Human dentine is a mineralised dental tissue that consists of dentinal tubules surrounded by two distinct dentinal phases: peritubular dentine (PTD) and intertubular dentine (ITD). Dental caries, which manifests itself as a consequence of demineralisation, is one of the most common chronic diseases that affect the function of human teeth. Due to the difference in the packing density of crystallites, PTD and ITD exhibit different reaction rates to acid dissolution. The present study evaluates how the effective Young's modulus degrades and how the effective stress redistributes in demineralised human dentine as a result of incremental acid dissolution process. An analytical two-layer composite model is proposed and used for the effective Young's modulus calculation. 3D numerical representative volume elements (RVEs) with different variations in PTD fraction and dentinal tubule density are established to evaluate effective stress redistribution and examine the critical factors that can affect the mechanical performance. The models are then applied on an actual dentine bulk sample. The results reveal how PTD serves as a protection to ITD thus highlight the important role that PTD plays for the structural integrity of dentine. The obtained insights are crucial for advancing the understanding of a variety of natural and therapeutic effects from the mechanical perspective, e.g. the mechanical performance assessment of human dentine subject to complex dynamic processes of de- and re-mineralisation that can occur in human dental caries and dental treatments. It will ultimately inspire the biomimetic design towards strengthening the dentine and dentine-like materials.

人牙本质是一种矿化的牙齿组织，由被两个截然不同的牙本质相包围的牙本质小管组成：肾小管周牙本质（PTD）和肾小管间牙本质（ITD）。龋齿是脱矿质的结果，是影响人类牙齿功能的最常见的慢性疾病之一。由于微晶的堆积密度不同，PTD和ITD对酸溶解表现出不同的反应速率。本研究评估了由于增加的酸溶解过程，有效的杨氏模量如何降低以及有效应力在去矿质人牙本质中的重新分布。提出了一种分析型两层复合材料模型，并将其用于有效的杨氏模量计算。建立了PTD分数和牙本质小管密度具有不同变化的3D数值代表体积元素（RVE），以评估有效的应力重新分布并检查可能影响机械性能的关键因素。然后将模型应用于实际的牙本质散装样品。结果揭示了PTD是如何保护ITD的，从而突显了PTD对牙本质结构完整性的重要作用。所获得的见解对于从机械的角度推进对各种自然和治疗效果的理解至关重要，例如，对人类牙本质进行机械，动态的脱牙和再矿化过程可能会发生在人类龋齿和脱矿过程中，对牙本质的机械性能进行评估。牙科治疗。