| Abstrakt: |
This investigation studied the strength of the substructure and veneering porcelain interface in all-ceramic systems. The ceramic systems tested were IPS-Empress2 with Eris (IE), Procera AllCeram with AllCeram (PA), Procera AllZircon with CZR (PZ), and DC-Zircon with Vita D (DC). The manufacturer recommended veneering porcelain for each material be fired to the ceramic core. A metal ceramic (MC) combination was used as a control. Twelve specimens were made for each group from a master die. A 2.4-mm-diameter cylinder of veneering porcelain was applied using a specially designed mold. After firing, the specimens were subjected to shear stress in a universal testing machine. Load was applied until failure occurred. Average shear stress was analyzed with one-way analysis of variance and the Tukey test. Failed specimens were examined at magnification x20 to classify the failure as cohesive in the core, in the veneer, or at the interface. The results demonstrated that the mean shear strengths (MPa) were the following: MC control = 30.16 ± 5.88; IE group = 30.86 ± 6.47; PZ group = 28.03 ± 5.03; DC group = 27.90 ± 4.79; and PA group = 22.40 ± 2.40. The bond strengths of IE, PZ, and DC were not significantly different from the control MC. Microscopic examination showed that failure mainly occurred near the interface with residual veneering porcelain remaining on the core. IE showed cohesive failure in both the core and the veneer. AllCeram applied to the Procera (PA) alumina core showed significantly lower bond strength when compared to the other systems tested. Because the bonding of veneering porcelain to a ceramic core for the materials tested were similar to that of the metal ceramic control, the authors projected that the clinical behavior may be similar. [ABSTRACT FROM AUTHOR] |
