The effect of storage time on dimensional accuracy of elastomeric impression materials
Several factors play a role in stability of impressions made from elastomeric impression materials. These include; polymerization shrinkage, loss of by-products during condensation, thermal contraction from oral temperature to room temperature, imbibition when exposed to water, disinfectant or high humidity and incomplete recovery from deformation due to viscoelastic behavior. An ideal impression material should be dimensionally stable over time to allow for pour at the convenience of the operator. Several studies evaluated the dimensional accuracy of elastomeric impression materials based on various factors including effects of repeat pour, temperature, humidity, disinfectants, impression techniques, and filler loading amongst others. Most of the previous studies did not use the standardized method described by the ADA specification for elastomeric impression materials.