Preparation of CMC/ACP/PHMB nanocomposites and preliminary study on their antibacterial and remineralization functions

Caries is a chronic oral disease causing a series of complications. This study aims to develop a material that could remineralize demineralized enamel and simultaneously exert antibacterial effects. A carboxymethyl chitosan (CMC)/amorphous calcium phosphate (ACP)/polyhexamethylene biguanide hydrochloride (PHMB) nanocomposite was synthesized for the first time, and its stability, remineralization ability, and antibacterial properties were investigated in this study. PHMB has excellent antibacterial properties, was used as an additive to stabilize ACP. The enamel surface covered with CMC/ACP/PHMB showed a uniform layer with a similar elemental ratio to that of natural hydroxyapatite and the ratio of crystal diffraction peaks was close to that of natural enamel. The mechanical properties, including hardness and elastic modulus, of the enamel in all experimental groups were restored. The antibacterial effect of 240 mg/L CMC/ACP/PHMB was comparable to that of 0.12% CMC/ACP/chlorhexidine. This study provides a theoretical and experimental basis for the development of novel dual-function anticaries agent.