The common structural description of bovine enamel used in materials science studies – nano-sized hydroxyapatite crystallites form micron-sized prisms surrounded by protein sheaths, which in turn build a complex decussation pattern – overlook many important morphological information. This hampers the correct interpretation of the data determined by mechanical analysis. For a profound structural description of enamel morphology, the visualization of its building blocks by high-resolution electron microscopy and focused-ion beam tomography technique, which reveals their form, orientation and configuration at different regions of a tooth (cut in different directions), is undertaken in this work. We adapted here the paleontological classification system and terminology developed for the description of enamel microstructures seen in different species, and accordingly documented the morphological singularities of bovine incisor enamel. The appearance of the boundary regions between crystallites and prisms contradicts to the well-known protein sheath concept. Neighboring crystallites and prisms are not separated by prominent gap zones but they are largely in contact with each other. Proteins might exist within the pores of 20–30 nm in size, which are distributed inhomogeneously through the boundary regions, rather than as protein sheaths covering each crystallite and prism.

材料科学研究中使用的牛牙釉质的常见结构描述-纳米级羟基磷灰石微晶形成被蛋白鞘包围的微米级棱柱，进而形成复杂的讨论模式-忽略了许多重要的形态学信息。这妨碍了对由机械分析确定的数据的正确解释。为了对珐琅质形态进行深刻的结构描述，可通过高分辨率电子显微镜和聚焦离子束断层扫描技术对其牙釉质进行可视化，从而揭示牙釉质在牙齿不同区域（沿不同方向切割）的形状，方向和构造，在这项工作中进行。我们在这里采用了古生物学分类系统和术语，以描述在不同物种中观察到的牙釉质微结构，并据此记载了牛切牙釉质的形态奇异性。微晶和棱柱之间的边界区域的外观与众所周知的蛋白质鞘层概念相矛盾。相邻的微晶和棱镜没有被明显的间隙区域隔开，但是它们之间相互接触很大。蛋白质可能存在于大小为20–30 nm的孔中，它们不均匀地分布在边界区域中，而不是覆盖每个微晶和棱柱的蛋白质鞘。相邻的微晶和棱镜没有被明显的间隙区域隔开，但是它们之间相互接触很大。蛋白质可能存在于大小为20–30 nm的孔中，它们不均匀地分布在边界区域中，而不是覆盖每个微晶和棱柱的蛋白质鞘。相邻的微晶和棱镜没有被明显的间隙区域隔开，但是它们之间相互接触很大。蛋白质可能存在于大小为20–30 nm的孔中，它们不均匀地分布在边界区域中，而不是覆盖每个微晶和棱柱的蛋白质鞘。