Title: Comparison of different methods for measuring flow properties of impression materials
Abstract:
The aim of this study is to compare different methods for measuring flow properties of impression materials. The flow properties were measured by shark-fin test and consistency test. Twelveaddition silicone impression materials(four commercial productseach with heavy, medium, and lightbody material) and two agar impression materials were usedin two different methods (n=10 per material and method). Shark-fin test was performed using a sharkfintestingapparatus(3M ESPE, Seefeld, Germany). A weighted metal castwas suspended above a cup of impression material. The castwas dropped into the impression material, which displaced the material and caused it to flow into a triangular notch within the cast, creating a “shark fin.” Consistency testwas determined according to ISO 4823(2015). The data were statistically analyzed by correlation analysis and two-way ANOVA with Tukey test (p=0.05) using PASW 18.0 (SPSS Inc., Chicago, U.S.A.). Good correlation was found between the shark-fin test and the consistency test (R2 = 0.587, p = 0.000). Strong correlation was found between the methods in addition silicone impression materials (R2 = 0.915, p = 0.000), however, correlation was not found in agar impression materials (R2 = - 0.249, p = 0.145). In detail, good and strong correlations were found in addition silicon materials with each consistency type (heavy body: R2 = 0.368, p = 0.019, medium body: R2 = 0.755, p = 0.000, light body: R2 = 0.865, p = 0.000) and mild correlation was found in three commercial addition silicone products. There were significant differences among the impression materials and test methods. Based on the results of this study, shark-fin test could be substituted for consistency test in measuring flow properties of addition silicone impression materials or one of the optionsfor them.
