Department of Mechanical Engineering, Mississippi State University, Mississippi State, MS 39762, USA; Center for Advanced Vehicular Systems, Mississippi State University, Mississippi State, MS 39762, USA.
Department of Mechanical Engineering, Mississippi State University, Mississippi State, MS 39762, USA; Center for Advanced Vehicular Systems, Mississippi State University, Mississippi State, MS 39762, USA.
Arch Oral Biol. 2018 May;89:1-8. doi: 10.1016/j.archoralbio.2018.01.013. Epub 2018 Feb 2.
This paper studies A. probatocephalus teeth and investigates the mechanical properties and chemical composition of the enameloid and dentin.
Nanoindentation tests with a max load of 1000 μN and X-ray Energy Dispersive Spectroscopy (EDS) were performed along the diameter of the polished sample. Microstructural analysis of the dentin tubules was performed from SEM images.
From nanoindentation testing, the dentin of the sheepshead teeth has a nanoindentation hardness of 0.89 ± 0.21 (mean ± S.D.) GPa and a reduced Young's modulus of 23.29 ± 5.30 GPa. The enameloid of A. probatocephalus has a hardness of 4.36 ± 0.44 GPa and a mean reduced Young's modulus of 98.14 ± 6.91 GPa. Additionally, nanoindentation tests showed that the enameloid's hardness and modulus increased closer to the surface of the tooth. X-ray Energy Dispersive Spectroscopy (EDS) data further suggests that the gradient may be a result of the wt% fluoride within the enameloid, where an increase in fluoride results in an increase in reduced Young's modulus and hardness.
The microstructural characterization of the number density and area of the dentin tubules were used to address the porosity effect in the dentin to achieve the experimentally validated microhardness. The mechanical properties of the sheepshead teeth were also compared with previous nanoindentation tests from other aquatic species. The sheepshead teeth exhibit a greater reduced Young's modulus and hardness compared to shark and piranha teeth.
本文研究了 A. probatocephalus 的牙齿，并研究了釉质和牙本质的力学性能和化学成分。
沿抛光样品的直径进行最大负载为 1000 μN 的纳米压痕测试和 X 射线能量色散光谱 (EDS)。从 SEM 图像中对牙本质小管进行微观结构分析。
从纳米压痕测试中，羊头鱼牙齿的牙本质具有 0.89±0.21 (均值±标准差) GPa 的纳米压痕硬度和 23.29±5.30 GPa 的降低杨氏模量。A. probatocephalus 的釉质具有 4.36±0.44 GPa 的硬度和 98.14±6.91 GPa 的平均降低杨氏模量。此外，纳米压痕测试表明，釉质的硬度和模量随着靠近牙齿表面而增加。X 射线能量色散光谱 (EDS) 数据进一步表明，这种梯度可能是釉质中氟化物重量百分比的结果，氟化物含量的增加会导致降低的杨氏模量和硬度增加。
利用牙本质中管腔数量密度和面积的微观结构特征来解决牙本质中的孔隙效应，以达到实验验证的微硬度。还将羊头鱼牙齿的力学性能与其他水生物种的先前纳米压痕测试进行了比较。与鲨鱼和食人鱼的牙齿相比，羊头鱼的牙齿表现出更大的降低杨氏模量和硬度。
