Abstract
In order to evaluate the mechanical properties of high elastic polyaddition-type silicone impression materials, the components and mechanical properties of hardening objects (i.e., hardness, compression set, and dynamic viscoelasticity) were investigated. The main components of these materials did not differ from previously tested materials of the same type. They showed a lower hardness and an equal or larger compression set than previous materials. In a dynamic test, they showed a smaller storage modulus and a larger loss tangent than previous materials. The softness of a hardening object is thought to be related to the combination of filler and prepolymer. The present findings indicate that the softness of the materials tested would allow them to be easily removed from the mouth or from a gypsum cast in a clinical setting. When stressed, they may have a greater permanent deformation than previous materials.
