Plate U, Arnold S, Reimer L, Höhling H J, Boyde A
Physikalisches Institut, Universität Münster, Germany.
Cell Tissue Res. 1994 Dec;278(3):543-7. doi: 10.1007/BF00331372.
The earliest crystallites in dentine appear as chains of "dots" in ultra-thin sections viewed by transmission electron microscopy. These dots rapidly coalesce along the longitudinal directions of the collagen microfibrils to form needle-like structures that coalesce preferentially in lateral directions to form ribbon-like or plate-like crystallites. This morphological interpretation is supported by line-scans of the corresponding zero-loss filtered electron spectroscopic diffraction patterns, which demonstrate the crystalline structure of the dentine mineral (apatite). The intensity ratio of the Debye-Scherrer rings of the characteristic Bragg-reflections (002 to 300, together with 1 or 2 unresolved reflections) shows a maximum in the region of early chain-like and needle-like crystallites, decreasing with maturation of the dentine mineral to the ribbon-plate-like crystallites. Detailed investigations using line-scans of the zero-loss filtered electron spectroscopic diffraction patterns through the dentine zone show that the intensity ratio found near the mineralisation front is repeated 3-5 times at distances of about 10-20 microns. This may represent a circadian pattern of mineralisation corresponding to light microscopically visible incremental lines in dentine.
在透射电子显微镜下观察的超薄切片中，牙本质中最早的微晶呈现为“点”链。这些点沿着胶原微纤维的纵向迅速合并，形成针状结构，这些针状结构优先在横向合并，形成带状或板状微晶。相应的零损失滤波电子光谱衍射图的线扫描支持了这种形态学解释，该图证明了牙本质矿物质（磷灰石）的晶体结构。特征布拉格反射（002至300，以及1或2个未解析反射）的德拜-谢乐环的强度比在早期链状和针状微晶区域显示出最大值，并随着牙本质矿物质成熟为带状-板状微晶而降低。通过牙本质区域对零损失滤波电子光谱衍射图进行线扫描的详细研究表明，在矿化前沿附近发现的强度比在约10-20微米的距离处重复3-5次。这可能代表了一种与牙本质中光学显微镜下可见的生长线相对应的昼夜矿化模式。
