IADR Abstract Archives
Characterisation of Fluoride Containing Bioactive Glass Composites for Dental Restoratives
Objectives: Bioactive glasses (BAGs) have been incorporated into resins to overcome the issue of polymerisation shrinkage and subsequent caries by forming a mineral apatite layer in the marginal gap to prevent secondary caries. The aim of this study was to characterise the effect of network connectivity (NC) on ion release, pH changes and apatite formation of fluoride-containing bioactive glasses.
Methods: BAG powders (<38 μm) with varying NCs (from 1.45 to 2.70) were synthesised and immersed into artificial saliva pH 7 (AS7) to investigate the effect of NC on bioactivity. One selected composition was silylated and mixed with a Bis-GMA and TEGDMA based resin to form a composite disc and was immersed into AS7 for timepoints up to 3 months. The powders and discs were characterised using ATR-FTIR, XRD, 31P-NMR and 19F NMR to detect fluorapatite (FAp) formation. The supernatant solution was characterised using ICP-OES and ISE to quantify the ion release and the pH changes were measured.
Results: ATR-FTIR and XRD showed that as the NC decreases, there is more rapid degradation of the glass powders. ICP-OES and ISE showed oscillations in the ion concentration, suggesting release and consumption of the ions to form apatite. 31P and 19F-NMR confirmed that the apatite formed is FAp. Similar results were found when the BAG was incorporated into the resin, however the effects were less pronounced, due to the presence of resin. The ATR-FTIR carbonyl vibration from the resin also decreased upon immersion, suggesting apatite formation occurs preferentially on the surface of the discs.
Conclusions: NC has been shown to affect the rate of degradation, apatite formation, ion release and pH rise of fluoride containing BAGs in artificial saliva. These glasses are attractive components for inclusion in composite resins with potential clinical benefits.
Methods: BAG powders (<38 μm) with varying NCs (from 1.45 to 2.70) were synthesised and immersed into artificial saliva pH 7 (AS7) to investigate the effect of NC on bioactivity. One selected composition was silylated and mixed with a Bis-GMA and TEGDMA based resin to form a composite disc and was immersed into AS7 for timepoints up to 3 months. The powders and discs were characterised using ATR-FTIR, XRD, 31P-NMR and 19F NMR to detect fluorapatite (FAp) formation. The supernatant solution was characterised using ICP-OES and ISE to quantify the ion release and the pH changes were measured.
Results: ATR-FTIR and XRD showed that as the NC decreases, there is more rapid degradation of the glass powders. ICP-OES and ISE showed oscillations in the ion concentration, suggesting release and consumption of the ions to form apatite. 31P and 19F-NMR confirmed that the apatite formed is FAp. Similar results were found when the BAG was incorporated into the resin, however the effects were less pronounced, due to the presence of resin. The ATR-FTIR carbonyl vibration from the resin also decreased upon immersion, suggesting apatite formation occurs preferentially on the surface of the discs.
Conclusions: NC has been shown to affect the rate of degradation, apatite formation, ion release and pH rise of fluoride containing BAGs in artificial saliva. These glasses are attractive components for inclusion in composite resins with potential clinical benefits.