SINTERED CARBONATE APATITES AS BIORESORBABLE BONE SUBSTITUTES

The dissolution behavior of sintered carbonate apatite was investigate d in a 10 mM/L acetic acid solution adjusted to pH 5.0 at 37 degrees C , and compared to that of sintered hydroxyapatite and bone apatite for the purpose of establishing some similarities between the physicochem ical dissolution of apatite biomaterials in vitro and their ability to be resorbed by osteoclasts in vivo. Both the sintered carbonate apati te and the bone apatite dissolved to an appreciable extent. Their solu tion compositions chanced in an almost identical manner until toward t he end of the reaction. The solution compositions for sintered carbona te apatite at 30 s was comparable with that for sintered hydroxyapatit e at 3.8 days with respect to the degree of supersaturation, indicatin g that the former specimen is much more soluble than the latter specim en. Osteoclasts which were obtained from the long bones of 1-day-old n eonatal rabbits resorbed bone and sintered carbonate apatite, but not sintered hydroxyapatite. These findings suggest that sintered carbonat e apatites, which have characteristics that can be favorably compared with those of bone, especially with respect to its reactivity to acid media, would be useful as bioresorbable bone substitutes. (C) 1998 Joh n Wiley & Sons, Inc.