Anti-caries nanostructured dental adhesive reduces biofilm pathogenicity and raises biofilm pH to protect tooth structures

The objectives were to: (1) develop a new nanostructured dental adhesive with antibiofilm and remineralization properties using dimethylaminohexadecyl methacrylate (DMAHDM) and nanoparticles of calcium fluoride (nCaF2); (2) investigate the effects on dentin bond strength and Streptococcus mutans biofilms. Bisphenol A glycidyl dimethacrylate, triethylene glycol dimethacrylate, 2-hydroxyethyl methacrylate, and methacryloyloxy ethyl phthalate formed the adhesive. Biofilm colony-forming units (CFU), metabolic activities, biomass, and acid-production were measured. Adding nCaF2 and DMAHDM into adhesive did not compromise the dentin bond strength (p > 0.1). The nCaF2 + DMAHDM-containing adhesive decreased biofilm CFU by 4 logs, with tenfold reduction in acid-production, compared to control (p < 0.05). The nCaF2 + DMAHDM-containing adhesive successfully shifted the acidic and cariogenic biofilm pH 4 to a safe pH of 7. In conclusion, a novel bioactive adhesive mitigated the cariogenic potential of S. mutans biofilm and raised biofilm pH to a safe level to protect tooth structures, without compromising dentin bond strength.