Shore R C, Bäckman B, Brookes S J, Kirkham J, Wood S R, Robinson C
Division of Oral Biology, Leeds Dental Institute, Clarendon Way, Leeds LS2 9LU, UK.
Connect Tissue Res. 2002;43(2-3):466-71. doi: 10.1080/03008200290000871.
Hypomaturation amelogenesis imperfecta (AI) is characterized clinically by enamel of normal thickness that is hypomineralized, mottled, and detaches easily from the underlying dentin. Autosomal dominant, autosomal recessive, X-linked, and sporadic modes of inheritance have been documented. The present study investigated the elemental composition of the enamel of teeth from individuals demonstrating clinical hypomaturation AI from families representing three of these patterns of inheritance. The aim of the study was to determine if there was any commonality in microscopic phenotype of this defect between families demonstrating the various inheritance patterns. One section from each tooth was microradiographed and then viewed in a scanning electron microscope (SEM) equipped with an ultrathin window energy-dispersive x-ray spectroscopy (EDX) detector. In the SEM, prisms and constituent crystals in discrete areas appeared to be largely obscured by an amorphous material. EDX analysis showed enamel outside these areas to have a composition indistinguishable from control teeth. However, within these affected areas there was a large increase in carbon content (up to a fivefold increase). In some teeth there was also a detectable but smaller increase in the relative amounts of nitrogen or oxygen. The results suggest the defect in these teeth with a common clinical phenotype, irrespective of the pattern of inheritance, demonstrates a commonality in microscopic phenotype. The large increase in carbon content, not matched by an equivalent increase in nitrogen or oxygen, suggests a possible increased lipid content. In those teeth with elevated nitrogen levels there may also be retained protein.
低成熟型釉质发育不全（AI）在临床上的特征是釉质厚度正常，但矿化不足、有斑点且容易从下方的牙本质上脱落。已记录到常染色体显性、常染色体隐性、X连锁和散发性遗传模式。本研究调查了来自代表三种遗传模式的家族中表现出临床低成熟型AI的个体牙齿釉质的元素组成。该研究的目的是确定在表现出各种遗传模式的家族之间，这种缺陷的微观表型是否存在任何共性。每颗牙齿的一个切片进行了显微放射照相，然后在配备超薄窗口能量色散X射线光谱仪（EDX）探测器的扫描电子显微镜（SEM）下观察。在SEM中，离散区域的棱柱和组成晶体似乎在很大程度上被一种无定形物质掩盖。EDX分析表明，这些区域之外的釉质成分与对照牙齿无法区分。然而，在这些受影响的区域内，碳含量大幅增加（高达五倍）。在一些牙齿中，氮或氧的相对含量也有可检测到但较小的增加。结果表明，这些具有共同临床表型的牙齿中的缺陷，无论遗传模式如何，在微观表型上都有共性。碳含量的大幅增加，而氮或氧没有相应增加，表明可能脂质含量增加。在那些氮水平升高的牙齿中，也可能保留了蛋白质。
