IXdent: Integrative X-ray techniques for chemical and structural characterizations of dental interzones

牙科治疗包括用人工不可降解材料修复退化的牙齿组织，目的是实现持久的机械和美学耐久性。在健康牙齿组织和牙齿修复体之间不可避免地形成一个厚的界面（区间）。我们将填充物和牙齿组织之间的过渡区域确定为一个独特的区域，因此我们将其命名为“牙齿间区”，其中的成分与构成填充物的填充物和牙齿组织都不同。因此，牙带间包含复杂的微观几何和化学梯度，介于各种牙科材料和天然硬组织（如牙釉质或牙本质）的分层结构之间。这种带间的退化往往是恢复失败和需要重新处理的原因。在牙科研究中，对材料成分的不稳定性、老化以及填充物与牙基之间邻近区域的变化和影响的方法学研究有限。在并放在一起的材料中跟踪动态降解是具有挑战性的，因为它们在主要成分（天然牙齿组织中普遍存在轻元素，而填充物中通常存在重元素）、密度和结构上存在差异。该项目的目的是通过同步加速器x射线折射成像（SXRR）和断层扫描（SXRCT）以及微x射线CT成像（µXCT）和微x射线荧光（µXRF）在2和3个维度上的耦合，推进一种适用于牙齿区域间的多模态定量成像方法。为此，所使用的方法将适应调查对象，3D数据集将被耦合（注册），包括不确定性评估在内的定量考虑将使该方法成为真正的分析工具。这一发展将为绘制牙齿修复失败铺平道路，并有助于了解牙齿组织和人工填充材料之间区域附近和周围的可预测变化。这是控制不必要的化学和结构/密度降解的重要一步，可能成为牙科研究中新的标准方法工具。未来的最终目标是支持和加强临床治疗程序。

Dental treatment includes restoration of degraded tooth tissue with artificial non-degradable materials with the aim of achieving long-lasting mechanical and aesthetic durability. Inevitably a thick interface (interzone) is formed between healthy tooth tissue and dental restoration. We identify the transition region between filling and tooth tissue as a distinct region that we henceforth name 'dental interzone', where composition is different from both the filling and dental tissue that comprise the filling. Thus, dental interzones comprise complex micro-geometries and chemical gradients, between a variety of dental materials and the hierarchical structure of natural hard tissues such as enamel or dentin. Degradation in such interzones is often the reason for restoration failure and a need for retreatment.In dental research there have been limited methodological studies on material composition instability, ageing and changes and effects on the immediate vicinity of interzones between filling and tooth substrate. Tracking of dynamic degradation in the juxtaposed materials is challenging, as they differ in main constituents (light elements prevail in the natural tooth tissue, whereas heavy elements are typical for fillings), density and structure. The aim of this project is to advance a multi-modal quantitative imaging methodology adapted to dental interzones by coupling synchrotron X-ray refraction radiography (SXRR) and tomography (SXRCT) as well as micro X-ray CT imaging (µXCT) with micro-X-ray fluorescence (µXRF) in 2 and 3 dimensions. For this purpose, the used methods will be adapted to the objects of investigation, the 3D data sets will be coupled (registered) and quantitative considerations including uncertainty evaluations will render the methodology into a true analytical tool.This development will pave the way to mapping tooth restoration failure and help understand predictable changes close to and around the interzones between dental tissue and artificial filling material. This is an important step towards controlling unwanted chemical and structural/density degradation and might become a new standard methodological instrument in dental research. The ultimate goal in the future is to support and enhance clinical treatment procedures.