Linear dimensional accuracy of a polyvinyl siloxane of varying viscosities using different impression techniques

Abstract Aim: The present study is an in vitro study to evaluate the linear dimensional accuracy of commercially available polyvinyl siloxanes of varying viscosities using different impression techniques. Methods: Different impression techniques used were: (a) putty wash, with a two‐step technique with polyethylene spacer, using a stock tray; (b) putty wash, with a one‐step technique, using a stock tray; (c) single‐mix technique, utilizing medium viscosity in a custom tray; and (d) multiple‐mix technique, utilizing a heavy‐ and low‐viscosity combination in a custom tray. For each technique, 10 impressions were made of a metallic maxillary dentulous master model. Results: The result of this study dictates that a heavy‐ and low‐viscosity combination, double‐mix technique in a custom tray produced an accurate result in all dimensions, followed by the single‐mix technique, utilizing medium viscosity in a custom tray, and the putty wash two‐step technique with polyethylene spacer, using a stock tray. Group 2 putty wash, one‐step, simultaneous technique produced the least accurate result in all dimensions. Conclusion: The putty wash two‐step techniques were found to be as accurate as the multiple‐mix technique, utilizing a heavy‐ and low‐viscosity combination in a custom tray, and the single‐mix technique, utilizing medium viscosity in a custom tray. Making custom trays is time consuming and costly.