The Remineralization Potential of Resveratrol and Cucurbit[ <i>n</i> ]uril

The degradation of exposed collagen fibers in the deep layers of dentin during bonding procedures hampers its durability. Inducing the remineralization of demineralized dentin areas and inhibiting collagen degradation can improve bonding durability. Resveratrol, a natural polyphenol, has garnered attention for its positive effects on bonding durability. The positive effects on dentin remineralization and matrix metalloproteinase (MMP) inhibition are concentration dependent; high concentrations increase cytotoxicity. This study investigated the use of complexes of resveratrol and cucurbit[<i>n</i>]uril (Q[6] and Q[7]) to maintain adequate concentrations and achieve a stable rate of release in the deep dentin layers without causing cytotoxicity. Resveratrol and Q[<i>n</i>] complexes (Res@Q[<i>n</i>]) were prepared and their structures and the extent of resveratrol release were examined using analytical chemistry methods and quantum chemical analysis. In addition, the effects of resveratrol and the complexes of Res@Q[<i>n</i>] on cell cytotoxicity, recombinant type I collagen and dentin mineralization, microtensile bond strength (µTBS), nanoleakage, rhMMP-9 colorimetric assays, and in situ zymography were compared. Resveratrol was stably released from the Res@Q[<i>n</i>] complexes for nearly a month, reducing the cell cytotoxicity of high concentrations of the polyphenol, exhibiting stronger inhibition of MMPs, and facilitating more pronounced remineralization of recombinant type I collagen and dentin. Pretreating the dentin surface with complexes significantly increased the µTBS values and reduced nanoleakage and MMP activity before and after aging compared with single resveratrol. In conclusion, Res@Q[<i>n</i>] complexes can promote the continuous stability of the hybrid layer and improve the durability of dentin bonding compared with resveratrol alone without inducing cytotoxicity.