Material aging abutting restorations: predicting dentine sclerosis

在InterDent研究小组的范围内，项目1研究了化学老化的牙本质的微/纳米结构和化学属性，这是一种天然的生物材料，经常变得硬化，特别是在牙齿填塞物附近。为了预测处理后牙本质发生的结构和成分变化的动态，有必要定量地评估这些化学和物质性质在牙本质硬化过程中的变化。尽管当代牙粘接剂的临床性能有了普遍的改善，但较少侵入性的治疗需要了解先前治疗过的、化学老化的牙本质作为基质的状态。我们假设牙本质邻近修复体经历了细微的微观结构和性质变化，随着时间的推移而积累。我们使用含锌牙齿填充材料来探索这种化学老化过程的时空方面。随着化学老化的逐渐增加，小管内部和周围的成分变化与填充的成分和沿小管的距离都有一定的关系。在这个项目中，通过三个研究所的合作，我们使用材料科学的方法来量化修复附近牙本质密度和矿物质属性的变化。高灵敏度3D XRF方法将结合衍射和成像研究来探索化学成分和机械变形能力的变化。这种天然材料转变为过渡“间区”的各个方面，仍然具有维持修复牙齿内功能的机械能力，正在使用高分辨率2D和3D方法进行量化。我们将阐明关键元素的分布和化学状态的变化，如牙本质的正常成分Ca和主要通过扩散过程引入结构的元素Zn。我们的总体目标是建立一个牙本质硬化模型系统，以高灵敏度和高分辨率非破坏性地量化变化，并将不同分析技术获得的结果相关联。我们期望获得更好的材料和关于结构和元素组成变化的临床理解，我们将在模型系统和体内发展的硬化组织之间进行比较。

Within the scope of the research group InterDent, project 1 examines micro/nano structural and chemical attributes of chemically-aged dentine, a natural biomaterial that often becomes sclerotic especially near dental fillings. To predict the dynamics of structural and compositional changes incurred in treated dentine, it is necessary to assess these chemical and material property changes during the process of dentine sclerosis in a quantitative manner. Despite a general improvement in clinical performance of contemporary dental adhesives, less invasive treatment requires knowledge about the state of previously treated, chemically aged dentine that serves as a substrate. We hypothesize that dentine abutting restorations undergoes subtle microstructure and property changes, accumulating with time. We use Zn-containing dental filling materials to explore spatio-temporal aspects of this chemical aging process. With increased gradual chemical aging, the composition within and around tubules changes with some relation to the filling both in terms of composition and with relation to distance along tubules. Within the project and through cooperation between 3 institutes, we use material science methods to quantify changes in the density and mineral attributes of dentine near restorations. High sensitivity 3D XRF methods will be combined with diffraction and imaging investigations to explore changes in chemical composition and mechanical deformability. Various aspects of the transformation of this natural material into a transition 'interzone' that still has mechanical competence to sustain function within restored teeth are being quantified using high resolution 2D and 3D methods. We will elucidate changes in the distribution and chemical state of crucial elements such as Ca - normal constituent of dentine - and Zn - an element primarily introduced into the structure through diffusion processes. Our overall objectives are to develop a dentinal sclerosis model system, to quantify the changes non-destructively with high sensitivity and with high resolution and to correlate results obtained by different analytical techniques. We anticipate obtaining a better materials and clinical understanding about changes in structure and elemental composition which we will compare between model systems to in-vivo developing sclerotic tissue.