Effects of the setting stage on the accuracy of double-mix impressions made with addition-curing silicone.

This study investigated the accuracy of double-mix impressions relative to the time of placing the tray impression material on preparations covered with medium-viscosity silicone. The curing kinetics of the addition-curing silicone impression materials and the accuracy of impressions were investigated. The observed kinetics showed the possibility of the appearance of elastic characteristics of the syringed material before the tray impression was placed. The accuracy of the impressions was not statistically different unless the setting reactions had progressed so that the consistencies of both the syringed and the tray impression were high. These results indicated that the double-mix impression was accurate independent of the curing kinetics of the syringed material alone.