Influence of aging methods on push-out bond strength of adhesive systems to dentin cavities

This study evaluated the effect of aging methods on the bond strength of etch-and-rinse adhesive systems to dentin cavities. Eighty bovine incisors were used to prepare dentin cavities, which were bonded with different adhesive systems [Adper Scotchbond Multipurpose (SBMP), and Adper Single Bond 2 (SB)], and restored with composite resin. The specimens were stored in water for 24?h, and subjected to each aging method (n?=?10): control group (not exposed to additional aging), thermal cycling (TC) (10,000 cycles; at temperatures of 5, 37, and 55?°C), mechanical loading (ML) (100,000 cycles; Hz; 60?N load), and TC?+?ML. The push-out bond strength test was performed using a universal testing machine. Failure modes were evaluated by scanning electron microscopy. Data were analyzed by two-way ANOVA and Tukey’s test (α?=?0.05). For SBMP, only TC?+?ML decreased the bond strength compared to control group. For SB, all aging methods decreased similarly the bond strength compared to control group. A high number of adhesive failures were observed. Therefore, SB was sensitive to all aging methods, whilst only TC?+?ML was able to decrease the bond strength for SBMP.