MULTISCALE MODELLING OF ENAMEL DEMINERALISATION AND ACELLULAR REPAIR

牙齿侵蚀被定义为牙齿结构的化学溶解导致牙齿硬组织的损失，而没有细菌的影响。侵蚀通常被定义为具有内在原因（由于牙齿表面暴露于胃肠道酸）或外在原因（由于牙齿暴露于饮食/环境酸）。在发达国家，牙齿侵蚀越来越普遍，对牙科医生来说，对受损牙齿的可预测管理是一个重大挑战。作为一种进行性疾病（由于牙釉质缺乏内在的生物修复机制），牙侵蚀与人口老龄化有关。因此，预防仍然是关键，虽然行为改变（饮食或改善内在因素）是必不可少的，但迫切需要能够延迟、预防和逆转早期脱矿的消费品。已经有相当多的努力来模拟离体牙侵蚀。这些方法通常将动物或人类牙齿表面暴露在酸中，并通过成像定性地测量所产生的表面变化[3,4]，或通过测量和表面微机械性能表征定量地测量所产生的表面变化[5-8]。两个主要限制是：(i)无法将分层组织的矿化牙齿结构（釉质棱柱取向，大小，羟基磷灰石晶体大小和质地，矿化牙齿结构中取代离子的存在）的特定可变性联系起来（ii）难以实时监测溶解顺序及其对结构完整性的影响。

Dental erosion is defined as the loss of dental hard tissues through chemical dissolution of the tooth structure without bacterial involvement [1]. Erosion is classically defined as having an intrinsic aetiology (due to exposure of tooth surfaces to gastro-intestinal acids) or extrinsic aetiology [2] (due to exposure of the teeth to dietary/environmental acids). Dental erosion has an increasing prevalence in the developed world and represents a significant challenge to dental practitioners in terms of the predictable management of the damaged dentition. As a progressive condition (due to the lack of intrinsic biological repair mechanisms for dental enamel), dental erosion is of relevance to our ageing population. Prevention therefore remains key, and whilst behavioural change (diet or amelioration of intrinsic factors) is essential, consumer products to delay, prevent and reverse early demineralisation are urgently sought. There have been considerable efforts to model dental erosion ex-vivo. These approaches typically expose animal or human tooth surfaces to an acid challenge and measure the resultant surface changes qualitatively through imaging [3, 4] or quantitatively through metrology and characterisation of surface micromechanical properties [5-8]. The two main limitations are (i) an inability to relate the specific variability of the hierarchically organised mineralised tooth structure (enamel prism orientation, size, hydroxyapatite crystallite size and texture, presence of substitutional ions within the mineralized tooth structure) (ii) difficulties in monitoring the sequence of dissolution and its impact on structural integrity in real-time.