Sintering hydroxyapatite (HA) and ß-tricalcium phosphate (ß-TCP) affects the chemical composition, the crystallinity, and the morphological features as demonstrated by means of X-ray diffraction (XRD) , infrared spectroscopy (IR), and scanning electron microscopy (SEM). When heated to 1230°C, 16.7% of HA had decomposed to ß-TCP. SEM investigations showed homogeneous, sharp angular polyhedric blocks of 30 to 50 µm with rare surface pores. On heating at 1230°C, ß-TCP had entirely transformed to a-TCP. During sintering, the size of the powder grains increased and progressive bridging between the grains was observed. At 1230°C, a network within round-shaped polyhedric blocks of 50 to 90 µm was formed. In both, HA and IJ-TCP, surfaces were smooth. The chemical composition and the crystallinity of calcium phosphate ceramics determine their dissolution behavior and osteogenic properties. Nevertheless, their temperature dependent morphological features, such as, particle shape and size, surface texture, and porosity, as demonstrated in the present study, also influence the resorption rates , tissue responses, and wound healing duration. This should be emphasized more by clinicians in choosing an appropriate material for bone substitution.
Bohne, W.; Pouezat, J. A.; Peru, L.; and Daculsi, G.
"Heating of Calcium Phosphate Crystals: Morphological Consequences and Biological Implications,"
Cells and Materials: Vol. 3
, Article 5.
Available at: http://digitalcommons.usu.edu/cellsandmaterials/vol3/iss4/5