Facile Ag+ assisted bonding strategy built a defect-low hybrid layer with intrinsic antibacterial and enzymolysis-inhibitory property

Abstract

As the most widely used material for dental tissue repair, dental resin composites face durability challenges, whose longevity critically depends on the hybrid layer's integrity. Incomplete adhesive infiltration within the demineralized dentin matrix (DDM) creates structural defects in this layer, rendering it vulnerable to stress concentration, enzymatic degradation, and bacterial invasion. These factors contribute to secondary caries, the predominant complication of resin-based restorations. Enhancing both adhesive infiltration and the hybrid layer’s antibacterial capacity is thus pivotal to extending restoration lifespan. Previous studies revealed that strong metal ion chelation can mobilize confined water to facilitate hydrophobic monomer infiltration, significantly improving dentin bonding efficacy and durability. In this study, leveraging the dual advantages of Ag⁺—potent chelation and antibacterial activity—we treated DDM with Ag⁺. A brief 20-second application enabled confined water release, enhanced adhesive infiltration, and conferred durable antibacterial functionality to chemically modified DDM. Additionally, matrix metalloproteinases (MMPs) activated during bonding were effectively inhibited. Crucially, subsequent light irradiation reduced Ag⁺ to metallic silver, enhancing structural stability by orders of magnitude. This approach successfully established a low-defect hybrid layer with intrinsic, long-lasting antimicrobial properties. The strategy offers a clinically viable solution for achieving durable dentin restoration with integrated antibacterial defense.