치과용 지르코니아 블록의 소결온도가 기계적 특성과 미세구조에 미치는 영향
The Effects of Sintering Temperature Influence on the Mechanical Property and Microstructure of Dental Zirconia Block
조준호, 서정일, 배원태,
소속 상세정보
조준호 ( Jo Jun-Ho ) - 경상대학교 나노신소재공학부
서정일 ( Seo Jeong-Il ) - 경상대학교 나노신소재공학부
배원태 ( Bae Won-Tae ) - 경상대학교 나노신소재공학부
KMID : 0362120140360010009
Abstract
Purpose: Generally dental technicians clinically decide the sintering temperature of zirconia artificial teeth to match the color of the teeth. However, the sintering temperature influence the microstructure and mechanical strength of ceramic body. In this study, to evaluate the free choice of sintering temperature which leads to color the problems in zirconia false teeth, the variation of microstructure, mechanical strength, and colortone of zirconia ceramics according to the change of sintering temperature was investigated.
Methods: Bar type specimens were prepared from commercial zirconia blocks by cutting and polishing into 0.8 cm(L) x 1.0 cm(W) x 4.8 cm(H). Specimens were fired from 1,400 to 1,700℃ at 50℃ intervals and held for 1hour at highest temperature. Apparent porosity, water absorption, firing shrinkage, bulk density, bend strength, whiteness were tested. Microstructures were observed by SEM.
Results: When fired above 1450℃, all specimens showed 0% apparent porosity and water absorption, 20% firing shrinkage, and 6.1g/cm2 bulk density regardless of firing temperatures. SEM photomicrographs showed grain growth of zirconia occurred above 1,600℃. Whiteness was also largely changed above this temperature. Maximum bend strength of 1,050 MPa was obtained at 1,550℃. Bend strength lowered slightly above this temperature and showed 950ßA at 1,700℃.
Conclusion: In order to fit the colortone of zirconia artificial teeth, arbitrary choice of firing temperature higher than 1,500℃, up to 1,700℃ did not influence the mechanical strength.
키워드
bending strength;zirconia block;whiteness
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