Evaluation of shear bond strength and microleakage of deproteinized dentin bonded with three total-etch adhesive systems

Purpose: To evaluate the effect of NaOCl conditioning on shear bond strength and marginal sealing of resin bonded dentin with three total-etching adhesive systems. Materials and Methods: Flat dentin surfaces were prepared and received the following treatments: Group I, 35% phosphoric acid for 15 s; Group II, 35% phosphoric acid for 15 s followed by 10% NaOCl for 60 s; Group III received no additional conditioning and served as control. Each group was applied with three adhesive systems: One Step plus, Prime&Bond NT and Single Bond. Resin restorations were built up and then submitted to bond strength test. For microleakage evaluation, 72 class V cavities were prepared and grouped as described above and then restored with composite resin, dye penetration along the bonding interface was assessed. All data were subjected to statistical analysis. Results: All specimens conditioned with phosphoric acid showed similar shear bond strength without statistical difference among adhesive systems used (p>0.05). Compared with that of the acid-etched groups, One Step plus demonstrated statistically increased bond strength following NaOCl application (p<0.05), while that of Prime&Bond NT remains unaffected though obviously decreased values were obtained (p>0.05). Single Bond yielded significantly lower bond strength (p<0.05). No statistical difference in microleakage scores was shown among dentin pretreatments or adhesive systems used (p>0.05). For all groups, the microleakage at the gingival margin was much severer than that at the occlusal margin (p<0.05). Conclusion: The efficacy of resin bonding to deproteinized dentin was systems specific, which was decided by the composition of adhesive systems. (Int Chin J Dent 2006; 6: 82-88.)