Fabrication of porous calcium phosphate bioceramics as synthetic cortical bone graft

The aim of this study was to fabricate porous Hydroxyapatite/Tricalcium phosphate (HA/TCP) bioceramics with an adequate degree of interconnected porosity combined with optimal mechanical proper-ties. Porous HA/TCP bioceramics with interconnected porosity and the controlled pore sizes necessary to simulate natural bone tissue morphology were fabricated by a novel technique of vacuum impregnation of reticulated polymeric foams with ceramic slip. By varying the characteristics of the slips and using foams of different pores per inch (ppi), samples of porous HA/TCP, blocks and granules, with a wide range of pore sizes were successfully manufactured. Functionally gradient materials (FGM) with porosity gradients were also made and no weakness was found at the interface. The pore size of the HA/TCP bioceramics was in the range of 197 - 254 mu m (for 20 ppi foam), 143 - 182 mu m (for 30 ppi foam) and 105 - 127 gm (for 45 ppi foam). The compressive strengths and the apparent densities of the HA/TCP samples were in the range of 30 - 170 MPa and 2.34 - 2.76 g/cm(3) respectively. These results indicate that it is possible to manufacture open pore HA/TCP bioceramics with compressive strengths comparable to human bone which could be of clinical interest.