In this work, molecular dynamics simulations are conducted to investigate the structural and mechanical properties of dental materials, i.e., the silica nanorod reinforced Bis-GMA/TEGDMA resin composite. The effects of loading content and size of the silica nanorods on the composite stiffness were performed by examining resin chain conformation, hydrogen bonds and matrix/filler binding energy. It is revealed that the presence of the silica nanorod causes polymer chain expansion, endowing the resins with higher stiffness. Moreover, the volumetric hydrogen bonds and binding energy increase considerably with the loading content, but decrease gradually with the diameter or show almost independence of the length. Furthermore, the composite moduli were quantified by the micromechanics models and the transverse moduli were well predicted by the Counto model, signifying a perfect bonding between the matrix and nanorod. The chain expansion and energetic matrix/filler interactions are believed to contribute to the significant mechanical reinforcement of the composites with the loading content. However, the length of the nanorod has a little effect on the composite moduli due to the unaltered interfacial interaction. In contrast, a smaller diameter is supposed to give a larger modulus, and this is not observed in this work due to the synergic effects of improved matrix/filler interaction and actual reduced filler volume fraction. The mechanical enhancement by the rod-like structures is more influenced by the loading content, but less so by the size of the nanorod, and it also exhibits superior mechanical performance as compared to nanoparticles. The findings thus extend the current understanding of the nanostructure and mechanical properties of silica nanorod reinforced dental resin composites from an atomic/molecular perspective.

在这项工作中，进行了分子动力学模拟以研究牙科材料的结构和机械性能，即二氧化硅纳米棒增强的 Bis-GMA/TEGDMA 树脂复合材料。通过检查树脂链构象、氢键和基体/填料结合能，来研究二氧化硅纳米棒的负载量和尺寸对复合材料刚度的影响。结果表明，二氧化硅纳米棒的存在导致聚合物链膨胀，赋予树脂更高的刚度。此外，体积氢键和结合能随着负载量的增加而显着增加，但随着直径的增加而逐渐减少或几乎与长度无关。此外，复合模量由微观力学模型量化，横向模量由 Counto 模型很好地预测，表明基体和纳米棒之间完美结合。链膨胀和高能基体/填料相互作用被认为有助于复合材料与负载含量的显着机械增强。然而，由于未改变的界面相互作用，纳米棒的长度对复合模量的影响很小。相比之下，较小的直径应该产生较大的模量，由于改善的基质/填料相互作用和实际降低的填料体积分数的协同效应，在这项工作中没有观察到这一点。棒状结构的机械增强受负载量的影响更大，但受纳米棒尺寸的影响较小，并且与纳米颗粒相比，它还表现出优异的机械性能。因此，这些发现从原子/分子的角度扩展了目前对二氧化硅纳米棒增强牙科树脂复合材料的纳米结构和机械性能的理解。