Preparation And The Ossific Process Of β-TCP Porous Ceramics

With various Ca/P ratios and different crystal structures, calcium-phosphate ceramics, especially the β-tricalcium-phosphate(β-TCP) and the hydroxyapatite(HA), which have a chemical composition close to that of bone, have been extensively explored as bone-graft materials. For the super biocompatible and the bioabsorbability, β-TCP ceramic was chosen for main experimental material. This paper introduced the mechanism of formation of apatite on surface of β-TCP and HA, discussed different factors working on the apatite formation, then deduced the bone-formation-mechanism after the ceramics implanted in vivo.The porous β-TCP ceramic was synthesized with pure β-TCP powder, bioglass and froths in special ratios by foaming way. Property examinations indicated that there were only a few other substances, and that the mechanical and biological performances are excellent.Apatite with structure of carbonate-hydroxyapatite was found on the surface of β-TCP when it was immersed in the SBF for some time. Different ions in SBF have different effects to the formation of apatite, calcium and phosphorus accelerating the process but magnesium blocking it. With the different results and some similarity after different immersed in SBF, with the examination of initial and final substances formed on different materials and with the test of Ca and P ions' change, a theory about the mechanism of apatite-formation was deduced.A chemical interaction was examined between β-TCP and albumin in our test. Amount and feature of apatite changed when β-TCP was immersed in SBF with albumin, adsorption competition was then found between nonorganic ions and organic molecules. Growth of cells on β-TCP, action between cells and β-TCP, growth of Ca-P crystal was found in the test, all indicated that cells could stimulate the process of apatite-formation on β-TCP.Different factors affecting growth of bone in vivo were examined in vitro experiment, then the mechanism of bone formation was deduced and it was proved in vivo experiment. The success of this paper is separating the single role of complicated factors in vivo.