Effect of proteolytic inhibitors in carious and eroded dentin adhesion

The longevity of the interaction established between restorative material and substrate has been the main focus of Adhesive Dentistry. Dentin is altered through challenges as dental erosion and caries and, on the other hand, technologies that attend for particular conditions of the substrate and favors for the chemical bonding has been developed. The aim of this study was to evaluate the performance of a universal adhesive system (etch-and-rinse mode) on bonding strength (BS) to dentin in different conditions (artificial caries or erosion) and pretreated with proteolytic inhibitors. Ninety molars were selected and prepared, obtaining flat surfaces treated with 600 sandspaper for 1 minute. The specimens were randomly divided into three groups according to the substrate: N- with no challenges (stored in artificial saliva), ERO-artificial erosion simulation (3x5min/5days with orange juice) and CA- artificial caries simulation (6h demineralizing+ 18h-remineralizing/ 5 days + 48 remineralizing). Then, each of these groups was redivided into three subgroups according to the pretreatment of dentin: A- treated with water; CHX-treated with 2% chlorhexidine and E-64- treated with 5 &#x3BC;M E-64 inhibitor. Therefore, they constituted 9 groups (n = 10): N-A, N-CHX, N-E-64, ERO-A, ERO-CHX, ERO-E-64, CA-A, CACHX, CA-E-64. All specimens were restored with Adper Single Bond ® Universal and composite resin Filtek Z250. The teeth were cut to obtain sticks (area of approximately 0.64 mm2), which were subjected to the microtensile bond test in the testing machine at 0.5 mm/min after 7 days and 6 months. The failure mode was classified according to the analysis of interfaces by optical microscopy 40X. Data was tested to verify normal distribution and homogeneity to be analyzed with three-way ANOVA and Tukey tests (p <0.05). Data revealed interaction between substrate x treatment (p=0.0011) and between substrate x time (p=0.0003). Dentin affected by artificial erosion and caries negatively contributed to the BS. The use of chlorhexidine negatively affected the RU for all tested conditions. E-64 showed to be effective to maintain the bonding stability to affected dentin for 6 months. The universal bonding system seems to be promissory to be employed to affected dentin, maintaining the BS overtime. The use of E-64 did not affect the bonding to dentin, controversial to the use of chlorhexidine. (AU)