IADR Abstract Archives
Multicomponent Bioactive Glasses With Lower Fluorine Content Can Form Apatite
Objectives: This study aimed to synthesis a series of multicomponent bioactive glasses with varying concentrations of fluorine and to investigate its degradation, apatite formation, pH increase and fluoride release in Tris buffer.
Methods: For this, three multicomponent SiO2-P2O5-Na2O-K2O-CaO-SrO-ZnO-CaF2-SrF2 glasses (F9, F13, F32) and one glass-ceramic (F32.2) were prepared through the melt-quench route. Glass degradation and apatite formation were investigated using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and 19F magic angle spinning-nuclear magnetic resonance (MAS-NMR) before and after immersion in Tris buffer for 24h and one week. The pH and the fluoride released were measured using a pH meter and an ion selective electrode.
Results: FTIR bands related to apatite formation were detected within one week only for F9 and F13. After 24h, these same two glasses were still amorphous or formed only nano crystals on XRD, but after one week, diffraction peaks suggesting the presence of apatite and CaF2 were detected for F9 and F13; both F32 and F32.2 presented diffraction peaks suggesting the presence of Ca0.5Sr0.5F2. On the 19F MAS-NMR, fluorapatite (FAp) and Sr-FAp were detected for the F9 and F13 glasses; CaF2 and SrF2 were detected for F32 after one week in Tris buffer; and F32.2 presented the same 19F MAS-NMR species before and after immersion with varying intensities, suggesting that Sr-containing apatite might not be as stable as previously investigated. All glasses increased the pH of the solution and released fluoride proportionally to the amount of fluorine in their composition.
Conclusions: Therefore, it can be concluded that fluorine-containing multicomponent bioactive glasses can form Sr-containing apatite. These glasses increase the pH of Tris buffer and release fluoride proportionally to their concentration.
Methods: For this, three multicomponent SiO2-P2O5-Na2O-K2O-CaO-SrO-ZnO-CaF2-SrF2 glasses (F9, F13, F32) and one glass-ceramic (F32.2) were prepared through the melt-quench route. Glass degradation and apatite formation were investigated using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and 19F magic angle spinning-nuclear magnetic resonance (MAS-NMR) before and after immersion in Tris buffer for 24h and one week. The pH and the fluoride released were measured using a pH meter and an ion selective electrode.
Results: FTIR bands related to apatite formation were detected within one week only for F9 and F13. After 24h, these same two glasses were still amorphous or formed only nano crystals on XRD, but after one week, diffraction peaks suggesting the presence of apatite and CaF2 were detected for F9 and F13; both F32 and F32.2 presented diffraction peaks suggesting the presence of Ca0.5Sr0.5F2. On the 19F MAS-NMR, fluorapatite (FAp) and Sr-FAp were detected for the F9 and F13 glasses; CaF2 and SrF2 were detected for F32 after one week in Tris buffer; and F32.2 presented the same 19F MAS-NMR species before and after immersion with varying intensities, suggesting that Sr-containing apatite might not be as stable as previously investigated. All glasses increased the pH of the solution and released fluoride proportionally to the amount of fluorine in their composition.
Conclusions: Therefore, it can be concluded that fluorine-containing multicomponent bioactive glasses can form Sr-containing apatite. These glasses increase the pH of Tris buffer and release fluoride proportionally to their concentration.