Relationship between the degradation behaviour of calcium phosphate ceramics and their physical-chemical characteristics and ultrastructural geometry.

The neck geometry of different calcium phosphate materials was studied by scanning electron microscopy. The dissolution rate of these materials, especially of the necks, was determined by chemical analysis. The degradation of calcium phosphate materials in lactate buffer, related to the detachment of sintered particles, was found to be determined by neck dissolution rate and neck geometry. The latter factor depends on the crystallography and stoichiometry of the material and the sintering conditions.