![]() ![]() The average grain size was found to vary from 0.65 ± 0.10 to 2.20 ± 0.35 μm. After sintering, the tetragonal ZrO2 polytypes t and t′ were observed under all sintering conditions, while a residual content of monoclinic ZrO2 was detected in samples sintered at 1600 ☌ for 24 h. Samples were sintered at 1475 ☌ for 2 h, and at 1600 ☌ for 2, 12, or 24 h. This work evaluates the effects of grain growth and tetragonality of the t-ZrO2 phase on the mechanical properties of 3Y-TZP ceramics. ![]() A compromise is always inevitable between translucency and aging resistance on one side and mechanical properties on the other side. We show that higher cubic phase content leads to better translucency and stability in water steam, but at the expense of strength and toughness. Important differences are found in terms of microstructures among the materials in terms of cubic phase content and yttria in the tetragonal phase, leading to different optical, mechanical and aging resistance properties. Aging was conducted on crowns with and without glaze to better represent clinical uses. The microstructural features (phase composition and assemblage, grain size) were carefully studied, as well as mechanical properties (biaxial bending strength and indentation toughness), translucency and aging behavior (in autoclave at 134☌). This paper aims at studying these aspects in the current generation of zirconia dental crowns showing different degrees of translucency.įour different commercial zirconia materials were investigated, including one standard 'full-strength' 3Y-TZP and three grades with improved translucency. ![]() ![]() The microstructural features and the mechanical performances of these materials are still controversial, as well as their susceptibility to aging. The dental market moves towards high-translucency monolithic zirconia dental crowns, which are usually placed either with - or without - a thin glaze layer. ![]()
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