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Abstract
Marginal impression tearing causes defect that reduce the accuracy of the impression and consequently affect the accuracy of final restoration. The aim of this study was to evaluate the effect of time elapsed after setting on the tear strength of different elastomeric impression materials. Three types of elastomeric impression materials (polyether, poly - vinyl siloxane and vinylsiloxanether). The specimens were divided into three groups with (n = 15) according to type of impression material. Each group were further subdivided into three subgroups (n = 5) according to time elapsed after setting. The specimens were loaded in tension until failure with a crosshead speed of 500 mm/minute. Regression analysis using two - way analysis of Variance (ANOVA) was used for studying the effect of impression material, time after setting and their interactions on mean tear strength