Evaluation of dimensional accuracy of master models as a function of impression technique material with Speedex

Impression making is one of the most important steps in fixed prosthodontics. Due to contradictory opinions on the issue of the accuracy of silicone impression material as a function of technique, this study was carried out to assess the dimensional accuracy of master casts made by Speedex silicone material as a function of three impression techniques: 2 step with space, 2 steps without space and one step. Method & Materials: This quasi–experimental study, was carried out by using laboratory models. 10 impressions were taken for each technique and stone models were poured. Die’s height, diameter and distance between die’s were measured by profile projector and compared with laboratory model by the use of ANOVA test and LSD analysis. Impression technique has statistical significant effect on dimensional accuracy of master models. 2 step technique with space is the most accurate technique for Speedex impression material. In the presence of undercut under finishing line, one step technique is preferable to two step technique without space.