Cells and Materials


Calcium phosphate ceramics are described as "bioactive". Evidence of biological activity associated with calcium phosphate implanted in bone and marrow can be seen as changes in the morphology of the interfaces. In this in vivo model the sequence of progressive bone growth and bone merger with a dense calcium phosphate ceramics were examined by light and transmission electron microscopy. A spectrum of tissue responses to dense tricalcium phosphate ceramics was observed at intervals over a six week period. It is now well established that calcium phosphate ceramics permit bone ingrowth with little or no immunological response; however, a layer of fibroblasts in a collagenous matrix had formed on the ceramic surface within one week. At the ceramic-bone interface collagen associated with ceramic particles did not mineralise into bone until the natural calcification front had advanced up to the ceramic surface. In the marrow a bony coating formed over the surface of the ceramic implant.