Full Coverage Crowns Flashcards

1
Q

90% of fixed restorations are…

A

Full coverage crowns

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2
Q

What material related parameters influence material selection? (5)

A
  • Mechanical properties
  • Optical properties (esthetic potential)
  • Minimal wall thickness necessary
  • Wear behavior
  • Bonding possibilities
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3
Q

What are the different types of full coverage crowns? (4)

A
  • metal
  • PFM
  • all ceramic
  • acrylic resin
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4
Q

What are the different types of metal full coverage crowns? (2)

A
  • Preformed

- Cast

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5
Q

What are the different types of PFM full coverage crowns? (4)

A
  • Veneer crowns
  • Full ceramic coverage
  • Porcelain with metal collar
  • Porcelain with ceramic shoulder
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6
Q

What are the different classifications of all ceramic full coverage crowns? (2)

A
  • by manufacturing method

- by material

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7
Q

What are the different manufacturing methods of all ceramic full coverage FC crowns? (3)

A
  • layered
  • pressed
  • CAD/CAM
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8
Q

What are the different materials of all ceramic full coverage FC crowns? (3)

A
  • feldspathic
  • aluminous
  • zirconia based (Y-ZTP)
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9
Q

What materials can be used for metal preformed FC crowns? (2)

A
  • Gold

- Steel / cobalt-chromium

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10
Q

What do we use steel or cobalt chromium metal preformed FC crowns for?

A

Provisionals, mainly in pediatrics

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11
Q

When do we use gold metal preformed FC crowns?

A

Uncoperative patients

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12
Q

What size of preparation do we need for gold metal preformed FC crowns?

A

small prep

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13
Q

Properties of gold metal preformed FC crowns? (4)

A
  • Soft
  • Malleable
  • Have to be adapted
  • Easy to handle
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14
Q

How is a metal cast FC crown prepared in comparison to PFM?

A

Metal cast crown has less reduction

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15
Q

What type of finish line is prepared for a metal cast FC crown?

A

0.5mm chamfer

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16
Q

How much space does a noble alloy metal cast FC crown need?

A

1mm

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17
Q

How much space does a non-noble alloy metal cast FC crown need?

A

0.8mm

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18
Q

What are the pro’s of a metal cast FC crown? (2)

A
  • good occlusal anatomy

- good marginal fit

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19
Q

Veneer PFM FC crowns are less… (2)

A
  • less esthetic

- less occlusal preparation = less prothestic space required

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20
Q

Where is the porcelain and metal in veneer PFM FC crowns

A
  • metal occlusal surface

- porcelain buccal/labial layer

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21
Q

Indication of veneer PFM FC crowns?

A
  • Short teeth OR

- patients that tend to break occlusal porcelain

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22
Q

What layers is a PFM FC crown made of?

A
  • Thin layer of cast metal (coping) in contact with tooth

- Covered by feldspathic porcelain

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23
Q

What is the purpose of each layer in a PFM FC crown?

A

Metal: toughness and fit
Porcelain: esthetics

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24
Q

Which FC crown is the most versatile?

A

PFM crown

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25
Q

How can you be more conservative for a PFM crown?

A

L/P metal collar

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26
Q

How can you inhance asethetics in PFM crowns? What occurs as well?

A
  • Ceramic shoulder

- Gains adhesion

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27
Q

How much of the crown is covered in conventional PFM crowns?

A
  • Almost all the crown is covered by porcelain

- small collar at lingual surface is not covered by porcelain

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28
Q

What does the translucency and toughness of all ceramic FC crowns depend on?

A

The material used

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29
Q

How are the aesthetics of all ceramic FC crowns?

A

High esthetic result

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30
Q

How much metal is used in all ceramic FC crowns?

A

No metal used

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31
Q

What are the types of zirconia-based FC crowns? (2)

A
  • Monolithic

- Stratified (veneers)

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32
Q

What are the types of lithium disilicate based FC crowns? (2)

A
  • Monolithic

- Stratified (veneers)

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33
Q

What are the different types of accrylic resin FC crowns? (4)

A
  • Direct technique
  • Indirect technique
  • Preformed crowns
  • Cellulose acetate
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34
Q

What are acrylic resin FC crowns used for?

A

Provisional restorations

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35
Q

What cement do you use for acrylic resin FC crown in the direct technique? (2)

A
  • Bis-acrylic resin

- PMMA

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36
Q

What are Bis-acrylic resin cements with acrylic resin FC crown used for ? (2)

A
  • For short-term provisional dentures.

- Can be used for long term too.

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37
Q

What are PMMA cements with acrylic resin FC crown used for ? (2)

A
  • Short-term provisional dentures (2-3 weeks).

- Options for indirect techniques also exist: milling technique or conventional.

38
Q

How long can the indirect technique acrylic resin FC crown last for?

A

Medium-long term provisional dentures (2-3months)

*reline in mouth (self curing)

39
Q

When do we use the indirect technique for acrylic resin FC crowns?

A
  • esthetic cases

- medium to longer term

40
Q

What is the advantage of the indirect acrylic resin FC crowns?

A

Tougher

41
Q

Polycarbonate acrylic resin FC crowns? (4)

A
  • Preformed crowns for provisionals.
  • Reline into the patient’s mouth.
  • For provisional dentures.
  • Mostly used in case of emergency
42
Q

What occurs if you did too little of a preparation for a FC crown?

A

Weak restoration

43
Q

What occurs if you do too much of a preparation for a FC crown?

A

not conservative with tooth structure

44
Q

How much space is needed for a PFM FC crown?

A

1.2-1.5mm rounded shoulder/ 0.5mm chamfer L or P

45
Q

How much space is needed for full ceramic layered FC crown?

A

1mm rounded shoulder

46
Q

How much space is needed for full ceramic monolithic FC crown?

A

0.5 chamfer or rounded shoulder

47
Q

How much space is needed for full metallic FC crown?

A

0.5 chamfer

48
Q

What is the importance of keeping the anatomic profile (emergence profile) for FC crowns? (2)

A
  • To respect the periodontal health

* Preservation of the integrity of the margins

49
Q

Why is a smooth preparation important for a FC crown? ($)

A

• Better impression taking=better reproduction of details
• Enhances waxing and casting (better fit).
• Enhances the digital workflow.
• Forces spread out over a greater and even surface:
- Lower risk of restoration or tooth fracture.

50
Q

What is the relevance of the smooth and roundish preps when working digitally?

A

Point cloud -> Mesh -> STL-file

51
Q

Why is having a neat finish line important for a FC crown? (4)

A
  • No undercuts, smooth.
  • Better reproduction.
  • Eases laboratory work.
  • Better fit -> less / no marginal leakage
52
Q

TWO-PLANE PREPARATION FOR CONVEX SURFACES in FC crown? (3)

A
  • Opaque porcelain may show through
  • Overcontoured Surface
  • The pulp may be encroached upon or invaded
53
Q

What are the parts of the PFM crown? (2)

A
  • metal coping

- 3 layers of veneering porcelain (1mm)

54
Q

What size is the metal coping for FC PFM crowns?

A
  • 0.5 mm for noble alloys.

- 0.3 mm for non-noble alloys.

55
Q

What are the layers of porcelain used in FC PFM crowns? (3)

A
  • Opaque porcelain
  • Dentin porcelain
  • Incisal / enamel porcelain
56
Q

What is the purpose of opaque porcelain in PFM crowns? (2)

A
  • Hides the color of the underlying metal framework.

- Joins and links the metal to the rest of porcelain layers.

57
Q

What is the purpose of dentin porcelain in PFM crowns? (2)

A
  • Main part of veneering porcelain.

- Provides the shade to the restoration

58
Q

What is the purpose of incisal/enamel porcelain in PFM crowns? (3)

A
  • Provides translucency.
  • Can be stained.
  • It is the outermost layer
59
Q

What are the characteristics of the metal margin in PFM crowns? (4)

A
  • Metal collar at lingual surface.
  • 0.3 – 0.5 mm thick.
  • 2-3 mm high.
  • Good fit and hygiene
60
Q

What are the characteristics of the metal-porcelain margin in PFM crowns? (2)

A
  • Metal coping gets thinner as it gets near the margin.

- Contraction of porcelain can put the coping out of fit.

61
Q

What are the characteristics of the ceramic shoulder/chamfer margin in PFM crowns? (4)

A
  • Low fusing ceramic in contact with margin.
  • Good esthetics.
  • Needs adhesive technique cementation at the porcelain.
  • Enough thickness to avoid fractures.
62
Q

How do you prepare a FC PFM crown occlusally? (2)

A
  • Functional cusps: 2 mm.

- Non-functional cusps: 1.5 mm.

63
Q

How do you prepare a FC PFM crown on the axial surface?

A

1.2-1.5mm

64
Q

How do you prepare the buccal/labial finish line for a FC PFM crown ?

A

Rounded shoulder 1-1.5mm

65
Q

How do you prepare the lingual finish line for a FC PFM crown ?

A
  • chamfer or

- deep chamfer 0.5 when metal collar

66
Q

Where should the margin be prepared normally for FC PFM crowns?

A

Yuxta or supragingivally

67
Q

When should a FC PFM crown be prepared subgingivally? (3)

A
  • Esthetics.
  • Short teeth.
  • Cervical caries or restorations.
68
Q

Young patients and PFM crowns? (2)

A

◦ Teeth partially erupted.

◦ Big pulp chambers

69
Q

Old patients and PFM crowns? (2)

A

◦ Gingival margin over cementum.

◦ Lack of cooperation

70
Q

The longer the edentulous space the ___ the load over abutment teeth

A

greater

71
Q

In what cases should you have a metal occlusal surface for FC PFM Crowns? (2)

A

Bruxers and epileptics

72
Q

Contraindication for FC PFM crowns

A

Bad hygiene

73
Q

Indications of PFM FC crown? (5)

A
  • Single crowns to strengthen the tooth.
  • Single crowns to change the shape of the tooth.
  • FPD retainer.
  • RPD retainer.
  • Combined prosthesis retainer
74
Q

When do you use a single FC PFM crown to change the shape of the tooth? (2)

A
  • To change the contour (crowding, conoid…).

- Occlusal modification.

75
Q

When do you use a single FC PFM crown to strengthen the tooth? (2)

A
  • Great tooth wear.

- Hyploplasia.

76
Q

When do you use a single FC PFM crown as FPD retainer? (4)

A
  • For maximum retention
  • Reinforce the abutment tooth
  • Intermediate abutment tooth.
  • Tooth splinting
77
Q

When do you use a single FC PFM crown as RPD retainer? (4)

A
  • Improves path of insertion.
  • Control the amount of retention.
  • Reinforces the abutment tooth.
  • Prevent caries over abutment tooth.
78
Q

What are the different lab procedures for FC PFM crowns? (2)

A
  • Copihng

- Veneering porcelain build up

79
Q

What are the different types of lab procedures for FC PFM coping? (3)

A
  • Lost-wax procedure (waxing and casting).
  • CAD/CAM.
  • CAD + laser sintering.
80
Q

What is the lab procedure to create FC PFM crowns?

A
  1. Cast prep
  2. waxing
  3. investment
  4. oven
  5. centrifuge
  6. removal of the coping
  7. trimming and finish
81
Q

What is the waxing procedure in lab for FC PFM? (4)

A
  • The wax pattern is the precursor of the finished cast
  • Made in the lab it is called Indirect waxing technique
  • Once the waxing of the core is over
  • Rods are attached to the non-functional cusps
82
Q

What happens during the investment lab procedure for FC PFM? (2)

A
  • Powder and liquid mixture.

- 30 min setting time.

83
Q

What happens during the oven lab procedure for FC PFM? (2)

A

When molten the metal is cast through the sprue inside the negative left by the
wax.

84
Q

What happens during the centrifuge lab procedure for FC PFM? (2)

A

CASTING STEP: step where the wax pattern is converted to his metal replica

85
Q

What are the solutions for volume changes during casting? (3)

A
  • Oversized wax pattern.
  • Correction of the crown. Manually.
  • Investment expansion
86
Q

What is used for investment expansion? (2)

A
  • INTERNAL, for pin cores.

- EXTERNAL, for crowns.

87
Q

What is the lab procedure for CAD/CAM FC crowns? (4)

A
  1. scanning
  2. design of CAD structure
  3. manufacturing CAM structure
  4. veneering porcelain
88
Q

What the different types of manufacting CAM structure? (2)

A
  • Mechanized or milling technique

- Laser sintering

89
Q

What does the mechanized or milling technique for CAM consist of?

A
  • drill of the milling machine

- material blocks can be different materials, non-noble metal alloys, zirconia, LDS, PMMA

90
Q

How does the laser sintering technique for CAM work? (2)

A
  • Printing technique

- Layers of the material poder is fused by a scanning laser

91
Q

Milling technique for CAM?

A
  • More accurate.
  • More material is wasted (the blocks used are nonrecyclables)
  • More polished surface.
  • Used for fixed prosthesis over teeth and implants
  • More indicated to work with over implants restorations.
92
Q

What are the layers in PFM FC crowns? (4)

A
  1. Opaquer: to block the light and
    mask the metal color.
  2. Base layer: thick layer, it gives the
    shape and the shade.
  3. Characterization layer: to make the tooth
    look more natural and mimics the adyacent teeth.
  4. Finishing or Glaze layer: thin layer that gives
    smoothness and translucency