CLINICAL IMPLANT COMPONENTS
Two-stage osseointegrated implants are generally designed to support screw-retained implant restorations. These twostage implant systems offer many advantages over conventional dental restorations and one-stage implant systems (Box 14-3). Fabrication of screw-retained implantrestorations requires the use of several component parts that heretofore had not been routinely described in conventional dental education. For the inexperienced implant clinician, the sheer number of parts within one system often creates an overwhelming obstacle to getting involved in implant dentistry. This section describes in generic terms the component parts typically necessary to
restore a screw-retained, osseointegrated implant. It should be noted that the components might differ slightly in design and materials among the ‘implant systems
The implant is theendosteal dental implant that is placed within the bone during stage I surgery. It may be either a threaded or non threaded cylinder. It is either titanium or titanium alloy, with or without hydroxyapatite (HA) coating (Fig. 14-11).
A.scrcw is placed in the implant during the healing phase after stage I surgery. This screw is usually low profile to facilitate easy suturing of the soft tissue over the implant. At stage II surgery the screw is’removed and replaced with subsequent components (rig. 14-12).
The healing cap is a dome-shaped screw that is placed after the stage 11 surgery and before prosthesis placement. This component may range III length from 2 mrn to 10 mrn and projects through the soft tissue into the oral cavity.The healing cap may scr w directly into the implant” -or, in some systems, may screw onto the abutment immediatelyafter stage II surgery. The cap may be made out ofa resin, such as polyoxyethylene, or one of the titanium metals (Fig. 14-13):
The abutment is that component of the implant system that screws directly into the implant. The abutment will eventually directly support the prosthesis. It is smooth, polished- straight-sided titanium Or titanium alloy. The length may range from 1 to 10 mm (Fig. 14-14).
The impression post facilitates the transfer of the intraoral location of the fixture or the abutment to a similar position in the laboratory cast. The impression post
screws directly into the fixture or into the abutment. Once the impression post is in place an impression is made intraorally. The impression post is then removed from the mouth and joined to the laboratory analog before being transferred into the impression in the properly keyed position (Fig. 14-15
The laboratory analog is a component machined-to exactly represent the abutment in the laboratory cast. The laboratory analog screws onto the impression post after it has been removed from the mouth and placed back into the impression before pouring(Figs. 14-16 and 14-17).
The waxing sleeve is attached to the abutment by the prosthesis-retaining screw on a laboratory model. The waxing sleeve will eventually become part of the prosthesis (Fig. -14-18). It may be a plastic pattern that is
“burned-out” inside the investment and replaced by a cast precious alloy, or it may be made of a precious all that is waxed around and “cast-to
The prosthesis-retaining screw penetrates the fixed restoration and secures it to the abutment. In non sgmented restorations the screw tightens the abutment directly to the implant (Fig. 11-19). The screws are tightened
into place with a screwdriver. The screw can be made of titanium, titanium alloy, or gold alloy.