Kodaka T, Mori R, Takiguchi R, Higashi S
Second Department of Oral Anatomy, School of Dentistry, Showa University, Tokyo, Japan.
Bull Tokyo Dent Coll. 1995 Feb;36(1):33-42.
In examining the prismless enamel (PL) distribution from the inner to surface layers of a human incisor with hypoplastic perikymatas with enamel pits, we determined the structural patterns and mineralization values by microradiographic, optical, and scanning electron microscopic observations. The PL containing abnormal prisms ranged from 20 to 250 micrometers in thickness. The alternated layers of the PL and prismatic enamel, in parallel with the Retzius lines, showed a roughly zigzag pattern based on the main orientation of enamel crystals. Such a pattern suggests an alternation of the disappearance and reappearance of Tomes' processes, which may have strong restorative and reactive capacities. In the mineralization values determined by microradiography, the PL was higher in the well-marked lines of Retzius, while the PL under the hypoplastic enamel pit and an area within the thick PL showed hypomineralization. The backscattered electron images indicated that the fine laminate striations and abnormal prismatic rows within the PL were hypomineralized, and the PL in the inner enamel showed a lower mineralization than the adjacent prismatic layer. Thus, the disappearance of Tomes' processes, which form prismless structures, may be unrelated to changing the mineral amount in amelogenesis.
在检查患有釉质凹陷的发育不全釉质嵴的人切牙从内层到表层的无棱柱釉质（PL）分布时，我们通过显微放射照相、光学和扫描电子显微镜观察确定了结构模式和矿化值。含有异常棱柱的PL厚度范围为20至250微米。PL和棱柱形釉质的交替层与芮氏线平行，基于釉质晶体的主要取向呈现出大致的锯齿状模式。这种模式表明托姆斯突的消失和重新出现，这可能具有很强的修复和反应能力。在显微放射照相确定的矿化值中，PL在明显的芮氏线处较高，而发育不全釉质凹陷下方的PL和厚PL内的区域显示矿化不足。背散射电子图像表明，PL内的精细层状条纹和异常棱柱排矿化不足，内釉质中的PL矿化低于相邻的棱柱层。因此，形成无棱柱结构的托姆斯突的消失可能与釉质形成过程中矿物质含量的变化无关。
