Ichijo T, Yamashita Y, Terashima T
Department of Oral Anatomy, Faculty of Dentistry, Tokyo Medical and Dental University, Tokyo Ika Shika Daigaku.
Bull Tokyo Med Dent Univ. 1993 Dec;40(4):193-205.
In a series of studies to investigate the structural features of the biological crystal, such as the tooth and bone, using an electron microscope, we examined the ultrastructure of the human enamel, dentin, and bone crystals at near atomic resolution and showed the configuration of the hydroxyapatite structure through the cross and longitudinal sections of the enamel, dentin, and bone crystals. Subsequently, based on the results of our observations of the ultrastructure of the tooth and bone crystals, we attempted to clarify the essential structural features and characteristics of the lattice imperfections in the hydroxyapatite structure composing of the human enamel, dentin, and bone crystals from the morphological viewpoint. Therefore, using the same approach, we examined the images of the lattice imperfection of the normal human enamel, dentin, and bone crystals. In this report, following the previous observation of the lattice imperfection on the point defect structure and the dislocations appearing in the inner structure of the crystal, we describe the image of the face defect structure obtained by using the same approach from the sections of the human enamel, dentin, and bone crystals, such as the stacking fault, grain boundary, and others. The materials used for this study were the human enamel, dentin, and bone crystals. The small cubes of the material were fixed in glutaraldehyde and osmium tetroxide and embedded in epoxy resin using the routine methods. The ultrathin sections were cut with a diamond knife without decalcification. The sections were examined with the HITACHI H-800 H and H-9000 type transmission electron microscopes operated at 200 kV and 300 kV respectively. Each crystal was observed at an initial magnification of 300,000 times and at a final magnification of 10,000,000 times and over. We sincerely believe that the electron micrographs shown in this report are the first to show the images of the lattice imperfections from the sections obtained from the hydroxyapatite crystal composing of the human enamel, dentin, and bone tissue, such as the grain boundary, stacking fault, and others, at near atomic resolution.
在一系列利用电子显微镜研究生物晶体（如牙齿和骨骼）结构特征的研究中，我们以近原子分辨率检查了人类牙釉质、牙本质和骨晶体的超微结构，并通过牙釉质、牙本质和骨晶体的横截面和纵截面展示了羟基磷灰石结构的构型。随后，基于我们对牙齿和骨晶体超微结构的观察结果，我们试图从形态学角度阐明构成人类牙釉质、牙本质和骨晶体的羟基磷灰石结构中晶格缺陷的基本结构特征和特性。因此，我们采用相同的方法，检查了正常人牙釉质、牙本质和骨晶体的晶格缺陷图像。在本报告中，继之前对晶体内部结构中出现的点缺陷结构和位错的晶格缺陷观察之后，我们描述了通过相同方法从人类牙釉质、牙本质和骨晶体切片中获得的面缺陷结构图像，如堆垛层错、晶界等。本研究使用的材料是人类牙釉质、牙本质和骨晶体。将材料的小方块用戊二醛和四氧化锇固定，并采用常规方法嵌入环氧树脂中。用金刚石刀切割超薄切片，无需脱钙。切片分别用工作电压为200 kV和300 kV的日立H - 800 H型和H - 9000型透射电子显微镜进行检查。每个晶体最初以300,000倍的放大倍数观察，最终放大倍数为1,000,000倍及以上。我们坚信，本报告中所示的电子显微照片首次以近原子分辨率展示了从由人类牙釉质、牙本质和骨组织构成的羟基磷灰石晶体切片中获得的晶格缺陷图像，如晶界、堆垛层错等。
