Polymer-hydroxyapatite composites for biodegradable bone fillers.

A number of composites made from biodegradable polymers and hydroxyapatite were studied in vivo and in vitro in an attempt to develop biodegradable artificial bone fillers. Histological observation in rats revealed that polylactic acid, of low molecular weight (PLAoligomer), was rapidly resorbed and replaced by newly formed bone tissue when incorporated with hydroxyapatite and this suggested that the incorporated hydroxyapatite seemed to play an active role in the new bone formation. In vitro testing revealed that the solubility of hydroxyapatite was markedly enhanced when mixed with PLAoligomer.