Carefully controlled calcination under steam pressure in a closed container is:
a. plaster
b. dental stone
c. high strength stone
d. high strength, high expansion stone
B. dental stone
to decrease the working time of a gypsum product without changing any physical properties, it is best to:
a. decrease the water to powder ratio
b. increase the rate of spatulation
c. increase the water temperature
d. decrease the water temperature
c. increase the water temperature
the main difference between model plaster and dental stone is:
a.chemical formula
b. solubility in water
c. particle size and shape
d. accelerators and retarders
c. particle size and shape
the most appropriate type of gypsum product to use for orthodontic casts is
a. type I
b. type II
c. type III
d. type IV
C. type III
Initial setting can be detected clinically by:
a. loss of gloss
b. the end of the exothermic reaction
c. a change in color
d. testing to see whether the material is hard enough to separate from the impression
a. loss of gloss
the area of the diagnostic cast that records the hard and soft tissues is called the:
a. art portion
b. base
c. anatomic position
d. impression
c. anatomic positon
a study model is a positive reproduction. an impression is a negative reproduction.
a. both statements are true
b. both statements are false
c. the first statement is true the second statement is false
d. the first statement is false the second statement
a. both statements are true
Material that will act as retarders for the set of gypsum products include:
a. saliva
b. set gypsum products
c. slurry water from the model trimmer
d. none of the above are considered retarders
a. saliva
it is important to consider the following statements when pouring an impression.
A. alginate impressions should remain unseparated from the model for only 1 hour
B. when the single step method is used, the material poured into the impression must reach th
D. A and B
diagnostic casts are used for:
A. patient education
B. fabricating dentures
C. fabricating crowns
D. fabricating orthodontic appliances
A. patient education
CAD/CAM fabrication of indirect restorations eliminates the need for:
a. investing
b. cutting the preparation
c. impression taking
d. A and B
e. A and C
E. A and C
The melting range can best be described as:
a. the point at which the wax flows
b. the point at which the wax softens
c. the required temperature of the heat source
d. a combination of melting points
B. The point at which the wax softens
a direct wax pattern is fabricated in the mouth. Which property of the inlay wax is the most important?:
A. flow
B. residual stress
C. melting range
D. excess residue
c. melting range
A wax pattern is invested and burned out by the lost wax procedure. Which property of the inlay wax is the most important?
a. melting range
b. flow
c. residual stress
d. removal of excess residue
d. removal of excess residue
The wax used to form a base into which to pour a gypsum model is:
a. boxing wax
b. sticky wax
c. pattern wax
d. baseplate wax
a. boxing wax
utility wax ropes are used to:
a. hold components together for repair
b. make forms for wax bite registrations
c. make connections in undercut areas of impressions
d. adapt a periphery of impression trays
d. adapt the periphery of impression trays
the sprue is used in the lost wax procedure to:
a. make the channel into which molten metal is forced
b. account for delayed expansion and contraction in the final casting
c. hold the wax pattern in the investment
d. aid in lowering the melting range of t
a. make a channel into which molten metal is forced
if it is necessary to store a wax pattern or bite registration, it should be stored:
a. at room temp
b. wrapped with gauze
c. in a cool, dry place
d. refridgerated
c. in a cool dry place
bite registrations are used to:
a. hold models together during articulation
b. record the occlusal relationship between maxillary and mandibular teeth
c. record the amount of force used in biting
d. record how much force is exerted by the teeth
b. record the occulsal relationship between maxillary and mandibular teeth