Methods: On 40 human molars, a flat superficial dentin surface was exposed by wet abrasion and randomly separated into five groups. Two coats of the Solvent-based (SB) and solvent-free(SF) adhesives were applied on either a dry (D) or rewetted surface (W), under vigorous rubbing action after phosphoric acid etching. Examined groups included: 1.SB adhesive on W dentin, 2.SB on D, 3.SF on W, 4.SFon D, 5.according manufacturer protocols as control group. After light curing (600mW/cm²/10 s), composite build-ups were constructed incrementally and specimens were stored in water (37 ◦C/24 h). They were longitudinally sectioned in the “x” and “y” directions to obtain bonded sticks (1mm²) to be immediately tested in tension at 1 mm/min. Resultant BS was expressed as an index that includes bond strength values of the different fracture patterns. The data were analyzed by a two-way ANOVA test.
Results: Distribution according to the fracture pattern showed 6.2 percent resin cohesive fracture mode and 93.8 adhesive/mixed fracture mode in each group. High μTBS (45.09±10.45) values were obtained for OSP, regardless of the presence or absence of solvents or the moisture condition of dentin and no difference among groups was detected (p > 0.05).
Conclusions: The presence of solvents was not essential for OSP to achieve high bond strength values to both dry and wet dentin when applied under vigorous application.