Current implant techniques—an overview 17

Fig. 1-45. The third pin is driven in at the proper angle.

possible, but not to such a degree that an unnatural-looking restoration results. If the angle is too broad, the ends of the pins may be bent parallel to each other. Also, it is extremely important to try to have the apical ends of the pins engage the buccal and palatal cortical plates of bone rather than end in medullary bone.

So far each pin has been driven in at a different angle to form the base of the tripod implant. At this point, these pins can be relatively easily pulled out one by one unless secured together. Therefore each protruding end is notched with a fissure bur to form greater surfaces for the adhering material. The three are then painted with a fast-setting acrylic resin to form a cap or core (Fig. 1-47). The acrylic is applied layer by layer, thus avoiding air pockets. The resulting hardened core is dense, and consequently the pins are securely held.

The acrylic core of the tripod is prepared for a full crown restoration, using fissure burs and diamond stones, in the same manner as in preparing a natural tooth. A rubber base or silicone impression of the prepared core and a wax interocclusal record of centric relation are then taken for the final restoration.

Second visit. The cast crown is fitted over the cap and radiographed. When any necessary adjustments have been made, the crown is permanently installed with cement and another x-ray film of the completed installation is taken.

In this example, only the technique of inserting and preparing a single triplant has been outlined. However, a triplant should never be used as a single restoration unless supported by other teeth or other vertical post implants.

Fig. 1-46. The third pin implant is in position. It assumes a distobuccal direction. Notice how each pin avoids the anatomic landmarks and forms a broad base for a tripod.

Fig. 1-47. A, The ends of the individual pins are fused together with cold cure acrylic using the paintbrush technique. Once the pins are fused, the single tripodial unit becomes extremely retentive. B, Roentgenogram showing completed case.