Objectives : To evaluate the fatigue resistance of adhesives bonded to dentin, in comparison to their micro-tensile bond strength (μTBS).
Materials and methods : The bonding effectiveness of three adhesives (3-step etch-and-rinse adhesive or 3-E&RA OptiBond FL, 2-step self-etch adhesive or 2-SEA Clearfil SE, and 1-step self-etch adhesive or 1-SEA G-Bond) was measured by means of a micro-tensile fatigue resistance (μTFR) and μTBS protocol. Preparation and test set-up of the micro-specimens for both μTFR and μTBS were identical. In fatigue, specimens were tested in a wide range of selected loads at 2 Hz and at 10 Hz until failure or until 10 4 cycles were reached. At 2 Hz, the μTFR was measured after 1 week and 3 months of water storage. The μTFR was determined (in MPa) using a logistic regression model. Two-way ANOVA and Tukey HSD multiple comparisons test were used to determine statistical differences in μTBS.
Adhesive | μTBS | μTFR 10 Hz 1 week | Statistics frequency | μTFR 2 Hz 1 week | Statistics storage | μTFR 2 Hz 3 months |
---|---|---|---|---|---|---|
3-E&RA | 51.0 ± 17.6 ( n = 49) | 20.5 ( n = 50) | p = 0.765 | 21.3 ( n = 31) | p = 0.3799 | 19.7 ( n = 34) |
2-SEA | 43.7 ± 14.3 ( n = 75) | 18.4 ( n = 44) | p = 0.4566 | 19.6 ( n = 24) | p = 0.0428 | 14.2 ( n = 33) |
1-SEA | 28.0 ± 15.3 ( n = 58) | 11.7 ( n = 41) | p = 0.0158 | 15.0 ( n = 26) | p = 0.0015 | 8.4 ( n = 43) |
Statistics adhesive | p < 0.0001 | p = 0.0011 | p = 0.0539 | p = 0.002 |