Fluoride-containing bioactive glasses: Glass design, structure, bioactivity, cellular interactions, and recent developments

Bioactive glasses (BGs) are known to bond to both hard and soft tissues. Upon exposure to an aqueous environment, BG undergoes ion exchange, hydrolysis, selective dissolution and precipitation of an apatite layer on their surface, which elicits an interfacial biological response resulting in bioactive fixation, inhibiting further dissolution of the glass, and preventing complete resorption of the material. Fluorine is considered one of the most effective in-vivo bone anabolic factors. In low concentrations, fluoride ions (F-) increase bone mass and mineral density, improve the resistance of the apatite structure to acid attack, and have well documented antibacterial properties. F- ions may be incorporated into the glass in the form of calcium fluoride (CaF2) either by part-substitution of network modifier oxides, or by maintaining the ratios of the other constituents relatively constant. Fluoride-containing bioactive glasses (FBGs) enhance and control osteoblast proliferation, differentiation and mineralisation. And with their ability to release fluoride locally, FBGs make interesting candidates for various clinical applications, dentinal tubule occlusion in the treatment of dentin hypersensitivity. This paper reviews the chemistry of FBGs and the influence of F- incorporation on the thermal properties, bioactivity, and cytotoxicity; and novel glass compositions for improved mechanical properties, processing, and bioactive potential. (c) 2015 Elsevier B.V. All rights reserved.