Comparison of Accuracy/Dimensional Stability of High-Rigid Vinyl Polysiloxane, Polyvinyl Siloxane, and Polyether Impression Materials in Full Arch Implant-Supported Prosthesis: In Vitro Study.

The aim of this study was to evaluate the accuracy/dimensional stability of High-rigid vinyl polysiloxane, polyvinyl siloxane, and polyether impression materials in full arch implant-supported prosthesis. Custom acrylic trays were made on a stone replica of the reference die. Two groups were present in this study: splinting and nonsplinting. A total of 30 samples of 15 for each group were made. Impressions were made and poured with type IV dental stone to obtain experimental casts and were evaluated for dimensional stability and accuracy by measuring with a coordinate measuring machine (CMM) in three dimensions (X, Y, and Z), and a verification jig was fabricated to check the accuracy both clinically and radiographically. Differences in measurements were analyzed using independent t-tests, analysis of variance, and chi-square tests. In terms of dimensional stability, the lowest mean deviation was found in casts made from open tray splinting and nonsplinting and within the impression materials (p > 0.05). But, significant differences (p > 0.05) were obtained with splinting over nonsplinting in terms of accurate fit of the verification jig. This study concludes that polyether material showed less deviation from the reference model, followed by High-rigid VPS and PVS. As results were statistically not significant, all the three impression materials can be used for making full-arch implant-supported prostheses. Splinting obtained more accurate casts over nonsplinting.