Mandibular endosseous implant interventions 349

mented with oxyphosphate of zinc cement (Fig. 9-44) . Postoperative x-rays illustrate the bridge (Fig. 9-45). In this case, the remainder of the arch was also splinted, as seen in the Panorex (Fig. 9-46).

Case 5

Unilateral posterior free-end saddle restoration using a prefabricated prosthesis and mixed implants

Sometimes it is difficult or too risky to use two post type implants to stabilize a prosthesis in a posterior free-end saddle area. As it was in this case, this may be caused by the presence of widely spaced trabeculae. Such alveolar bone sometimes occurs in the second lower molar region, and post type implants are inadvisable because fairly dense bone is needed to stabilize them. In this case it was necessary to immediately replace a vent-plant with a triplant. From the moment of the vent-plant's insertion it was loose, even though the intervention proceeded cautiously and without mistake.

The triplant pins were driven across the socket vacated by the vent-plant and into the surrounding bone (Fig. 9-47). (Again, it is necessary to note that only a type of implant that can extend into the bone around an open socket should be used.) As each pin was inserted, its depth and direction were radio-graphed. When the three pins were in place, angled as obliquely as possible without perforating the buccal or lingual plates of bone, the excess portion protruding into the mouth was trimmed.

Normally, the pins are then fused together with acrylic, using the paintbrush technique to avoid air bubbles, and final impressions taken for completing the bridge. In this case, however, a prefabricated bridge was processed prior to the interventions (Fig.

Fig. 9-48. The ends of the pin implants are shortened and the bridge is tried in position.

Fig. 9-49. After the pins are fused together with acrylic, the bridge is cemented into position.

Fig. 9-47. A post type implant and a triplant are seen.

Fig. 9-50. The postoperative x-ray.