Method: Glass powders (<38µm) of 3 melt-derived glasses in the system SiO2-P2O5-CaO-Na2O-CaF2 with increasing Sr for Ca substitution (0, 50, 100% atomic substitution) were treated in tris-buffer and simulated body fluid (SBF) for up to 1 week. Analysis of the glasses was made using Differential Scanning Calorimetry, Particle size analysis, X ray diffraction (XRD), Fourier transform infrared spectroscopy and Ion Coupled Plasma Mass Spectroscopy. An in vitro dentine disk model was used to investigate the effect of the glasses on tubule occlusion by 1) changes in hydraulic conductance (Lp) rates and 2) Scanning Electron Microscopy (SEM).
Result: An increase in Sr content (0 to 31 molar %) resulted in a faster apatite formation rate: XRD showed apatite forming within 6 hours of immersion in SBF for all Sr glasses, and within 24 hours for the calcium glass. Decreasing glass transition temperatures with increasing Sr content suggests that higher Sr content produces more readily degradable glasses with an increased bioactivity. Sr glasses demonstrated the highest reduction in hydraulic through the dentine disk indicating that Sr glasses may be effective in reducing DH
Conclusion: Greater reduction in Lp and increased tubule occlusion was noted with an increasing Sr concentration which would suggest that Sr containing bioactive glasses may be beneficial in the treatment of DH.