Effect of cross-linker's incorporation into two adhesive systems with self-etch mode applied on sound and caries-affected dentin

This study investigated the effect of incorporation of two cross-linkers agents, proanthocyanidin (PA) or epigallocatechin-3-gallate (EGCG), into two adhesive systems with a self-etch approach, on microtensile bond strength (μTBS), nanoleakage (NL), and in inhibition potential of MMP`s activity, in immediate (24 h) time and after 12 months of water storage (12 M), on sound dentin (SD) or caries affected dentin (CAD). Dentin middle surfaces of 96 human molars were exposed, and half of them were submitted to a microbiological cariogenic challenge. Specimens were randomly allocated into twelve groups (n = 8) according to the following factors under study: 1. adhesive incorporation at three levels (1 wt% EGCG x 1 wt% PA x Control); 2. dentin status (CAD x SD); 3. adhesive approach: AUSE (Ambar Universal, FGM) or CSE (Clearfil SE Bond, Kuraray). Data of μTBS were evaluated according to 3-way-repetead measures ANOVA and Bonferroni post-hoc (p ˂ 0.05). No group showed statistical difference at different times (24 h × 12 M) regardless of the substrate (SD or CAD), p = 0.65. In general, CSE showed higher BS when compared with AUSE (p < 0.001), and SD presented higher values than CAD (p < 0.001), when these factors were evaluated individually. There was statistical interaction between dentin status versus time (SD-12 M > SD-24 h = CAD-12 M = CAD-24 h). The enzymatic activity was more intense for CAD groups, except for AUSE + PA. All groups exhibit silver nitrate deposits along the bonding interface. The cross-linkers tested appear to have no advantage when applied to caries affected dentin.