RETRACTED ARTICLE: Characteristics of porous zirconia coated with hydroxyapatite as human bones

Abstract

Since hydroxyapatite has excellent biocompatibility and bone bonding ability, porous hydroxyapatite ceramics have been intensively studied. However, porous hydroxyapatite bodies are mechanically weak and brittle, which makes shaping and implantation difficult. One way to solve this problem is to introduce a strong porous network onto which hydroxyapatite coating is applied. In this study, porous zirconia and aluminaadded zirconia ceramics were prepared by ceramic slurry infiltration of expanded polystyrene bead compacts, followed by firing at 1500°C. Then slurry of hydroxyapatite-borosilicate glass mixed powder was used to coat the porous ceramics, followed by firing at 1200°C. The porous structures without the coating had high porosities of 51-69%, high pore interconnectivity, and sufficiently large pore window sizes (300-500 μm). The porous ceramics had compressive strengths of 5⋅3∼36⋅8 MPa, favourably comparable to the mechanical properties of cancellous bones. In addition, porous hydroxyapatite surface was formed on the top of the composite coating, whereas a borosilicate glass layer was found on the interface. Thus, porous zirconia-based ceramics were modified with a bioactive composite coating for biomedical applications.

Shellac Coated Hydroxyapatite (HA) Scaffold for Increasing Compression Strength

“…In HA TZP with porosity size 1.31 mm, it had a compression strength of 21 MPa at the level of porosity of 51%. The compression strength decreased to 15 MPa at level of porosity 54% and to 6 MPa at level of porosity 69% [8].…”