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BASIC STUDIES ON DENTAL GLASS CERAMICS WITH HIGH FORMBILITY AND TOUGHNESS

高成形高韧性牙科玻璃陶瓷的基础研究

基本信息

批准号：
07457469
负责人：
TSUTSUMI Sadami
金额：
$ 4.48万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07457469/
关键词：
GLASS CERAMICS RESTORATION FORMABILITY TOUGHNESS DIOPSIDE PRESS FORMING CRYSTALIED GLASS 歯科用ガラスセラミックス

项目摘要

We have developed a glass ceramic material of Diopside (CaO・MgO・2SiO_2) for dental restoration with very high press-formability at low temperatures, remarkable toughness and esthetic transparency. The results are as follows ;1.It becomes possible to have an enough flowability under a low pressure of 0.1 MPa at low temperatures between 900 and 930ﾟC Since the conventoinal glass ceramics can be pressed only at higher temperatures than 1200ﾟC,our material enables to save the heating energy and to use the conventional common gypsum-bonded investments.2.I is possible to crystallize this glass after the press forming in the investment mold directly without any heat re-treatment. The bending strength of our material is higher than 400 MPa which is more than double of those of the conventional dental ceramics. And, its toughness is 2.7 MPa・m^<1/2> which is more than 3-4 times as high as those of them.3.In observation s by a high temperature optical microscope with a graphical analyzer at heating rate of 50ﾟC/min up to 900-1100ﾟC,band structures have generated. They gradully and continuously grew from the glass matrix. This structure should be the crystal grains of Diopside with 1% shrinkage.4.From the observations by SEM and TEM the crystallizing process of Diopside can be summarized below. Under the heat treatment the "ordering" was happened by the ion dispersing in the amorphous matrix. In the initial stage, irregular precipitates appeared accompanying micro cracks (crater-like). The repetition of this process has finally constructed scale-like and plate-like structures of very fine grains.

我们研制了一种透辉石（CaO·MgO·2SiO_2）玻璃陶瓷材料，该材料具有良好的低温压制成型性、韧性和透明性。结果如下：1.可以在900 - 930 ℃的低温下在0.1MPa的低压下具有足够的流动性。由于传统的玻璃陶瓷只能在高于1200 ℃的温度下压制，我们的材料能够节省热能，并使用传统的普通石膏，2.在熔模模具中压制成型后，可以直接使这种玻璃结晶，而无需任何热再处理。该材料的抗弯强度大于400 MPa，是传统牙科陶瓷材料抗弯强度的2倍以上。3.在高温光学显微镜下，以50 ℃/min的升温速率升温至900-1100 ℃，观察到带状结构的形成。它们从玻璃基质中逐渐地、不断地生长。这种结构应该是透辉石的晶粒，收缩率为1%。4.通过SEM和TEM的观察，透辉石的结晶过程可以概括如下。在热处理条件下，通过离子在非晶基体中的分散，实现了有序化。在初始阶段，不规则的析出物出现伴随着微裂纹（火山口状）。重复这一过程，最终形成了非常细的颗粒的鳞片状和板状结构。