Bioactive glass powder

Example application bioactive glass powders, with a composition of SiOi-CaO-PaOs Coatings—because the sol is a viscous liquid and can be applied to a substrate by spiiming... 

Figure 22.4 Scanning electron micrograph of bioactive glass powder [7, 21].

Kawanabe K, Tamura J, Yamamuro T, Nakamura T, Kokubo T, Yoshihara S. New bioactive bone cement consisting of bis-GMA resin and bioactive glass powder. J Appl Biomater 1993 4 135 1. 

Bioactive glasses are currently used as granulate for bone and dental grafting in small defects, or as powder incorporated into toothpaste. Although silica-based bioactive glasses meant an extraordinary advance in the field of bone tissue regeneration, their application as pieces for medium and large defects is not possible due to their very poor mechanical properties. 

Glasses and ceramics can bond to living tissues if there is bioactive layer. The development of a bioactive hydroxyapatite layer in vivo at body temperature is therefore an important problem.89 Materials with the highest level of bioactivity develop a silica layer that enhances the formation of such a layer. Such sol-gel processes are used to produce bioactive coatings, powders and substrates which allow molecular control over the incorporation and behavior of proteins and cells with applications as sensors and implants. Sol-gel encapsulation of biomolecules within silica matrices has encompassed... 

Silva W, Lameiras FS, Domingues RZ (2001) Evaluation of stoichiometry of hydroxylapatite powders prepared by coprecipitation method. Key Eng Mater 189-191 79-84 Silver I A, Deas J, Erecinska M (2001) Interactions of bioactive glasses with osteoblasts in vitro Effects of 45S5 Bioglass, 58S and 77S bioactive glasses on metabolism, intracellnlar ion concentrations and cell viability. Biomaterials 22 175-185... 

As a result of this combination of properties bioactive glasses are not found in load-bearing applications, rather they are used as coatings on metals, in low-loaded or compressively loaded devices, in the form of powders, and in composites. The first successful use of Bioglass 45S5 was as a replacement for the ossicles (tiny bones) in the middle ear. The position of these bones (the malleus, incus and stapes) is illustrated in Figure 35.6. 

In powder form, bioactive glasses have been used in the treatment of periodontal disease and for the treatment of patients with paralysis of one of the vocal cords. When mixed with autologous bone they have been used in maxillofacial reconstruction (i.e., mixed with natural bone to rebuild a jaw). 

Ceramic powders SiC tor abrasives Nanosized TiQs tor sunscreen Bioactive glasses tor bone reconstruction Bayer process AI2Q3 tor the production of Al using Hall-H4roult cells... 

The powder processing route has also been used in the fabrication of bioactive glass ceramics [1.54] mentioned in Sect. 1.4. A more recent development combines powder processing of glass ceramics and sol-gel techniques. 

An alternative route to the production of bioactive glasses is to use low temperature processing methods including Sol-Gel Technology. Materials can be prepared from colloidal powders and simple molecular alkox-ide precursors. The glass phase originally forms as a gel that can subsequently be dried by supercritical methods or conventional heating to moderate temperatures of... 

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