A Novel Zinc-Doped Bioactive Glass Nanoparticles for Dentin Adhesion

Objectives: To obtain more durable adhesion to dentin, bioactive materials have been incorporated into the dental adhesive systems to promote remineralization along the resin-dentin bonded interface. This study aims to design a novel zinc-doped bioactive glass nanoparticles (Zn@BGN) for dental adhesive systems to enable antimicrobial activity and to provide calcium ions for mineral deposition within the resin-dentin bonded interface.
Methods: BGN and Zn@BGN were synthesized by sol-gel template method via the catalysis of dodecylamine, and characterized by transmission electron microscope (TEM), scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). The optimum ratio of zinc-doped was explored by biological activity test in vitro. The antibacterial activity of Zn@BGN against Streptococcus mutans biofilms was analyzed by colony forming units counts (CFU). Zn@BGN was added at 2.5wt.%, 5wt.%, 7.5wt.% and 10wt.% to Adper™ Single Bond 2 Adhesive (SB2) respectively. The effects of Zn@BGN on curing performance, wettability property, and bonding performance of SB2 adhesive were evaluated by measuring the degree of conversion (DC), the contact angle (CA), and the microtensile bond strength.
Results: Zn@BGN showed regular spherical particles with diameter about 150nm, good monodispersity and biological activity. Compared to BGN, Zn@BGN dramatically decreased the biofilm CFU, (p< 0.05). In SB2 + 7.5wt.% Zn@BGN and SB2 + 10wt.% Zn@BGN, DC and CA were significantly different from those in SB2 control (p < 0.05). Dentin bond strength (n = 20) had 62.3% and 66.8% loss in SB2 + 7.5wt.% Zn@BGN and SB2 + 10wt.% Zn@BGN, respectively. However, SB2 + 2.5wt.% Zn@BGN and SB2 + 5wt.% Zn@BGN showed no loss in bond strength (p > 0.05).
Conclusions: Zn@BGN can be incorporated into dental adhesive systems to provide the antimicrobial and remineralization microenvironment, which indicates a suitable strategy to extend the longevity of resin-dentin bonds.