IADR Abstract Archives
Fluoride-Releasing Glasses Based on Sodium Fluoride-Modified 45S5 Bioglass
Objectives: Fluoride-releasing filling materials can potentially protect restored teeth from secondary caries. Dental composites are the most common aesthetic filling materials but the majority of products currently do not release fluoride. Bioglass 45S5 (BG) has recently been incorporated in dental composites as a smart filler with promising results. However, BG does not contain any fluoride. This study aims to develop novel fluoride-releasing glasses, by modifying the BG composition with different percentages of sodium fluoride NaF (5, 10 and 20wt%).
Methods: Glasses were synthesised by a conventional melt-quenching technique, then characterised for physical, morphological and chemical properties. X-ray diffraction (XRD) was used to confirm their amorphous nature, and differential thermal analysis (DTA) to analyse glass characteristic temperatures (glass transition Tg, crystallisation Tc and melting Tm). Ion-selective electrode (ISE) was used to measure the cumulative release of fluoride ions. Glass particles (≤45µm) were immersed in deionised water (DI) for 84 days at 37°C. The cumulative fluoride release was measured after 1, 3, 7, 14, 28, 56 and 84 days of immersion. Statistical significance of fluoride release was assessed using one-way ANOVA with Tukey’s post-hoc test.
Results: All samples were amorphous. The DTA characteristic temperatures and the cumulative fluoride release of BG and modified BGs are shown in Table 1. Modified BGs showed a second crystallisation peak, compared to the original BG. The addition of sodium fluoride decreased all DTA characteristic temperatures (Tg, Tc and Tm). The pattern of fluoride release was similar for all modified BGs, being highest on the first days of immersion and diminishing subsequently, and it was proportional to the square root of time. The highest amount of fluoride was released by 20NaF (20wt% NaF) and it was statistically significantly higher (p<0.001) than 5NaF (5wt% NaF) and 10NaF (10wt% NaF) at each time point. Also, 10NaF was statistically significantly higher (p<0.001) than 5NaF at each time point.
Conclusions: 20NaF showed the potential to be used in fluoride-releasing dental filling materials.
Methods: Glasses were synthesised by a conventional melt-quenching technique, then characterised for physical, morphological and chemical properties. X-ray diffraction (XRD) was used to confirm their amorphous nature, and differential thermal analysis (DTA) to analyse glass characteristic temperatures (glass transition Tg, crystallisation Tc and melting Tm). Ion-selective electrode (ISE) was used to measure the cumulative release of fluoride ions. Glass particles (≤45µm) were immersed in deionised water (DI) for 84 days at 37°C. The cumulative fluoride release was measured after 1, 3, 7, 14, 28, 56 and 84 days of immersion. Statistical significance of fluoride release was assessed using one-way ANOVA with Tukey’s post-hoc test.
Results: All samples were amorphous. The DTA characteristic temperatures and the cumulative fluoride release of BG and modified BGs are shown in Table 1. Modified BGs showed a second crystallisation peak, compared to the original BG. The addition of sodium fluoride decreased all DTA characteristic temperatures (Tg, Tc and Tm). The pattern of fluoride release was similar for all modified BGs, being highest on the first days of immersion and diminishing subsequently, and it was proportional to the square root of time. The highest amount of fluoride was released by 20NaF (20wt% NaF) and it was statistically significantly higher (p<0.001) than 5NaF (5wt% NaF) and 10NaF (10wt% NaF) at each time point. Also, 10NaF was statistically significantly higher (p<0.001) than 5NaF at each time point.
Conclusions: 20NaF showed the potential to be used in fluoride-releasing dental filling materials.