title: Differences in solubility of two types of heterogeneous fluoridated hydroxyapatites.
abstract: Two types of heterogeneous fluoridated apatites, H-F and F-H, were synthesized by supplying fluoride over the whole range of the degree of fluoridation (X = 0-1.0) during the initial or final half of the experimental period. Although X-ray diffraction patterns and scanning electron microscopy (SEM) photographs of both H-F and F-H type apatites were not significantly different, high-resolution transmission electron microscopy (HR-TEM) showed quite different features; H-F type apatites were elongated hexagons with electron beam damage in the core, while F-H type apatites were rather wider hexagons and approached the typical hexagon of fluorapatite. These results supported the previous speculations on the two different types of heterogeneous fluoridated hydroxyapatites synthesized with fluoride concentration stoichiometrically equivalent to that of fluorapatite: hydroxyapatite covered with fluorapatite and fluorapatite covered with hydroxyapatite. The apparent solubility of H-F type apatites decreased with increases in degree of fluoridation, while that of F-H type apatites decreased markedly and then remained almost constant.
authors.affiliation: Department of Dental Materials Science and Technology, Osaka University, Faculty of Dentistry, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Okazaki
authors.forename: H
authors.initials: H
authors.lastname: Tohda
authors.forename: T
authors.initials: T
authors.lastname: Yanagisawa
authors.forename: M
authors.initials: M
authors.lastname: Taira
authors.forename: J
authors.initials: J
authors.lastname: Takahashi
mesh_terms: D001031:Apatites / Q000138:chemical synthesis / Q000737:chemistry*; D005457:Fluoridation; D006845:Hydrocarbons, Fluorinated / Q000138:chemical synthesis / Q000737:chemistry; D006882:Hydroxyapatites / Q000138:chemical synthesis / Q000737:chemistry*; D008854:Microscopy, Electron; D012995:Solubility; D014961:X-Ray Diffraction
chemical_list: D001031:Apatites; D006845:Hydrocarbons, Fluorinated; D006882:Hydroxyapatites; C025105:fluorapatite