Novel orthodontic cement containing dimethylaminohexadecyl methacrylate with strong antibacterial capability.

Orthodontic treatments increase the incidence of white spot lesions. The objectives of this study were to develop an antibacterial orthodontic cement to inhibit demineralization, and to evaluate its enamel shear bond strength and anti-biofilm properties. Novel antibacterial monomer dimethylaminohexadecyl methacrylate (DMAHDM) was synthesized and incorporated into Transbond XT at 0, 1.5 and 3% by mass. Anti-biofilm activity was assessed using a human dental plaque microcosm biofilm model. Shear bond strength and adhesive remnant index were also tested. Biofilm activity precipitously dropped when contacting orthodontic cement with DMAHDM. Orthodontic cement containing 3% DMAHDM significantly reduced biofilm metabolic activity and lactic acid production (p<0.05), and decreased biofilm colony-forming unit (CFU) by two log. Water-aging for 90 days had no adverse influence on enamel shear bond strength (p>0.1). By incorporating DMAHDM into Transbond XT for the first time, the modified orthodontic cement obtained a strong antibacterial capability without compromising the enamel bond strength.