Okazaki M
Department of Dental Technology, Osaka University Faculty of Dentistry, Japan.
Biomaterials. 1991 Nov;12(9):831-5. doi: 10.1016/0142-9612(91)90070-q.
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.
在80摄氏度和60摄氏度下合成了含有少量镁离子和碳酸根离子的氟化羟基磷灰石，以研究它们对磷灰石晶体生长的抑制特性，这与氟化物的促进作用形成对比。X射线衍射分析表明，磷灰石晶体的a轴和c轴尺寸缩短，这表明镁离子和碳酸根离子都被取代进入了磷灰石晶体。a轴尺寸也随着氟化程度的增加而减小。875厘米-1处碳酸根离子产生的红外光谱随着氟化物含量的增加而发生位移。与不含镁和碳酸根的氟化羟基磷灰石相比，整体结晶度受到抑制，但随着氟化物含量的增加而有相当程度的恢复。在pH值为4.0和37摄氏度时，磷灰石的表观溶解度在较低氟化物含量下高于不含镁和碳酸根的氟化羟基磷灰石，但在较高氟化物含量下逐渐接近后者。经过1个月的孵育，由在60摄氏度下合成的无氟镁-碳酸根磷灰石形成了二水磷酸二钙。
