Implantable zirconia bioceramics for bone repair and replacement: A chronological review

Bone tissue engineering applies scientific principles to repair, regenerate, and restore the functions of defected hard tissues or to replace them with purposely built biomaterials. In the past few decades, the design, construction and modification of biomaterials possessing desirable properties-those mimicking natural bone-remained the center of attention. Consequently, zirconia is found to be the material of choice for bone repair and replacement applications due to its unique biomechanical properties. This paper aims to present a succinct review of the applications of zirconia based biomaterials in bone tissue engineering; for instance, as implantable bioceramic, as coating or thin film on other metallic implants, as porous bone scaffold and substitute material, and as a radio-opacifying agent in bone cements. The evolution of zirconia as an essential material in biomedical applications, especially those concerning bone repair and replacement, is presented in a chronological order. Particular emphasis is placed on recent progress and drawbacks of zirconia and its composites in terms of their mechanical and biological properties. It is concluded that zirconia certainly enjoys the best combination of mechanical strength, fracture toughness, biocompatibility, and bioactivity; however, its properties can be further improved either by suitable surface modification or through combination with other bioactive ceramics and glasses.