Comparison of the accuracy of open-tray and snap-on impression techniques of implants with different angulations

Abstract

Background: A precise transfer of the position of an implant to the working cast is particularly important to achieve an optimal fit of the final restoration. Different variables affect the accuracy of implant impression. The purpose of the present study is to compare the accuracy of open-tray and snap-on impression techniques in implants with different angulations. Materials and Methods: In this experimental study: A reference acrylic resin model of the mandible was fabricated. Four implants were positioned with the angles of 0 degrees , 10 degrees , 15 degrees , and 25 degrees in the model. Ten impressions were prepared with open-tray technique and ten impressions were made using snap-on technique. All impressions were made from vinyl polysiloxane impression material. Linear (Deltax, Deltay, and Deltar) and angular displacements (Deltatheta) of implants were evaluated using a coordinate measuring machine. Measured data were then analyzed using two-way analysis of variance and Tukey's test (alpha = 0.05). Results: The results showed that the accuracy of open-tray impression technique is significantly different from snap-on technique in Deltax (P = 0.003), Deltay (P = 0.000), Deltar (P = 0.000), and Deltatheta (P = 0.000). Implants with 25 degrees angulation are significantly less accurate than 0 degrees , 10 degrees , and 15 degrees implants in Deltax, Deltay, Deltar, and Deltatheta. Fifteen-degree implants are less accurate than 0 degrees and 10 degrees ones in Deltatheta. Conclusion: Regarding the findings of this study, it can be concluded that snap-on technique is less accurate than open-tray technique, and the accuracy of 25 degrees implant is less than that of 0 degrees , 10 degrees , and 15 degrees implants.