Kodaka T, Hirayama A, Mori R, Sano T
Department of Oral Anatomy, Showa University School of Dentistry, Tokyo, Japan.
J Electron Microsc (Tokyo). 1998;47(1):57-65. doi: 10.1093/oxfordjournals.jmicro.a023559.
Pulp stones of human teeth usually contain biological apatite. In the dental pulp of a cow, aged 12 years, we observed spherulitic pulp stones, up to approximately 200 microns in diameter, consisting of radially arranged crystals with several kinds of light microscopy and scanning electron microscopy including the secondary electron and the backscattered electron signals. The crystals extending fan-like towards the periphery showed a rectangular shape, and they had subunits of elongated crystallites and fine slits of NaOCl-dissolved substances, probably including organic matter and amorphous mineral. By using energy-dispersive X-ray microanalysis, large amounts of Ca and P, and trace elements of Na, Mg, Cl, and Fe were detected from the stones. The calcium phosphate crystals were identified as biological brushite by shape, Ca/ P molar ratio, and electron diffraction pattern. Core regions of the stones containing granular structures, probably erythrocytes, were always present in blood vessels, and rectangular crystals frequently penetrated the vessel walls. Under the decalcified sections, the nidi were completely or incompletely dissolved, but the peripheries showed a radial arrangement of erythrocytes. Thus, the nidi may be thrombus or necrotic blood cells including erythrocytes. Such calcospherulites in the dental pulp of a cow were similar to the spherulitic pulp stones in human deciduous teeth reported previously, however, their nidi were present in different regions.
人类牙齿的牙髓石通常含有生物磷灰石。在一头12岁奶牛的牙髓中，我们观察到球状牙髓石，直径达约200微米，由径向排列的晶体组成，通过几种光学显微镜和扫描电子显微镜观察，包括二次电子和背散射电子信号。向周边呈扇形延伸的晶体呈矩形，它们有细长微晶的亚基和次氯酸钠溶解物质的细缝，可能包括有机物和无定形矿物。通过能量色散X射线微分析，从这些结石中检测到大量的钙和磷，以及钠、镁、氯和铁等微量元素。通过形状、钙/磷摩尔比和电子衍射图谱，磷酸钙晶体被鉴定为生物透钙磷石。结石的核心区域含有颗粒状结构，可能是红细胞，总是存在于血管中，矩形晶体经常穿透血管壁。在脱钙切片下，核心完全或不完全溶解，但周边显示红细胞呈放射状排列。因此，核心可能是血栓或包括红细胞在内的坏死血细胞。奶牛牙髓中的这种钙球与先前报道的人类乳牙中的球状牙髓石相似，然而，它们的核心存在于不同区域。
