Accessing Polyphenols Effect on Bond Strength and Dentin Enzymatic Degradation

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.

This study evaluated the effects of quercetin and resveratrol on bond strength and the protection of dentin collagen fibrils against enzymatic degradation.

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).

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).

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.