Valente Valdimar da Silva, Zanetti Artêmio Luiz, Feltrin Pedro Paulo, Inoue Ricardo Tatsuo, de Moura Carmem Dolores Vilarinho Soares, Pádua Luiz Evaldo de Moura
Department of Restorative Dentistry, Federal University of Piaui (UFPI), Terezina, PI, Brazil.
ISRN Dent. 2012;2012:730674. doi: 10.5402/2012/730674. Epub 2012 Dec 24.
Aim. The aim of the present study was to compare the dimensional accuracy of stone casts obtained with vinyl polysiloxane molds through the double-impression technique with three pours into the same mold. Methods. A stainless steel master model was constructed simulating a three-unit fixed prosthesis. Twelve impressions were taken of this master model with addition silicone, using the double-impression technique. Three pours of type IV gypsum were then made into each mold, thus producing 36 casts. The pours were made 1 hour, 6 hours and 24 hours after the impression procedure. Next, intra- and interabutment measurements were made in a coordinate measuring machine. Results. Comparative analysis of the dimensional accuracy of stone casts resulting from multiple pours was not statistically significant in pours first and second (P > 0.05). These values, however, were statistically significant at third pour in the height in abutment 1 and upper distance interabutment. Conclusion. The wait time (1 hour, and 6 hours) observed before pouring the stone into the same molds did not cause significant dimensional accuracy of the casts.
目的。本研究的目的是比较通过双重印模技术用乙烯基聚硅氧烷模具获得的石膏模型的尺寸精度，该技术是在同一模具中进行三次灌注。方法。构建一个模拟三单位固定义齿的不锈钢主模型。使用双重印模技术，用加成型硅橡胶对该主模型取12次印模。然后向每个模具中灌注三次IV型石膏，从而制作出36个模型。灌注在印模操作后1小时、6小时和24小时进行。接下来，在坐标测量仪上进行基牙内和基牙间测量。结果。多次灌注产生的石膏模型尺寸精度的比较分析在第一次和第二次灌注时无统计学意义（P>0.05）。然而，在第三次灌注时，基牙1的高度和基牙间上距离的值具有统计学意义。结论。在将石膏灌注到同一模具之前观察到的等待时间（1小时和6小时）不会导致模型的尺寸精度出现显著差异。
