COMPUTER-GRAPHICS OF HYDROXYAPATITE AND BETA-TRICALCIUM PHOSPHATE

Hydroxyapatite (HA) and β-tricalcium phosphate (TCP) were studied by computer graphics with a personal computer. Crystal models of fluoridated hydroxyapatite and fluorapatite, in which F- ions are substituted into some or all OH- positions, were also drawn. Data on the structural coordinates of the hydroxyapatite and β-TCP crystals were put into a protein graphics program in Angstrom units. The connection of each element, with front and rear, was displayed by the shade-line erasing method, and the solidity of the image was expressed by the degree of lightness from the light source. The colour tint was obtained by the Raster graphics method. A fine picture can be obtained with the photo program. Rotating the graphics freely around the X, Y, and Z axes gives a view from any direction. The computer graphics demonstrated visually that F~ ions contribute to stabilize the hydroxyapatite crystal and that β-TCP has an unstable structure due to 0.5 probability of Ca2+ ions and [P04-Ca-Ca-Ca-PO4] zigzag chain. © 1990.