Fixed Prostodontics > Definitive Casts and Dies > Flashcards

Definitive Casts and Dies Flashcards

(65 cards)

Study These Flashcards
1
Q

Definitive (Master or Working)
Cast:

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Die:

A

Positive reproduction of the
individual prepared tooth; used for
wax pattern fabrication.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

A good cast must be:
(2)

A

Bubble free
Distortion free

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q
  • Reproduce both (2) tooth surfaces, and be free
    of voids
A

prepared and unprepared

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

All occluding surfaces must allow for precise — of the
opposing casts

A

articulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

All relevant — should be reproduced.

A

soft tissues
* Edentulous spaces and ridge contours involved in FPD

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Requirements for the Die:
(4)

A
  • Reproduces the prepared tooth exactly.
  • All surfaces must be accurately duplicated.
  • The unprepared tooth structure apical to the finish line should be
    easily visible (0.5 – 1mm).
  • Adequate access for carving wax pattern margin.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q
  • All surfaces must be accurately duplicated.
A
  • No bubbles or voids especially along the finish line.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q
  • Adequate access for carving wax pattern margin.
A
  • Establish correct cervical contour of the restoration
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Advantages of the FULL ARCH CAST:
(4)

A
  • Guide to occlusal surfaces and contours
  • Ease of articulation
  • Development of optimum occlusion
  • (Development of optimum pontic adaptation and esthetics)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

*Type I and II:

A

impression plaster / model and
mounting plaster

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

*Type III:

A

dental stone (general purpose casts)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

*Type IV:

A

high strength / lowest expansion (die
stone)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

*Type V:

A

high strength / high expansion (die stone)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Desirable Properties of Cast / Die Materials
(4)

A
  • Accuracy
  • Reproduce fine detail (20μ-wide-line)
  • Strong and durable
  • Color
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q
  • Strong and durable
    (3)
A
  • Strength (wet strength / dry strength)
  • Resistance to shearing forces (edge
    strength)
  • Abrasion resistance
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q
  • Color
    (2)
A
  • Contrast to wax
  • Scanning visibility
    (CAD-CAM)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Water : Powder Ratio
(3)

A
  • Least amount of water necessary to obtain proper manipulation of stone
  • Manufacturer’s recommendation
  • Add powder to liquid in mixing bowl for proper wetting.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q
  • Many properties are either directly or inversely related to the
A

W/P ratio

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q
  • Directly proportional:
A

setting times / manipulation
* ↑water = ↑ setting time; ↑ fluidity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q
  • Inversely related:
A

strength and setting expansion
* ↑water = ↓ compressive strength
* ↑water = ↓ setting expansion
* (important in gypsum investment)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q
  • — that has already set acts as a catalyst when in contact with
    unset — and can cause changes in the set and working times.
A

Gypsum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Excessive disinfectant solution or water can give you

A

unset or
powdery gypsum at the surface.
* Make sure that your impressions are clean and only slightly damp before you
pour

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q
  • Excessive use of alcohol based surfactants or debubblizers can also
    create
A

surface issues like softness or chalkiness.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Mechanical-Vacuum Mixing of Gypsum * Helps eliminate --- * --- the cast * time
porosity Strengthens * 20 seconds / 425 rpm / >25mmHg * Over-spatulation → decreased working time
26
Dimensional Accuracy and Strength (4)
* Minimal expansion for procedure * Surface should be hard and smooth when removed from impression * Wet strength – Dry strength * Set in an upright posit
27
Wet strength – Dry strength
* Strength doubles 1H → 24H
28
* Set in an upright position
* Prevents stone slumping from cusps
29
Alginate Impressions: 2-Pour Technique (2)
* Anatomic pour with Type III Stone: cover vestibule; stack up stone; add nodules * Base: 2o mix after initial set of anatomic pour or after separation from impression (45 min).
30
Solubility: Gypsum immersion in water Linear dimension ↓ per every --- minutes of immersion
20
31
Solubility: Gypsum immersion in water Linear dimension ↓ per every 20 minutes of immersion (4)
* Accuracy: Reproduce fine detail (20μ-wide-line) * Immersion in water saturated with calcium sulfate (slurry) will decrease solubility * Avoid sludge formation (cast trimming) * Scrubbing cast will remove surface detail
32
Resistance to Abrasion (3)
* Surface hardness ≠ abrasion resistance * Surface impregnation** - Cyanoacrylate cement * Strengthened products - Resin (CAD-CAM)*
33
Pour the impression twice… (3)
* Check interproximal contacts, solder relation on rigid cast. * Verify fit of casting or margin at try-in. * Can be used if original is damaged.
34
* Removable Dies (2)
* Retained by pins in a base (stone or plastic) * One die used for entire wax pattern - proximal contacts, occlusion and margins
35
* Solid Cast / Separate Dies (Multiple Pour System) (2)
* Single (separate) die for wax coping and margins * Solid cast for waxing proximal contacts and occlusion
36
Solid Cast – Separate Die System Advantages: (2)
* Simple fabrication - requires minimum trimming * Provides a rigid relation for FPD components
37
Removable Die Systems (2)
* The die can be lifted and replaced in the master cast with embedded pins or dowels. * Requires less manipulation of wax pattern
38
* Requires less manipulation of wax pattern (2)
* Reduces chance of breakage and distortion * Handling of restorations is easier (porcelain margins)
39
Removable Die Systems * Disadvantage: Technique sensitive (2)
* Error in pattern if die does not re-seat accurately * Margin or pin damage by improper saw cuts
40
Digitally Milled Casts (2)
* Digital impression systems *CAM process (Cadent)
41
*CAM process (Cadent) (3)
* Milled resin cast * Sectioned dies * Articulation
42
Requirements for Removable Die Systems (3)
* Dies must return to exact original position. * Dies must remain stable, even when inverted. * Master cast must be easily mounted on an articulator.
43
Definitive Cast and Die Preparation Pindex Technique (6)
1. Pouring the impression / cast trimming 2. “Pin” the cast and pour base 3. Section the cast by sawing 4. Die Preparation * Die trimming * Mark finish line 5. Articulate the master cast * Interocclusal record in MIP 6. Preparation for waxing * Die relief (cement spacer) * Die hardening (finish line)
44
Definitive Cast Preparation: Pindex Base * Base is poured --- pins/sleeves are cemented
after
45
Definitive Cast Preparation: Pindex Base * 1st pour carefully separated from
cast base. * Cast base interface should be free of voids
46
* Each die section must slide out --- -
independently
47
* Yet have adequate stone around pins for --- -
strength
48
* Avoid cutting or abrading a ---.
margin
49
* All sections are --- removable from the base.
independently
50
* Die base should seat flush and be --- to cast base.
perpendicular
51
Definitive Cast Preparation: Solid Cast – Separate Die (5)
* Pour individual die section (1st pour) * Separate cast from impression and re-pour impression * The first pour is sectioned/trimmed into individual die * The 2nd pour is completed as a full arch cast with base * The solid cast (full arch) is mounted on articulator
52
Definitive Cast – Die Trimming (4)
* Die is trimmed to remove areas corresponding to the gingival tissue. * Die contour approximates the root and emergence profile. * Provides access to margin. * Smooth surface
53
Die Trimming: Emergence Profile (2)
* The surface of the “un-prepared” tooth apical to the finish line is left intact. * Stone is removed with scalpel blade below this line.
54
Cervical Margin: Emergence Profile (3)
* A properly trimmed die must have the same cervical contour as the tooth. * Adequate access to the margin is necessary for carving the wax to the proper emergence profile. * ≈ 5mm below finish line
55
Definitive Cast – Die Trimming * Trimmed from below and parallel to the margin. (2)
* Leave small lip of stone below margin. * Margin trimming is finished with Bard-Parker #25 blade.
56
AVOID:
Sharp ditching of the die apical to the margin → over-contouring (angulation of wax carver) → weakening of the die
57
Definitive Cast: Articulation (4)
* Ensure accurate tooth - tooth contact. * Verify contact of incisal pin. * Accuracy of mounting is critical to accurate occlusion in final restoration. - Compare intraoral and articulated cast occlusal contacts
58
Interocclusal Records for Orienting Casts on Articulator
An interocclusal registration is necessary to orient dies of prepared teeth to the opposing occlusion.
59
Interocclusal Records: Materials *Material Requirements: (3)
* No resistance to closure *Rigid when set * Dimensional stability / accuracy
60
Rigid, Fast-set VPS (3)
* Least rigid, most efficient * Always some rebound * CAD-CAM scanning
61
* ZnOE paste; Resin (rigid) (1)
* Technique sensitive, time consuming
62
* Wax - should not be used for fixed prosth * WHY?
?
63
Interocclusal Records: Materials (3)
*Rigid, Fast-set VPS * Plaster (Removable Prostheses) * ZnOE paste; Resin (rigid)
64
Definitive Cast: Occlusal Registration (MIP) (3)
* Record the maxillary and mandibular teeth in total contact. * Stone - stone contact with hand articulation where possible. * Place record material between prepared and opposing teeth only.
65
Definitive Cast: Occlusal Registration (5)
* Reduce record to include only cusp tips for proper seating. * Cut back facial to visualize seating. * Ensure accurate tooth - tooth contact elsewhere. - Mark with articulating paper - Check with shimstock
Fixed Prostodontics
flashcards
Decks in class (19)
# Cards
Brainscape helps you reach your goals faster, through stronger study habits.
© 2026 Bold Learning Solutions. Terms and Conditions