: One of the most important steps in achieving passive fit of a prosthesis is making precise impressions. The aim of the present study was to evaluate the accuracy of open tray implant impression made with two different impression trays and impression materials. Methodology: The study was carried on a simulated acrylic resin model with two implants placed at premolar and molar region. Open tray implant impressions were made using two different impression trays and materials as follows: Group 1: Polyether custom tray impression, Group 2: Polyether stock tray impression, Group 3: Polyvinylsiloxane custom tray impression and Group 4: Polyvinylsiloxane stock tray impression. Total of Forty impressions were made, making ten for each, and all casts were made with type IV die stone. The accuracy was determined by measuring the inter-implant distance from four impression technique study casts using a profile projector. The stone casts' dimensions were compared to the dimensions of the reference model, which served as a control. To evaluate group means, oneway ANOVA was used to analyse the significant difference between the two implant analogues of each group with the reference model, followed by Tukey's post hoc test for multiple comparison procedures. Results: The results showed the mean deviation from reference model for inter-implant distances for group 1,2,3 & 4 casts were .005 mm, .018 mm, .011 mm, and .026mm, respectively. The four groups that were tested in our study revealed notable variations between them with p-value of 0.005. Conclusion: The custom tray proved to be more accurate than stock tray impression. Whereas casts produced by polyether impression material were comparable with polyvinyl siloxane impression material.

Keywords : Implant, Impressions, Polyether, Polvinylsiloxane, Trays