Mazzetto M O, Roselino R B, Gabrielli F, Campos G M
Departamento de Materiais Dentários e Prótese, Universidade de São Paulo.
Rev Odontol Univ Sao Paulo. 1990 Apr-Jun;4(2):144-9.
The authors studied the ability of three elastomeric impression materials in reproducing and transmitting three grooves, engraved in the polished surface of a stainless steel model, to gypsum models. The grooves were 17, 21 and 25 micrometers wide, and the fails in reproducing, as well as in transmitting the minor details to gypsum, were also investigated as to the effects of gypsum particle size, proportional relation water/powder and plasticity of the mixture. The three elastomeric impression materials used were a polysulfide, a silicone and a polyether, and the six gypsum products were two improved stones type IV, two dental stones type III and two dental plasters type II. Scores 3, 2 and 1 were attributed respectively to the 17, 21 and 25 micrometers grooves reproduced in the molds, as well to the same grooves transmitted to the gypsum models. The results showed that all the impression materials tested were able to reproduce in the molds all the three grooves present in the steel model. Nevertheless, when gypsum models were examined, it was verified that the grooves so well reproduced in the molds were neither equally nor uniformely registered in the respective models, the best results being achieved by the polysulfide and the silicone, an the worst by polyether, As to the gypsum products, the type II gypsum presented the most unfavorable results.
作者研究了三种弹性印模材料在将刻于不锈钢模型抛光表面的三条凹槽复制并传递至石膏模型方面的能力。这些凹槽宽度分别为17、21和25微米，还研究了在复制以及将微小细节传递至石膏过程中的失败情况，涉及石膏粒度、水/粉比例关系以及混合物可塑性的影响。所使用的三种弹性印模材料分别是聚硫橡胶、硅橡胶和聚醚，六种石膏产品为两种改良IV型石膏、两种III型牙科石膏和两种II型牙科石膏。模具中复制出的17、21和25微米凹槽以及传递至石膏模型的相同凹槽分别被赋予3分、2分和1分。结果表明，所有测试的印模材料都能够在模具中复制出钢模型上的所有三条凹槽。然而，在检查石膏模型时发现，在模具中复制得很好的凹槽在各自模型中既没有被同等也没有被均匀地记录下来，聚硫橡胶和硅橡胶取得了最佳结果，聚醚最差。至于石膏产品，II型石膏呈现出最不利的结果。
