Antibacterial properties of copper iodide-doped glass ionomer-based materials and effect of copper iodide nanoparticles on collagen degradation.

Abstract

This study investigated the antibacterial properties and micro-hardness of polyacrylic acid (PAA)-coated copper iodide (CuI) nanoparticles incorporated into glass ionomer-based materials, and the effect of PAA-CuI on collagen degradation. PAA-CuI nanoparticles were incorporated into glass ionomer (GI), Ionofil Molar AC, and resin-modified glass ionomer (RMGI), Vitrebond, at 0.263wt%. The antibacterial properties against Streptococcus mutans (n=6/group) and surface micro-hardness (n=5/group) were evaluated. Twenty dentin beams were completely demineralized in 10wt% phosphoric acid and equally divided in two groups (n=10/group) for incubation in simulated body fluid (SBF) or SBF containing 1mg/ml PAA-CuI. The amount of dry mass loss and hydroxyproline (HYP) released were quantified. Kruskal-Wallis, Student's t test, two-way ANOVA, and Mann-Whitney were used to analyze the antibacterial, micro-hardness, dry mass, and HYP release data, respectively (p<0.05). Addition of PAA-CuI nanoparticles into the glass ionomer matrix yielded significant reduction (99.999%) in the concentration of bacteria relative to the control groups. While micro-hardness values of PAA-CuI-doped GI were no different from its control, PAA-CuI-doped RMGI demonstrated significantly higher values than its control. A significant decrease in dry mass weight was shown only for the control beams (10.53%, p=0.04). Significantly less HYP was released from beams incubated in PAA-CuI relative to the control beams (p<0.001). PAA-CuI nanoparticles are an effective additive to glass ionomer-based materials as they greatly enhance their antibacterial properties and reduce collagen degradation without an adverse effect on their mechanical properties. The use of copper-doped glass ionomer-based materials under composite restorations may contribute to an increased longevity of adhesive restorations, because of their enhanced antibacterial properties and reduced collagen degradation.