Mandibular endosseous implant interventions 369

Fig. 9-114. The copings (with hollow recesses made in their extensions), the mesostructures, and a superstructure are fabricated.

Fig. 9-116. The superstructure fits exactly over the mesostructures and secures itself to them with its four set screws. (From Linkow, L. I.: Internally threaded endosseous implants, Dent. Concepts 10:16-20, 1967.)

Fig. 9-115. The mesostructures have two sets of screws that fasten it to the internally threaded portions of the duplicate implant shafts. They also contain two sets each of internai threadings that allow the superstructure to be screwed into them. (From Linkow, L. I.: Internally threaded endosseous implants, Dent. Concepts 10:16-20, 1967.)

The superstructure could also have been fabricated from the master model by first waxing over the mesostructure, removing the completed wax-ups, spruing, and then casting it (Fig. 9-116). Alternately, the mesostructure could first have been tried in the mouth and returned to the master model before fabricating the superstructure.

At the next visit, after inserting the three copings (Fig. 9-117), the mesostructure was screwed into its

proper position (Fig. 9-118) and radiographed. The superstructure was then screwed into the threading of the mesostructure (Fig. 9-119) and radiographed. An accurate wax interocclusal record of centric re-

Fig. 9-117. The copings over the prepared teeth and the healed implant sites. (From Linkow, L. I.: Internally threaded endosseous implants, Dent. Concepts 10:16-20, 1967.)

lation was taken, then the superstructure, mesostructure, and gold copings were all removed from the mouth and reset on the master model. The super-structure was then processed. In this case it was

fabricated in acrylic (Fig. 9-120) .

On the final visit the copings, the mesostructure,

and the processed superstructure were tried in the mouth and equilibrated. After necessary adjustments,

everything was removed. The three remaining teeth were dried, and the three gold copings were ce-

mented over them with a hard cement. Using a soft, temporary cement mixed with some Vaseline, the mesostructure was cemented over the copings and