Abstract
Purpose: The aim of this study was to evaluate creep and viscoelastic properties of dental impression materials after different storage times.
Methods: Six commercially available impression materials (one polyether and five silicones) were tested after being stored for 30 min to 2 weeks under both static and dynamic testing. Shear and Young's moduli, dynamic viscosity, loss tangent and other viscoelastic parameters were calculated. Four of the materials were tested 1 h after setting under creep for three hours and recovery was recorder for 50 h.
Results: The tested materials showed differences among them, while storage time had significant influence on their properties. Young's modulus E ranged from 1.81 to 12.99 MPa with the polyether material being the stiffest. All of the materials showed linear viscoelastic behavior exhibiting permanent deformation after 50 h of creep recovery.
Conclusion: As storage time affects the materials’ properties, pouring time should be limited in the first 48 h after impression.
