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Flashcards in 3. Finish Line Deck (82)
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1
Q

Where is the supra-gingival margin located?

A

0.5-1mm from surrounding gingiva

2
Q

How are the esthetics of supra gingival?

A

Poor

3
Q

When is a supra-gingival finish line indicated? (2)

A
  • NO ESTHETIC IS COMPROMISED

- ENOUGH HEIGHT OF THE ABUTMENT TOOTH TO HAVE ADEQUATE RETENTION

4
Q

Which finish line is the most hygenic?

A

Supragingival

5
Q

Where is the yuxtagingival margin?

A

At the level of the gingiva to 0.5mm-1mm under the gingival margin

6
Q

Main advantage of subgingival finish line?

A
  • Ethetics
7
Q

Main disadvantage of subgingival finish line?

A

High risk of biological width invasion

8
Q

What does increasing the occluso-cervical dimension do for the sibgingival finish line?

A

Increased retention and resistance

9
Q

Indications of the subgingival margin? (6)

A
  • Aesthetic (bucally)
  • Short clinical tooth (to increase the height and gain retention)
  • Subgingival caries.
  • Subgingival composites (the FL should always be over healthy structure)
  • Subgingival fractures of the tooth.
  • Caries propension over the roots.
10
Q

Contraindications of subgingival margin? (3)

A
  • Scaling and root planning
  • Periodontal surgery
  • Gingival recession and high clinical crown
11
Q

How long after scaling and root planning can you prepare a subgingival finish line?

A

2-3 months

12
Q

How long after periodontal surgery can you prepare a subgingival finish line?

A

5-6 months

13
Q

Define marginal integrity

A

Configuration of the preparation finish line dictates the shape and bulk of
restorative material in the margin of the restoration

14
Q

How many microns is a high accuracy marginal integrity?

A

20-40 microns

15
Q

How many microns is the maximum clinically acceptable marginal integrity?

A

100 microns

16
Q

How do you check the marginal integrity? (2)

A

Explorer and x-rays

17
Q

What occupies the marginal integrity?

A

Cement

18
Q

What occurs if there is an undercontoured horizontal marginal fit?

A

Higher risk of caries

19
Q

What occurs if there is an normocontoured horizontal marginal fit?

A

Adequate emergence profile

20
Q

What occurs if there is an overcontoured horizontal marginal fit?

A

higher tendency for gingival retraction and periodontal issues

21
Q

The FL must have the correct shape and size so the restoration CAN fulfil
the following requirements: (4)

A
  • marginal integrity.
  • structural strength.
  • localisation.
  • adequate emergency profile
22
Q

What burs are more commonly used for the finish line? (4)

A
  • 856-016
  • 856-012
  • 847-016
  • 847-016KR
23
Q

What is the shape of the 856 bur?

A

Round end tapered diamond

24
Q

What is the shape of the 847 bur?

A

Flat end tapered diamond

25
Q

What are the dimensions of the 856-016 bur?

A

Base 1.6mm

Tip 1mm

26
Q

What are the dimensions of the 856-012 bur?

A

Base 1.2mm

Tip 0.8mm

27
Q

What bur do you use for chamfer in veneers?

A

856-012

28
Q

What are the dimensions of the 847-016 bur?

A

Base: 1.6mm
Tip: 1.1mm

29
Q

Whats the difference between the 847-016 bur and the 847-016KR

A

The 847-016KR has a more rounded angle

30
Q

What is the 837-012 bur used for?

A

Occlusal and incisal reduction

31
Q

What shape is the 858 bur?

A

Needle shape

32
Q

What is the 858 bur used for?

A

Proximal reduction to break contact point

33
Q

What shape is the 368-023 bur?

A

Rugby/football

34
Q

What is the 368-023 bur used for?

A

Lingual or palatal concavity for anterior teeth

35
Q

Shape of a cahmfer?

A

Curved

36
Q

Depth of a chamfer?

A

0.5-0.7mm

37
Q

How conservative is a chamfer?

A

Very conservative

38
Q

What bur do you use for a chamfer?

A

856-016

39
Q

A chamfer needs ___ at the end of the restoration

A

metal

40
Q

Chamfer: with smaller angles…

A

the margin increases fit

41
Q

Chamfer: stress?

A

Less stress at cement area

42
Q

Indications of chamfer? (5)

A
  • Metal-end restorations (metal collar).
  • Lingual or palatal surfaces of PFM crowns.
  • low aesthetic demand
  • Periodontal teeth ( metallic finishing over cementum)
  • Feldspathic veneers(856-012 RK, for a 0.3 to 0.5mm FL)
43
Q

Whats another name for a deep chamfer? (2)

A
  • Heavy chamfer

- Rounded chamfer

44
Q

Deep chamfer: Angle at the margin ?

A

90 degrees approximately

45
Q

What is the difference between a deep chamfer and normal chamfer?

A

Inner shape has a smaller radius than the normal chamfer

46
Q

Indications of a deep chamfer? (5)

A
  • Full coverage crowns
  • proximal surfaces of PFM crowns
  • Crowns when long teeth (metal margin)
  • Porcelain veneers
  • CAD/CAM
47
Q

How do you prepare a chamfer for a full coverage crown?

A
  • Lingual/buccal PFM 0.5-0.7mm (metal collar)

- PFM posterior teeth buccal surface when esthetics are not jeopardized 1.2mm

48
Q

How many mm should the deep chamfer of porcelain veneers be?

A

0.3-0.5mm

49
Q

What bur do we use to prepare a butt-shoulder?

A

Flat-tip cylinidrical bur

50
Q

When do we use a butt shoulder finish line?

A

Was used for all ceramic crowns

51
Q

What is the cavosurface angle of a buttshoulder finish line?

A

90 degrees

52
Q

What is the depth and angle at the margin of a butt shoulder finish line?

A

90 degrees

1.0-1.2mm deep

53
Q

What are the indications of a butt-shoulder finish line? (2)

A
  • Jacket crowns (all ceramic feldspathic)

- Labial surface of PFM anterior crowns

54
Q

Which finish line is not used anymore?

A

Butt shoulder

55
Q

What are the disadvantages of the butt shoulder finish line? (4)

A
  • CAD/CAM scanners read it badly
  • least conservative
  • 90 degree inner angle creates tension making it difficult for alloy casts or porcelain to fit well
56
Q

Which finish line is the least conservative?

A

Butt-shoulder

57
Q

What is the angle at the margin for a rounded shoulder?

A

93 degrees at axial wall and gingival wall

58
Q

How does the inner angle of a rounded shoulder compare to the butt shoulder?

A

inner angle is rounded in rounded shoulder

59
Q

What is the benefit of using the rounded shoulder finish line?

A
  • reduces tension and stress concentration over the tooth
  • Good CAM/CAM scanning
  • Good space for porcelain
  • more conservative than butt
60
Q

What bur do we use to prepare a rounded shoulder?

A

847-016KR cylindrical with rounded tip

61
Q

Indications of a rounded shoulder? (3)

A
  • Full ceramic crown (1mm full perimeter)
  • Labial surface of upper anterior PFM crown (or posteriors when esthetics jeopardized)
  • PFM anterior crowns/bridges
62
Q

How many mm is a rounded shoulder in full ceramic crowns?

A

1mm all around

63
Q

How many mm is a rounded shoulder in PFM crowns?

A

1.0-1.5mm

64
Q

Rounded finish lines and rounded angles of the prep facilitate.. (2)

A
  • laboratory fabrication and
    procedures
  • restoration fit
65
Q

Rounded finish lines and rounded angles of the prep reduces …

A

Stress concentration

66
Q

Rounded finish lines and rounded angles of the prep is easier for.. (2)

A
  • taking impressions

- capture working digitally/using CAD/CAM

67
Q

Rounded finish lines and rounded angles of the prep has less..

A
  • air bubble trapping while pouring

- air trapping when investing the die with wax pattern

68
Q

When do we use a ceramic shoulder? (2)

A
  • Porcelain labial shoulder

- PFM anterior sector

69
Q

What is the benefit of ceramic shoulder?

A
  • High aesthetic
  • allows yuxtagingival finish line
  • metal only covers axial wall
70
Q

Which finish line is the best option from an esthetic point of view?

A

Ceramic shoulder

71
Q

What is the fit for a ceramic shoulder?

A

acceptable fit 45 microns

72
Q

Metal margin finish line? (3)

A
  • 0.2-0.3 mm showed labially.
  • To be placed subgingivally.
  • Doesn’t warp because of the bulk of metal at the shoulder.
73
Q

What is the purpose of a shoulder with bevel?

A

Diminishing the marginal discrepancy

74
Q

What is the purpose of a feather/knife edge?

A

Allows acute margin of metal but can create complications

75
Q

What finish line do you use for PFM crowns buccal/labially with small esthetic concern? (2)

A
  • Deep chamfer (porcelin-metal margin 0.4mm metal collar)

- Shoulder with bevel (porcelin-metal margin 0.5mm metal collar)

76
Q

What finish line do you use for PFM crowns buccal/labially with medium esthetic concern?

A

Rounded shoulder (porcelin-metal margin 0.2-0.3mm metal collar)

77
Q

What finish line do you use for PFM crowns buccal/labially with high esthetic concern?

A

Rounded shoulder (porcelain margin)

78
Q

What finish line do you use for PFM crowns lingually ? (2)

A
  • chamfer (metal margin)

- deep chamfer (metal margin)

79
Q

What finish line do you use for PFM crowns proximally?

A
  • Deep chamfer (metal margin)

- Rounded shoulder (metal margin)

80
Q

What finish line do you use for all ceramic crown porcelain jacket? (2)

A
  • Rounded shoulder
  • Chamfer

1mm both

81
Q

What finish line do you use for all ceramic crown porcelain jacket full ceramic crown? (2)

A
  • Rounded shoulder
  • Rounded chamfer

1mm both

82
Q

What finish line do you use for all ceramic crown porcelain veneer?

A

Chamfer (0.3-0.5mm)