Sintering behaviour of calcium phosphate filaments for use as hard tissue scaffolds

Lattices consisting of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) mixtures were prepared by extrusion freeforming to serve as bone substitute structures in which both shape and structural hierarchy are determined by computer control. Fine ceramic filaments were prepared from a non-aqueous, solvent-based, ceramic–polymer paste and sintered at temperatures from 1100 to 1300 °C. The characteristics of the sintered filaments were investigated because this determines the resulting microporosity and phase content while the higher levels of porosity are computer controlled. The effects of HA/β-TCP ratio and sintering temperature on the microstructure, density, shrinkage and final phase content were studied. These results provide a design reference for hard tissue engineering scaffolds built from these materials.