Porous calcium polyphosphate scaffolds for bone substitute applications - in vitro characterization

Porous structures were formed by gravity sintering calcium polyphosphate (C PP) particles of either 106-150 or 150-250 mum size to form samples with 30 -45 vol% porosity with pore sizes in the range of 100 mum (40-140 mum). Ten sile strength of the samples assessed by diametral compression testing indi cated relatively high values for porous ceramics with a maximum strength of 24.1 MPa for samples made using the finer particles (106-150 mum). X-ray d iffraction studies of the sintered samples indicated the formation of beta -CPP from the starting amorphous powders. In vitro aging in 0.1 M tris-buff ered solution (pH 7.4) or 0.05 M potassium hydrogen phthalate buffered solu tion (pH 4.0) at 37 degreesC for periods up to 30d indicated an initial rap id loss of strength and P elution by 1 d followed by a more gradual continu ing strength and P loss resulting in strengths at 30 d equal to about one-t hird the initial value. The observed structures, strengths and in vitro deg radation characteristics of the porous CPP samples suggested their potentia l usefulness as bone substitute materials pending subsequent in vivo behavi our assessment. (C) 2001 Elsevier Science Ltd. All rights reserved.