Polyphenol-enriched extract incorporated into a total-etch adhesive system: Effect on water sorption and solubility, extract compound release and dentin enzymatic activity over time

This study evaluated water sorption, solubility and compound release of 2.5% Arrabidaea chica polyphenolic extract ( Ac ) incorporated into the primer of a total-etch adhesive system; and dentin metalloproteinases inhibition when using Ac as dentin pretreatment in aqueous solution or incorporated either into acid or adhesive system primer. Adhesive system discs (Adper Scotchbond Multipurpose/3 M Oral Care/SB) with and without Ac were prepared (n = 10) for water sorption, solubility and compound release. Concentration of extract released in water was evaluated at 1, 3, 7, 14, 28, 36 days immersion. Dentin-resin interfaces were prepared for zymography analysis (control (SB); dentin pretreatment with water; dentin pretreatment with 2.5% Ac aqueous solution; Ac incorporated into phosphoric acid; Ac incorporated into SB primer) and assessed for in situ zymography tests after 24-h and 6-month storage. Primer incorporated with Ac showed lower water sorption (p = 0.0102) and solubility (p = 0.0065) than non-incorporated. Ac release was observed at third and seventh days (p = 0.0031). There was no significant difference between treatments (p = 0.4298) either immediately or after 6 months regarding relative fluorescence unit means among groups, and these means decreased after 6 months (p < 0.0001). Ac incorporated into SB primer decreased water sorption and solubility properties, and was released in water the adhesive system over time. Higher gelatinolytic activity was observed in deep dentin layer at immediate versus 6-month timepoints.