Abstract
Aims: To evaluate the accuracy of two different impression materials and to evaluate the effect of time of pouring on the accuracy of impression. Materials and Methods: Four parallel implant placed in foam arch to obtain study model. Medium body addition silicone and medium body polyether are used. 20 impressions of study model were taken under monophase technique, 10 by addition silicone and 10 by polyether by closed tray technique, half of them were pour after one hour and another half of the impressions were poured after 24 hours by die stone to obtain casts. By using Traveling microscope three linear measurements were measured between 4 implants and comparsime was made between distances on the model and on the casts to assess the dimensional changes of impression materials. Results: Statistical analysis of data by paired sample T-test at (p≤0.05) reveals no significant difference in the accuracy of each material after one and 24 hours and the results analyzed by independent samples T-test reveals no significant difference between materials after one and 24 hours under closed tray technique (dimensional change don’t exceed 1%). Conclusions: The results appeared that there is no difference in the accuracy between addition silicone and polyether and there is no effect of time (1h-24h) on the accuracy of impression, also results showed the high dimensional stability of two materials.
