Dental gypsum slurry

Patent metadata

Field	Value
Publication number	US-11583376-B2
Application number	US-201816621837-A
Country	US
Kind code	B2
Filing date	Jan 30, 2018
Priority date	Jun 13, 2017
Publication date	Feb 21, 2023
Grant date	Feb 21, 2023

Abstract

A dental gypsum slurry includes water and a dental gypsum powder containing hemihydrate gypsum and a polycarboxylic acid salt-based water-reducing agent, wherein a powder-water ratio of the water to the dental gypsum powder is 0.24 to 0.50, and when the water and the dental gypsum powder being mixed are poured up to a height of 50 mm in a cylindrical mold having an inner diameter of 35 mm, which is vertically placed on a flat surface, and then, the cylindrical mold is pulled upward at 10 mm/s at 30 seconds after start of mixing so that a mixture spreads planarly, the diameter of the mixture is 141.4 mm or more.

First claim

The invention claimed is:

1. A dental gypsum slurry comprising water and a dental gypsum powder containing hemihydrate gypsum and a polycarboxylic acid salt-based water-reducing agent, wherein
a powder-water ratio of the water to the dental gypsum powder is 0.34 to 0.50, and
when the water and the dental gypsum powder being mixed are poured up to a height of 50 mm in a cylindrical mold having an inner diameter of 35 mm, which is vertically placed on a flat surface, and then, the cylindrical mold is pulled upward at 10 mm/s at 30 seconds after start of mixing so that a mixture spreads planarly, the diameter of the mixture is 141.4 mm or more.

2. The dental gypsum slurry according to claim 1 , wherein setting time is 4 minutes and 25 seconds or less from start of mixing.

3. The dental gypsum slurry according to claim 1 , wherein compressive strength at 1 hour after start of mixing is 10 MPa or more.

4. The dental gypsum slurry according to claim 1 , wherein when the water and the dental gypsum powder being mixed are poured up to a height of 50 mm in a cylindrical mold having an inner diameter of 35 mm, which is vertically placed on a flat surface, and then, the cylindrical mold is pulled upward at 10 mm/s at 90 seconds after start of mixing, a spread in a diameter direction is 2% or less.

5. The dental gypsum slurry according to claim 1 , wherein linear expansion coefficient at 2 hours after start of mixing relative to at start of mixing is 0.10% to 0.15%.

6. The dental gypsum slurry according to claim 5 , wherein linear expansion coefficient at 24 hours after start of mixing relative to at start of mixing is 0.10% to 0.20%.

Assignees

• G C Dental Ind Corp

Inventors

• Mori Daizaburo
• Yoshinaga Masatoshi
• Kojima Kenji
• Watanabe Kaori
• Kaneko Tsukasa

Classifications

• A61K6/889

  Polycarboxylate cements; Glass ionomer cements · CPC title

• A61K6/90

  Compositions for taking dental impressions · CPC title

• A61C13/34 Primary

  Making or working of models, e.g. preliminary castings, trial dentures; Dowel pins [4] · CPC title

• A61C13/083

  Porcelain or ceramic teeth {(A61C13/081 takes precedence; preparations A61K6/80)} · CPC title

• A61K6/858

  Calcium sulfates, e.g, gypsum · CPC title