Effect of water temperature on the accuracy of stone casts recovered from addition-reaction elastomeric impression materials.

This study investigated the accuracy of casts produced by mixing dental stone with water at different temperatures. Consecutive impressions of an acrylic resin model of the mandibular arch, on which the occlusal surfaces of three teeth had been indented with reference points, were made in two poly(vinyl siloxane) impression materials using a one-stage technique. After 1 hour these were cast in one of two stones using water at temperatures of 18 degrees C, 20 degrees C, or 24 degrees C. Five impressions were cast for each material at each temperature. The distances between the points were measured using a reflex microscope, and the difference between each cast and the model was calculated. Analysis of variance of the mean differences showed that there was no significant interaction between the temperature of the water and the accuracy of casts (P greater than 0.05).