Tensile strength of elastomeric impression materials, adhesive and cohesive bonding.

Numerous factors are known to effect the accuracy of elastomeric impression materials. Factors often overlooked are the quality of the bond between low-viscosity and high-viscosity elastomers and the presumed cohesive bond between materials during an impression reline procedure. This study examined the bond strength of condensation polymerization polysiloxanes, addition polymerization polysiloxanes, polyethers, and a light-cured polyether urethane dimethacrylate. Of the tested materials, light-cured polyether urethane dimethacrylate exhibited the greatest bond strength. The reline technique, light-body cured to previously cured heavy-body putty, yielded results similar to the simultaneous-cure technique. In terms of bond strength there is no advantage of one technique over the other. The corrective reline technique yielded acceptable results in bond strength. In general, the tested materials exhibited greater tensile strength than bond strength.