Method: Seven sample groups (n=20 each group) were created using a stainless steel mold (101.6 mm long, 19.05mm wide and 2.7mm thick) and different elastomeric impression materials. A notch was created in the central region of each sample using a stainless steel insert that created either a 0.30mm (n=10) or 0.50mm thick (n=10) notch. Each mold was immersed in a water bath of 35±1°C for five minutes and removed. The elastomeric impression materials were loaded into the mold and immersed after 20 seconds for the manufacturer minimum recommended setting time. Specimen was removed from water bath, immediately placed into universal testing machine (Instron® 5582), and subjected to tensile force at a crosshead speed of 500 mm/min until failure. Statistical analysis was conducted using one-way ANOVA with a post hoc Tukey HSD for pair wise analysis among groups. Statistical differences were predetermined at p<0.05.
Result:
Groups |
Material |
Average Stress MPa (Psi/mean±SD) Mold 338 (0.50mm thickness) |
Average Stress MPa (Psi/mean±SD) Mold 348 (0.30mm thickness) |
1 |
AquasilTM Monophase (Dentsply Caulk) |
607.541±39.013 A |
462.585±49.221F |
2 |
Tissue Management Impression Material (Dentsply Caulk) |
534.072±28.980 B |
493.367±28.320 F |
3 |
Tissue Management Impression Material Tray (Dentsply Caulk) |
533.654±55.597 B |
497.955±58.582 F |
4 |
ImprintTM 4 Light (3M ESPE) |
349.668±31.245 C |
287.535±55.853 G |
5 |
Take 1® Advanced (Kerr) |
288.123±37.414 D |
253.665±22.578 G |
6 |
Flexitime® (Heraeus) |
268.576±33.100 D |
256.620±9.212 G |
7 |
ImpregumTM Soft Lightbody (3M ESPE) |
175.791±21.673 E |
183.210±34.355 H |
Groups with the same letter superscript are not statistically different from one another.
Group 1 yielded statistically higher tensile strength compared to the other groups in the 0.5mm thickness. For the 0.3mm thickness, Group 3 showed statistically higher tear strengths compared to Groups 4, 5, 6, 7.
Conclusion: Capturing crown and bridge margins accurately is critical for a well-fitting prosthesis. Impression materials should exhibit high tear strengths to avoid tearing in thin areas, such as those within the sulcus, when impression trays are removed from the mouth.