Dexamethasone-doped nanoparticles improve mineralization, crystallinity and collagen structure of human dentin

Objectives: Bioactive materials have been used for functionalization of adhesives to promote dentin reminerali-zation. This study aims to evaluate bonding ability and both mechanical and chemical behavior of demineralized dentin infiltrated with polymeric nanoparticles doped with dexamethasone (Dex-NPs).Methods: Dentin conditioned surfaces were infiltrated with NPs, Dex-NPs or Dex-Zn-NPs. Bonded interfaces were also created and stored for 24 h or 21d, and then submitted to microtensile bond strength testing. Dentin remineralization was analyzed by Nanohardness, Young's modulus and Raman analysis.Results: At 21d of storage, dentin treated with undoped-NPs attained the lowest nanohardness and Young's modulus. Dex-NPs and Zn-Dex-NPs increased dentin nanohardness and Young's modulus after 21d Raman analysis showed high remineralization, crystallinity, crosslinking and better structure of collagen when func-tionalized Dex-NPs were present at the dentin interface.Conclusions: Infiltration of dentin with Dex-NPs promoted functional remineralization as proved by nano -mechanical and morpho-chemical evaluation tests. Dexamethasone in dentin facilitated crystallographic matu-rity, crystallinity and improved maturity and secondary structure of dentin collagen.Clinical significance: Using dexamethasone-functionalized NPs before resin infiltration is a clear option to obtain dentin remineralization, as these NPs produce the reinforcement of the dentin structure, which will lead to the improvement of the longevity of resin restorations.