Dental cement containing poly(carboxylic acid), chelating agent and glass cement powder
AssigneeNational Research Development Corporation
InventorsAlan D. Wilson, Stephen Crisp
Life of this patent
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Abstract
A poly(carboxylate) cement pack comprising a water soluble poly(carboxylic acid) having a relative viscosity of from 1.05 to 2.00, a chelating agent and a cement powder which will react with the poly(carboxylic acid) in the presence of the chelating agent and water to give a plastic mass which rapidly hardens to form a poly(carboxylate) cement.
Claims22
A process for the production of a poly(carboxylate) cement which comprises mixing a water soluble poly(carboxylic acid) having a relative viscosity of from 1.05 to 2.00 measured with a capillary viscometer of a 1% by weight to volume solution of the poly(carboxylic acid) in twice molar sodium hydroxide solution at 25.degree. C. relative to the viscosity of the twice molar sodium hydroxide solution with an ion leachable glass cement powder in the presence of a water soluble chelating agent selected from the group consisting of compounds containing both chelating hydroxyl and carboxyl groups and metal chelates, and water to give a plastic mass which rapidly hardens to form a poly(carboxylate) cement, the amount of the chelating agent being at least 0.01% by weight based on the weight of the poly(carboxylic acid) and sufficient to improve the rate of hardening of the cement, as compared to the rate of hardening of the cement in the absence of said compound.
A cement composition consisting essentially of an intimately blended mixture of an ion-leachable surgically acceptable glass cement powder, a water soluble poly(carboxylic acid) having a relative viscosity of from 1.05 to 2.00 measured with a capillary viscometer of a 1% by weight to volume solution of the poly(carboxylic acid) in twice molar sodium hydroxide solution at 25.degree. C. relative to the viscosity of the twice molar sodium hydroxide solution and a water-soluble chelating agent selected from the group consisting of compounds containing both chelating hydroxyl and carboxyl groups and metal chelates, the ratio of cement powder to poly(carboxylic acid) being from 1:1 to 10:1, and said chelating agent being present in an amount of at least 0.01% by weight based on the weight of the poly(carboxylic acid) and sufficient to increase the rate of hardening of the cement as compared to the rate of hardening of the cement in the absence of said chelating agent, said cement composition being characterized by forming a poly(carboxylate) cement upon the addition of water thereto.
A hardened poly(carboxylate) cement, particularly for dental purposes, which has been prepared by the process consisting essentially of mixing a water soluble poly(carboxylic acid) having a relative viscosity of from 1.05 to 2.00 measured with a capillary viscometer of a 1% by weight to volume solution of the poly(carboxylic acid) in twice molar sodium hydroxide solution at 25.degree. C. relative to the viscosity of the twice molar sodium hydroxide solution with an ion-leachable surgically acceptable glass cement powder in the presence of water and in the presence of a water soluble chelating agent selected from the group consisting of compounds containing both chelating hydroxyl and carboxyl groups and metal chelates, the chelating agent being present in an amount of at least 0.01% by weight based on the weight of the poly(carboxylic acid) and sufficient to improve the rate of hardening of the cement as compared to the rate of hardening of the cement in the absence of said chelating agent.
Dependencies are inferred from the claim text.