Bigeard L, Hemmerle J, Sommermater J I
Department of Pedodontics, Faculty of Odontology, Louis Pasteur University, Strasbourg, France.
ASDC J Dent Child. 1996 Jan-Feb;63(1):23-31.
A natal tooth, the lower left central primary incisor, extracted from a twenty-eight-day-old boy was the subject of a clinical and ultrastructural (S.E.M., T.E.M., H.R.T.E.M.) study. The right one having been lost shortly after birth, the places of the natal teeth were taken by two hyperplastic structures which disappeared one year later, ejecting two little pearls of hard tissue. Scanning electron microscopic investigation of the extracted natal tooth showed a reduced enamel thickness corresponding to the development stage of the tooth as well as the absence of Hunter-Schreger bands and of an outer prism-free layer probably related with amelogenesis perturbations. Transmission electron microscopy disclosed characteristic ultrastructure of the enamel rods, the morphology of the enamel crystals evaluated by their width-to-thickness ratio taking logically place between fetal and adult enamel. A central dark line, which is thought to be in relation to the initial growth process, was observed in enamel crystals. Dentin aspects did not reveal significant perturbations compared to normal primary teeth.
从一名28天大的男婴口中拔除的一颗诞生牙——左下中切乳牙，成为了一项临床及超微结构（扫描电子显微镜、透射电子显微镜、高分辨率透射电子显微镜）研究的对象。右侧的诞生牙在出生后不久就脱落了，其位置被两个增生性结构占据，这两个结构在一年后消失，同时排出了两颗小的硬组织珠。对拔除的诞生牙进行扫描电子显微镜检查发现，牙釉质厚度减小，这与牙齿的发育阶段相符，同时没有亨特-施雷格带以及可能与釉质形成紊乱有关的无釉柱外层。透射电子显微镜揭示了釉柱的特征性超微结构，通过宽度与厚度之比评估的釉质晶体形态在逻辑上介于胎儿釉质和成人釉质之间。在釉质晶体中观察到一条中央暗线，据认为这与初始生长过程有关。与正常乳牙相比，牙本质方面未显示出明显的紊乱。
