Preparation of silver-loaded metal-organic frameworks as a novel agent for arresting dental caries of primary teeth

This study assessed the remineralization efficacy of a novel agent that contains silver-loaded metal-organic frameworks with fluoride (Ag@MOF/F) on dentin surface of primary teeth. Ag@MOF/F was prepared and characterized by scanning electron microscopy (SEM). The dentin surfaces of 104 sound primary canine were demineralized for 4 days and randomly divided into four groups (n = 26/group): (1) 400 ppm Ag@MOF/F, (2) 1400 ppm Ag@MOF/F, (3) 38% silver diamine fluoride (SDF), and (4) 5% sodium fluoride (NaF). Topographic changes, depth of penetration, and crystal formation were evaluated by SEM, energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD), respectively. Vickers microhardness and spectrophotometry were used to assess surface hardness and discoloration of the samples. The 1400 ppm Ag@MOF/F group indicated greater depth of penetration and sharper hydroxyapatite peak than the SDF and NaF. The 1400 ppm Ag@MOF/F group had a significantly greater increase in surface and cross-sectional microhardness than the other groups (P < 0.001). The 400 ppm Ag@MOF/F and SDF groups showed similar recovery of microhardness (P = 0.913). SDF-treated specimens were significantly darker than the other groups (P < 0.05), whereas the Ag@MOF/F samples had minimal discoloration. Our results indicate that Ag@MOF/F can be an alternative for SDF in arresting dentin caries because of its enhanced remineralization property and minimal discoloration.