Tear strength of elastomeric impression materials.

1. Under simulated clinical conditions the maximum tear strength of those materials tested was reached in 10 to 15 minutes. 2. The polysulfide materials showed three to six times the tear strength of the silicones. 3. The polyether material displayed a tear resistance slightly higher than that of the silicones but one third to one fifth as high as that of the polysulfides. 4. The clinical significance of the differences in tear strength was undetermined since other factors (such as adhesion) were not considered.