Water-enhanced crystallization of leucite in dental porcelain.
Water-enhanced crystallization of leucite in dental porcelain.
复制标题
牙科瓷中白榴石的水强化结晶。
DOI：
10.1016/s0109-5641(00)00040-3
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
Russell,CM
中科院分区：
文献类型：
--
作者：
MackertJr,JR;Williams,AL;Ergle,JW;Russell,CM
ObjectiveThe purpose of this study was to determine whether long-term exposure of dental porcelain to saliva during temporary cementation of a porcelain-fused-to-metal (PFM) restoration could enhance leucite crystallization if the restoration is refired. Such water-enhanced leucite crystallization in dental porcelains could lead to porcelain–metal thermal incompatibility problems.MethodsSix commercial dental body porcelains and the Component No. 1 (leucite-containing) frit of the patent were studied. For each porcelain, 30 coupon specimens were randomly assigned to a treatment group. Ten specimens were placed in artificial saliva, 10 in distilled water, and 10 in a desiccator and were stored for six months. At the end of the six months, an additional 10 coupons of each porcelain were prepared to serve as a control. All 40 specimens of each porcelain were randomized and subjected to one additional firing. Leucite weight fraction was determined by quantitative X-ray powder diffraction analysis via an internal standard technique.ResultsComparisons among the treatments via the least-squares-means test-adjusting for porcelain showed that the saliva group mean leucite weight fraction was significantly higher than that of the other groups. The change in porcelain thermal expansion that would be associated with a leucite change in this range would be between 0.2×10−6K−1and 0.3×10−6K−1.SignificanceThe results of this work constitute the first demonstration that moisture absorbed by a porcelain can act as a glass modifier and enhance the crystallization of the glass during subsequent firing. The effect was sufficiently large to generate thermal expansion changes that would exceed the maximum safe mismatch between porcelain and metal.
