ROLE OF DENTIN PHOSPHOPROTEIN IN DENTIN REMINERALIZATION

这项资助的主要目的是阐明牙本质磷蛋白（DPP）在人类牙本质矿化（和矿化）中所起的作用;并确定根与冠DPP可能存在差异。认为牙本质中的蛋白质序列、分子量、氨基酸和免疫反应性决定了其数量和质量，从而影响了牙本质的矿物组成、晶体取向和矿物分布。进一步假设，这种修复的组织将表现出某些相关的临床特征;对脱矿作用不太敏感;适合于脱矿物质的结合，并且具有生理功能。将分析人牙本质的连续提取物和浸提物，以确定其DPP组成。然后，将评估DPP的不同“池”;降解与非降解、可提取（可溶）与不可提取（不溶性）的分子种类（这些提取后保留在牙本质中）对牙本质的再矿化潜力、修复组织的矿物质特征和机械性能的影响。将使用化学特性与血清（矿化）相似的人工溶液对脱矿物质和浸提基质进行矿化。澄清的唾液（唾液化）也将用于尝试和估计唾液蛋白对该过程的影响。再矿化将在接近中性pH的37摄氏度下进行，并延长三周，或直到再矿化“完成”。将使用X射线衍射、SEM、TEM和显微放射照相术对组织进行表征，并使用原子力显微镜通过整体压缩试验和局部硬度和刚度分析机械性能。将在体外龋齿系统中测试组织耐受脱矿（龋齿）的能力，并与正常牙本质进行比较。将使用定量显微放射照相术分析牙本质样本。这些观察结果将是第一次比较人类冠状牙本质与牙根牙本质中DPP的数量和质量。它还将把矿化的人类牙本质的矿物特征与高度纯化和表征的DPP的各种“池”相关联。与这些基础科学发现同样重要的是，再矿化过程的临床意义，它可能会改善继发性、复发性和根龋等严重且昂贵的疾病。最终，一旦DPP及其活性（例如，引发或阻断矿物质形成）已经被鉴定，它们可用于优化患病和/或受损牙齿硬组织的修复。

The primary aims of this grant are to clarify the role played by dentin phosphoprotein (DPP) in the remineralization (and mineralization) Of human dentin; and identify that there may be differences in root versus crown DPP. It is proposed that both the quantity and quality, as defined by protein sequence, molecular weight, amino acid and immunoreactivity, affect the mineral composition, crystal orientation and mineral distribution in remineralized (repaired) dentin. It is further hypothesized that this repaired tissue will exhibit certain relevant clinical characteristics; be less susceptible to demineralization; be amenable to the bonding of restorations, and be physiologically functional. Sequential extracts and digests of human dentin will be analyzed to establish their DPP composition. Then the effects that the different "pools" of DPP; molecular species, degraded versus non-degraded, extractable (soluble) versus non-extractable (insoluble), which remain in dentin after these extractions, will have on the remineralization potential of the dentin, the mineral characteristics and the mechanical properties of the repaired tissue will be assessed. The demineralized and extracted matrices will be remineralized using an artificial solution with chemical characteristics similar to that of serum (mineralization). Clarified saliva (remineralization) will also be used to try and estimate the effects of the salivary proteins on the process. The remineralization will take place at 37 degrees C at near neutral pH, and extend for a period of three weeks, or until remineralization is "complete". The remineralized tissue will be characterized using x-ray diffraction, SEM, TEM and microradiography and the mechanical properties analyzed by bulk compression tests and local hardness and stiffness using atomic force microscopy. The ability of the tissue to withstand demineralization (caries) will be tested in an in vitro caries system and compared with normal dentin. The dentin specimens will be analyzed using quantitative microradiography. The observations will be the first to compare the quantity and quality of DPP in human coronal, versus root dentin. It will also relate the mineral characteristics of the remineralized human dentin to the various "pools" of highly purified and characterized DPP. Of equal importance to these basic science findings will be the clinical implications of the remineralization process which may ameliorate the significant and costly conditions, secondary, recurrent and root caries. Ultimately, once the DPP's and their activity (for example, initiating or blocking mineral formation) have been identified they can be used in optimizing the repair of diseased and/or compromised dental hard tissues.