Background: This laboratory study was carried out to find out the accuracy of the impression of a master die using polysulfide, polyether and addition silicone rubber base material in different consistencies and their combinations using custom made tray and readymade stock tray and using different techniques. Methods: Standardized type IV dental stone was poured into impressions immediately and obtained stone die was measured by using scanning electron microscope. Totally forty stone dies were prepared and measurements recorded and were compared with the master die. Chi-square test and Anova-test were used for comparing various measurements statistically and the level of significance was set at 0.05. Results: The study revealed that, all the impressions were undersized in dimensions. Polysulfide elastomer impression material produces most accurate impressions. Single mix single impression technique produces most accurate impressions than any other type of impression techniques. Impressions made with custom tray are more accurate than impressions made with stock tray. Conclusion: This study forms the first part for the further clinical study. It is better to study the accuracy of impression material clinically as certain other factors like saliva, change in temperature from mouth to room temperature also contributes to the inaccuracy of the material.
Key words: Impression techniques, Polysulphides, Polyethers, Addition silicone, Elastomers.