Fabrication of the Metal Framework Flashcards
What parts of the design need to be transfered to the lab for fabrication?
- Diagnostic Cast
- Master Cast
- Work Authorization
All parts of the framework are non-flexible except for the…
clasp tips
Casts are blocked out to eliminate __________ areas that will be crossed by the rigid parts of the RPD.
undercut
What is the diagnostic cast for?
Draw, design, and map out the plan for treatment
Design transfer requires what on the casts before sending to lab?
- Surveying table (align tripod marks)
- Mark retentive undercuts
Arbitrary block-out in less critical areas such as:
- Gingival crevices
- Spaces between teeth not in the design
- Gross tissue undercuts
- Areas that would complicate the duplication process
What is relief?
Space between the framework and cast/soft tissue
Where is relief required for the framework?
Beneath framework extension in edentulous areas
- Provide attachment of the denture base
- Form internal finish line
Prepared master casts are duplicated to produce…
an exact copy of master cast in investment material (refractory cast)
Framework pattern will be fabricated on the _________ cast using wax
refractory
An impression using __________ _________ is made of the wax pattern on the refractory cast
reversible hydrocolloid (Agar)
- can also use alginate, reversible plastic gel (polyvinyl chloride)
_________ ________ which has been warmed, is poured and it flows into the duplication flask.
Reversible hydrocolloid
__________ material is used to make the refractory cast
Investment
What do you do after making the refractory cast?
- Waxing and Spruing
- Investing, Burnout and Casting
- Framework Fabrication
During investing you paint on layer of investment about ______ mm thick
3-4
What does waxing entail?
- waxing up guideplanes
- waxing up major connectors
- etc.
Why do you invest over the top of the wax?
Leaves a space for the wax to evaporate and the metal to get centrifudged in (forms the metal framework)
Do you need to polish the metal framework or do you leave it?
Polish the metal!
What do you mark on the master cast?
Survey line
Undercut areas
- all design features are on diagnostic cast
When do you make the master cast to send to the lab?
After tissue/patient modifications
What happens to metal when it cools?
It shrinks
Why do you make the framework a little bit at first?
After it cools it shrinks down
What does freehand waxing sometimes lead to?
Different thicknesses in the components that could lead to some error in final metal framework thinkness
What are the different ways to wax up and build the metal framework?
- analogue
- semi-digital
- digital
- 3D printed
