Distorção de modelos de gesso obtidos a partir de duas técnicas de moldagem preliminar

Abstract

The aim of this study was to compare, through three-dimensional measurements, stone casts obtained by two preliminary impression techniques: compound (CG) and double-alginate (AG) impression. For this purpose, a metal pattern model with three cylinders positioned in the left (A) and right (B) molars and incisal papilla (C) regions was used. For CG, conventional impression with plasticized material between 60-65°C was carried out. For AG, the equalized minimum pressure technique was used with the first impression taken according to the proportion indicated by the manufacturer, and the second with 25% increase in the water quantity. To evaluate the distortion, the stone casts of each group were submitted to three-dimensional measurements in equipment by coordinates (n=10/group). The leveling plane was considered at the top of the three cylinders, and the center of origin by A and B cylinders symmetry, which allowed measurement of the distance between the cylinders (AB and BC), diameter of each cylinder (A, B and C) and palate height. The data were evaluated by two-way ANOVA and Tukey tests (α=0.05). There was influence on the interaction of impression material and location of the measurements (p 0.05) between the groups, CG resulted in greater dimensional change in the measurements of A, B and C diameters. CG and AG did not differ in dimensional stability, thus being considered clinically feasible techniques