Accessing Polyphenols Effect on Bond Strength and Dentin Enzymatic Degradation

INTRODUCTION: Polyphenols have been investigated in dental materials and restorative techniques due to their interactions with metal cations, antioxidant activity, and collagen crosslinking ability, which make them a promise for reinforcing the dental substrate and improving material adhesion. However, more studies are necessary before to support their use in clinical procedures. OBJECTIVES: This study evaluated the effects of quercetin and resveratrol on bond strength and the protection of dentin collagen fibrils against enzymatic degradation. MATERIALS AND METHODS: Demineralized human dentin specimens were immersed for 1 min in solutions of quercetin or resveratrol (100, 250, and 500 µg/mL), 2% chlorhexidine (CHX), or 0.9% saline (control). The specimens were then incubated in collagenase for 24 h at 37°C, and changes in dry mass were measured. For microtensile bond strength testing, quercetin, resveratrol, CHX, or distilled water (DW) were applied to phosphoric acid-conditioned dentin, followed by application of Single Bond 2 (3 M/ESPE) adhesive and Z350XT resin (3 M/ESPE). Adhesive strength was measured after 24 h and after 1 year in distilled water. Data were analyzed using the Kruskal-Wallis and Dunn tests or ANOVA followed by Tukey's test (p < 0.05). RESULTS: Quercetin-treated specimens showed a significant weight increase compared with CHX (p < 0.05). Both quercetin- and resveratrol-treated groups exhibited resistance to collagenase similar to CHX (p > 0.05). After 1 year, only the DW group showed a significant decrease in bond strength (p = 0.001). CONCLUSIONS: Dentin treatment with quercetin or resveratrol effectively preserved adhesive strength and protected collagen against enzymatic degradation, suggesting their potential as agents to improve the longevity of adhesive restorations.