Bioactive glass composition
A bioactive glass composition comprising one or more glasses comprising Si02, P205 and a fluoride, the Si02 content being less than 40 mole %, the P205 content being at least 4 mole %, and the fluoride content being greater than 1 mole %. The bioactive glass or glass-ceramic can be used in a number of medical applications, including dental applications such as toothpaste.
1. A bioactive glass composition comprising one or more glasses comprising SiO 2 , P 2 O 5 and a fluoride, the SiO 2 content being less than 40 mole %, the P 2 O 5 content being at least 4 mole %, and the fluoride content being greater than 1 mole % and less than 25 mole %, wherein the bioactive glass composition forms fluorapatite instead of hydroxycarbonated apatite (HCA) and suppresses formation of fluorite (CaF 2 ) at the expense of fluorapatite when immersed in a body fluid or in simulated body fluid.
2. The bioactive glass composition of claim 1 , wherein the SiO 2 content is less than 39 mole %.
3. The bioactive glass composition of claim 1 , wherein the SiO 2 content is more than 25 mole %.
4. The bioactive glass composition of claim 1 , wherein the P 2 O 5 content is greater than 4.5 mole %.
5. The bioactive glass composition of claim 1 , wherein the P 2 O 5 content is less than 10 mole %.
6. The bioactive glass composition of claim 1 , wherein the fluoride content is greater than 3 mole %.
7. The bioactive glass composition of claim 1 , wherein the composition comprises up to 57 mole % of CaO and SrO combined.
8. The bioactive glass composition of claim 1 , wherein the composition comprises up to 40 mole % K 2 O.
9. The bioactive glass composition of claim 1 , wherein the composition comprises up to 5 mole % ZnO and ZnF 2 combined.
10. The bioactive glass composition of claim 1 , wherein the composition comprises up to 12 mole % of MgO and MgF 2 combined.
11. The bioactive glass composition of claim 1 , wherein the composition further comprises an apatite prior to immersion in the body fluid or in the simulated body fluid.
12. The bioactive glass composition of claim 11 , wherein the composition comprises at least 0.1 weight percent of the apatite present prior to immersion in the body fluid or in the simulated body fluid.
13. The bioactive glass composition of claim 11 wherein the apatite present prior to immersion in the body fluid or in the simulated body fluid is fluorapatite.
14. The bioactive glass composition of claim 11 wherein the apatite present prior to immersion in the body fluid or in the simulated body fluid is crystallised from the glass, and the size of the crystals is in the range 30 nm to 5μ.
15. The bioactive glass composition of claim 1 wherein the glass(es) have been pre-treated so that they have crystallised fluorapatite on their surface prior to immersion in the body fluid or in the simulated body fluid.
16. The bioactive glass composition of claim 15 , wherein the surface fluorapatite has a crystal size less than 5 μm.
17. The bioactive glass composition of claim 1 , for use in dental applications or as a bone substitute.
18. A toothpaste comprising a bioactive glass composition according to claim 1 .