Akabane Chika, Kimura Mitsuo, Yamamoto Yukio, Shimizu Nobukata, Weinkamer Richard, Wagermaier Wolfgang, Fratzl Peter, Kashiwagi Yoichiro, Sawada Keigo, Murakami Shinya
Research and Development Headquarters, LION Corporation, 7 Chome-2-1, Hirai, Edogawa, Tokyo, 132-0035, Japan.
Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Ibaraki, Japan.
Calcif Tissue Int. 2025 Jan 3;116(1):12. doi: 10.1007/s00223-024-01318-w.
Human dentin performs its function throughout life, even though it is not remodeled like bone. Therefore, dentin must have extreme durability against daily repetitive loading. Elucidating its durability requires a comprehensive understanding of its shape, structure, and anisotropy at various levels of its structure. However, few studies have examined the nanostructure of dentin as a whole and not much is known about its age-related changes. Our aim is to characterize the mineral particle characteristics of human dentin and age-related changes using synchrotron scanning small- and wide-angle X-ray scattering. 30 molar and premolar teeth extracted from 16 to 77-year-old individuals for orthodontic or periodontal reasons were used. Synchrotron-based X-ray scattering was employed to acquire two-dimensional maps of nanostructural features. These maps revealed a negative gradient of particle size toward the pulp chamber. The preferential orientation of particles was position-dependent, with a higher orientation in the area from the pulp horn to the cusp tip and root region. These patterns were maintained in different tooth types. The mineral particle thickness of the inner crown increased significantly with age. This increase could relate to the filling of tubules and, therefore, likely contribute to the deterioration of the mechanical performance of teeth with age.
人类牙本质在整个生命过程中都发挥着作用，尽管它不像骨骼那样会进行重塑。因此，牙本质必须具备极强的耐久性以抵抗日常的反复负荷。要阐明其耐久性，需要全面了解其在不同结构层次上的形状、结构和各向异性。然而，很少有研究对牙本质的整体纳米结构进行过研究，对其与年龄相关的变化也知之甚少。我们的目标是利用同步加速器扫描小角和广角X射线散射来表征人类牙本质的矿物颗粒特征及其与年龄相关的变化。使用了因正畸或牙周原因从16至77岁个体中拔除的30颗磨牙和前磨牙。采用基于同步加速器的X射线散射来获取纳米结构特征的二维图谱。这些图谱显示出朝着牙髓腔方向颗粒尺寸呈负梯度。颗粒的优先取向取决于位置，在从牙髓角到牙尖和牙根区域的区域中取向更高。这些模式在不同的牙齿类型中都保持一致。内冠的矿物颗粒厚度随年龄显著增加。这种增加可能与牙本质小管的填充有关，因此可能导致牙齿的机械性能随年龄而恶化。
