LECTURE 16: LABORATORY PROCEDURES Flashcards by Love Dog

Q

T/f

DESIGN TRANSFER FROM DIAGNOSTIC CAST

without removing the master cast from the survey table or changing the tilt, the technician transfers the design from the diagnostic cast to the master cast with extreme care and clearly marked to avoid confusion

→ design should mimic the design on diagnostic cast

A

T

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

the simplest and traditionally used for recording of the final orientation of the cast on the surveyor

A

RETRIPODING THE MASTER CASTS

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

the primary cast is mounted on a surveying table and a carbon marker is used to contact three points of the cast

A

RETRIPODING THE MASTER CASTS

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

In MARKING THE HEIGHT OF CONTOUR , marking the greatest _______ of the tooth

A

convexity

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

MARKING THE HEIGHT OF CONTOUR, determines if the tooth has an adequate ______ area

A

retention

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

“survey line”

A

MARKING THE HEIGHT OF CONTOUR

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

→ scraping the outline of the major connector into the master cast
→ ensures intimate contact of the major connector with the palatal
tissues
→ reduce the packing of food particles underneath the major
connector

A

BEADING OF THE MAXILLARY MAJOR CONNECTOR

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

treating the master cast with a surface sealer using a brush or an aerosol spray to seal the cast and protect the design during the other steps of cast preparation and duplication

A

SPRAYING

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

T/f

In SPRAYING for the PREPARATION OF MASTER CAST

sealer application should be done in front of a suction vent because inhaling aerosol is potentially dangerous

A

T

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

elimination of undesirable undercuts on the master cast with wax is commonly referred to as ____

A

blocking out

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

T/f

both hard and soft tissue areas will require block out

A

T

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

proximal tooth surfaces used as guiding planes

A. parallel block out
B. shaped blockout
C. arbitrary blockout

A

A

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

beneath all minor connectors

A. parallel block out
B. shaped blockout
C. arbitrary blockout

A

A

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

tissue undercuts to be crossed by rigid connectors

A. parallel block out
B. shaped blockout
C. arbitrary blockout

A

A

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

tissue undercuts to be crossed by origin clasps

A. parallel block out
B. shaped blockout
C. arbitrary blockout

A

A

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

on buccal and lingual surfaces to locate plastic or wax patterns for clasp arms

A. parallel block out
B. shaped blockout
C. arbitrary blockout

A

B

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

all gingival crevices

A. parallel block out
B. shaped blockout
C. arbitrary blockout

A

C

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

gross tissue undercuts situated below areas involved in design of
denture framework

A. parallel block out
B. shaped blockout
C. arbitrary blockout

A

C

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

tissue cuts distal to cast framework

A. parallel block out
B. shaped blockout
C. arbitrary blockout

A

C

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

labial and buccal tooth and tissue undercuts not involved in
denture design

A. parallel block out
B. shaped blockout
C. arbitrary blockout

A

C

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

beneath lingual bar connectors or the bar portion of the linguoplates when indicated

A

RELIEF

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

retentive meshwork must be raised above the edentulous area to allow resin to completely surround it

A

RELIEF

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

RELIEF

at least ___ mm of resin should surround the tissue surface of the mesh

A

1

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

T/f

RELIEF

the finish line should be sharply defined

A

T

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

→ areas in which major connectors will contact thin tissue, such as hard areas so frequently found on lingual or mandibular ridges and elevated palatal raphes → beneath framework extensions onto ridge areas for attachment of resin bases

RELIEF

TISSUE STOP → a small square of ____ mm of relief wax is removed at the distal end of the saddle

2x2

it provides stability of the framework during acrylic metal processing

TISSUE STOP

______ can better support and restrict the material; can also prevent it from over covering the tissue surface

tissue stops

PREPARATION OF MASTER CAST

1. DESIGN TRANSFER FROM DIAGNOSTIC CAST 2. RETRIPODING THE MASTER CASTS 3. MARKING THE HEIGHT OF CONTOUR 4. BEADING OF THE MAXILLARY MAJOR CONNECTOR 5. SPRAYING 6. BLOCK OUT 7. RELIEF 8. TISSUE STOP

INVESTMENT MATERIALS → there are three types:

o gypsum bonded o phosphate bonded o silica bonded

“low heat investments” are used for casting Type IV partial denture gold and ticonium A. gypsum bonded B. phosphate bonded C. silica bonded

A

refractory materials are used for chrome cobalt alloys, titanium and titanium alloys are termed ____

“high-heat investments”

composed of a mixture of silica (SiO2) and calcium sulphate hemihydrates A. gypsum bonded B. phosphate bonded C. silica bonded

A

thermal expansion type; for casting inlays and crowns Type 1 2 3

Type 1 (GYPSUM BONDED)

hygroscopic expansion type; for casting inlays and crowns Type 1 2 3

2 (GYPSUM BONDED)

casting complete and partial dentures Type 1 2 3

3 (GYPSUM BONDED)

powder contains silica, magnesium oxide and ammonium phosphate A. gypsum bonded B. phosphate bonded C. silica bonded

B

can be mixed with water or colloidal silica A. gypsum bonded B. phosphate bonded C. silica bonded

B

for inlays, crowns and other fixed restorations Type 1 2 3

1 (PHOSPHATE BONDED)

for partial dentures and other cast removable restorations Type 1 2 3

2 (PHOSPHATE BONDED)

consists of powdered quarts or cristobalite which is bonded together with silica gel or ethyl silicate A. gypsum bonded B. phosphate bonded C. silica bonded

C

used for high fusing alloys A. gypsum bonded B. phosphate bonded C. silica bonded

C

DESIGN TRANSFER before the waxing begins, design must be transferred again from the master cast to the ____ cast

refractory

master cast is evaluated and the outline of framework design is transferred precisely to refractory cast

DESIGN TRANSFER

plastic patterns are glued to the cast with a mixture of acetone and plastic pattern scraps mixed to a watery consistency

WAXING TECHNIQUE

1. What technique? → tacky liquid is painted on the design outline with a fine brush and allowed to dry for a few seconds → patterns are carefully adapted to the cast with the help of a soft rubber pencil eraser shaped into a 2. _____

1. WAXING TECHNIQUE 2. wedge

the areas where the retentive meshwork joins the major connector must be reinforced

WAXING TECHNIQUE

____ is attaching wax or plastic form to the wax pattern, to provide an entrance to the mold space and to serve as a reservoir of metal during the casting procedure

spruing

T(f rules of SPRUING: o sprues should be large enough o sprues should lead into the molten cavity as directly as possible o sprues should be attached to the wax pattern at its bulkier sections

T

SPRUING preferred for complete denture metal bases A. Single B. Multiple

A

SPRUING majority of partial denture castings A. Single B. Multiple

B

a cone shaped plastic sprue is attached to the central sprue from which auxiliary sprues run to each corner of the wax pattern

top spruing

this provides the strength necessary to resist forces created by the stream of molten metal A. INVESTING THE REFRACTORY CAST B. BURNOUT C. RECOVERY OF CASTING D. FINISHING THE FRAMEWORK E. FITTING THE FRAMEWORK

A

→ to make a smooth surface of the mold cavity so that the casting obtained will require as little as finishing required → to establish an avenue of release for the gases created by burnout and casting procedures A. INVESTING THE REFRACTORY CAST B. BURNOUT C. RECOVERY OF CASTING D. FINISHING THE FRAMEWORK E. FITTING THE FRAMEWORK

A

to compensate for the dimensional changes that occur when the metal goes from the molten to the solid state A. INVESTING THE REFRACTORY CAST B. BURNOUT C. RECOVERY OF CASTING D. FINISHING THE FRAMEWORK E. FITTING THE FRAMEWORK

A

the time and temperature required to eliminate wax from the mold cavity is specific to the refractory-alloy system that is being used A. INVESTING THE REFRACTORY CAST B. BURNOUT C. RECOVERY OF CASTING D. FINISHING THE FRAMEWORK E. FITTING THE FRAMEWORK

B

expands the mold to compensate for contraction of the metal during cooling A. INVESTING THE REFRACTORY CAST B. BURNOUT C. RECOVERY OF CASTING D. FINISHING THE FRAMEWORK E. FITTING THE FRAMEWORK

B

T/f steps: o should be dry at the start of the burnout cycle; steam will then carry the heat into the investment during the early stages of the burnout

steps: o should be MOIST at the start of the burnout cycle; steam will then carry the heat into the investment during the early stages of the burnout

mold should be placed in the oven with the sprue hole down A. INVESTING THE REFRACTORY CAST B. BURNOUT C. RECOVERY OF CASTING D. FINISHING THE FRAMEWORK E. FITTING THE FRAMEWORK

B

o should start with a cold oven o temperature should be increased slowly and be maintained o when the cycle is complete, all of the wax pattern is eliminated A. INVESTING THE REFRACTORY CAST B. BURNOUT C. RECOVERY OF CASTING D. FINISHING THE FRAMEWORK E. FITTING THE FRAMEWORK

B

→ if little force is used, the mold is not completely filled before the metal begins to freeze → if excess force is used, turbulence may result in the entrapment of gasses in the casting A. INVESTING THE REFRACTORY CAST B. BURNOUT C. RECOVERY OF CASTING D. FINISHING THE FRAMEWORK E. FITTING THE FRAMEWORK

B

______ is the method of choice for base metal alloys

induction casting

1. → mold is removed from the machine and allowed to cool accordingly → at the appropriate time, the mold is broken by tapping it with 2. _____ to break off the outer layer of investment → remaining investment is then removed by 3. ___ blasting → if not removed, may cause tarnish and corrosion A. INVESTING THE REFRACTORY CAST B. BURNOUT C. RECOVERY OF CASTING D. FINISHING THE FRAMEWORK E. FITTING THE FRAMEWORK

1. C 2. wooden mallet 3. sand

rubber wheels, rubber points, knife edge wheels A. INVESTING THE REFRACTORY CAST B. BURNOUT C. RECOVERY OF CASTING D. FINISHING THE FRAMEWORK E. FITTING THE FRAMEWORK

D

→ magnification and bright light for defects → point is formed on truing stone or heatless stone → separating disk to cut sprue A. INVESTING THE REFRACTORY CAST B. BURNOUT C. RECOVERY OF CASTING D. FINISHING THE FRAMEWORK E. FITTING THE FRAMEWORK

D

T/f major connector finished with abrasive stones

T

→ remove nodules from latticework → felt cylinder used with Tripoli on surfaces that contact teeth → felt wheel to polish tissue side and tongue side of major connector → knife edge wheels for finish line → rag wheel with Tripoli to polish rest of framework → scrub casting to remove tripoli A. INVESTING THE REFRACTORY CAST B. BURNOUT C. RECOVERY OF CASTING D. FINISHING THE FRAMEWORK E. FITTING THE FRAMEWORK

D

______ on cotton can be used to remove last traces of tripoli

chloroform

T/f the technician begins to fit the framework by carefully seating the casting on the master cast and attempts to identify the first spots that bind

T

→ as the retentive clasp tip engages an undercut area, they will most likely be the first area that binds → technician must carefully relieve the cast in the area of the clasp tip undercuts to allow the clasps to pass the height of contour → some technician bend the retentive clasp arms away from the cast and then attempt to recontour the clasp back into contact A. INVESTING THE REFRACTORY CAST B. BURNOUT C. RECOVERY OF CASTING D. FINISHING THE FRAMEWORK E. FITTING THE FRAMEWORK

E