CHARACTERIZATION OF NORMAL AND ALTERED FORMS OF DENTIN

正常和变异形式牙本质的特征

• 批准号: 6201773
• 负责人: GRAYSON W MARSHALL
• 金额: $ 24.56万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-08-01 至 2000-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6201773
• 关键词: X ray crystallography; X ray microscopy; atomic force microscopy; chemical structure; collagen; cryopreservation; dental caries; dental development; dental structure; dentin; histology; human tissue; infrared spectrometry; interferometry; morphology; nanotechnology; scanning electron microscopy; surface property; transmission electron microscopy

Dentin microstructure and properties are determinants of nearly all operations in restorative dentistry. Normal dentin exhibits variation in structure and properties with location, but among the various additional dentin types, the altered forms of carious coronal dentin and sclerotic root dentin are particularly important. They result from vital defensive mechanisms associated with the odonoblasts which alter composition, hardness and permeability. These altered forms of dentin are important substrates for dentin bonding. Thus progress in adhesion to dentin and dentin physiology require a thorough knowledge of their basic microstructure, composition, and properties. This project will extend the knowledge and techniques developed ina th prior period for normal dentin to these two important variations of dentin which are encountered in many clinical situations. Caries produces a multi-layered structure in dentin with varying degrees of structural loss, demineralization and hypermineralization. Traditionally the deepest altered layer is termed transparent dentin, due to its altered refractive index or sclerotic dentin to reflect the increase in hardness due to increased mineralization. However, in some cases, transparent dentin is softer than normal dentin. This suggests that varying subclasses of transparent dentin could result from caries and suggests that the use of transparent and sclerotic dentin as interchangeable terms may not be correct. Sclerotic dentin of the root is much less studied, and is considered to form due to a variety of irritation processes in the cervical region and aging throughout the root, even in the absence of caries and is characterized by occlusion of the tubule lumen with additional crystals that are acid resistant, at least in cervical lesions. Alteration of the intertubular dentin has not been established. it is clear that there is insufficient information on the structure and properties of these altered dentins and their particular zones. The central hypothesis to be tested is that the structure of transparent carious dentin and sclerotic non-carious root dentin exhibit important structural, compositional, and properties differences as compared with normal dentin. We will test this hypothesis and clarify the structure and properties of these altered forms of dentin through conduct of ten specific aims, five related to caries and five parallel aims related to sclerotic cervical and root dentin. These include mapping zones of altered dentin including the mineral level by XTM, structure by SEM/EDS and AFM, hardness by microhardness and AFM nano-hardness (aims 1,6). We also will test the hypothesis that altered forms of dentin respond differently to demineralization and exhibit changes in permeability (aims 2,6). The hypothesis that the composition and structure of the intertubular zone mineral is altered, while the peritubular is not, will be tested for carious dentin using micro-FTIR, AFM, SEM/EDS/WDS and TEM with electron diffraction and PEELS (aims 3,4). Similar studies will be conducted for sclerotic cervical and root dentin using similar methods (aims 8,9).

牙本质微观结构和特性几乎是所有的决定因素 修复牙科的操作。 正常牙本质表现出变化 结构和属性具有位置，但在各种附加 牙本质类型，变化的龋齿冠状牙线和硬化 根牙本质特别重要。 它们是由重要的防御造成的 与改变组成的ODONOBLASTS相关的机制， 硬度和渗透性。 这些改变形式的牙本很重要 牙本质结合的底物。 因此，牙本的粘附进展和 牙本质生理学需要透彻了解其基本 微结构，组成和属性。 该项目将扩展 普通牙本的知识和技术在前期开发了 这两个重要的牙本质变体在许多人中遇到 临床情况。 龋齿在牙本质中产生多层结构，不同程度 结构损失，脱矿化和高矿化。 传统上 最深层改变的层被称为透明牙本质，由于其改变了 折射率或硬化牙本质以反映硬度的增加 由于矿化增加。 但是，在某些情况下，透明 牙本质比正常牙本质柔软。 这表明各种子类 透明的牙本质可能是由龋齿造成的，并建议使用 透明和硬化性牙本作为可互换的术语可能不是 正确的。 根的硬化牙本质的研究要少得多，并且是 由于颈椎的各种刺激过程而被认为是形成的 区域和衰老整个根，即使在没有龋齿的情况下， 以其他晶体的阻塞为特征 至少在宫颈病变中是抗酸性的。 改变 尚未建立细胞间牙本质。 显然有 关于这些已更改的结构和属性的信息不足 牙本质及其特定区域。 要测试的中心假设是透明的结构 龋齿牙本质和硬化非讽刺根牙本质很重要 与结构，成分和特性差异相比 正常牙本质。 我们将检验该假设，并阐明结构和 这些改变形式的牙本质的特性，通过执行十个特异性 目的，五个与龋齿有关，五个与硬化有关的平行目的 宫颈和根牙本质。 这些包括改变牙本质的映射区域 包括XTM的矿物水平，结构SEM/EDS和AFM，硬度 按照微标志和AFM纳米硬度（目标1,6）。 我们还将测试 牙本质形式改变形式的假设对 去矿化和渗透性的变化（目标2,6）。 这 假设的组成和结构 矿物质已改变，而周围的矿物质则不会进行测试 使用Micro-FTIR，AFM，SEM/EDS/WDS和Elector的TEM使用Micro-FTIR，使用Micro-FTIR 衍射和剥离（目标3,4）。 类似的研究将进行 使用类似的方法（目标8,9），硬化宫颈和根牙本质。