Ultrastructure and Crystallographic Study of Enamel in Human Dental Fluorosis.

本研究使用的材料为人类氟斑牙和猪氟斑牙的恒磨牙。氟斑牙患者的牙釉质表面通常浑浊到不透明，有几个不同大小和程度的凹坑或缺陷。然而，氟斑牙的猪受试者没有看到凹坑或缺陷。在矿化程度相对较高的最外层牙釉质层的正下方是一个广泛的低矿化区域。高矿化层由许多大的细长六边形晶体和小的六边形晶体组成。在大晶体的某些部分，可以观察到晶体在表面生长或极小的晶体附着在表面。大晶体和极小晶体的晶格条纹以精确的寄存器相互连接。在（100）平面上，大长条形六方晶体的晶格间距为0.817 nm。小晶体的形状为正六边形、非正六边形和点阵，其间距为0.812 nm。结果表明，大的长条形六方晶体为羟基磷灰石，小的晶体为氟磷灰石。低矿化牙釉质区由排列相当稀疏的大晶体和少量小晶体组成。大晶体通常比在表层观察到的小。在这个区域的某些地方，大晶体要么在中心有穿孔，要么在表面形成不规则的缺陷。然而，猪的实验对象没有看到这些晶体。在地表高矿化层与次地表低矿化区之间的过渡区域，可观察到大小晶体。大晶体的中心孔洞经常含有明显新形成的晶体碎片。原始晶体和新形成的晶体材料之间的晶格条纹并不总是彼此一致。波色散电子探针线分析表明，高矿化表层氟化物浓度很高，低矿化区氟化物浓度很低。少

Materials used in this work were permanent molars of human and porcine dental fluorosis.Enamel surfaces from human subjects with dental fluorosis were generally cloudy to opaque, with several pits or defects of various size and degrees. Porcine subjects with dental fluorosis, however, were not seen pits or defects. Immediately below the relatively highly mineralized outermost surface enamel layer was an extensive hypomineralized area. The highly mineralized layer was composed of many large elongated hexagonal crystals and small hexagonal crystals. In some parts of the large crystals, crystal growth on the surface or attachment of extremely small crystals to the surface were observed. The lattice striations of the large and extremely small crystals were connected to each other in exact register. In views along the (100) plane, lattice intervals of large elongated hexagonal crystal were 0.817 nm. Shapes of small crystals were equilateral-hexagonal or nonequilateral-hexagonal and lattice … More intervals of it were 0.812 nm. This result showed that large elongated hexagonal crystals were hydroxyapatite and small crystals were fluorapatite. The hypomineralized enamel area was composed of fairly sparsely arranged, large crystals and a few small crystals. Large crystals were generally smaller than those observed in the surface layer. In some parts of this area, either the crystals large had perforations in their centers or irregular defects formed on their surfaces. Porcine subjects, however, were not seen those crystals. Both large and small crystal were observed in the transitional region between the highly mineralized surface layer and the subsurface hypomineralized area. Central perforations within the large crystals frequently contained apparently newly formed crystal fragments. Lattice striations between the original crystals and the newly formed crystalline material were not always in register with each other. Wave-dispersive electron-probe line analysis indicated that fluoride concentration was very high in the highly mineralized surface layer and low in the hypomineralized area. Less