Sodium silicate crystallization in the formation of bioglass
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Bioglass 45S5, commonly referred to by its commercial name Bioglass, is a glass specifically composed of 45 wt% SiO2, 24.5 wt% CaO, 24.5 wt% Na2O, and 6.0 wt% P2O5.[1] Glasses are non-crystalline amorphous 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.[2] Lower Ca:P ratios do not bond to bone.[3] Bioglass 45S5's specific composition is optimal in biomedical applications because of its similar composition to that of hydroxyapatite, the mineral component of bone. This similarity provides Bioglass' ability to be integrated with living bone.
This composition of bioactive glass is comparatively soft in comparison to other glasses. It can be machined, preferably with diamond tools, or ground to powder. Bioglass has to be stored in a dry environment, as it readily absorbs moisture and reacts with it.[3]
The morphology of bioglass using SEM, sintered at 900°C
Bioglass 45S5 is the first formulation of an artificial material that was found to chemically bond with bone. One of its main medical advantages is its biocompatibility, seen in its ability to avoid an immune reaction and fibrous encapsulation. Its primary application is the repair of bone injuries or defects too large to be regenerated by the natural process.[3]
The first successful surgical use of Bioglass 45S5 was in replacement of ossicles in the middle ear, as a treatment of conductive hearing loss. Other uses include cones for implantation into the jaw following a tooth extraction. Composite materials made of Bioglass 45S5 and patient's own bone can be used for bone reconstruction.[2] Further research is being conducted for the development of new processing techniques to allow for more applications of Bioglass.
History
Applications
Mechanism of action
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Methods of improvement
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Last edited 2 days ago by Pcourteau123
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