Bone-bonding ability of Ce-TZP/Al2O3 nanocomposite with a microporous surface and calcium phosphate coating

The nano-composite of a ceria-stabilized tetragonal zirconia polycrystals (Ce-TZP) and alumina (Al2O3) polycrystals (Ce-TZP/Al2O3) is attractive as a load-bearing bone substitute because of its mechanical properties and phase stability. We have developed a new method of hydrofluoric acid and heat treatment (HFT) to give a microporous structure to the surface of this Ce-TZP/Al2O3 nanocomposite ceramic. Bone-bonding ability of a microporous surface and calcium phosphate coating on Ce-TZP/Al2O3 composite has been investigated through in vivo detaching model. Thin calcium phosphate coating layer was added by alternate soaking process, and thick CaP layer was produced by soaking in simulated body fluid for 5 days. HFT treated Cc-TZP/Al2O3 composite showed high bone-bonding ability compared with the control group. Thick and thin CaP coating accelerated bone-bonding ability in early post-implantation period. The submicron microporous surface was beneficial for achieving mechanical interlocking between the ceramic and surrounding bone. These results suggest the possibility of using a Cc-TZP/Al2O3 nanocomposite ceramic with microporous surface and calcium phosphate coating as the bearing material for uncemented total joint replacements.