks were transferred to the fibromucosal tissue by firmly pressing the pros-thesis against the gums (Fig. 10-116). At this point holes were also made in the template to accommodate the pin implants.

The implants were then inserted deep into the bone, using the indelible pencil marks as starting guides (Fig. 10-117). As each implant was inserted, the tissue-bearing surfaces of its pontic were hollowed out. For easy fit, each hole was made much larger than its corresponding implant shaft.

Interchangeable prefabricated gold copings were seated over the protruding implant shafts (Fig. 10-118) and the bridge reseated and checked for impingement. Cold cure acrylic was then added to the hollowed-out pontics and the bridge reseated. After the acrylic hardened, the bridge was removed with the gold copings locked inside the pontics. All excess acrylic was trimmed away and polished. The full arch splint was then cemented in with a hard type of cement (Fig. 10-119) .

After the bridge was cemented, the triplants were driven through the template (Fig. 10-120). Their heads were fused together with acrylic (Fig. 10-121)

Fig. 10-118. Interchangeable gold copings are placed over the protruding implant shafts.

Fig. 10-119. With hard cement the prosthesis is cemented over the teeth and implant abutments.

Fig. 10-120. The pin implants are driven through the template.

Fig. 10-121. The pins are affixed to each other with acrylic resin and the hardened cores are prepared for crown preparations.