Subperiosteal implants 573

periosteal implant was made for the atrophied lower jaw (Fig. 12-110) .

Technique

An incision was made along the soft tissue covering the residual bony crest from tuberosity to tuberosity (Fig. 12-111, A). The tissue covering the hard palate was carefully retracted, exposing the posterior nasal spine and a portion of the greater and lesser palatine foramina (Fig. 12-111, B). An acrylic tray was fabricated directly over the hard palate (Fig. 12-111, C).

A rubber base impression was taken of the exposed palate using the acrylic tray for support (Fig. 12-111, D), and the tissues were sutured (Fig. 12-111, E) . A wax interocclusal record of centric relation was then taken.

Fig. 12-109. The flattened maxillary ridge.

The implant was cast in cobalt-chrome. It contained two holes to accommodate two Vitallium screws to fix the implant to the hard palate. The casting also included three parallel posts 12 mm. long (Fig. 12-112, A). The implant was radiographed commercially to check for any porosities (Fig. 12-112, B) .

Two weeks later the tissue was again incised and retracted and the toroplant was screwed directly to the hard palate (Fig. 12-113). The tissues were then sutured. The three posts can be seen protruding through the central area of the soft tissues covering the hard palate (Fig. 12-114,A).

A hole was made in the bite registration to accommodate the protruding implant posts (Fig. 12-114 B and C) . The palatal portion of the tray was then relined with quick cure acrylic resin in order to obtain an accurate seat over the three posts (Fig. 12-114, D) . A wax interocclusal record of centric relation was taken.

The tissue healed uneventfully around the protruding implant posts in less than 10 days (Fig. 12-115 A). The tissue-bearing surface of the bite registration trays was lined with silicone material, and a final wax interocclusal record of centric relation was accomplished (Fig. 12-115, B).

A specially designed template was cast in gold. It contained two resilient anchorage attachments* that were only 1 mm. in height (Fig. 12-116). The circumferential attachments become an integral part of the denture.

*Rothermann's Resilience Anchorage-Eccentric 747, Cendres & Metaux, S. A. 2501, Biel-Biemme, Switzerland.

Fig. 12-110. A subperiosteal implant was fabricated for the mandible. Note the absence of bone below the sinus in the maxilla.