The effect of kaempferol on the dentin bonding stability through matrix metalloproteinases inhibition and collagen crosslink in dentin biomodification

Background/purpose: Naturally derived collagen crosslinkers with matrix metalloproteinases (MMPs) inhibitory activity for dentin bonding have been previously studied. One of these crosslinkers is flavonoids. The purpose of this study was to investigate whether dentin pretreatment with kaempferol (KEM), one of the flavonoids, enhances dentin bond stability and nanoleakage at the dentin-resin interface through MMPs inhibition and collagen crosslinking.Materials and methods: The experimental KEM-containing solution was used to pretreat demineralized dentin prior to the application of a universal adhesive. KEM is a natural flavonoid and those which did not take the experimental solution served as the control group (CON). Microtensile bond strength (mTBS) and nanoleakage tests were conducted before and after the thermocycling to evaluate the influence of KEM on dentin bond strength. The MMPs inhibition activity of KEM was analyzed via MMPs zymography using a confocal microscopy. Fourier-transform infrared (FTIR) spectroscopy was used to demonstrate that KEM inhibits MMPs and enhances collagen crosslinking.Results: The mTBS values of KEM group exhibited a higher bond strength after thermocycling. At the resin-dentin interface, the KEM group did not exhibit any signs of nanoleakage after thermocycling. Furthermore, MMPs zymography confirmed that there was a relatively low activity of MMPs in the presence of KEM. In FTIR analysis, the PO4 peak representing the cross-link between dentin and collagen was significantly higher in the KEM group.Conclusion: Our findings suggest that pretreatment with KEM enhances the dentin bonding stability at the resin-dentin interface by acting as a collagen crosslinker and MMPs inhibitor. 2022 Association for Dental Sciences of the Republic of China. Publishing services by Else-vier B.V. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

This study investigated the effect of pretreating demineralized dentin with the flavonoid kaempferol (KEM) on dentin bond stability and nanoleakage at the dentin-resin interface. The results demonstrated that KEM enhanced the bond strength between dentin and resin, reduced nanoleakage, and achieved these effects by inhibiting MMPs activity and enhancing collagen crosslinking.