Synergistic effects of graphene quantum dots and carbodiimide in promoting resin–dentin bond durability

Objective Resin-based dental adhesion is mostly utilized in minimally invasive operative dentistry. However, improving the durability and stability of resin–dentin bond interfaces remain a challenge. Graphene quantum dots (GQDs) reinforced by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) were introduced to modify the resin–dentin bond interfaces, thereby promoting their durability and stability. Methods GQDs, EDC, and EDC+GQDs groups were designed to evaluate the effects of GQDs and EDC on collagenase activity, the interaction of GQDs with collagen, and the resin–dentin interface. First, the effects of GQDs and EDC on collagenase activity was evaluated by Collagenase (EC 3.4.24.3) reacting with its substrate. The interaction of GQDs and EDC with collagen were evaluated by cross-linking degree analysis, sodium dodecyl sulfate–polyacrylamide gel electrophoresis, attenuated total reflection Fourier transform infrared spectroscopy and enzymatic hydrolysis. Second, the acid-etched and rinse adhesive system was used to evaluate the resin–dentin bond on the basis of microtensile bond strength, in situ zymography and fluorescence confocal laser scanning microscopy. Results GQDs could inhibit collagenase activity. GQDs with the aid of EDC could cross-link collagen via covalent bonds and improve the anti-enzymatic hydrolysis of collagen. In the resin–dentin adhesion model, the μTBS of the EDC+GQDs group was significantly higher than the other control groups after thermocycling. The addition of EDC to GQDs could inhibit matrix metalloproteinase activity and promote the integrity of the bonding interfaces after thermocycling. Significance This study presents a novel strategy to modify the resin–dentin interface and provides a new application for GQDs. This strategy has the potential to improve the durability of resin-based restoration in dentistry.