Chapter 9

Question 1

define calcination

Answer 1

The process of heating a solid material to drive off volatile chemically combined com- ponents such as water and carbon dioxide.

Question 2

define cast

Answer 2

A reproduction of the shape and surface of a structure made in an impression of the surface.

Question 3

define plaster of paris

Answer 3

The beta form of calcium sulfate hemihydrate (CaSO4• 12 H2O).

Question 4

define dental stone

Answer 4

The alpha form of calcium sulfate hemihydrate (CaSO4• 12 H2O).

Question 5

define die

Answer 5

a reproduction of a prepared tooth made from a gypsum product, epoxy resin, a metal, or a refractory material.

Question 6

define gypsum

Answer 6

Calcium sulfate dihydrate (CaSO4•2H2O).

Question 7

define gypsum-based investment

Answer 7

A refractory material consisting of silica and gypsum as a binder used
to produce a mold for the metal casting process.

Question 8

define hygoscopic expansion

Answer 8

The expansion that occurs when gypsum or a gypsum-bonded investment sets while immersed in water (usually heated to approximately 38 °C [100 °F]).

Question 9

define model

Answer 9

A positive likeness of an object

Question 10

define normal setting expansion

Answer 10

The expansion that occurs when gypsum or a gypsum-bonded investment sets in ambient air.