Photomechanical characterization of dentin hard tissue mechanics

牙本质硬组织是一种复杂的、水合的、生物复合材料，构成了牙齿的主要部分。虽然牙本质的无机和有机组分与力学性能的相关性是已知的，但微观结构变化和材料性能梯度对牙本质对机械力响应的影响尚未得到很好的确定。了解功能适应的微观结构和材料性质梯度对牙本质等重要结构生物材料的机械完整性的作用一直是一个具有挑战性的问题；然而，组织各向异性对牙硬组织功能反应的影响在以往的研究中尚未得到一致的探讨。缺乏对牙齿硬组织功能特征的了解是牙齿断裂和修复体/假体/种植体遇到的其他许多问题的主要原因。照相力学实验是高分辨率的全场实验，在生理负荷下提供实时的原位信息。目前的研究重点是开展牙本质硬组织显微应变的显微力学实验，研究成分变化和显微结构变化对牙本质对机械载荷响应的影响。将采用光力学实验、有限元分析和牙本质模型体外实验。提出的基于微应变/应力的牙本质组织对力响应的理解不仅将为生物材料的开发提供良好的机制基础，而且有助于建立预测牙本质在不同模拟条件下的生物力学响应的模型。该项目将为硬组织表征和硬组织康复开辟新的前景。

Dentin hard-tissue is a complex, hydrated, biocomposite that forms the major bulk of teeth. Though the relevance of the inorganic and organic fractions of dentin on the mechanical properties is known, the effect of microstructural variations and material property gradients on the response of dentin to mechanical forces is not well established. Understanding the role of functionally adapted microstructural and material property gradients on the mechanical integrity of an important structural biomaterial such as dentin has always been a challenging problem; however, past research have made no concerted effort to investigate the effect of tissue-anisotropy on the functional response of dental hard-tissues. This dearth in the understanding of the functional characteristics of dental hard-tissue is the primary reason for tooth fracture and other numerous problems encountered with restorations/prostheses/implants. Photomechanical experiments are high resolution whole-field experiments that provide real-time in situ information, under physiological loads. The current research program will focus on developing photomechanical experiments to determine the microstrains of dentin hard tissue, study the role of compositional changes and microstructural changes on the response of dentin to mechanical loads. Photomechanical experiments, Finite Element Analysis and in vitro experiments on dentin models will be employed. The proposed microstrain/stress based understanding of the dentin tissue response to forces will not only provide a sound mechanistic basis for biomaterial development, but also aid in developing models to predict biomechanical response of dentin at different simulated conditions. This project will open new vistas in hard-tissue characterization and rehabilitation of hard-tissues.