Abstract

Background: Secondary caries often result in a high failure rate of resin composite restoration. Herein, we studied the dodecylmethylaminoethyl methacrylate–modified resin adhesive ([email protected]) to investigate its pH-responsive antimicrobial effect onStreptococcus mutansandCandida albicansdual-species biofilms and on secondary caries. Methods: Firstly, the pH-responsive antimicrobial experiments including colony-forming units, scanning electron microscopy and exopoly-saccharide staining were measured. Secondly, lactic acid measurement and transverse microradiography analysis were performed to determine the preventive effect of[email protected]on secondary caries. Lastly, quantitative real-time PCR was applied to investigate the antimicrobial effect of[email protected]on cariogenic virulence genes. Results:[email protected]significantly inhibited the growth, EPS, and acid production ofStreptococcus mutansandCandida albicansdual-species biofilms under acidic environments (p< 0.05). Moreover, at pH 5 and 5.5,[email protected]remarkably decreased the mineral loss and lesion depth of tooth hard tissue (p< 0.05) and down-regulated the expression of cariogenic genes, virulence-associated genes, and pH-regulated genes of dual-species biofilms (p< 0.05). Conclusions:[email protected]played an antibiofilm role onStreptococcus mutansandCandida albicansdual-species biofilms, prevented the demineralization process, and attenuated cariogenic virulence in a pH-dependent manner.Keywords:Streptococcus mutans;Candida albicans;secondary caries;antimicrobial effect;pH response