Effect of Impression Materials and Techniques on Impressions Accuracy for Angulated Implants

Abstract

Purpose: Reproducing the intraoral relationship of implants through impression procedures is the first step in achieving an accurate, passively fitting prosthesis. This study was designed to evaluate the effect of three different impression materials, polyether (PE, ImpregumTMSoft ), additional silicone (PVS, Enthus) and vinyl siloxanether (VSXE, EXA’lence), on the accuracy of impressions in nonparallel implants. Material and Methods: An epoxy resin completely edentulous mandibular model with three implants (OsseoLink USA LLC. 4 mm ×9 mm, internal connection type) with different angles (0 and 15 degrees) was used as reference model. Sixty stone casts were made from the reference model using three impression materials; polyether (PE, ImpregumTMSoft) Group 1, additional silicone (PVS, Enthus) Group 2 and vinyl siloxanether (VSXE, EXA’lence) Group 3 with two impression techniques indirect and direct technique. The inter-implant distances were measured for casts using a coordinate measuring machine and the deviations compared to the reference models were calculated. Data were collected, tabulated and statistically analyzed using one-way ANOVA followed by Tukey’s Post-hoc test to detect significance between groups (P=0.05). Results: Tukey’s Post-hoc test in the indirect technique showed non-significant differences (p>0.05) between VSXE and PVS for ∆ r1 and ∆ r2 while showed significant differences (p> 0.05) between VSXE and PE also between PVS and PE for ∆ r1 and ∆ r2, while Tukey’s Post-hoc test in the direct technique showed significant differences (p<0.05) between VSXE and PVS, between VSXE and PE and between PVS and PE groups for ∆ r1 and ∆ r2.Conclusion: Within the limitations of this study, for nonparallel implant conditions, the distortion values of casts produced by VSXE was significantly lower than casts produced by PVS, which was significantly lower than casts produced by PE in direct impression technique, while VSXE and PVS produced casts with more accuracy compared to casts produced by PE group in the indirect impression technique.