Dental Materials Ch. 16
Gypsum Products - correct answer ✔Used mainly for making positive
productions or replicas of oral structures, often referred to as casts, dies or
models.
Gypsum - correct answer ✔Mineral found in nature in various parts around
the world known as calcium sulfate dihydrate and has been used in dentistry
since 1756 for making casts/dies
Diagnostic Cast - correct answer ✔Generally made from dental plaster or
stone and used for patient education, treatment planning, and tracking the
progress of treatment, as with orthodontic models
Working Casts - correct answer ✔Casts generally made from one of the
dental stones that are strong enough to resist the stresses of fabricating an
indirect restoration or prosthesis
Dies - correct answer ✔Replicas of prepared teeth that are generally
removable from the working cast
Types of Gypsum Products - correct answer ✔Type I: Impression Plaster
(Rarely used today and has been replaced with less rigid , elastic impression
material)
Type II: Model Plaster
Typer III: Dental Stone
Type IV: Dental Stone High Strength
Type V: Dental Stone High Strength & Expansion
, What are some factors affecting mixing and working time of gypsum
products? - correct answer ✔- how warm or cold the water is/ how much
water you put
-
What are some methods for pouring gypsum products? - correct answer
✔1.Double- Pour Method
2.Single-Step Method
3.Boxing Method
What are the steps involved in trimming a study model? - correct answer ✔
¢Produces an attractive and symmetric model
¢Provides a base of sufficient bulk for stability
¢Bases should be soaked in water for 5 to 10 minutes before trimming to
saturate the stone making it easier to trim
¢Exercise care when using the model trimmer
¢Always wear protective eyewear and pay attention to your hand positions
¢Use even steady pressure using both hands
¢Maintain an adequate flow of water on the trimming wheel
¢Clean the wheel and work surface of all gypsum products immediately after
finishing
How are gypsum powder products produced? - correct answer ✔Produced
by heating gypsum and driving off part of the water of crystallization by a
process called calcination. The resulting product is known as calcium sulfate
hemihydrate.
Whats the by-product of the calcination process? - correct answer ✔Heat
therefore known as exothermic reaction. (when mixed in water its converted
back to a dihydrate)
Gypsum Products - correct answer ✔Used mainly for making positive
productions or replicas of oral structures, often referred to as casts, dies or
models.
Gypsum - correct answer ✔Mineral found in nature in various parts around
the world known as calcium sulfate dihydrate and has been used in dentistry
since 1756 for making casts/dies
Diagnostic Cast - correct answer ✔Generally made from dental plaster or
stone and used for patient education, treatment planning, and tracking the
progress of treatment, as with orthodontic models
Working Casts - correct answer ✔Casts generally made from one of the
dental stones that are strong enough to resist the stresses of fabricating an
indirect restoration or prosthesis
Dies - correct answer ✔Replicas of prepared teeth that are generally
removable from the working cast
Types of Gypsum Products - correct answer ✔Type I: Impression Plaster
(Rarely used today and has been replaced with less rigid , elastic impression
material)
Type II: Model Plaster
Typer III: Dental Stone
Type IV: Dental Stone High Strength
Type V: Dental Stone High Strength & Expansion
, What are some factors affecting mixing and working time of gypsum
products? - correct answer ✔- how warm or cold the water is/ how much
water you put
-
What are some methods for pouring gypsum products? - correct answer
✔1.Double- Pour Method
2.Single-Step Method
3.Boxing Method
What are the steps involved in trimming a study model? - correct answer ✔
¢Produces an attractive and symmetric model
¢Provides a base of sufficient bulk for stability
¢Bases should be soaked in water for 5 to 10 minutes before trimming to
saturate the stone making it easier to trim
¢Exercise care when using the model trimmer
¢Always wear protective eyewear and pay attention to your hand positions
¢Use even steady pressure using both hands
¢Maintain an adequate flow of water on the trimming wheel
¢Clean the wheel and work surface of all gypsum products immediately after
finishing
How are gypsum powder products produced? - correct answer ✔Produced
by heating gypsum and driving off part of the water of crystallization by a
process called calcination. The resulting product is known as calcium sulfate
hemihydrate.
Whats the by-product of the calcination process? - correct answer ✔Heat
therefore known as exothermic reaction. (when mixed in water its converted
back to a dihydrate)
