Maxillary endosseous implant interventions 393

The second pin was driven through the soft tissue and into the bone in a distopalatal direction, and the third pin driven in a distobuccal direction (Fig. 10-25). It is imperative to circumvent the maxillary sinus along its mesial and distal extensions. If an at-tempt is made to circumvent the sinus buccopalatally, the pins inevitably terminate in the sinus.

The three pins were carefully locked to each other with acrylic monomer and polymer, using the brush-on technique, until a dense core was built (Fig. 10-26). When the core hardened, it was prepared for a crown preparation with a tapered diamond stone (Fig. 10-27).

Impressions were then taken. Elastic impression material, either in a tray or copper tube, should be used for this purpose. When the casting was made, it was fitted over the acrylic core and a wax inter-occlusal record of centric relation made. A full mouth plaster index was then taken of all the castings. (A

Fig. 10-24. With a slow-running contra-angle and a water spray, the first pin is driven through the mucoperiosteal tissue and into the bone.

Fig. 10-26. Using the brush-on technique, the pins are fastened to one another with the polymer and monomer.

Fig. 10-27. The hardened acrylic core is prepared for a full crown restoration with a tapered diamond stone.

Fig. 10-25. Two other pins are driven in different directions into the bone.

Fig. 10.28. The completed full arch fixed denture prior to cementation.