Effectiveness of experimental adhesive systems containing carbodiimide and solvated in different solvents

Objectives: To evaluate the influence of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide – EDC (C) on the degree of conversion (DC%), resin-dentin bonding stability, collagen degradation, and MMP inactivation produced by experimental adhesive systems solvated in acetone (A), ethanol (E) or tetrahydrofuran (T). Methods: EDC was added to experimental primers consisting of HEMA, PMGDM, and water, solvated in A, E, or T, performing six groups (A, AC, E, EC, T, TC). The adhesive consisted of BISGMA, HEMA, camphorquinone, and EDMAB. DC% was evaluated by FT-IR spectroscopy. The μTBS was evaluated after 24 h or 1 yr of artificial saliva storage at 37°C. The degradation of the dentin collagen was evaluated using FT-IR spectroscopy at three periods: after primer application, 15, and 30 days, and the enzymatic activity within the hybrid layer using in situ zymography. Data was analyzed using ANOVA and Tukey's HSD test (α = 0.05). Results: No statistical significance in DC% was found among all adhesive systems (p > 0.05). EDC-containing primers maintained μTBS stability after 1 yr of artificial saliva storage (p > 0.05). The intensity of the Amide I and II bands from the dentin collagen was preserved for AC and EC after immersion in collagenase solution. The dentin treated with EDC-containing primers presented reduced fluorescein in the hybrid layer. Conclusions: The incorporation of EDC into primers contributed to resin-dentin bonding stability and reduced the enzymatic activity and collagen degradation.