Fluoride Release and Biological Properties of Resin-Modified Glass Ionomer Cement Doped with Copper

Glass ionomers are utilized extensively within the domain of dentistry, for instance, as provisional restorations, liners, or bases, in addition to their application as pit and fissure sealers. It is imperative that this type of material exhibits favorable physico-chemical and biological properties. The primary objective of the presented study is to modify commercial resin-modified glass ionomer (Riva Light Cure, RMGIC) by doping it with copper particles (RMGIC + Cu) and to evaluate its properties in terms of potential beneficial clinical applications. Susceptibility to adhesion of microbial species and potential antimicrobial activity was evaluated against the Candida albicans, Streptococcus mutans, and Lactobacillus rhamnosus strains. Antiviral properties were evaluated against two viruses: Herpes simplex virus type 1 and human Adenovirus 5. Cytotoxicity of the materials was assessed using Balb/3T3 mouse fibroblast cell line. Temporal fluoride release up to 168 h in water and artificial saliva of different pH levels were also measured and assessed using statistical analysis. Samples were also subjected to Attenuated Total Reflectance Fourier-Transform Infrared Spectroscopy and Fourier-Transform Raman Spectroscopy. The findings of the present study demonstrate that RMGIC + Cu displays reduced biofilm formation against the tested strains when compared to non-modified material. The influence of the Cu presence on fluoride release is most pronounced in artificial saliva with a low pH (4.5), where the difference is significantly higher in samples with Cu than in samples without it. No reduction in herpes simplex 1 titers under the influence of either material was observed, whereas both materials exhibited virucidal properties against human adenovirus 5. Commercial glass ionomer presented no cytotoxicity, while the modified biomaterial caused changes in the fibroblast culture only under the sample (slight cytotoxicity, grade 1). Considering all the acquired results, doping glass ionomer with copper may be an interesting modification enhancing antimicrobial properties of the biomaterial, but it requires further evaluation in terms of long-term cytotoxicity before further in vivo studies.