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）在人类牙本质再矿化（和矿化）中的作用；并确定根与冠的DPP可能存在差异。由蛋白质序列、分子量、氨基酸和免疫反应性所定义的数量和质量影响再矿化（修复）牙本质中的矿物组成、晶体取向和矿物分布。进一步假设，修复后的组织将表现出某些相关的临床特征；不易脱矿；适应修复的结合，并具有生理功能。将对人类牙本质的顺序提取物和消化物进行分析，以确定其DPP组成。然后分析了不同“池”对民进党的影响；这些提取后留在牙本质中的分子种类，降解与非降解，可提取（可溶性）与不可提取（不可溶性），将对牙本质的再矿化潜力产生影响，将评估修复组织的矿物特征和机械性能。脱矿和提取的基质将使用化学特性与血清相似的人工溶液（矿化）进行再矿化。澄清的唾液（再矿化）也将被用来尝试和估计唾液蛋白在这一过程中的影响。再矿化将在37摄氏度下进行，pH值接近中性，并持续三周，或直到再矿化“完成”。再矿化组织将使用x射线衍射、扫描电镜、透射电镜和显微放射照相进行表征，并通过体压缩测试和原子力显微镜分析局部硬度和刚度的力学性能。组织承受脱矿（龋齿）的能力将在体外龋齿系统中进行测试，并与正常牙本质进行比较。牙本质标本将使用定量显微放射照相进行分析。该观察将是第一个比较人类冠状牙本质与根牙本质中DPP的数量和质量的观察。它还将再矿化人类牙本质的矿物特征与各种高度纯化和表征的DPP“池”联系起来。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，它可以改善继发性、复发性和根性龋齿的严重和昂贵的情况。最终，一旦DPP及其活性（例如，启动或阻断矿物质形成）被确定，它们就可以用于优化患病和/或受损牙硬组织的修复。

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.