Fluoride-containing bioactive glasses: Fluoride loss during melting and ion release in tris buffer solution

► Nominal and analysed fluoride contents correlate linearly, allowing tailoring of fluoride-containing compositions. ► Bioactive glasses can form apatite in buffered solutions completely devoid of calcium and phosphate ions. ► Bioactive glasses cause a pH rise, which depends on the amount of phospho-silicate (rather than CaF2) phase present. ► Fluoride-release has a much smaller effect on the overall pH than suggested previously. ► Fluoride improves apatite formation of bioactive glasses in physiological solutions.