Department of Surgical Sciences, University of Wisconsin-Madison, School of Veterinary Medicine, Madison, WI, USA.
Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI, USA.
J Biomech. 2022 Aug;141:111218. doi: 10.1016/j.jbiomech.2022.111218. Epub 2022 Jul 8.
Investigations into teeth mechanical properties provide insight into physiological functions and pathological changes. This study sought to 1) quantify the spatial distribution of elastic modulus, hardness and the microstructural features of dog dentin and to 2) investigate quantitative relationships between the mechanical properties and the complex microstructure of dog dentin. Maxillary canine teeth of 10 mature dogs were sectioned in the transverse and vertical planes, then tested using nanoindentation and scanning electron microscopy (SEM). Microstructural features (dentin area fraction and dentinal tubule density) and mechanical properties (elastic modulus and hardness) were quantified. Results demonstrated significant anisotropy and spatial variation in elastic modulus, hardness, dentin area fraction and tubule density. These spatial variations adhered to a consistent distribution pattern; hardness, elastic modulus and dentin area fraction generally decreased from superficial to deep dentin and from crown tip to base; tubule density generally increased from superficial to deep dentin. Poor to moderate correlations between microstructural features and mechanical properties (R = 0.032-0.466) were determined. The results of this study suggest that the other constituents may contribute to the mechanical behavior of mammalian dentin. Our results also present several remaining opportunities for further investigation into the roles of organic components (e.g., collagen) and mineral content on dentin mechanical behavior.
对牙齿力学性能的研究为生理功能和病理变化提供了深入的了解。本研究旨在：1）量化狗牙本质的弹性模量、硬度和微观结构特征的空间分布；2）研究力学性能与狗牙本质复杂微观结构之间的定量关系。10 只成熟犬的上颌尖牙分别在横切和纵切面上进行了切片，然后使用纳米压痕和扫描电子显微镜（SEM）进行了测试。对微观结构特征（牙本质面积分数和牙本质小管密度）和力学性能（弹性模量和硬度）进行了量化。结果表明，弹性模量、硬度、牙本质面积分数和小管密度具有显著的各向异性和空间变化。这些空间变化遵循一致的分布模式；硬度、弹性模量和牙本质面积分数通常从牙本质表面到深部逐渐降低，从牙冠尖端到根部逐渐降低；小管密度通常从牙本质表面到深部逐渐增加。微观结构特征与力学性能之间存在较差到中度的相关性（R = 0.032-0.466）。本研究结果表明，其他成分可能对哺乳动物牙本质的力学行为有贡献。我们的研究结果还为进一步研究有机成分（如胶原）和矿物质含量对牙本质力学行为的作用提供了几个机会。
