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Purpose: The aim of this study was to evaluate the influence of collagen removal on shear bond strength (SBS) of three hydrophilic one-bottle adhesive systems in dentin. Materials and Methods: Test specimens were taken from one-hundred twenty bovine incisors. The specimens were debrided, polished with 320- to 600-grit Al2O3 paper, and randomly divided into 6 groups (n = 20): G1: acid/10%NaOCl + Bond 1 (B1H); G2: acid + Bond 1 applied according to manufacturers instructions (B1); G3: acid/10%NaOCl + Optibond Solo (OSH); G4: acid + Optibond Solo used according to manufacturers instructions (OS); G5: acid/10%NaOCl + Single Bond (SBH); G6: acid + Single Bond used according to manufacturers instructions. In all groups, dentin was etched for 15 s, rinsed, and dried. In groups 1, 3, and 5, the 10% NaOCl was applied with a dwell time of 60 s, rinsed, and dried. In all groups, the adhesive systems were applied and light cured, and then a restorative composite resin (Z-100) was inserted in a teflon matrix and cured. The specimens were stored in humid conditions for 7 days at 37°C. The SBS tests were performed in an EMIC universal testing machine with a crosshead speed of 0.5 mm/min. The mean bond strengths in MPa (ąSD) were analyzed with two-way ANOVA and Tukeys test (α = 0.05). Results: The application of NaOCl significantly increased the SBS values of all systems except Optibond Solo. The means (SD) for adhesive systems with 10% NaOCl treatment were: SBH = 14.28 (4.21)a; B1H = 14.39 (3.61)a; OSH = 10.35 (5.74)a; and values without 10% NaCOl were: SB = 10.35 (2.95)a; B1 = 9.38 (3.10)a; OS = 9.79 (3.48)b. Different superscripts indicate significant difference. Conclusion: The removal of collagen increased the strength of dentin bonding, depending on the adhesive system used.
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