Poly-methyl methacrylate (PMMA)-based dental resins with strong and long-lasting antifungal properties are critical for the prevention of denture stomatitis. This study evaluated the antifungal effects on Candida albicans ATCC90028, the cytotoxicity toward human dental pulp cells (HDPCs), and the mechanical properties of a silver bromide/cationic polymer nano-composite (AgBr/NPVP)-modified PMMA-based dental resin. AgBr/NPVP was added to the PMMA resin at 0.1, 0.2, and 0.3 wt%, and PMMA resin without AgBr/NPVP served as the control. Fungal growth was inhibited on the AgBr/NPVP-modified PMMA resin compared to the control (P < 0.05), and the antifungal activity increased as the incorporation of the AgBr/NPVP antimicrobial composite increased. Confocal laser scanning microscopy (CLSM) showed that the number of fungal cells attached to the modified PMMA resin was considerably lower than in the control. The relative growth rate of HDPCs of modified groups were higher than 75%. The flexural strength (FS) and flexural modulus (FM) were not significantly different (P > 0.05) between the experimental and control groups. These data indicate that the incorporation of AgBr/NPVP conferred strong and long-lasting antifungal effects against Candida albicans to the PMMA resin, and it has low toxicity toward HDPCs, and its mechanical properties were not significantly affected.

Mussels can form tough and long-lasting adhesions to organic and inorganic surfaces in saline and impactive severe aquatic environments. Similar to mussel adhesion, dentin bonding occurs in a wet environment. However, unlike mussels, it is difficult to achieve long-lasting bonds with dentin. Moreover, water is considered a major hindrance in dentin bonding. Inspired by the synergistic effect of cationic lysine (Lys) and catechol on the elimination of the hydration layer during mussel adhesion, a catechol- and Lys-functionalized polymerizable polymer (catechol–Lys–methacrylate [CLM]) was synthesized to replicate the complex synergy between amino acids and catechol. The bond-promoting potential of 5 ​mg/mL CLM primer was confirmed using an in vitro wet dentin-bonding model, which was characterized by an improvement in bond strength and durability. CLM can adhere to wet demineralized dentin, with Lys acting as a molecular vanguard to expel water. Subsequently, a myriad of interfacial interactions can be obtained by introducing the catechol group into the interface. Additionally, tough and long-lasting adhesion, similar to that formed by mussels, can be achieved by grafting CLM onto type I collagen via covalent bonds, hydrogen bonds, Van der Waals interactions, and cation–π interactions, which can enhance the mechanical and chemical stability of collagen, increase the enzymatic resistance of collagen, and provide additional physical/chemical adhesion to dentin bonds. Catechol- and cationic Lys-functionalized polymers can improve the stability of the resin–dentin interface under wet conditions.

Dentin bonding is a dynamic process that involves the penetration of adhesive resin monomers into the extrafibrillar and intrafibrillar demineralized collagen matrix using a wet-bonding technique. However, adhesive resin monomers lack the capacity to infiltrate the intrafibrillar space, and the excess water that is introduced by the wet-bonding technique remains at the bonding interface. This imperfectly bonded interface is inclined to hydrolytic degradation, severely jeopardizing the longevity of bonded clinical restorations. The present study introduces a dentin bonding scheme based on a dry-bonding technique, combined with the use of extrafibrillar demineralization and a collagen-reactive monomer (CRM)-based adhesive (CBA). Selective extrafibrillar demineralization was achieved using 1-wt% high-molecular weight (MW) carboxymethyl chitosan (CMCS) within a clinically acceptable timeframe to create a less aggressive bonding substance for dentin bonding due to its selectively extrafibrillar demineralization capacity. CMCS demineralization decreased the activation of in situ collagenase, improved the shrinking resistance of demineralized collagen, and thus provided stronger and more durable bonding than traditional phosphoric acid etching. The new dentin bonding scheme that contained CMCS and CBA and used a dry-bonding technique achieved an encouraging dentin bonding strength and durability with low technical sensitivity. This bonding scheme can be used to improve the stability of the resin-dentin interface and foster the longevity of bonded clinical restorations.