ABSTRACT
Background: Flow characteristics of vinyl polysiloxane (VPS) impression materials are important determinants in the selection of impression materials for the fabrication of accurate indirect restorations. Aims: The purpose of this study was to determine the flow of three commercially available VPS impression materials at different time intervals using a shark fin device (3M ESPE, Seefeld, Germany). Study Setting and Design: This in?vitro study was carried out at the prosthodontics department of a dental institution. Methods and Material: The height of the shark fin produced by each impression material determined the rate of flow. Statistical Analysis: The data were analysed using one?way analysis of variance (ANOVA) and post?hoc Tukey’s test (p?0.05). Results: Shark fin height of group A VPS impression material was significantly higher at 30 and 120 seconds compared to group B and group C VPS impression materials. Shark fin height produced by group B VPS impression materials at 60 and 90 seconds was significantly higher than the group C VPS impression material but non?significant compared to group A. At 120 seconds, there was no significant difference in the shark fin heights of all the tested materials. Conclusion: All the materials exhibited adequate flow characteristics within clinically acceptable limits
ABSTRACT
94 cases with 148 abutments treated by all-ceramic restoration in premaxillary teeth region were randomly divided into 4 groups, and the impressions were prepared by one-step method,double curettage method,double polish method and double microfilm method respec-tively using 3M ESPE Vinyl polysiloxane as impression material.The cervical margin precision of the impressions was compared.Four kinds of impression method can produce qualified impression.Double polish method is easy to teach and learn.