In vitro degradation behavior of porous calcium phosphates under diametral compression loading

Four different types of porous calcium phosphates were made on addition of a pore-forming compound (PVA) by sinter processing. Mechanical properties, morphology, and weight change with immersion time in Hanks' physiological solution were evaluated. The in vitro fatigue test was also performed. Experimental results showed the pore microstructure of the as-sintered bodies to be made up of the macropores and micropores. The initial strength of the porous bodies was dependent on the contents of the PVA additive. Porous bodies subjected to cycling fatigue in Hanks' solution remarkably decreased in the strength. With increasing immersion time in solution, the tensile strength and elastic modulus of various porous bodies decreased. The weight loss data confirmed the degradation behavior of the porous bodies in Hank's solution. The biomedical uses of the present porous materials are limited to non-load bearing applications such as bone defect repair.