- Bioactive glass
Bioactive glasses are a group of surface reactive
glass-ceramic s and include the original bioactive glass,Bioglass . Thebiocompatibility of these glasses has led them to be investigated extensively for use asimplant materials in the human body to repair and replace diseased or damaged bone.History
Larry Hench and colleagues at the
University of Florida first developed these materials in the late 1960s and have been further developed by his research team at theImperial College London and other researchers worldwide.Compositions
There have been many variations on the original composition which was
Food and Drug Administration (FDA) approved and termed bioglass. This composition is known as 45S5. Other compositions are in the list below.
*45S5: 46.1 mol% SiO2, 26.9 mol% CaO, 24.4 mol% Na2O and 2.5 mol% P2O5.Bioglass
*58S: 60 mol% SiO2, 36 mol% CaO and 4 mol% P2O5.
*S70C30: 70 mol% SiO2, 30 mol% CaO.Structure
Solid state NMR spectroscopy has been very useful in elucidating the structure ofamorphous solids . Bioactive glasses have been studied by 29Si and 31P solid stateMAS NMR spectroscopy. The chemical shift from MAS NMR is indicative of the type of chemical species present in the glass. The 29Si MAS NMR spectrscopy showed that Bioglass 45S5 was a Q2 type-structure with a small amount of Q3; i.e.,silicate chains with a few crosslinks. The 31P MAS NMR indicated a Q0 species; i.e., PO44- with predominately sodium cations. (Lockyer et al. 1995)Medical Applications
Bioactive glasses have many applications but these are primarily in the areas of bone repair and bone regeneration via
tissue engineering .
*Synthetic bone graft materials for generalorthopaedic , craniofacial (bones of the skull and face),maxillofacial and periodontal (the bone structure that supports teeth) repair. These are available to surgeons in a particulate form.
*Cochlear implants .
*Bone tissue engineering scaffolds. These are being investigated in many forms, in particular as porous (contains pores into which cells can grow and fluids can travel) 3-dimensional scaffolds.
*TreatingDentine hypersensitivity and promoting enamelremineralization in the form ofNovaMin .ReferencesLockyer, M. W. G., Holland, D. & Dupree, R., NMR investigation of the structureof some bioactive and related glasses. J. Non-Crys. Sol., 1995, 188, 207-219.External links
NovaBone Products in Alachua, FL manufactures and markets bioactive glass. The Musculoskeletal Transplant Foundation distributes NovaBone internationally. Visit: www.novabone.com and www.mtf.org
Vivoxid Ltd in Finland manufactures, markets and sells bioactive glass.Visit: www.vivoxid.com
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