RESUMEN
Objective: among the various impression materials, for alginate tear strength is probably more important than the compressive strength. The tear strength is important when an impression involves a mechanical undercut and/or lacks bulk strength to resist tearing. This study evaluated tear strength of Iralgin and compared it with tear strength of Alginoplast
Methods: in this invitro experimental study A mold was made with 100mm×20mm×1mm dimensions and a longitudinal prominence in 0.3 mm depth. Twenty-seven specimens [9 Super Iralgin, 9 Pocket Iralgin, and 9 Alginoplast] were selected non-randomizedly. Each specimen prepared corresponding to manufacturer and injected into the mold. And the mold was placed under press. After removing the mold from press, every specimen formed as a trouser-shaped specimen. The specimen was pulled in tensile machine with 50 mm/min speed. The data of specimens in different groups were statistically analyzed using one-way ANOVA, Kolmogorov- Smirnov, and Levene's tests
Results: mean of tear strength in first specimen [Super Iralgin], second specimen [Pocket Iralgin], and third specimen [Alginoplast] were 640+/-38 grf/cm[2], 500 +/-20grf/cm[2], and 1100+/-27 grf/cm[2] respectively. According to ANOVA test, the mean of tear strength was not equal in three specimens [p<0.01]. According to LSD Multiple Comparison, the first and second specimens were same in tear strength, whereas the third specimen was different from the two former [p<0.05 and p<0.01]
Conclusion: super Iralgin and pocket Iralgin were the same in tear strength. Alginoplast was significantly higher than super and pocket Iralgin in tear strength