Translucency and biaxial flexural strength of four ceramic core materials

Abstract

Objectives: To assess the relative translucencies and flexural strengths of four dental restorative ceramic core materials.

Methods: Eight disk specimens (14 mm in diameterx 0.5+/-0.05 mm in thickness) were prepared for each group of four ceramic core materials (IPS Empress 2 dentin, VITA In-Ceram Alumina, VITA In-Ceram Zirconia, Cercon Base Zirconia), according to the manufacturers' instructions. A color meter was used to measure the relative translucencies of the specimens. The biaxial flexure test (ISO 6872) was then used to measure their flexural strengths. Data for relative translucency (0.0-1.0), fracture load (N) and biaxial flexural strength (MPa) were analyzed by one-way ANOVA, followed by Tukey's multiple comparison test for significant findings (alpha = 0.05).

Results: For relative translucency: IPS Empress 2 (0.78+/-0.03), VITA In-Ceram Alumina (0.94+/-0.01), VITA In-Ceram Zirconia (1.00+/-0.01), Cercon Base Zirconia (1.00+/-0.01), P<0.0001. For biaxial flexural strength: IPS Empress 2 (355.1+/-25.7), VITA In-Ceram Alumina (514.0+/-49.5), VITA In-Ceram Zirconia (592.4+/-84.7), Cercon Base Zirconia (910.5+/-95.3), P<0.0001.

Significance: IPS Empress 2 and VITA In-Ceram Alumina were significantly more translucent than the two opaque zirconia-containing core materials. IPS Empress 2 was significantly weaker, and Cercon Base Zirconia was significantly stronger, than the other two ceramic core materials.