Porous zirconia/hydroxyapatite scaffolds for bone reconstruction

Objective. Highly porous apatite-based bioceramic scaffolds have been widely investigated as three-dimensional (3D) templates for cell adhesion, proliferation, and differentiation promoting the bone regeneration. Their fragility, however, limits their clinical application especially for a large bone defect. Methods. To address the hypothesis that using a ZrO2/hydroxyapatite (HAp) composite might improve both the mechanical properties and cellular compatibility of the porous material, we fabricated ZrO2/HAp composite scaffolds with different ZrO2/HAp ratios, and evaluated their characteristics. In addition, porous ZrO2/HAp scaffolds containing bone marrow derived stromal cells (BMSCs) were implanted into critical-size bone defects for 6 weeks in order to evaluate the bone tissue reconstruction with this material. Results. The porosity of a ZrO2/HAp scaffold can be adjusted from 72% to 91%, and the compressive strength of the scaffold increased from 2.5 to 13.8 MPa when the ZrO2 content increased from 50 to 100 wt%. The cell adhesion and proliferation in the ZrO2/HAp scaffold was greatly improved when compared to the scaffold made with ZrO2 alone. Moreover, in vivo study showed that a BMSCs-loaded ZrO2/HAp scaffold provided a suitable 3D environment for BMSC survival and enhanced bone regeneration around the implanted material. Significance. We thus showed that a porous ZrO2/HAp composite scaffold has excellent mechanical properties, and cellular/tissue compatibility, and would be a promising substrate to achieve both bone reconstruction and regeneration needed in the treatment of large bone defects. (C) 2012 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.