치과용 시멘트액의 대기 노출시 인산아연 시멘트의 압축 및 인장강도에 관한 연구
A study on the compressive and Tensile strengths of zinc phosphate cement when the cement liquid is exposed to air
계기성, 김청규,
소속 상세정보
계기성 ( Kay Kee-Sung ) - 조선대학교 치과대학 치과보철학교실
김청규 ( Kim Chung-Kyu ) - 조선대학교 치과대학 보철학교실
KMID : 0353319860090010001
Abstract
The purpose of this study was to investigate the compressive and tensile strengths of zinc phosp?late cement specimens stored in both distilled water and saliva media 24 hours after the cement liquid was exposed at 0, 30, 60, 90,120 minutes and 24 hours respeetivelt with the air condition of 23±2℃ and 50±5% relative humidity, and then the cement powder and liquid was mixed by means of the standard consistency test described in the manufacturer.
20 specimens of control group and each experimental group, that is 240 zinc phosphate cement specimens were tested and compared.
The test specimens were prepared in a cylindrical split stainless steel mold 12^(㎜) high and 6^(㎜) in diameter.
After the mold was filled, the cement specimens were allowed to harden fbr one hour in a humidor at 37±1℃.
Upon removal from the humidor, the ends of the specimens were planed by the use of 1,000 Cw silicone carbide abrasive paper and water, and then they were separated from the mold and stored in distilled water and saliva media respectively at 37±℃
After 24 hours starting the mixing, the compressive strength was tested with the load applied axial along the cylindrical specimen and the tensile strength was employed by means of the diametral compression test.
The testing machine, Instron Universal Testing Machine, Model 4201, was operated at a cross-head speed of 0.5^(㎜)/min.
The results of this study were obtained as follows:
1. In compressive strength, the experimental group of 0 minute exposure stored in saliva media was highest, and the experimental group of 2´ hour exposure stored in distilled water media was lowest.
2. In tensile strength, the experimental group of 0 minute exposure stored in saliva media was highest, and the experimental group of 24 hour exposure stored in saliva media was lowest.
3. The compressive and tensile strengths of test specimens stored in each medium were decreased when the exposing time of the cement liquid increased.
4. Generally in compressive strength, the experimental group stored in saliva were a little stronger the experimental groups stored in distilled solution media, while in tensile strength the experimental groups stored in distilled solution media were a little stronger than the experimental groups stored in saliva media.
5. The physical properties should not be reduced opening the bottle of the cement liquid more than needed and if the cement liquid becomes cloudy, it *should not be used.
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