Marginal tearing of an elastomer reduces the accuracy of the impressed prepared teeth and the success and quality of the restoration. Objective s: Tear strength of a new low viscosity elastomeric impression material was compared to similar commercially marketed products. Methods: Experimental TMIM Low Viscosity Fast Set (Caulk), Aquasil Ultra XLV Fast Set (Caulk), Flexitime Xtreme Correct Flow (Heraeus), Exa'lence Extra Light Body Fast Set (GC), Imprint 3 Quick Step Light Body (3M ESPE), Genie Extra Light Body Rapid Set (Sultan), Impregum Soft Quick Step Light Body (3M ESPE), and Take 1 Advanced LB Wash Super Fast Set (Kerr) were the eight formulations tested. Five axial notch specimens, per cohort, measuring 109 mm x 19 mm x 0.238 mm, were made in a proprietary stainless steel injection mold. The sealed mold was filled with impression material and immediately placed in water at 35°C. The mold was removed from the bath at manufacturers' recommended oral removal times. The rapidly demolded specimens were secured in custom grips, leaving the notch centered in 50 mm of gauge length. Under continuous loading in a tensile mode at a crosshead speed of 254 mm/minute specimens were stretched until failure. Mean and standard deviation values for each cohort were calculated and statistically analyzed using ANOVA and the post-hoc Student's t-test (α ≥ 0.05). Letters (a-e) denote statistically significant differences between the groups. Results: See table.
Impression Material | Tear Strength (MPa) | |
TMIM | 5.9 ± 0.1 | a |
Aquasil Ultra XLV Fast Set | 4.6 ± 0.3 | b |
Imprint 3 Quick Step Light | 4.5 ± 0.2 | b |
Exa'lence Extra Light Body Fast Set | 4.2 ± 0.5 | c |
Genie Extra Light Body Rapid Set | 3.2 ± 0.2 | d |
Take 1 Advanced LB Super Fast | 2.7 ± 0.3 | e |
Flexitime Xtreme Correct Flow | 2.6 ± 0.1 | e |
Impregum Soft Quick Step Light | 2.0 ± 0.1 | f |
Conclusions: TMIM was the strongest material tested (p ≤ 0.001.) Acknowledgement: Northwestern University Department of Mechanical Engineering.