Evaluation of dimensional stability of condensation of silicones according to their pouring time

Abstract

Two commercial by available condensation silicones were evaluated for their dimensional stability at different pouring times. A master metallic model was developed simulating two teeth prepared for a fixed partial prosthesis with the same height and different diameters. This model was used to obtain 36 molds using the two-time shaping technique and 1-mm uniform relief on standard trays. The molds were divided into 6 groups (n=6) using: Zetaplus (Zermach) and Speedex (Vigodente) poured at 30 min; 36 h and 72h, respectively after molding. Then, they were poured with type IV dental stone (Polidental) being vacuum spatulated. Measurements over 3 distinct areas of each prepared tooth: mesiodistal and buccolingual diameters, cervico-occlusal height and the distances among them were made and registered. A three-dimensional gauging device (Zeiss) for 0.002-mm precision coordinates was use for the measurements. The results showed statistically significant differences in the smaller diameter mold height and in the distance among the teeth prepared (ANOVA; p<0.05) There were no statistically significant differences in all remaining areas measured for all silicone applied. From these results, we can conclude that all of the silicones tested showed a totally satisfactory dimensional behavior through all researching periods of time.