One of the critical steps in prosthodontics is the impression.
The precision of an impression determines the fit of the restoration.
Following final impressions, an inter-occlusal record is taken in order to articulate the upper and lower models. In the Kennedy class one and two, partial edentulism, there is no posterior occlusal support. Therefore, bite registration can be performed accurately, utilizing a bite block. The bite block is fabricated in the dental laboratory on the working model made of the final impression. This procedure requires an additional appointment. When restoring a unilateral or bilateral free-end saddle with an implant-retained Fixed Partial Denture (FPD) (Figure 1), the implants can be used to provide posterior occlusal support. The objective is to use the most accurate technique that is the least time consuming.
This article presents an alternative tool to the bite block, which is more accurate and less time consuming.
The Implant carrier or mount can be modified and utilized to facilitate the bite registration procedure (Figure 2, 3). A disc is then used to cut the implant mount. The part of the implant mount with the Clip and Hex (Clip and hex connection A.B. Dental Implant System) is attached to the implant intra-orally (Figure 4).
The components attached to the implants should be under the occlusal level to allow for the bite registration material to fill the space (Figure 5). G.C resin is mixed and placed over the components. In the case presented, two posterior A.B. Dental implants were used as posterior support to the bite registration (Figure 6). The G.C. resin index is then removed from the mouth and sent to the lab along with the impression (Figure 7). Consequently, the resin jig will be placed on the implant analogs, allowing accurate articulation of the working models (Figure 8). Abutments are selected and the final restoration is completed (Figures 9, 10, 11 and 12). OH
Eli Raviv is Associate Professor, Faculty of Dentistry, McGill University and Director of Prosthodontics, Dept. of Dentistry, JGH, Montreal, Quebec. www.ravivimplant.com
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