Definitive Cast and Dies Flashcards
A replica of the tooth surfaces, residual ridge areas, and/or other parts of the dental arch and/or facial structures used to fabricate a dental restoration or prosthesis.
Definitive (Master or Working) Cast:
Positive reproduction of the individual prepared tooth; used for wax pattern fabrication.
Die:
Advantages of the \_\_\_\_\_\_\_ CAST: •Guide to occlusal surfaces and contours •Ease of articulation •Development of optimum occlusion •(Development of optimum pontic adaptation and esthetics)
FULL ARCH Cast
Type ___ and Type _____ ADA type of gypsum pdts: impression plaster / model and mounting plaster
Type I and II
Type _____ ADA type of gypsum pdts: dental stone (general purpose casts)
Type III
Type _____ ADA type of gypsum pdts
high strength / lowest expansion (die stone)
Type IV:
Type _____ ADA type of gypsum pdts
high strength / high expansion (die stone)
Type V:
Do you add water to powder or powder to water for gypsum products?
Powder to water
- Helps eliminate porosity
- Strengthens the cast
- 20 seconds / 425 rpm / >25mmHg
Mechanical-Vacuum Mixing of Gypsum
•Over-spatulation→ ____ working time
decreased
In a two pour cast pourup, should you invert the impression/cast?
No: leave in upright position
Linear dimension ↓ per every ____ minutes of immersion
20 minutes
Does surface hardness = abrasion resistance?
No
•Retained by pins in a base (stone or plastic)•One die used for entire wax pattern -proximal contacts, occlusion and margins
Removable Dies
(Multiple Pour System)•Single (separate) die for wax coping and margins•Solid cast for waxing proximal contacts and occlusion
Solid Cast / Separate Dies
Advantages:
•Simple fabrication -requires minimum trimming
•Provides a rigid relation for FPD components
Solid Cast –Separate Die System
•The die can be lifted and replaced in the master cast with embedded pins or dowels.•Requires less manipulation of wax pattern•Reduces chance of breakage and distortion•Handling of restorations is easier (porcelain margins)
Removable die systems
•Disadvantage:
Technique sensitive
•Error in pattern if die does not re-seat accurately
•Margin or pin damage by improper saw cuts
Removable dies
Base is poured ____ pins/sleeves are cemented.
after
All sections are ______removable from the base
independently
T/F: Die is trimmed to remove areas corresponding to the gingival tissue.
•Die contour approximates the root and emergence profile.
True
An ______ is necessary to orient dies of prepared teeth to the opposing occlusion.
interocclusal registration
What material should not be used to take a bite registration in fixed prosth?
Wax
