14 Theories and techniques of oral implantology

Fig. 1-39. A, Occlusal surfaces of the implant shafts are marked with an indelible pencil. B, The markings register on the tissue-bearing surfaces of the pontics of the acrylic splint. C, Holes are made in the acrylic splint to coincide with the transferred indelible markings, and cold cure acrylic is placed inside the holes. The splint is placed in position and removed before the acrylic hardens. The excess acrylic is then polished away. D, The temporary splint in position.

The implant consists of three pins used to form a tripod. Its design is based upon the same physical and engineering concepts used in setting stakes in the ground. If a single stake is driven into the ground, it can be moved in any direction rather easily be-cause of the leverage afforded by its protruding shaft. The stake soon becomes loose and can be pulled out. If, however, three stakes are driven in at slightly different angles, so that their bases form a triangle, and if their tops are fastened together, they can be moved only with great difficulty.

Unlike the spiral-shaft and vent-plant designs, which are posts that must be set perpendicular to the line of the jaw, the triplant allows greater freedom in placement of its pins. This is particularly helpful when trying to avoid, say, a maxillary sinus; the sinus is simply circumvented by the pins. Also, if little alveolar bone remains, there is greater freedom in placing the implant in it.

Materials and equipment required. The equipment and materials required for the endosseous tripod implant technique include a slow-speed contra-angle with water attachment or 10:1- reduction gear contra-angle; metal tripod pins; a series of three chucks to engage the tripod pins in the contra-angle; long helical burs of the same diameter as the tripod pins for penetration of very dense bone; two Dappen dishes, one containing acrylic resin and the other containing liquid; a paintbrush, size 0 or 1; and a general or local anesthetic.

Procedures. Normally, only two visits are necessary to install a tripod endosseous implant for a single tooth restoration.

First visit. During the first visit an intraoral x-ray film is taken of the edentulous area into which the tripod implant is to be set. If such implantation is to be done in the maxilla—as is illustrated here—the floor of the antrum must be outlined clearly.