1 Scope
This standard gives a classification of, and specifies requirements for, gypsum products used for dental purposes such as making oral impressions, moulds, casts or dies. It specifies the test methods to be employed to determine compliance with these requirements. It also includes requirements for the labelling of packaging and for adequate instructions to accompany each package.
2 Definition
For the purposes of this Standard, the following definition applies.
2.1
dental gypsum product
dental product composed essentially of hemihydrate of calcium sulfate and any necessary modifiers
NOTE Colouring matter and flavouring, if present, are regarded as necessary modifiers.
3 Classification
The five types of gypsum product used in dentistry are classified in accordance with this standard as follows:
Type 1: Dental plaster, impression
Type 2: Dental plaster, model
Type 3: Dental stone, model
Type 4: Dental stone, die, high strength, low expansion
Type 5: Dental stone, die, high strength, high expansion
4 Requirements
4.1 Quality
The material shall be uniform and free from foreign matter and lumps, and when mixed according to the manufacturer's instructions shall produce a homogeneous mix.
4.2 Fluidity at pouring time (Type 1 materials only)
When tested according to 6.2 at a pouring time of 1 min 15s, the fluidity of type 1 materials shall be equal to or greater than 70 mm.
