Concept

Bioglass 45S5

Résumé
Bioglass 45S5 or calcium sodium phosphosilicate, is a bioactive glass specifically composed of 45 wt% SiO2, 24.5 wt% CaO, 24.5 wt% Na2O, and 6.0 wt% P2O5. Typical applications of Bioglass 45S5 include: bone grafting biomaterials, repair of periodontal defects, cranial and maxillofacial repair, wound care, blood loss control, stimulation of vascular regeneration, and nerve repair. The name "Bioglass®" was trademarked by the University of Florida as a name for the original 45S5 composition. It should therefore only be used in reference to the 45S5 composition and not as a general term for bioactive glasses. Bioglass 45S5 is available commercially under the registered trade name NovaMin, which is owned by the pharmaceutical company GlaxoSmithKline. NovaMin is bioactive glass that has been ground into a fine particulate with a median size of less than 20 microns. It can reduce dentin hypersensitivity by blocking open dentinal tubules and by supplying calcium (Ca2+) and phosphate (PO43−) ions to form hydroxycarbonate apatite (HCA), the principal mineral component of bone tissue in mammals. NovaMin is the active ingredient in Sensodyne "Repair & Protect" toothpaste, except when sold in the United States, containing stannous fluoride instead. 45S5 bioactive glass is white in color and is in powder form, with particulates with a median size of less than 20 microns. Its chemical composition by weight is: silica (SiO2) 43-47%, calcium oxide (CaO) 22.5-26.5%, phosphorus pentoxide (P2O5) 5-7% and sodium oxide (Na2O) 22.5-26.5%> Glasses are non-crystalline disordered solids that are commonly composed of silica-based materials with other minor additives. Compared to soda-lime glass (commonly used, as in windows or bottles), Bioglass 45S5 contains less silica and higher amounts of calcium and phosphorus. The 45S5 name signifies glass with 45 weight % of SiO2 and 5:1 molar ratio of calcium to phosphorus. This high ratio of calcium to phosphorus promotes formation of apatite crystals; calcium and silica ions can act as crystallization nuclei.
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