Dumitrescu A L, Ionescu N
Department of Odotology and Periodontology, Dental Faculty, University of Medicine and Pharmacy, Bucharest, Romania.
Rom J Morphol Embryol. 1996 Jan-Jun;42(1-2):123-30.
The recent use in biology of the Scanning Electron Microscope allows a new vision of the sample, completing the previous ones: the Optical Microscope (OM) and the Conventional Electron Microscope--CEM. The object is observed in space, in a direct way and, due to a system of variable sizes, the passage from a general image to the detailed tissue and cell study is permitted. The outer enamel surface with its perikymaties, its flaws and its changes caused by usage as well as by the internal enamel structure on the fractured area have been studied. On the occlusal surface of the decayed teeth, focal holes have been found; they resulted probably from creation disturbances due to some amelogenetic disorders that damage the ameloblast, matrix creation or its mineralization. These lacunar flaws are the favourite zones for the microbe plate accumulation and propitious to carious lesions initiation. The same clinical aspect, of profound enamel creation defects with an anfractuous crevass network aspect, having a variable expansion and depth, can be found in microscope with some healthy teeth. Regrouping in fascicles of the different prism directions can be found after structural analysis of the prismatic morphology of the parodontotic tooth enamel. An aspect of a more compact structure is thus obtained sectionally. This explains partially the increased resistance to decay of these teeth. In a comparative study of the fractioned area of some decayed and ruined temporary teeth, significant differences in prism arrangement can be found. The decayed teeth show expansions of the intraprismatic spaces, accusing reduced resistance against decay attack.
扫描电子显微镜最近在生物学中的应用为样本提供了一种全新的观察视角，完善了之前的观察手段：光学显微镜（OM）和传统电子显微镜（CEM）。该物体能够在空间中被直接观察到，并且由于存在可变尺寸系统，使得从整体图像过渡到对组织和细胞的详细研究成为可能。研究了牙釉质外表面及其釉质横纹、瑕疵以及因使用和断裂区域的牙釉质内部结构所引起的变化。在龋坏牙齿的咬合面上发现了一些局灶性空洞；它们可能是由于某些成釉细胞紊乱导致的生成干扰造成的，这些紊乱会损害成釉细胞、基质生成或其矿化过程。这些腔隙性瑕疵是微生物菌斑积聚的理想区域，有利于龋病病变的起始。在一些健康牙齿的显微镜观察中，也能发现相同的临床特征，即牙釉质深层生成缺陷呈现出曲折的裂隙网络状，且具有不同的扩展范围和深度。对牙周病牙齿牙釉质的棱柱形态进行结构分析后发现，棱柱会按不同方向重新组合成束状。这样在切片上就呈现出一种结构更为紧密的形态。这在一定程度上解释了这些牙齿抗龋能力增强的原因。在对一些龋坏和损坏的乳牙断裂区域进行的对比研究中，可以发现棱柱排列存在显著差异。龋坏牙齿的棱柱内间隙扩大，表明其抗龋能力下降。
