Porous Ca-P-O bio-glassceramics by loose-powder-sintering

Porous resorbable Ca-P-O glassceramic tooth roots based on calcium biphosphate were prepared by loose-powder-sintering then crystallization-annealing. The glass composition is, by weight, CaO/(CaO + P2O5) = 0.33, The sintering behavior of the glass can be described by a conventional viscous flow model. The resultant glassceramic has a pore size of 6 to 36 mu m, depending on starting particle size and sintering temperature, while the pore size distribution is independent of sintering time. The flexural strength is 33 to 150 MPa depending mostly on crystallization-annealing treatment. The crystalline phases are beta-Ca2P2O7 and CaP2O6. After being implanted into rabbits, these porous implants show remarkable biocompatibility and induce the ingrowth of new bone within 30 days. They are partly resorbed after 90 days and replaced by new bone. In spite of the original small porosity, the ingrowth of blood vessels and bone cells is abundantly seen after 90 days, due to enlarged pores produced by progressive resorption. This glassceramic is a good candidate for resorbable tooth and bone implants. The loose-powder-sintering technique resulting in intricate bulk shapes with controllable pore size distribution and good machinability as well as adjustable mechanical strength hence is a powerful technique for the preparation of porous glassceramics.