Poly-vinylphosphonic acid and metal oxide or cermet or glass ionomer cement
AssigneeNational Research Development Corporation
InventorsAlan D. Wilson, John Ellis
Life of this patent
Estimating the term…
Abstract
A glass ionomer cement composition comprises poly(vinyl phosphonic acid) dissolved in its own mass of water; and (in treble the total mass of the solution) a powder, being glass or MgO or a cermet. The powder has to be deactivated so that the setting reaction with the acid is not too fast, and this is achieved either by a raised Si:Al ratio or by heat-treating.
Claims15
A cement composition, comprising an intimately blended mixture of a water-containing liquid, a cation-crosslinkable polymeric acid containing on average one phosphonic acid group per one to three backbone carbon atoms, and a cation-leachable surgically acceptable glass powder containing Si and Al in the mole proportions 0.6-0.2:1 if previously heat-treated, otherwise exceeding 1.6:1, in the mass proportions (1-x) polymeric acid:
- (1-5) glass:
- x liquid, where x is from 0.3-0.7.
A cement composition, comprising an intimately blended mixture of a water-containing liquid, a cation-crosslinkable polymeric acid containing on average one phosphonic acid group per one to three backbone carbon atoms, and a metal oxide powder, in the mass proportions (1-x) polymeric acid:
- (1-5) oxide:
- x liquid, where x is from 0.3-0.7.
Dependencies are inferred from the claim text.