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열가압 및 열처리에 따른 IPS Empress 2 세라믹의 굴곡강도와 미세구조
FLEXURE STRENGTH AND MICROSTRUCTURE OF IPS EMPRESS 2 GLASS-CERAMIC ON HEAT PRESSING AND HEAT TREATMENTS

대한치과보철학회지 2000년 38권 5호 p.575 ~ 582

오상천, 동진근, Luthy Heinz, Scharer Pater,

소속 상세정보

오상천 ( Oh Sang-Chun ) - 원광대학교 치과대학 치과보철학교실
동진근 ( Dong Jin-Keun ) - 원광대학교 치과대학 치과보철학교실
( Luthy Heinz ) - 취리히대학교 치과대학 치과보철학교실
( Scharer Pater ) - 취리히대학교 치과대학 치과보철학교실

KMID : 0362420000380050575

Abstract

This investigation was designed to determine whether heat-pressing and/or simulated heat treatments affected the flexure strength and the microstructure of the lithium disilicate glassceramic in the IPS Empress 2 system. Four groups of the specimens were prepared as follows group 1 - as-received material ; group 2 - heat-pressed material ; group 3 - heat pressed and simulated initial heat-treated material ; group 4 - heat-pressed and the simulated heat-treated material with full firings for a final restoration. The three-point bending test and the scanning electron microscope (SEM) analysis was conducted for the purpose of this study. The flexure strength of group. 2 was significantly higher than that of group 1. However, there were no significant differences in strength among group 2, 3, and 4, and between group 1 and 4. The SEM micrographs of the lithium disilicate glass-ceramic showed the closely packed, multi-directionally interlocking microstructure of numerous lithium disilicate crystals protruding from the glass matrix. The crystals of the heat-pressed materials (group 2, 3, and.4) were a little denser and about two times bigger than those of the as-received material (group 1). This change of microstructure is more obviously exhibited particularly between group 1 and 2. However, there was no a marked difference among group 2, 3, and 4 after the heat pressing procedure. Although there were significant increase of the strength and some changes of the microstructure after the heat-pressing operation, the conr bination of the heat-pressing and the simulated subsequent heat treatments did not produce the increase of strength of IPS Empress 2 glass-ceramic.