362 Theories and techniques of oral implantology

Fig. 9-92. A, Three vent-plants are set into the bone on the right side. B, Three vent-plants are set into the bone on the left posterior quadrant.

ing up all the castings and copings (Fig. 9-93). (If copings are not used over the implant shafts, the plaster will pick up the impressions of the shafts themselves. Duplicate shafts are placed inside the copings or in the impressions of the shafts, and the duplicate tooth dies are placed inside the castings.) The master stone model was poured, allowed to harden, and then articulated with the model of the opposing jaw.

The full arch fixed denture was made. Wax-ups can be accomplished directly over the implant copings for the final contoured crown restorations and fabricated with the double casting technique, or the wax-ups can be accomplished directly over the duplicate implant shafts after first removing the copings from them. Prior to waxing directly over these shafts, however, at least two coats of nailpolish or lacquer should be painted over that portion of the shafts that will support the castings. In this manner, the final castings will not fit too snugly. This allows room for cement and compensates for any errors in parallelism of the implant shafts.

The finished prosthesis was inserted (Fig. 9-94). The marginal fits of the castings and occlusion and articulation with the opposing jaw were thoroughly

Fig. 9-93. The gold copings are picked up in the plaster index.

Fig. 9-94. The full arch fixed denture was processed and ready to be cemented. Note the darker type of screw shafts on the right side (tantalum) as compared to the lighter colored ones (titanium) on the left side. (From Linkow, L. I.: The era of endosseous implants, J. D. C. Dent. Soc. 42 [2] :14-19, 1967.)

checked (Fig. 9-95). It was quite important at this time to check the tissue-bearing surfaces of all the castings that fit over the implants. These surfaces are much wider than the implant shafts themselves and, unless relieved considerably, often impinge on the soft tissues directly under them.

Prior to final cementation, radiographs were taken of the finished prosthesis in place (Fig. 9-96) .

THE PARTIALLY EDENTULOUS MANDIBLE

As long as there is sufficient alveolar bone, implants may be used in any part of the mandible to act as abutments for fixed bridgework. The following cases illustrate some of these situations.