Okuda N, Ueno S, Kawada E, Nakanishi K, Sumii T
Department of Dental Technology, Tokyo Dental college.
Shikwa Gakuho. 1990 Feb;90(2):225-30.
In this study, the authors have attempted to discover optimum conditions for eliminating all porosity, except what is caused by manual error, in the surfaces of Die Stone. Five vinyl-porisiloxane impression materials, two other kinds rubber impression materials, and two kinds of die materials were used. Die materials were poured at intervals of 0, 15, 30, 60, and 120 minutes after the impression had been removed. Cast-surface porosity was measured by means of SPICCA II. Results 1. Practically surface porosities were not scarcely observed in casts made from any of the impression materials except vinyl silicone rubber. Among the five vinyl-polysiloxane impression materials, Hydrophilic Exaflex produced the least porosity. 2. Porosity in casts made with Provil tended to decrease definitely as pouring time progressed. This tendency occurred with no other materials. 3. When the die material was mixed at a low water-powder ratio, cast-surface porosity was reduced in the case of all materials except President. 4. Concentration of hydrogen gas, which was released from all vinyl-polysiloxane impression materials, decreased with the passing of time. 5. In the case of Provil, a correlation existed between hydrogen-gas concentration and the degree of cast-surface porosity. But no similar correlation was observed in the case of any other vinyl-polysiloxane impression materials.
在本研究中，作者试图找出消除铸模石膏表面所有孔隙（人为误差导致的孔隙除外）的最佳条件。使用了五种乙烯基聚硅氧烷印模材料、另外两种橡胶印模材料和两种铸模材料。取出印模后，分别在0、15、30、60和120分钟的间隔时间灌注铸模材料。通过SPICCA II测量铸模表面孔隙率。结果如下：1. 除乙烯基硅橡胶外，实际上用任何印模材料制作的铸模表面几乎都未观察到孔隙。在五种乙烯基聚硅氧烷印模材料中，亲水性Exaflex产生的孔隙最少。2. 用普维（Provil）制作的铸模孔隙率往往随着灌注时间的延长而明显降低。其他材料未出现这种趋势。3. 当铸模材料以低水粉比混合时，除总统牌（President）外，所有材料制作的铸模表面孔隙率均降低。4. 所有乙烯基聚硅氧烷印模材料释放的氢气浓度随时间降低。5. 对于普维材料，氢气浓度与铸模表面孔隙率程度之间存在相关性。但在任何其他乙烯基聚硅氧烷印模材料中未观察到类似的相关性。
