Fluoridated apatite synthesized using a multi-step fluoride supply system.
Fluoridated apatite was synthesized at 80 +/- 1 degrees C, pH 7.4 +/- 0.2, using a 5-step fluoride supply system. During the synthesis experiment, 0, 5, 10, 15 and 20 mmol/l of fluoride were each supplied for one-fifth of the experimental period with calcium and phosphate. X-ray diffraction analysis showed a typically apatitic pattern, although the (3 0 0) reflection was broader than that of homogeneous fluorapatite. Scanning electron micrographic observation indicated that the apatite was composed of needle-like crystals similar to hydroxyapatite and fluorapatite. High-resolution transmission electron microscopy showed a slender hexagonal shape similar to homogeneous hydroxyapatite in cross-sections perpendicular to the c-axis and the structural damage in the core of the crystal, although no boundary of step-like layers was observed. The apparent solubility in 0.5 mol/l acetate buffer solution (37 degrees C and pH 4.0) was 12.1 +/- 0.2 mmol/l, much less than that of homogeneous hydroxyapatite 32.3 +/- 1.9 mmol/l, and similar to that of heterogeneous two-layer fluoridated apatite with an outer fluoride-rich layer 12.5 +/- 0.6 mmol/l, which was synthesized previously by supplying fluoride during the latter half of the experimental period.
Okazaki
M
M
Department of Dental Materials Science and Technology, Osaka University, Faculty of Dentistry, Japan.
Miake
Y
Y
Tohda
H
H
Yanagisawa
T
T
Takahashi
J
J
D001031:Apatites / Q000138:chemical synthesis* / Q000737:chemistry; D001672:Biocompatible Materials / Q000138:chemical synthesis*; D002118:Calcium; D017886:Durapatite / Q000138:chemical synthesis* / Q000737:chemistry; D005459:Fluorides; D007202:Indicators and Reagents; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D012995:Solubility; D014961:X-Ray Diffraction
D001031:Apatites; D001672:Biocompatible Materials; D007202:Indicators and Reagents; D017886:Durapatite; C025105:fluorapatite; D005459:Fluorides; D002118:Calcium