A new method for improving the accuracy in fixed prosthesis and epitesi on implants

Background: Computer-aided design and machining (CAD/CAM) technology is frequently used to produce titanium fixed implant frameworks. The greater the accuracy of the master cast, the better is the fit of the framework on the implant. We propose an easy way to construct a precise verification jig to check the accuracy of the master cast for implant-supported prostheses and on implant epithesis. Materials and Methods: Six implants were placed in a metal base to represent the ideal maxillary teeth arch position, and six multi-unit abutments were screwed onto them. Then, 80 identical jigs were constructed using titanium abutments embedded in dental stone. All of the jigs were produced in the same implant position, called “standard position” (SP). Then, horizontal, vertical, and angled implant positions, all different from SP, were created to simulate different types of misfits. After the screws were tightened, the stone jigs were fitted on the abutments, and their capacity to detect misfits was evaluated. Results: Horizontal misfits of 150 µm, vertical misfits of 50 µm, and angled misfits of 1 degree were detected by the stone jig. Conclusions: The breakage of the stone jig provided the detection of misfits at an acceptable level. The chosen jig dimensions provide a compromise between sensitivity and ease of handling.