An epigallocatechin gallate-amorphous calcium phosphate nanocomposite for caries prevention and demineralized enamel restoration

Biomineralization with amorphous calcium phosphate (ACP) is a highly effective strategy for caries prevention and defect restoration. The identification and interruption of cariogenic biofilm formation during remineraliza-tion remains a challenge in current practice. In this study, an epigallocatechin gallate (EGCG)-ACP functional nanocomposite was developed to prevent and restore demineralization by integrating the antibacterial property of EGCG and the remineralization effect of ACP. The synthesized EGCG-ACP showed good biocompatibility with L-929 cells and human gingival fibroblasts. Under neutral conditions, the sustained release of ACP from EGCG-ACP restored the microstructure and mechanical properties of demineralized enamel. Under acidic conditions, pro-tonated EGCG released from EGCG-ACP exerted a strong antibacterial effect, and the ACP release rate doubled within 4 h, resulting in the prevention of demineralization in the presence of cariogenic bacteria. The pH-responsive features of EGCG-ACP to promote the protonation of EGCG and ACP release facilitated its perfor-mance in remineralization effect to overcome the difficulty of restoring demineralized enamel in a cariogenic acidic environment, which was evidenced by the in vivo experiment carried out in a rat oral cariogenic envi-ronment. The results of this study indicate the potential of EGCG-ACP for the prevention of enamel demineral-ization and provide a theoretical basis its application in populations with high caries risk.

Automated summary

In this study, a functional nanocomposite of epigallocatechin gallate (EGCG) and amorphous calcium phosphate (ACP) was developed for the prevention and restoration of demineralization. The EGCG-ACP exhibited good biocompatibility and showed sustained release of ACP to restore the microstructure and mechanical properties of demineralized enamel under neutral conditions. Under acidic conditions, protonated EGCG exerted a strong antibacterial effect, preventing demineralization in the presence of cariogenic bacteria. The pH-responsive features of EGCG-ACP facilitated its performance in remineralization to overcome the difficulty of restoring demineralized enamel in a cariogenic acidic environment.