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|