Biscoordinated Strontium–Phenolic Networks for Bidirectional Repair of Dentin Hypersensitivity

Dentin hypersensitivity (DH) is a widespread dental disease characterized by transient and sharp pain affecting routine oral activities, with a reported prevalence that can exceed 70%. While remineralization offers a promising therapeutic strategy to address the anatomical basis of exposed dentinal tubules, achieving long-term efficacy remains challenging due to mechanical abrasion and cariogenic biofilms. Herein, strontium–phenolic network nanoparticles (Sr-EGCG NPs) are developed via a facile, one-pot aqueous process for DH treatment. Unlike conventional transition-metal-based metal-phenolic networks (MPNs), the assembly of Sr-based MPNs is found to be dependent on alkaline conditions, yielding a distinct biscoordinated structure. When applied to exposed dentin, Sr-EGCG NPs exhibit rapid and stable adhesion mediated by abundant galloyl groups, maintaining tubule occlusion ratios exceeding 91.8% after simulated oral challenges, especially surpassing commercial Duraphat in thermocycling (Duraphat: 2.0%), while simultaneously reducing live bacterial coverage by over 97.5% at day 3. Crucially, Sr-EGCG NPs enable bidirectional dentin repair: in situ remineralization (achieving complete mineralized occlusion by day 7 both in vitro and in vivo) and the induction of tertiary dentin formation via the CaSR-mediated MAPK signaling pathway. Overall, this work provides insights into the rational design of Sr-based MPNs and expands the framework for developing biomaterials targeting DH.