W3 - Types of casts, casting as a kind of information transfer Flashcards
What is impression?
Negative imprint of the mouth
What is cast?
Positive likeness of a patient’s upper or lower jaw
What is die?
Small model of prepared teeth
As we know, casting is a kind of information transfer
-> describe the information flow (starting from patient)
How do we name impressions?
- It is not coming directly from the used impression material
- The name depending on the information needed to send to the dental lab
How many types of gypsum are there?
5 types
What is Type I Gypsum used for?
Impression plaster
What is type II gypsum used for?
Lab or model plaster
What is type III Gypsum used for?
Dental stone ordinary, model stone
What is type IV Gypsum used for?
Dental stone with high strength, low expansion
What is type V gypsum used for?
Dental stone with high strength, high expansion
What is this?
Study impression - study cast
Study impression should be mounted on ___
An articuator
2 pieces of info that we can obtain from study cast
- Relationship between hard and soft tissues
- Occlusal analysis (also from the lingual side)
Which type of gypsum is used to make study impression?
Type III
What is this?
Complete denture
Which types of impressions are used during the process of making complete denture?
- Primary impression
- Secondary impression
Which types of casts are used to make?
- Primary cast
- secondary cast
Which type of gypsum used to make primary cast?
Type III
3 pieces of information that secondary impression provides
- Gives more precise details about the hard and soft tissues
- Functional impression
- Vestibular sulcus
What is the function of impression boxing? (secondary cast)
- Provides a protective rim around the cast
- use sticky wax
Which type(s) of gypsum used to make secondary cast?
Type III/IV
Secondary cast is made according to which type of impression?
Secondary impression
What is this?
Fixed partial denture
2 characteristics of impression for making fixed partial dentures
- Precisional situation impression
- Antagonist impression
Which types of models are used for making fixed partial denture?
- Sectional model
- Antagonist model
What are the 3 requirements for precisional situation impression?
- perfect copy of the prepared tooth (the dentist and technician need to follow the preparation line)
- Need to contain the other non-prepared surfaces
- No bubbles, no distortion
What is sectional cast?
In sectional cast, the dies of the prepared teeth or roots that can be removed seperately from the cast to make a very accurate or precise wax pattern for making a fixed dental appliance
Which type(s) of gypsum are used to make sectional model?
Type IV/V
Which piece of information does the base of die provide?
It provides a means of locating the die within a larger localizing model which includes the other teeth on the arch next to the prepared tooth
3 types of materials to make preparing dies
- Die stone (most common)
- Acrylic
- Polyurethan
What is this?
Complex denture
2 parts that complex denture include
- Fix part
- Removable part
3 types of impressions for making complex denture
- Precisional situation impression
- Antagonist impression
- Situation “pick-up” impression
4 types of casts for making complex denture
- Sectional cast
- Antagonist cast
- Master cast
- Working cast
Which type(s) of impression(s) and cast(s) are used for fixed part of complex denture?
- Precisional situation impression
- Sectional cast
Which type(s) of impression(s) and cast(s) are used for removable part of complex denture?
- Stuation impression; “pick-up” impression
- master cast
What is master cast?
The cast that is first poured out with stone after taking impression at the dental office
!!! Ready appliances are also transported on it
Name of this process
Duplicating (to make working cast)
What is working cast?
- A copy that is made from the master cast
Function of working cast
Used for making the wax pattern for the metal framework of a removable partidal denture on its surface with prefabricated wax elements
