Stability of the Adhesive Interface after Different Artificial Aging Techniques

This study evaluated the stability of resin-bonded dentin interfaces using a two-step etch-and-rinse adhesive submitted to different artificial aging methods. Thirty human molars had the occlusal middle-dentin exposed and treated with Adper Single Bond 2 system, as recommended by manufacturer. Resin composite buildups were incrementally placed on bonded dentin. Specimens for micro tensile test were obtained according to the “non-trimming” technique and tested in tension, at 0.5 mm/minute, after one of the storage conditions: G1) water for 24 h (control group), G2) 10% NaOCl for 1 h, G3) continuous thermocycling (60,000 cycles at 5°-55°C for 3 months), G4) water for three months, G5) intermittent thermocycling (10,000 cycles/month at 5°- 55°C for 6 months) and G6) water for six months. Results showed that all tested methods induced a significant decrease in bond strength to dentin when compared with that observed for the control group (p<0.05). The highest decrease in bond strength values were observed for groups G2 and G3. Storage in 10% NaOCl and continuous thermocycling were the most aggressive methods to reduce the micro tensile bond strength to bonded dentin.