The indentation method has been widely used to measure the fracture toughness in fragile materials due to its simplicity and that only needs of a small sample. However, it is well known that the fracture toughness values obtained by indentation methods can be substantially different from the values obtained from more rigorous methods which are based on a precise knowledge of all parameters invo...

PURPOSE An in vitro study was performed to assess the effect of different degrees of clinical reduction of zirconia abutments on the failure load of clinical assemblies. MATERIALS AND METHODS Zirconia abutments (Y-TZP Ceramic Abutment, Astra Tech) were prepared with 0, 0.5, or 1 mm of external axial reduction starting 1 mm above the height-of-contour. Abutments (n = 10) were attached to impla...

The objective of the study was to measure the marginal and internal fit of zirconia-based all-ceramic three-unit fixed partial dentures (FPDs) (Y-TZP - LAVA, 3M-ESPE), using a novel methodology based on micro-computed tomography (micro-CT) technology. Stainless steel models of prepared abutments were fabricated to design FPDs. Ten frameworks were produced with 9 mm2 connector cross-sections usi...

The effects of CeO2 addition on the sintering behavior and mechanical properties of Y-TZP have been investigated over a wide sintering regime by pressureless sintering. It has been revealed that small additions of CeO2 (0.3-1.0 wt%) to Y-TZP were beneficial in enhancing the mechanical properties and hydrothermal ageing resistance of Y-TZP. Sintered samples were used to evaluate the bulk density...

Assuming that the energy dissipation decreases inversely with distance from the crack tip, the increase in steady-state toughness of a transformation-toughened ceramic is estimated to be AJ = (AJ,/w) In (1 + w), where (i) AJo denotes the toughness increment which would be expected for a given zone height h , assuming full transformation throughout the zone, and (ii) w is a nondimensional parame...

This study evaluated the effect of grinding protocols and resintering on flexural fatigue limit and surface characterization of LavaTM Y-TZP. Bar-shaped specimens (20×4.0×1.2 mm, n=40; 20×4.0×1.5 mm, n=80) were obtained. Half of the thinner specimens (1.2 mm) constituted the as-sintered group (AS), while the thicker ones (1.5 mm) were ground with diamond burs under irrigation (WG) or not (G). T...