1996 Fiscal Year Final Research Report Summary
BASIC STUDIES ON DENTAL GLASS CERAMICS WITH HIGH FORMBILITY AND TOUGHNESS
| Project/Area Number |
07457469
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
補綴理工系歯学
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
TSUTSUMI Sadami Kyoto University, Research Center for Biomedical Engineering, Professor, 生体医療工学研究センター, 教授 (00028739)
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| Co-Investigator(Kenkyū-buntansha) |
NAMBU Toshiyuki Life Tech Insttitute, Inc., Director, 所長
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| Project Period (FY) |
1995 – 1996
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| Keywords | GLASS CERAMICS / RESTORATION / FORMABILITY / TOUGHNESS / DIOPSIDE / PRESS FORMING / CRYSTALIED GLASS |
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| Research Abstract |
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.
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