G-c Dental Industrial Corp.

Satoshi Tosaki

Kentaro Tomioka

Kazuo Hirota

Shoji Akahane

Nobukazu Ohi

Koji Ohno

Shigenobu Kusakai

Yukiharu Kusayanagi

A dental glass ionomer cement composition comprises:

Dental glass ionomer cement compositions

A fluoroaluminosilicate glass powder for dental glass ionomer cements has a specific gravity of 2.4 to 3.5 and a mean particle size of 0.02 to 10 .mu.m, contains in its components 20 to 50% by weight of SiO.sub.2, 20 to 40% by weight of Al.sub.2 O.sub.3, 15 to 40% by weight of SrO, 1 to 20% by weight of F.sub.2 and 0 to 15% by weight of P.sub.2 O.sub.5 on the converted oxide basis, and is substantially free from alkali metal ions such as Li, Na, K, Rb and Cs ions, and Be, Mg (and Ca) and Ba ions of alkali earth metal ions. For further improvements in physical properties, 100 parts by weight of the glass powder are surface-treated with 0.01 to 5 parts by weight of an acid and/or a fluoride.

Glass powders for dental glass ionomer cements

A gypsum composition for denture investment comprises 100 parts by weight of a mixture of 50-90 parts by weight of .alpha.-Gypsum hemihydrate (.alpha.-CaSO.sub.4.1/2H.sub.2 O) with 10-50 parts by weight of .beta.-Gypsum hemihydrate (.beta.-CaSO.sub.4.1/2H.sub.2 O) and 0.2-2.0 parts by weight of a soluble potassium salt and 0.5-3.0 parts by weight of mannitol. As the soluble potassium salt, use may be made of one or more of potassium sulfate, potassium chloride and potassium tartrate. The gypsum composition may further include 0.5-5.0 parts by weight of dihydrate gypsum.

Gypsum composition for denture investment

A gypsum composition for denture investment consists of 100 parts by weight of a mixture of 50-90 parts by weight of .alpha.-Gypsum hemihydrate (.alpha.-CaSO.sub.4.1/2H.sub.2 O) with 10-50 parts by weight of .beta.-Gypsum hemihydrate (.beta.-CaSO.sub.4.1/2H.sub.2 O) and 0.2-2.0 parts by weight of a soluble potassium salt. As the soluble potassium salt, use may be made of one or more of potassium sulfate, potassium chloride and potassium tartrate. The gypsum composition may further include 0.5-5.0 parts by weight of dihydrate gypsum.

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Omiya, Japan

Satoshi Tosaki