Biomaterials

Biography

Biography: Helen Reveron

Abstract

Yttria-stabilized (Y-TZP) zirconia ceramics are increasingly used for developing metal-free restorations and are now considered as promising alternatives to titanium as dental implants. Zirconia indeed possesses high strength and good toughness for a ceramic, together with excellent bio-integration, biocompatibility and translucency. However, Y-TZP ceramics are still considered as brittle ceramics, since transformation induced toughening occurs after cracks start to propagate. Moreover, Y-TZP can undergo low temperature degradation (LTD) or ageing, leading to a loss of strength and micro-cracking. Therefore, our current research is focusing on strategies to develop alternative zirconia-based materials with better stability in-vivo and higher degree of ductility, especially for dental implants applications in which the translucency is less important but for which a perfect stability, good mechanical properties and long lifetime should be ensured. In this work the mechanical characterization of a new type of very-stable zirconia-based composites is presented. These materials are composed of ceria-stabilized zirconia (Ce-TZP) and two second-phases (alumina and strontium aluminate) and can exhibit very high strength, toughness and ductility. In other words, in these ceramics, plastic deformation occurs before failure driven by the tetragonal (t) to monoclinic (m) zirconia phase transformation, which leads to mechanical behavior laws similar to metals. During the oral presentation, the effect of the composition and/or the microstructure on the strength-toughness relationship will be presented and the validity of various mechanical tests used to measure the fracture strength on these materials discussed.