Objectives: to evaluate the effects of application mode and storage time on the microtensile bond strength (µTBS) of a self-etch adhesive (SEA) that can be applied as 1-step or 2-step modes. Methods: Dentin surfaces from human teeth were exposed flat and polished on wet 320-grit sandpaper for 30s. All Bond SE (ABSE) (Bisco) was applied according to manufacturer's instructions with or without the optional liner (HIX). Light Core Blue composite (Bisco) was built-up and cured 40s each 1-2 mm increment. Teeth were cut into 0.8mmX0.8mm beams and randomly distributed among selected time intervals and stored either in water (H2O) or in mineral oil (Oil) at 37◦C. Specimens were tested until failure using Microtensile Tester (Bisco) at 0.5mm/min. Averages below include all specimens regardless of fracture pattern. Data was analyzed by 2-way ANOVA for each storage media (p≥0.05). Results: MPa (SD).
Storage Media | 24 Hrs | 3 Months | 6 Months |
ABSE/H2O | 34.9(11.6) N=21 Aa | 61.1(9.1) N=18 Bb | 40.2(9.2) N=18 Aa |
ABSE/Oil | 45.4(12.6) N=15 Ab | 60.6(13.1) N=17 Bb | 63.5(14.1) N=17 Bb |
ABSE+HIX/ H2O | 49.6(8.1) N=19 Ab | 38.3(8.1) N=16 Ba | 58.5(12.2) N=16 Cb |
ABSE+HIX/Oil | 49.0(11.0) N=14 Ab | 61.9(13.5) N=15 Bb | 74.8(10.4) N=14 Cc |
[Capital letters compare rows and lower cases compare columns.]
The use of two-step application mode significantly improved bond strength. Bond strength was significantly higher at 6 months storage when two-step mode was used. Conclusions: Improved bond strengths were obtained with the 2-step application mode at 6 months in water. As expected, there was a trend in increasing bond strength for specimens stored in mineral oil.