Resistência de união de sistemas adesivos atuais em dentina submetida a diferentes tratamentos

Abstract

Studies have shown that the longevity of adhesive restorations is adversely affected by collagen degradation. The purpose of this study was to evaluate the effect of different treatments on the bond strength of adhesive systems in different dentin surfaces. Forty healthy human third molars were randomly assigned to 24 experimental groups (n = 5) according to adhesive systems (Single Bond - SB, Clearfil SE Bond - SE, Adper SE Plus - AP, G Bond - GB), treatments (control and deproteination) and dentin surfaces (proximal, superficial and deep occlusal). For the deproteinization treatment was applied 10% sodium hypochlorite, for 1 minute, to previously conditioned dentin and the adhesive systems were applied according to manufactures directions. In each specimen were made cylindrical cavities in the proximal and occlusal surfaces and, after immersion in destilated water for 24 hours, one slice and 2 slices of occlusal and proximal surfaces were, respectively, obtained. The slices were submitted to push-out test and after it a fracture analysis was performed. The values in MPa were submitted to ANOVA 3-factors and Tukey (p <0.05), indicating a statistically significant difference between the adhesive systems (p = 0.000) and dentin surfaces (p = 0.005), However, the type of treatment (p = 0.058) did not significantly affect the values of bond strength. The bond strength values were higher for proximal surface, followed by superficial oclusal and later by deep occlusal, being influenced by the adhesive system. The collagen removal from the conditioned surface can be considered a way to decrease the sensitivity technique without compromising the adhesive effectiveness.