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염근창,고대진,장감용,이서영,김경남 大韓齒科器材學會 1994 대한치과재료학회지 Vol.21 No.1
In this study, the prepared glasses were heat-treated to precipitate the leucite crystal in order to control the thermal expansion coefficient which is an important property of dental porcelain powder. The effect of addition of Li₂O and Na₂O on the amount of the precipitated leucite crystal were also examined. The mixing ratio of the leucite-containing glass must be controlled to match the thermal expansion coefficient of dental porcelain to that of metal. The physical properties of the dental porcelain powder prepared in this study were characterized. The results of this study were obtained as follows : 1. Conditions for the preparation of the maximum amount of leuctie crystal were compostion L-2(2.0 wt% Li₂O added) heat-treated at 950℃. 2. The phase of the precipitated crystals was turned out to be the tetragonal leucite crystal. 3. Maximum relative crystallinity was 64.2% for composition L-2, heat-treated at 950℃. Its linear thermal expansion coefficient was 16.1×10-6/℃ in the range of room temperature to 500℃. 4. The optimum mixing ratio of the leucite-containing glass was 45% in order to match the thermal expansion coefficient of dental porcelain to that of metal. In this case, the thermal expansion coefficient of the prepared dental porcelain was 10.6×10-6/℃ (∼500℃). 5. The physical and chemical properties of the prepared dental porcelain were suitable for the requirements of ISO 6872 and 9693.