Bioactive Glass Properties

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Bioactive Glass Background

• The 45S5 formulation of bioactive glass has been the primary material used in today's bioactive glass bone graft products (45% SiO2, 24.5% CaO, 24.5% Na2O, and 6% P2O5).

• When implanted, 45S5 bioactive glass undergoes a dissolution process that releases ions from the glass.  45S5 bioactive glass particles are fully resorbed and replaced by bone within approximately 9-12 months.

• The dissolution process is governed by the shape and size of the particle.  Due to a higher surface area, smaller particles will dissolve faster than larger particles.  In addition, spherical particles will have more reproducible ion release.

Standard bioactive glass is ground and sieved into
a broad particle size range of irregular particles.

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Bioactive Properties

• The bioactive properties of 45S5 glass are due to the ability of the material to form a bone-like mineral layer on its surface (hydroxy-carbano-apatite - HCA). [1]  As the bioactive glass particles begins to dissolve in vivo, the ions released from the glass combine with local ions to form an HCA coating on the surface.

• Due to the similarity of the HCA layer to bone mineral, the coating provides an optimal surface for new bone formation and results in a chemical bond between the bioactive glass particles and the surrounding bone.

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Cellular Effects

• During the dissolution of 45S5 bioactive glass, a variety of ions are released from the material (silica, calcium, phosphate, and sodium ions).

• In vitro testing of 45S5 bioactive glass has shown that the dissolution ions positively affect cells involved in bone formation. [2,3]  

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References

1. Hench l.  "Bioactive Materials:  The Potential for Tissue Regeneration."  J. Biomed. Mat. Res.41: 511-518 (1998).
2. Xynos I.  "Gene-expression profiling human osteoblasts following treatment with the ionic products of Bioglass 45S5 dissolution."  J. Biomed. Mat. Res. 55:151-157 (2001).
3. Bosetti M.  "The effect of bioactive glasses on bone marrow stromal cells differentiation."  Biomaterials.  26:3873-3879 (2005).