Ion Measurements Following Chewing of Fluoride Containing Bioactive Glass Gums

Bioactive glass gums containing the glass system SiO₂ – P₂O₅ – CaO – Na₂O-CaF₂ were used to assess its ion releasing efficacy and remineralising potential. 

• Measure released ions into solution using ISE and ICP-OES.
• Identify the relationship between the Fluoride (F) content and ion concentrations in solution.
• Confirm apatite formation using FTIR.

Method:

Increasing amounts of F were added to a high phosphate (6 mol %) glass. Gums contained 5 wt % glass, the F content varied by blending two glasses together containing 0 mol % and 4.5 mol% CaF₂ and then incorporated into individual gum bases coded as 0F, 0.25F, 0.5F, 1F and 5F representing F weight percentage. F, Ca and P ion releasing ability of the gums following manual mastication in 5ml tris buffer solution over 5mins, 10mins and 20mins (duplicates) was analysed using ISE and ICP-OES. Apatite presence was assessed using FTIR. Data was compared to a control containing no glass or F.

Result: All bioactive glass gums released F (max. 7ppm F), Ca and P. Ion concentration in solution correlated with both chewing time and F content. Ratios of Ca/P/F ions shifted towards ideal Fluorapatite ratio (5:3:1) as both F content and chewing time increased. Apatite was not conclusively confirmed by FTIR, although, data suggested a potential apatite formation as peaks shifted towards the apatite region of 560-600 cm^-1 and 1080 cm^-1.

Conclusion: Gums released a maximum of over 2% of total fluoride content therefore may not be suitable as an efficient drug delivery vehicle. F levels above the therapeutic valuewere achieved therefore the gum may offer the benefits of fluoride release.  The provision of Ca, P and F ions released from the gum suggested that Fluorapatite may form thereby indicating a potential use as a remineralising and caries preventative agent.