In this study, the hypothesis was tested that the marginal and internal fit of CAD/CAM fabricated all-ceramic three-unit fixed partial dentures (FPDs) can be as good as in metal-ceramic FPDs. Twenty-four all-ceramic FPDs were fabricated and randomly subdivided into three equally sized groups. Eight frameworks were fabricated using the Digident CAD/CAM system (DIGI), another eight frameworks using the Cerec Inlab system (INLA). Vita Inceram Zirkonia blanks were used for both groups. In a third group frameworks were milled from yttrium-stabilized Zirconium blanks using the Lava system (LAVA). All frameworks were layered with ceramic veneering material. In addition, six three-unit metal-ceramic FPDs served as control group. All FPDs were evaluated using a replica technique with a light body silicone stabilized with a heavy body material. The replica samples were examined under microscope. The medians of marginal gaps were 75 microm for DIGI, 65 microm for LAVA and INLA and 54 microm for the conventional FPDs. Only the DIGI data differed significantly from those of the conventional FPDs. Within the limits of this study, the results suggest that the accuracy of CAD/CAM generated three-unit FPDs is satisfactory for clinical use.

Clinical fit of all-ceramic three-unit fixed partial dentures, generated with three different CAD/CAM systems

Clinical evaluation of all-ceramic crowns fabricated from intraoral digital impressions based on the principle of active wavefront sampling

Statement of Problem. Color stability, strength, and accuracy of fit are the main requirements for complete-ceramic crowns. The Procera AllCeram crown system is a CAD/CAM system used to fabricate individual complete-ceramic crowns that have a dry sintered, aluminum oxide core and appear to match clinical requirements. However, there are few articles about the clinical fit of all-ceramic crowns. Purpose. This in vivo study measured the accuracy of fit of Procera AllCeram crowns in anterior and posterior teeth. Material and Methods. The clinical fit of 80 anterior and posterior Procera AllCeram crowns was evaluated by a replica technique with a light body silicone to fill space between crown and tooth and a heavy body silicone to stabilize the light body film. After removal from the artificial crowns, the replicas were segmented, and measurements of the film thickness were performed with a light microscope. Results. Medians of mean marginal gap widths were between 80 and 95 μm in anterior teeth and between 90 and 145 μm in posterior teeth. Medians of maximal marginal gap widths ranged from 80 to 180 μm in anterior teeth and from 115 to 245 μm in posterior teeth. Conclusion. The accuracy of fit achieved by Procera AllCeram was comparable to other conventional and innovative systems. (J Prosthet Dent 2000;84:419-24.)

Clinical fit of Procera AllCeram crowns

The fit of cobalt-chromium three-unit fixed dental prostheses fabricated with four different techniques: a comparative in vitro study

In prosthodontics, conventional methods of fabrication of oral and facial prostheses have been considered the gold standard for many years. The development of computer-aided manufacturing and the medical application of this industrial technology have provided an alternative way of fabricating oral and facial prostheses. This narrative review aims to evaluate the different streams of computer-aided manufacturing in prosthodontics. To date, there are two streams: the subtractive and the additive approaches. The differences reside in the processing protocols, materials used, and their respective accuracy. In general, there is a tendency for the subtractive method to provide more homogeneous objects with acceptable accuracy that may be more suitable for the production of intraoral prostheses where high occlusal forces are anticipated. Additive manufacturing methods have the ability to produce large workpieces with significant surface variation and competitive accuracy. Such advantages make them ideal for the fabrication of facial prostheses.

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B. Fransson

Papers

The fit of metal-ceramic crowns, a clinical study.