National Research Development Corporation

Other

Btg International Limited

Alan D Wilson

Stephen Crisp

John Ellis

Havard J Prosser

David M Groffman

John W Nicholson

William M Allen

Bernard F Sansom

John Nigel Ellis

Bipin C Patel

Gavin John Pearson

John C Skinner

Pauline J Brookman

Edward Henry Davies

Anthony J Dunsdon

Edward C Combe

Ben C Cohen

Gary S Sayers

Glass polyalkenoate (glass ionomer) cements are used formed into dental crowns, despite their reputedly inadequate toughness, strength and wear-resistance early after forming for such an application, by heating the newly formed glass ionomer crown under a relative humidity of 100% in a bomb under silicone oil at 120-200.degree. C. for an hour.

Treated glass polyalkenoate cement

A phosphonate ester (vinyl phosphonic acid reacted with equimolar diol) will cure on command (e.g. exposure to light) in the presence of an initiator. By adding inert filler, poly(vinyl phosphonic acid), ion-leachable glass powder and water, a command-curable dental cement with glass ionomer characteristics is obtained.

Command-curable composition

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 cement. 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. The glass contains heavy ions such as La, Ba or Sr.

Poly(vinylphosphonic acid) glass ionomer cement

Dental cement comprising (a) calcium or zinc oxide or hydroxide, (b) a substituted aromatic compound capable of forming a cement with (a), the calcium or zinc oxide or hydroxide of (a) being in stoichiometric excess over (b), and (c) dry poly(carboxylic acid), or a precursor thereof, or dry cation-crosslinkable polymeric acid containing on average 1 phosphonic acid group per 1 to 3 backbone carbon atoms. The cement has bacteriostatic properties, stimulates the formation of secondary dentine, forms an adhesive bond and can be used where pulp tissue is exposed.

Dental cement

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.

Poly-vinylphosphonic acid and metal oxide or cermet or glass ionomer

A metallic container for beverage is protected from its contents by electrodeposited zinc, which is anodized in alkali then anodically reacted with weak poly(acrylic acid) and finally cured at 85.degree. C. at 100% relative humidity.

Coating substrates

A sustained release device which comprises a source of at least one trace chemical element incorporated in a cement and releasable therefrom on contact with an aqueous medium. The trace chemical element is exemplified by selenium, cobalt and iodine and the cement is exemplified by a phosphate cement.

Sustained release composition

A process for the preparation of a coherent protective layer on a substrate surface of a body, the substrate surface comprising elemental metal or an alloy thereof, which process comprises applying to the substrate surface an aqueous solution of a partially neutralised homo- or copolymer of a mono- or polybasic ethylenically unsaturated acid; and heat-curing the layer so formed at a temperature above 180.degree. C.

Coating process for the preparation of coherent protective layer

A body having a substrate surface which comprises corrodible material and on which substrate surface is present a coherent protective layer of an anti-corrosion composition which comprises a solid matrix of electrical conductivity .gtoreq.10.sup.-6 mho cm.sup.-1 and formed by reaction between at least water-soluble Bronsted acid and at least one Lewis base in which matrix is incorporated an elemental metal, or an alloy thereof, the matrix and metal being effective in service as electrolyte and sacrificial anode, respectively.

Coated substrates

A hardenable composition which comprises (i) a poly(carboxylic acid) or precursor thereof (as herein defined); (ii) a particulate ion-leachable silicate, aluminosilicate or metal oxide reactable with (i) in the presence of water to set to a hardened composition; and (iii) a compound comprising at least one phosphorus-carbon or phosphorus-boron covalent bond, in an amount effective in service to extend the working time of the composition.

Cement-forming compositions

A sustained release device which comprises a source of at least one trace chemical element incorporated in a cement and releasable therefrom on contact with an aqueous medium. A preferred cement is copper phosphate cement.

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.

Dental cement composition comprising poly(carboxylic acid) and chelating

Hardenable compositions

A cement-forming liquid suitable for use as a component of a poly(carboxylate) cement comprises an aqueous solution of a copolymer of acrylic acid, the copolymer having an average molecular weight of less than 20,000, and the solution having a viscosity of less than 50 poise.

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Liphook, United Kingdom

Alan D Wilson