Overview

stone, dental


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A specially calcined gypsum derivative similar to plaster of Paris manufactured to provide improved properties of strength and hardness. It is frequently coloured yellow. Dental stone is produced by heating gypsum under steam pressure in an autoclave at 120–150°C (248–302°F). Because of its small particle size and low porosity it requires less water to form a mix than plaster of Paris. Dental stones are classified by the American Dental Association (ADA specification no. 25) according to their properties.High-expansion dental stone compensates for the very high shrinkage of some metal alloys.

Further Reading:

Contemporary dental materials, ed. V. B. Dhuru, 199–200. Oxford University Press, 2004.

The American Dental Association classification of dental stone

Type

Description

Principal uses

I

Impression plaster (plaster of Paris)

Impressions, occlusal registration

II

Model plaster (β-calcium sulphate hemihydrate)

Study models, denture flask investment

III

Dental stone (Hydrocal) (α-calcium sulphate hemihydrate)

Denture casts

IV

Dental stone, high strength (Densite) (α-calcium sulphate hemihydrate)

Wax pattern dies

V

Dental stone, high strength, high-setting expansion

Wax pattern dies for high-shrinkage alloys

Subjects: Dentistry.


Reference entries

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