Application Modes Affect Two Universal Adhesive Systems' Nanoleakage Expression and Shear Bond Strength

OBJECTIVES: The aim of this study was to evaluate the shear bond strength and the nanoleakage expression of CLEARFIL Universal Bond Quick and Tetric N-Bond adhesive systems bonded to dentin. MATERIALS AND METHODS: 100 freshly extracted human premolar teeth were utilized. The teeth were sectioned to expose dentin. All dentin specimens were assigned into 4 experimental groups; 2 groups had Universal Bond Quick (Universal(self) group) and Tetric N-Bond (Tetric(self) group) applied in the self-etch mode, while 2 groups had Universal Bond Quick (Universal(total) group) and Tetric N-Bond (Tetric(total) group) applied in the total-etch mode. n = 15 for shear bond strength and n = 10 for nanoleakage experiment. One-way ANOVA and Kruskal-Wallis test were utilized to analyze the shear bond strength test and the nanoleakage expression, respectively. RESULTS: The highest significant bond strength value was recorded by the Tetric(self) specimens (p < 0.05) when compared to the remaining three groups. There were no statistically significant differences between the shear bond strength values recorded in the Tetric(total), Universal(self), and Universal(total) groups (p < 0.05). Both bonding systems applied in the self-etch mode (Universal(self), Tetric(self)) had no silver nitrate deposits in the hybrid layer and the hybrid layer-adhesive interface (p < 0.001); however, both bonding systems applied in the total-etch mode (Universal(total), Tetric(total)) had silver nitrate deposits in the hybrid layer, the hybrid layer-adhesive interface, and the bonding layer (p < 0.001). CONCLUSION: Applying the Universal Bond Quick and Tetric N-Bond in the self-etch mode exhibited better results in terms of nanoleakage expression. Universal Bond Quick showed the stability of the shear bond strength to dentin when applied using the total-etch or self-etch modes. Tetric N-Bond showed significant deterioration in bond strength when applied in the total-etch mode and exhibited the highest bond strength when applied in the self-etch mode.