| abstract |
In our Patent No. 2099702B, we have described and claimed a temporary prosthesis comprising a body of non-toxic material, e.g. a glass, soluble in body fluids over an extended period. The prosthesis provides post-operative support for bone or tissue members. As healing proceeds, the prosthesis slowly dissolves into the body fluids, which obviates the need for surgical removal. The glass thus used is typically a P2O5/CaO/Alkali metal oxide, whose dissolution rate can be controlled to the desired value. The principles of the above Patent have been extended to give glasses which dissolve in water of pH of 6 to 8 at less than 20mg.cm<-2>h<-1> at 38 DEG C. Such glasses include P2O5 as glass-forming oxide, with one or more of CaO, ZnO, MgO, plus one or both of the additional modifying oxides Na2O and K2O. The proportion of P2O5 is in the range 28 mole % to 50 mole %, and the proportion of the one or more of CaO, ZnO, MgO is in the range 2 mole % to 47 mole %. |