Biological properties of a novel solution based on silver nanoclusters for arresting dentin caries.

Objectives: To test the biological properties of a novel non-restorative treatment method for arresting dentin caries based on silver nanoclusters (AgNCls) synthesized in polymethacrylic acid (PMAA). Methods: Synthesis of AgNCls was performed by photoreduction of AgNO3 in PMAA with 355 nm/wavelength light. AgNCls/PMAA was characterized by absorption/fluorescence spectroscopy and optical and atomic force microscopy. The stability of the clusters in an aerated PMAA solution was evaluated by means of fluorescence spectroscopy. Cytotoxicity was assessed using the MTT assay and antibacterial effect was determined for minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and colony forming (CFU) of Streptococcus mutans (S. mutans) and Lactobacillus acidophilus (L. acidophilus). 38% Silver Diammine Fluoride (SDF) was used for the control groups. Results: Chemical and structural identity of the clusters did not change within 9 months; Cell viability of 92%-89% was found after 24-48 h respectively. MIC and MBC were determined from 1:16 and 1:8 dilutions, respectively. Log CFU counts of S. mutans, and L. acidophilus treated with AgNCls/PMAA (3.4 ppm of silver) were significantly lower than in the control groups and even lower than when the same bacterial strains were treated with SDF (15,525 ppm of silver). Conclusions: AgNCls/PMAA presented chemical stability, acceptable cytotoxicity, and a potential antibacterial effect for strains associated with caries lesions at very low concentrations of silver.

Does previous application of silver diammine fluoride influence the bond strength of glass ionomer cement and adhesive systems to dentin? Systematic review and meta-analysis.

BACKGROUND: Silver diammine fluoride (SDF) applied before a restoration may prevent recurrent caries; therefore, its effect on the bonding of restorative materials is contradictory. AIM: To assess through a systematic review and meta-analysis the influence of SDF on the bonding performance of adhesive materials to dentine. DESIGN: A systematic search was carried out in PubMed, Web of Science, LILACS, and Scopus. Studies comparing bond strength of adhesive systems or glass ionomer cement to SDF-treated and -untreated (control) dentine were included. Global analysis comparing the bond strength data was performed, separately for adhesive systems and glass ionomer cement, using RevMan5.1, with a random-effect model, at a 5% significance level. RESULTS: Eleven studies were included in the review and ten in the meta-analyses. Overall pooled effect for glass ionomer cement has shown no significant difference between the groups (Z = 0.47; P = .64). SDF treatment significantly impairs the bonding of adhesive systems to dentine (Z = 2.11; P = .03); this effect can be eliminated by the rinsing step (Z = 0.85; P = .40). CONCLUSIONS: The previous application of SDF does not influence the dentine bond strength of glass ionomer cement, but compromises the bonding of adhesive systems.