Mechanical properties of partially stabilized zirconia for dental applications

In esthetic dental care, porcelain-fused-to-metal crowns have long been used for dental restoration. Since a dental prosthesis is placed in the harsh environment of the oral cavity over long periods, metal allergy due to eluate from the metal frame has proved to be problem, prompting the development of new methods for tooth repair. Zirconia ceramics are used in dental prostheses for tooth restoration because of their excellent strength and high biocompatibility. They are widely used clinically for cosmetic dentistry. This study evaluates the suitability of yttria-based zirconia and ceria-based nano-zirconia for use in dentistry. The mechanical properties of zirconia powders with different compositions are evaluated in terms of sintering density, crystalline phases, structure, translucency, bending strength, fracture toughness, and impact toughness. In addition, a fracture strength test was carried out on sintered bodies that imitate a single crown coping assuming a molar tooth. Yttria-based zirconia was found to have a natural tooth tone and excellent light transmission. Ceria-based nano-zirconia was found to have more than double the fracture toughness (single-edge pre-cracked beam method) and bending strength compared to yttria-based zirconia and excellent strength for dental prostheses.