Microstructure and bioresorbable properties of α-TCP ceramic porous body fabricated by direct casting method

Abstract

We attempted to fabricate α-tricalcium phosphate (α-TCP) ceramic porous body with interconnected continuous pores through conventional sintering process. Porous bodies were obtained by sintering the bodies prepared from slurry composed of β-TCP, potato starch and ultra-pure water. Distribution in pore size was uniform ranging between 10-100 um in diameter. The pore size was mainly due to similarity of distribution in particle size of the potato starch. The porous body (CP-50), that is prepared from the slurry containing 50 mass% of starch, has 73.8% of porosity, and is able to be easy in secondary machining with surgical knife. Porosity of porous body increased with increasing the amount of potato starch added to the slurry. Compressive strength of porous bodies remarkably decreased with increasing the porosity of the porous body. Dissolution behavior was evaluated by released amounts of calcium and phosphate ions from the porous body in buffered solutions. Higher porosity of the ceramic body resulted in higher dissolution rate in the buffered solution. In vivo evaluation by peripheral quantitative computed tomography (pQCT) shows higher density of regenerated bone after the implantation of CP-50 than that of no specimen at defect in rabbit tibia, at four weeks postoperatively. α-TCP ceramic porous body was almost completely absorbed within four weeks after implantation. Consequently, we successfully fabricated α-TCP ceramic porous body with uniform pore distribution through a process with a direct casting method of slurry containing potato starch. This microstructure of the porous body gives high machinablity as well as bioresorbability.