Gypsum Flashcards
What is a study model?
It is a positive replica of the dentition produced from an impression.
What is the purpose of a study model?
To record the position and she of teeth.
Aids visualisation and assessment of the dentition.
Enables manufacture of dental protheses.
What structure of gypsum determines its properties?
Crystalline structure.
What are the 4 main uses of gypsum?
Cast, die, mould material and investment binder.
What are the 3 main types of gypsum?
- Plaster (beta hemihydrate)
- Dental stone (alpha hemihydrate)
- Densite (improved stone).
How is plaster heated and what are the arrangements of its crystals?
Plaster is heated in an open vessel and it has large porous crystals.
How is dental stone heated and what are the arrangements of its crystals?
It is heated in an autoclave and it it non-porous, regular crystals and it requires less water.
How is Densite heated and what are the arrangements of its crystals?
It is heated in the presence of calcium and magnesium chloride and it consists of compact smoother particles.
