Heap P F, Berkovitz B K, Gillett M S, Thompson D W
Arch Oral Biol. 1983;28(3):195-200. doi: 10.1016/0003-9969(83)90147-4.
Electron-dense particles, approximately 4 nm (40 A) in diameter were present. Evidence is offered that these particles represent iron probably in the form of amorphous hydrous ferric hydroxide. From X-ray probe analytical data, it is suggested that this iron component is accommodated through the process of adsorption rather than by direct substitution of calcium and phosphorus. The iron-rich surface layer was more resistant to acid etching than subsurface enamel. Reported areas of reduced mineral density of enamel at the enamel-dentine junction appear to be preparation artifacts.
存在直径约4纳米（40埃）的电子致密颗粒。有证据表明这些颗粒代表的可能是无定形含水氢氧化铁形式的铁。从X射线探针分析数据来看，表明这种铁成分是通过吸附过程容纳的，而不是通过直接取代钙和磷。富含铁的表层比釉质次表层更耐酸蚀刻。在釉质 - 牙本质交界处报道的釉质矿物质密度降低区域似乎是制备假象。
