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Studies on the calcification mechanism of dental hard tissue by graded tracing of apatite precursors

磷灰石前驱体分级示踪研究牙齿硬组织钙化机制

基本信息

批准号：
63570862
负责人：
MORIWAKI Yutaka
金额：
$ 1.34万
依托单位：
Asahi University School of Dentistry
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1988
资助国家：
日本
起止时间：
1988 至 1989
项目状态：
已结题

项目摘要

Cation-selective membrane were used as a model cell for tissue cell to get better understanding of calcification mechanism in tooth enamel. Our previous in vitro finding has suggested that hydroxyapatite obtained by hydrolysis of octacalcium phosphate that nucleated on and grew perpendicular to the cation-selective membrane is comparable to human enamel in respect to crystal shape, crystallinity and the degree of orientation.In this report,the influence of pH and initial concentration of calcium, phosphate,carbonate,magnesium and fluoride ions on the morphology and orientation of octacalcium phosphate is studied in the cation-selective membrane system to elucidate the calcification mechanism and growth process in enamel. In order to clarify the reaction that might be taking place in the diffusion layer on the cation-selective membrane, some reactions were carried out in non-membrane system in which precipitation was initiated by adding calcium solution dropwise to phosphate solution.In most cases,these ions suppressed the crystal growth in the c-axis direction of OCP, particularly when they coexisted. The morphology of OCP crystal changed from ribbon-like to flake-like, depending on the inhibitory activity. The inhibitory activity, particularly that F^- ions, was suppressed at pH lower than pH 6.8 . Antagonistic effect of Mg^<++> and F^- ions was observed at pH 6.5 . In the case of F^- ion, OCP crystals showed a unique pattern, which suggests hydrolysis of OCP and subsequent growth of apatite. These findings indicate that inorganic ions, particularly F^- ion, influence the growth of OCP. Although CO_3 Mg^<++> and F^- ions coexisted, extended growth in the c-axis direction of OCP took place at pH 6.0.

使用阳离子选择性膜作为组织细胞的模型细胞，以更好地了解牙釉质的钙化机制。我们之前的体外研究结果表明，通过磷酸八钙水解获得的羟基磷灰石在阳离子选择性膜上成核并垂直生长，在晶体形状、结晶度和取向度方面与人牙釉质相当。在本报告中，pH和钙、磷酸根、碳酸根、镁和氟离子的初始浓度对羟基磷灰石的影响研究了阳离子选择性膜系统中磷酸八钙的形态和取向，以阐明牙釉质的钙化机制和生长过程。为了阐明阳离子选择性膜扩散层中可能发生的反应，在非膜系统中进行了一些反应，其中通过将钙溶液滴加到磷酸盐溶液中来引发沉淀。在大多数情况下，这些离子抑制了OCP c轴方向的晶体生长，特别是当它们共存时。 OCP 晶体的形态从带状变为片状，具体取决于抑制活性。抑制活性，特别是F^-离子，在pH低于6.8时被抑制。在pH 6.5时观察到Mg ^ ++ 和F ^ - 离子的拮抗作用。在 F^- 离子的情况下，OCP 晶体显示出独特的模式，这表明 OCP 水解并随后生长磷灰石。这些发现表明无机离子，特别是 F^- 离子，影响 OCP 的生长。虽然CO_3 Mg^<++>和F^-离子共存，但在pH 6.0时OCP的c轴方向发生了扩展生长。