Novel pit and fissure sealant containing nano-CaF2 and dimethylaminohexadecyl methacrylate with double benefits of fluoride release and antibacterial function

Pit and fissure sealants with antibacterial and remineralization properties have broad application prospects in caries prevention. The objectives of this study were to: (1) develop a novel pit and fissure sealant containing CaF2 nanoparticles (nCaF2) and dimethylaminohexadecyl methacrylate (DMAHDM); and (2) investigate the effects of nCaF2 and DMAHDM on biofilm response and fluoride (F) ion release for the first time. Helioseal F was used as a control. Bioactive sealants were formulated with DMAHDM and nCaF2. Flow properties, enamel shear bond strength, hardness and F ion releases were measured. Streptococcus mutans (S. mutans) biofilms were grown on sealants. Biofilm metabolic activity, lactic acid production, colony-forming units (CFU), and pH of biofilm culture medium were measured. Adding 5% DMAHDM and 20% nCaF2 did not reduce the paste flow and enamel bond strength, compared to control (p < 0.05). Hardness of sealants with 20% nCaF2 and DMAHDM was higher than control (p < 0.05). The F ion release from 20% nCaF2 was much higher than that of commercial control (p < 0.05). The sealant with DMAHDM reduced the S. mutans biofilm CFU by 4 logs. The pH in biofilm medium of the new bioactive sealant was much higher (pH 6.8) than that of commercial sealant (pH 4.66) (p < 0.05). The new bioactive pit and fissure sealant with nCaF2 and DMAHDM achieved high fluoride release and strong antibacterial performance. This novel fluoride-releasing and antibacterial sealant is promising to inhibit caries and promote the remineralizaton of enamel and dentin.