Quiz 3 Flashcards
-Naturally occurring mineral
-Used to make replicas of hard and soft tissue
Gypsum products
Planning treatment and observing final models
Diagnostic cast
Replica of singular tooth
Crown or bridge
Die
What qualities do all models have?
Accuracy
Hardness
Dimensional stability
What contains the most excess of water?
Plaster
What contains the most air bubbles?
Plaster
What contains the least excess of water?
Die stone
What do gypsum products produce?
Model plaster
Dental stone
Die stone
Dry process
Porous, irregularly shaped
Diagnostic cast
Model plaster
Formed under stream, heat, and pressure
Less porous, more uniform shape
Working cast
Dental stone
Boiled in 30% calcium chloride – BEFORE steam, heat, & pressure
Product of densite
High resistance to heat and stress
Blue, pink, or green
Die stone
What hemihydrate is model plaster?
Beta hemihydrate
What hemihydrate is dental stone?
Alpha hemihydrate
What hemihydrate is die stone?
Alpha hemihydrate
What model type would expansion be most detrimental?
Die
What is model plaster (type II) used to create?
Diagnostic cast
What is dental stone (type III) used to create?
Denture/ortho models
What is High-strength/low-expansion stone (type IV) used to create?
Die stone
Cast restorations
What are the chemical accelerators?
Potassium sulfate
Set gypsum
What factors accelerate set time?
-Chemical accelerators
-Increased water temp.
-Increased spatulation
What factors retard set time?
-Chemical retards
-Decreased water temp.
-Decreased spatulation
What is the chemical retard?
Borax
What are the model parts?
-Anatomic portion
-Art portion/base
What are the pouring methods?
Double-pour
Inverted-pour
Boxing
What are the factors to model trimming?
Neat
Symmetrical
Occlusal plane parallel to base
What are the properties of wax?
Melting range
Flow
Excess residue
Thermal expansion
What must the melting range be higher than?
Environment temperature
What are the three classifications of wax?
Pattern wax
processing wax
Impression waxes
What are the types of pattern wax?
Inlay wax
Casting wax
Baseplate wax
- Direct patterns in mouth
- Indirect patterns on dies
Inlay wax
Constructing metal framework of dentures
Casting wax
- Impression in cool & warm climates
- Recreate contours on dentures
- Hold position of teeth on wax Trian
Baseplate wax
What are the types of processing waxes?
Boxing wax
Utility wax
Sticky wax
- Used to help pour up base portion of model
- 1 ½ inch red strip
Boxing wax
Used to fill in areas
Utility wax
- Used like glue
- Used for fabrication & repairs
Sticky wax
What are the types of impression waxes?
Corrective impression wax
Bite registration wax
Used to take impression on edentulous patient
Corrective impression wax
- Helps to articulate two models together
- Deforms easily
Bite registration wax
What are the steps to the lost wax technique?
o 1. Pour the die
o 2. Wax the die
o 3. Sprue the die
o 4. Attach sprue to sprue base
o 5. Invest wax pattern
o 6. Burn out wax
o 7. Cast restoration
o 8. Final steps
hannel that metal can flow through to fill the area
Sprue
What happens when we mix?
hemihydrate -> H2O -> Dihydrate
What is the main difference between model plaster and stone?
Partical size and shape
What is the positive reproduction of the hard and soft tissues on a study model called?
Anatomic portion
What can be added to increase the wetting compatibility of a non-aqueous impression and gypsum material?
Surfactant
What gypsum product has a W/P ratio of 30/100?
Dental stone
What is the process of heating dihydrate of calcium sulfate to eventually form powered calcium sulfate hemihydrate?
Calcination
What has higher abrasion resistance than model plaster?
Dental stone
What has a higher setting expansion than dental stone?
Model plaster
What wax type is used to form a base into which to pour a gypsum model?
Boxing wax
