Tear Strength of Low-viscosity Vinyl Polysiloxane Elastomeric Impression Materials

Marginal tearing of an elastomer reduces the accuracy of the impression. Objectives: The purpose of this study was to determine the tear strength of various low viscosity, fast set vinyl polysiloxane elastomers. Methods: Ten materials were tested: Aquasil Ultra XLV(Caulk), Imprint 3 Quick Step Light Body (3M ESPE), Splash Light Body Half Time and Precision Lite Viscosity (Discus), Genie Light Body Rapid Set (Sultan), Affinis Light Body Fast (Coltene/Whaledent), Stand Out Wash Fast Set and Take 1 Wash (Kerr), Exafast NDS Injection and Senn Light Body Rapid Set (GC). Five axial notch specimens, measuring 4" x 0.75" x 0.0090", were made in a proprietary stainless steel injection mold. The mold was filled with impression material, sealed, and immediately placed in a water bath at 35C. At the manufacturer's recommended mouth removal time, the mold was retrieved from the water bath. The specimens were gripped over the first inch from either end leaving 2 inches of gage length and continuously loaded on an Instron testing machine at a crosshead speed of 10 inch/minute until failure occurred. The data was statistically analyzed using ANOVA and post-hoc testing of means by the Scheffe test (p≤0.01). Letters (a-c) denote statistically significant differences between the groups. Results: