Aiming to replace the infrastructure of metallic dental prostheses, structural ceramics have been improved and increasingly used in dentistry. Among the dental ceramics, the zirconia has emerged as a versatile and promising material because of its biological, mechanical and optical properties, which has certainly accelerated the routine use of CAD/CAM technology in different types of prosthetic treatment.Routinely, zirconia based ceramics are used in structural applications in engineering as the manufacture of cutting tools, gas sensors, refractories and structural opacifiers. To meet structural demands, zirconia has to be doped with stabilizers to achieve high strength and fracture toughness. The bioceramics nowadays, used in medical and dental care, derived from structural materials used in aerospace and military armor, which were modified to suit the additional requirements of biocompatibility
