Biomaterial Database

Crystallographic behaviour of fluoridated hydroxyapatites containing Mg2+ and CO3(2-) ions. 1991

M Okazaki

Department of Dental Technology, Osaka University Faculty of Dentistry, Japan.

Fluoridated hydroxyapatites containing small amounts of magnesium and carbonate ions were synthesized at 80 and 60 degrees C to examine their inhibiting properties regarding apatite crystal growth, in contrast to the promoting action of fluoride. The shortening of a-axis and c-axis dimensions of the apatite crystals, as revealed by X-ray diffraction analysis, suggested that both magnesium and carbonate ions were substituted into the apatite crystals. The a-axis dimensions also decreased with the degree of fluoridation. The infrared spectra due to CO3(2-) ions at 875 cm-1 were shifted with increasing fluoride content. The overall crystallinity was inhibited in comparison with that of Mg and CO3-free fluoridated hydroxyapatites, but recovered considerably with increased fluoride content. The apparent solubility of the apatites at pH 4.0 and 37 degrees C was higher than that of Mg and CO3-free fluoridated hydroxyapatites at lower fluoride contents, but gradually approached the latter at higher fluoride content. After 1 month's incubation, dicalcium phosphate dihydrate was formed from fluoride-free Mg-CO3 apatite synthesized at 60 degrees C.

UI	MeSH Term	Description	Entries
D008274	Magnesium	A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.
D002254	Carbonates	Salts or ions of the theoretical carbonic acid, containing the radical CO2(3-). Carbonates are readily decomposed by acids. The carbonates of the alkali metals are water-soluble; all others are insoluble. (From Grant & Hackh's Chemical Dictionary, 5th ed)	Carbonate
D003461	Crystallography	The branch of science that deals with the geometric description of crystals and their internal arrangement. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Crystallographies
D005457	Fluoridation	Practice of adding fluoride to water, and other food or beverages, for the purpose of preventing DENTAL CARIES.	Milk Fluoridation,Salt Fluoridation,Water Fluoridation,Fluoridation, Milk,Fluoridation, Salt,Fluoridation, Water
D006882	Hydroxyapatites	A group of compounds with the general formula M10(PO4)6(OH)2, where M is barium, strontium, or calcium. The compounds are the principal mineral in phosphorite deposits, biological tissue, human bones, and teeth. They are also used as an anticaking agent and polymer catalysts. (Grant & Hackh's Chemical Dictionary, 5th ed)	Hydroxyapatite Derivatives,Derivatives, Hydroxyapatite
D014961	X-Ray Diffraction	The scattering of x-rays by matter, especially crystals, with accompanying variation in intensity due to interference effects. Analysis of the crystal structure of materials is performed by passing x-rays through them and registering the diffraction image of the rays (CRYSTALLOGRAPHY, X-RAY). (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Xray Diffraction,Diffraction, X-Ray,Diffraction, Xray,Diffractions, X-Ray,Diffractions, Xray,X Ray Diffraction,X-Ray Diffractions,Xray Diffractions