1986 Fiscal Year Final Research Report Summary
Development of in vitro Testing Method Predicting the Durability of Posterior Resins
| Project/Area Number |
60440087
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
Conservative dentistry
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| Research Institution | Tokyo Medical and Dental University |
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Principal Investigator |
HOSODA Hiroyasu Tokyo Medical and Dental University Faculty of Dentistry, 歯学部, 教授 (30018410)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAJIMA Akitomi Department of Operative Dentistry, Faculty of Dentistry Tokyo Medical and Dental, 歯学部, 助手 (20143597)
HORIE Kyoichi Department of Operative Dentistry, Faculty of Dentistry Tokyo Medical and Dental, 歯学部, 助手 (40173629)
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| Project Period (FY) |
1985 – 1986
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| Keywords | Posterior Composite Resin / Durability / 繰り返し圧縮 |
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| Research Abstract |
This study was undertaken to develop the in vivo testing method which can properly predict the durability of the posterior restorative composite resins for a short period of time and to supply some information regarding improvement of the resin materials having superior durability.
The findings were as follows:
1. Composite resins under the repeated stress decreased the compressive strength as compared with the specimens under the static condition.
2. The compressive strength of the resins stored in 0.1N NaOH solution was remarkably lower than that of the specimens stored in distilled water.
3. When the resins stored in NaOH solution were abraded under the compressive load of 20kg/ <cm^2> at 500,000cps by a new type wear testing machine deviced by our department, the wear rate was nearly equal to that of the restorations served in mouth for two years.
4. Resin specimens including air bubbleless remarkably decreased the phusical properties and wear rate. Therefore, it is suggested that bubbleless mixing technique deviced by HOSODA may contribute to the improvement of the durability of the resins.
From these findings, it is proved that both the repeated loading test and the wear test set up on the basis of the new idea would be feasible properly to forecast the long-term durability in vivo of the posterior restorative composite for a short period of time. Furthermore, it is concluded that the ideal posterior composite resins should have the strong resistance against the hydrolysis, heavy fill of the stress bearing filler material and tight bond between the fillers and matrix resins.
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