CARBONATO APATITE FORMATION IN ENAMEL MINERALIZATION

牙釉质矿化过程中碳磷灰石的形成

• 批准号: 3222495
• 负责人: TAKAAKI AOBA
• 金额: $ 10.5万
• 依托单位: ADA FORSYTH INSTITUTE, INC.
• 依托单位国家: 美国
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-09-01 至 1991-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3222495
• 关键词: X ray crystallography; apatites; calcification; calcium; carbon dioxide; carbonates; chlorine; chromatography; dental caries; electron microscopy; fluorine; infrared spectrometry; macromolecule; magnesium; phosphates; phosphorus; potassium; radiotracer; sodium; stoichiometry; swine; tooth enamel; tritium

Of the inorganic constituents different from calcium and phosphorus, carbonate in the enamel fluid seems to be high enough to affect the mineralization process during amelogenesis. Carbonate is incorporated in substantial amounts into the crystalline lattice of the enamel crystals; this incorporation results in defects which function as reactive sites for demineralization or caries formation. The present proposal, intends to elucidate the mechanisms of carbonato apatite formation during amelogenesis and the chemical properties of enamel mineral, includes the following aspects: 1) Determination of the solubility and solubility product of enamel apatites separated at specific developmental stages of amelogenesis. The enamel samples will be obtained from the permanent dentitions of piglets. Equilibration of the mineral in acidic solutions will be conducted under partial pressures of CO2 similar to those in the enamel fluid. The analytical results of the equilibrating solutions will be used to test several models with respect to the stoichiometry and the type of the carbonate substitution in the lattice of the enamel crystals. 2) Assignment of the location of carbonate ions (adsorption onto enamel apatites and/or substitutions in the PO4 or OH sites of the lattice). Special interest will be focused on the carbonate associated with the initially forming crystals. The proposed approach will combine chemical, IR, EM, and ion chromatography techniques. 3) Investigation of adsorption of enamel matrix proteins onto carbonato apatites. Batches of the adsorbents will be prepared in aqueous systems and characterized with respect to chemical composition, carbonate substitution, specific surface area and crystal morphology. The adsorbates will be obtained from secretory porcine enamel. Adsorbate-adsorbent equilibrations will be conducted in solutions having partial CO2 pressures and ionic strength similar to those of enamel fluid. 4) The possible mechanism of carbonate incorporation into the forming enamel apatite. The experimentation will be conducted using synthesized carbonato apatites as seen in supersaturated solutions having similar composition to that of enamel fluid. The proposed research will give basic information about the developmental maturation of enamel crystals, the formation of crystal defects, and the effect that pertinent biological parameters have on the stability of dental enamel in normal and cariogenic environments.

无机成分不同于钙， 牙釉质液中的磷、碳酸盐似乎足够高 影响釉质形成过程中的矿化过程。 碳酸盐以大量掺入到 釉质晶体的晶格;这种结合 导致作为反应位点的缺陷， 去矿化或龋齿形成。 目前的提案， 旨在阐明碳磷灰石的机制 釉质形成过程中的化学性质 釉质矿物质，包括以下几个方面： 1)牙釉质溶解度和溶度积的测定 磷灰石在特定的发展阶段分离， 釉质形成 搪瓷样品将从 仔猪的恒牙列。 矿物质平衡 酸性溶液将在CO2分压下进行 与釉质液中的相似 的分析结果 平衡溶液将用于测试几个模型， 关于碳酸盐的化学计量和类型 在釉质晶体的晶格中的取代。 2)碳酸根离子位置的分配（吸附到 釉质磷灰石和/或在PO 4或OH位点的取代 晶格）。 特别的兴趣将集中在碳酸盐 与最初形成的晶体有关。 拟议 方法将结合联合收割机化学、IR、EM和离子色谱 技术. 3)牙釉质基质蛋白质吸附在生物材料上的研究 碳磷灰石 吸附剂批次将在 水性体系，其特征在于化学 组成、碳酸盐取代、比表面积和 晶体形态 吸附物将从 猪分泌釉质 吸附-吸附平衡 将在具有CO2分压的溶液中进行， 离子强度与釉质液相似。 4)碳酸盐掺入的可能机制 形成釉质磷灰石。 实验将在 使用合成的碳酸磷灰石， 具有与釉质流体相似的组成的溶液。 拟议的研究将提供有关 釉质晶体的发育成熟， 晶体缺陷，以及相关生物学效应 参数对正常牙釉质稳定性的影响， 致龋环境