EDTA functionalized mesoporous silica (mSiO₂-EDTA) for Ca^2 + and Zn²⁺ rechargeable dental resin composites

The aim of this study was to (1) graft ethylenediamine tetraacetic acid (EDTA) onto mesoporous SiO₂ (mSiO₂) fillers to fabricate Ca²⁺ and Zn²⁺ rechargeable dental composites, (2) investigate the effect of EDTA modification on the properties of the composite resins.

EDTA modified mSiO₂ (mSiO₂-EDTA) were prepared by a facile one-step silylating reaction. Ca²⁺ and Zn²⁺ were adsorbed onto mSiO₂-EDTA via an ion solution immersing method to obtain mSiO₂-EDTA-Ca and mSiO₂-EDTA-Zn. The ion release behavior and recharge ability of the particles was investigated. Different mass fractions (5, 10, and 20 %) of the functional fillers were added into dental resins to investigate the ion release behavior of the composites. Dental composites containing 20 % fillers were selected to assess their ion recharge capacity, the remineralization potential of mSiO₂-EDTA-Ca loaded composites, and the antibacterial efficacy of those incorporating mSiO₂-EDTA-Zn. The effect of the fillers on the mechanical properties, light-curing performance, and biocompatibility of the dental composites was further evaluated.

mSiO₂-EDTA were successfully synthesized, and Ca²⁺ and Zn²⁺ were adsorbed on the particles by the ion solution immersing method. The ions within the mSiO₂-EDTA-Ca and mSiO₂-EDTA-Zn particles as well as their corresponding dental composites could be released at acidic conditions, and fully recharged after releasing. Even after 10 release-recharge cycles, the ions in the dental resins could still be fully recharged by simply immersing the samples in ion solution for just 10 min. The continually released Ca²⁺ and Zn²⁺ exhibited corresponding functions as promoting mineralization or antibacterial activity. Furthermore, surface modification of mSiO₂ with EDTA did not affect the mechanical properties, light curing performance, and biocompatibility of dental composites.

Novel dental composites with fully Ca²⁺ and Zn²⁺ recharge ability were obtained by surface functionalization of mSiO₂ fillers with EDTA, which provided a potential way for the inhibition of secondary caries.