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.