Résumé
Alginate is the common impression material in dentistry and its preparation with water in various temperatures is required in some instances. Does the temperature of water affect on dimensional accuracy of alginate is the question of studies? The aim of this study was to compare the effect of different temperatures of water on dimensional accuracy of stone models in impression with Iralgin and Bayer alginate. In this experimental study, one laboratory model was used with two metallic dies and alginate impression materials [Iralgin and Bayer]. Sixty impressions were taken at temperatures of 8 degree C, 23 degree C and 28 degree C for Iralgin and Bayer alginate and stone models were poured. Five dimensions of 60 models including height and diameter for each die and distance between the dies were measured by digital caliper and compared with laboratory model by the use of ANOVA and t tests and LSD analysis. Temperature change of water had statistically significant effect on dimensional accuracy of stone model. At 8 degree C, all dimensions of Iralgin and Bayer increased. There was statistically significant changes [p<0.05] in diameter and external distance between the two dies for Iralgin and in diameter of small die for Bayer. At 28 degree C, all of the dimensions of the dies decreased, that in Bayer except for the diameter of the large die and in Iragin only for small die, the difference was statistically significant. The results of this research showed that at 23 degree C temperature of water, Bayer alginate was more accurate than Iralgin alginate. At 28 degree C, Iralgin and at 8 degree C, Bayer alginate was the most accurate