Okazaki M, Miake Y, Tohda H, Yanagisawa T, Matsumoto T, Takahashi J
Department of Biomaterials Science, Hiroshima University School of Dentistry, Japan.
Biomaterials. 1999 Aug;20(15):1421-6. doi: 10.1016/s0142-9612(99)00049-6.
Fluoridated hydroxyapatite was synthesized at 80 +/- 1 degree C and pH 7.4 +/- 0.2 using a gradient fluoride supply system. 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 rod-like crystals similarly to fluorapatite. High-resolution transmission electron microscopy showed electron damage in the core of the crystal. When the apatite pellet was prepared, electron spectroscopy for chemical analysis showed a negative gradient of fluoride concentration with depth in the crystals. The apparent solubility in 0.5 mol/l acetate buffer solution (37 degrees C and pH 4.0) was 9.16 +/- 0.39 mmol/l, much less than that of homogeneous hydroxyapatite 32.3 +/- 1.9 mmol/l, and less than 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. These results suggest that graded fluoridated apatite may be formed by this process and have higher acid resistance than two-layer fluoridated apatite.
使用梯度氟供应系统在80±1℃和pH 7.4±0.2的条件下合成了含氟羟基磷灰石。X射线衍射分析显示出典型的磷灰石图谱，尽管(3 0 0)反射比均匀氟磷灰石的更宽。扫描电子显微镜观察表明，该磷灰石与氟磷灰石类似，由棒状晶体组成。高分辨率透射电子显微镜显示晶体核心存在电子损伤。制备磷灰石颗粒时，化学分析电子能谱显示晶体中氟化物浓度随深度呈负梯度。在0.5 mol/l乙酸盐缓冲溶液（37℃，pH 4.0）中的表观溶解度为9.16±0.39 mmol/l，远低于均匀羟基磷灰石的32.3±1.9 mmol/l，也低于先前在实验后期通过供应氟合成的具有富氟外层的非均匀双层含氟磷灰石的12.5±0.6 mmol/l。这些结果表明，通过该过程可能形成梯度含氟磷灰石，并且其耐酸性高于双层含氟磷灰石。
