Novel self-etch adhesive with antibacterial and protein-repellent functions to prevent enamel demineralization

Enamel demineralization is the most undesired side-effect of fixed orthodontic treatments. This study were to develop a novel adhesive that is self-etching instead of using the traditional etching method, and to form a sealant on the enamel to prevent demineralization. 2-methacryloyloxyethyl phosphorylcholine (MPC) and quaternary ammonium dimethylaminohexadecyl methacrylate (DMAHDM) were mixed into a self-etch adhesive (Adper Easy One, 3M, St. Paul, MN, USA; referred to as AEO). Enamel shear bond strength (SBS) was measured. Protein adsorption onto the resins was measured. An oral microcosm biofilm model with saliva was tested. Incorporation of 7.5% MPC and 5% DMAHDM into AEO did not reduce the SBS (p>0.1). AEO with 7.5% MPC+5% DMAHDM had protein adsorption that was only 1/18 that of AEO control. AEO with 7.5% MPC+5% DAMHDM had much stronger antibacterial properties (p<0.05). In conclusion, the new self-etch adhesive with MPC and DAMHDM greatly reduced protein adsorption and inhibited biofilm viability.