Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Fixed Prosthodontics I > Crown Preparations- Margin Design > Flashcards

Crown Preparations- Margin Design Flashcards

1
Q

Parts of a crown preparation: (4)

A
  1. axial wall
  2. interproximal wall
  3. finish line
  4. occlusal anatomy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

A full coverage restoration can survive in the biologic environment of the oral cavity only if:

A

the margins are closely adapted to the surface finish line of the preparation

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

The design of the preparation ___ dictates the shape an bulk of restorative material in the marginal area of the restoration

A

finish line

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

Types of finish line designs include:

A
  1. knife edge
  2. chamfer (light & heavy)
  3. shoulder
  4. beveled shoulder
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

A chamfer finish line can be described as:

A

light or heavy

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

Finish line used primarily for full metal crowns only. (especially gold crowns):

A

knife edge

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

Most conservative preparation design for finish line:

A

knife edge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What types of burs may be used to create a knife edge finish line?

A

flame or needle-shaped diamond bur

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

The disadvantages of knife edge finish lines include:

A
  1. difficult to see the finish line in an impression or scan
  2. metal can be thin and is susceptible to distortion under heavy occlusal load
  3. often leads to an over-bulking of crown material to compensate for thinness along margin
  4. easy to miss creating distinct end of finish line and instead axial wall never terminates
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

This image shows a knife edge finish line. What is the disadvantage to B?

A

Margin is thin and susceptible to distortion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

This image shows a knife edge finish line. What is the disadvantage to C?

A

To compensate for thin marginal area, labs all overbulk crown at margin

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

What are the indications for knife edge finish lines?

A
  1. Generally NOT indicated
  2. In certain instances like a tipped molar, a knife edge margin is possible to be conservative in an abnormal area
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

In certain instances like a tipped molar, a ____ margin is possible to be conservative in an abnormal area

A

knife edge margin

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

What is required for a knife edge margin?

A

An excellent lab technician

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

Label the following image: (left to right)

A
  1. shoulder margin
  2. chamfer margin
  3. knife edge
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the two types of chamfer margins?

A
  1. heavy chamfer
  2. light chamfer
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What type of crowns use a light chamfer?

A

metal crowns & zirconia crowns

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What type of crowns would you use a heavy chamfer?

A
  • ceramic crowns
  • zirconia crowns
  • metal-ceramic crowns
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What type of bur can be used to create a chamfer finish line?

A

round-end tapered diamond

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

A heavy chamfer will work for what type of crowns?

A

Any type of crown

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

When creating a chamfer axial depth more than 1/2 the bur, can create ____ of the margin which leave ___ likely to chip or break leaving an open and exposed margin

A

lipped edges, unsupported enamel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the advantages of a chamfer margin? (5)

A
  1. chamfer is well suited for full metal crowns and zirconia crowns
  2. ease of seating crown & placing of crown
  3. Ease of detecting margin on impression or scan
  4. If full metal, chamfer is easy to wax and cast
  5. provides adequate thickness of restoration material at margin area
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

A light margin chamfer is ___ deep into axial wall.

A light chamfer produces ___ degree margin with ____ internal angle

A

0.3-0.5

30-45 degrees; rounded

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Type of margin finish line that combines a knife edge burnish-ability with bulk of material of all metal crowns:

A

light chamfer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Label the parts of the following crown prep:

A

A) chamfer finish line
B) functional cusp bevel
C) planar occlusal reduction
D) rounded angles
E) axial reduction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

The chamfer finish line promotes:

A

marginal integrity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

The functional cusp bevel promotes:

A

structural durability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

The planar occlusal reduction promotes:

A

structural durability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

The rounded line angles promote:

A

structural durability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

The axial reduction promotes:

A

retention & resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

A heavy chamfer provides room for:

A

thicker ceramic margin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

The ___ of the heavy chamfer decreases material stress in the margin area.

A

internal rounded angle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What are the measurements of a heavy chamfer? (how deep)

A

1.0-1.2 mm deep

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What bur is used to accomplish a heavy chamfer?

A

typically a large round-ended diamond bur

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Label which chamfer is light and which is heavy:

A

left: light
right: heavy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

A ___ margin design produces a close to 90 degree angle

A

shoulder

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

A shoulder margin design produces a close to ___ degree angle

A

90

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

A shoulder margin design is primarily used for ____ crowns and ____ crowns where thickness of material is important bur can also be used for ____ crowns

A

metal ceramic crowns and all ceramic crowns; zirconia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Modified shoulder produces a ___ angle

A

rounded

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

A shoulder margin is typically created with:

A

flat-end diamond burs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

In a shoulder margin design, the angle of axial wall and finish line is close to 90 degrees and this functions to:

A

decrease stresses on restoration material

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

A shoulder margin design is used mostly for ____ and __ crowns

A

metal-ceramic & all ceramic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

label the different margins shown:

A

left: shoulder margin
right: beveled shoulder

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Some shoulder finish lines can include a bevel at a ___ degree angle

A

30-45

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

A shoulder with a bevel is often used for ___ & ___

A

inlays & onlays

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

What type of margin can be used for metal ceramic crowns where there is a metal collar?

A

beveled shoulder

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

A beveled shoulder allows for ____ of metal to ensure marginal fit

A

adaptability

48
Q

Significant roughness of preparation finish line can prevent:

A

close adaptation of crown margin

49
Q

Rough margin = ____ = ____

A

plaque accumulation; recurrent decay

50
Q

Finish line designs vary based on: (3)

A
  1. restoration material
  2. location in the mouth
  3. desired results
51
Q

The type of tooth preparation in which the finish line forms a 90-degree angle with the unprepared tooth surface:

52
Q

The advantage of this type of margin includes:

  • less distortion of crown margins
  • provides adequate bulk
  • good crown contours
  • can attain good esthetics
53
Q

The disadvantages of this margin includes:

  • marginal adaptation can be affected
  • more tooth structure needs to be removed
54
Q

Indications of this type of margin include:

  • all ceramic crowns
  • PFM crowns
55
Q

This type of margin is similar to a shoulder but has a bevel placed at the border:

A

beveled shoulder

56
Q

Indications of this type of margin include:

  • gingival finish line on the proximal box of inlays or onlays
  • occlusal shoulder of onlays and mandibular three-quarter crowns
  • the finish line for extremely short walls
  • the facial margin of posterior metal-ceramic crowns with a supragingival margin
A

beveled shoulder

57
Q

The advantages of this type of margin include:

  • to get proper marginal adaptation
  • the bulk of the material in border
A

beveled shoulder

58
Q

The disadvantages of this type of margin include:

  • more tooth structure is removed
  • less conservative approach
  • preparation should be extended apically
A

beveled shoulder

59
Q

A finish line designs for tooth preparation in which the gingival aspect meets the external axial surface at an obtuse angle:

60
Q

Indications for this type of margin include:

  • cast metal restorations
  • lingual margin of metal-ceramic restorations
61
Q

Advantages of this type of margin include:

  • conservative tooth prep
  • good marginal adaptation
  • provides bulk to the restoration
62
Q

Disadvantages of this type of margin include:

  • technique sensitive
  • any defect in fabrication can lead to unsupported tip of the crown
63
Q

Similar to chamfer finish line but comes with a 90 degrees cavosurface angle with a large radius rounded internal angle:

A

heavy chamfer

64
Q

In cases of metal restorations using a heavy chamfer margin, a ___ is added to the finish line

65
Q

Indications of this type of margin include:

  • ceramic crowns and metal crowns with a bevel
A

heavy chamfer

66
Q

Advantages of this type of margin include:

  • best finish line for a ceramic crown
A

heavy chamfer

67
Q

Disadvantages of this type of margin include:

  • technique sensitive
  • little discrepancy can lead to the formation of a lip or unsupported fragile enamel
A

heavy chamfer

68
Q

Also considered a thin-edge or feather-edge margin:

A

knife-edge

69
Q

Indications of this type of margin include:

  • young patients
  • metal restorations
  • MOD onlay
  • inaccessible areas
  • when the finish line extends to the cementum
  • the lingual surface of mandibular posterior teeth
  • pin ledge 3/4 quarter crown
A

knife-edge/feather-edge

70
Q

Advantages of this type of margin include:

  • Conservative
  • Helps in preserving tooth structure
  • Ideal for marginal adaptation
  • Useful in gold and metal crowns/restorations as it lets you burnish it to a fine finish
  • considered an ideal finish line
A

knife-edge/feather-edge

71
Q

Disadvantages of this type of margin include:

  • distinct or proper finish is not visible
  • polishing and casting become critical
  • overcontouring of restorations to obtain a bulk is a usual complication
A

knife-edge/feather-edge

72
Q

Crown preparation concerns:

Scientists seem to oscillate back and forth as to whether heat produced during a crown preparation will:

A

kill the pulp

73
Q

Crown preparation concerns:

It is agreed that the ___ becomes irritated and inflamed during ___.

A

pulp; crown preparation

74
Q

Crown preparation concerns:

A rise in the pulp temperature by ___ degrees significantly increases the chance of ____.

A

10 degrees; pulpal necrosis

75
Q

Crown preparation concerns:

Because of the concerns with overheating the pulp during a crown preparation we should: (7)

A
  1. use lots of water
  2. use sharp burs
  3. use light pressure
  4. use high speed
  5. use diamond burs
  6. avoid desiccation of the teeth
  7. if visibility is compromised, with an assistant, with water off from the handpiece, an assistant can use air and small amounts of water to help keep tooth cool
76
Q

The main cause of postoperative inflammation and necrosis of the pulp is probably the injury of ____, a tissue in direct functional and physiological connection with the pulp

77
Q

Margin design instrumentation:

For the preparation what is used? (3)

A
  1. high-speed handpiece
  2. air/water spray
  3. diamond burs
78
Q

Margin design instrumentation:

For finishing the preparation, what is used? (3)

A
  1. slow-speed handpiece
  2. fine diamond burs (possible some carbide burs)
  3. hand instruments
79
Q

Margin design instrumentation:

For caries removal of the crown preparation, what is used? (2)

A
  1. slow-speed with 2, 4, or 6 round bur
  2. spoon excavators
80
Q

Burs that function too remote enamel and dentin by grinding it away

A

diamond bur

81
Q

Burs that function to remove tooth by shearing it away:

A

carbide burs

82
Q

___ burs that are most efficient, 2-3 time faster than ___ burs

A

diamond; carbide

83
Q

What type of bur is being described?

-Cut precision prep features with smooth surfaces

  • Often used to place extra retentive features in a crown preparation such as a seating groove
A

carbide burs

84
Q

___ can be used to help smooth finish lines:

A

hand instruments

85
Q

Hand instruments that can be used to help smooth finish lines include: (4)

A
  1. chisel
  2. hatchet
  3. hoe
  4. margin trimmer
86
Q

Advantages of full metal crowns:

gold and many metal crowns are:

A

soft metals

87
Q

Full metal crowns are ____ to opposing teeth

88
Q

Advantages of full metal crowns:

Metal is strong so:

A

material can be quite thin

89
Q

Describe the preparations involving a full metal crown:

A

very conservative preparations

90
Q

Advantages of full metal crowns:

metals have some antibacterial properties making:

A

recurrent decay less likely

91
Q

Describe the effects of most gold and full metal crowns on the gingiva:

92
Q

_____ crowns are very durable even if warn through or with an endo access

A

metal crowns

93
Q

In a metal crown, if the contact is missing:

A

you can add material to the contact to re-establish it

94
Q

List the disadvantages of full metal crowns:

95
Q

Discuss the margin design for a full metal crown preparation:

A

Can use knife edge margin but usually a light chamfer is recommended (0.3-0.5mm)

96
Q

In a full metal crown preparation, axial walls are reduced to create a tapered wall between ___ to ___ degrees ideally, but can have TOC up to ___ degrees

97
Q

In a full metal crown preparation, axial walls can be reduced as little as ____, but can be reduced more if needed.

98
Q

Discuss the occlusal reduction in a full metal crown preparation:

A

uniform occlusal reduction depth of 1.0-1.5 mm following tooth anatomy

99
Q

Nothing is ___ in dentistry, except for our tools

100
Q

In a full metal crown preparation, line angles and corners need to be rounded to prevent:

A

pressure points and possible fracturing of a restorative material

101
Q

In a full metal crown preparation, rounded preps make the:

A

crown fabrication process easier

102
Q

In a full metal crown preparation, prepared surfaces and finish line are smoothed with a fine grit diamond bur, what does this ensure?

A

preparation walls are scored but with a smoother more consistent shape for seating and longevity of the restoration

103
Q

Full metal crown summary:

A) Chamfer finish line:

B) Axial reduction:

C) Total occlusal taper:

D) Occlusal clearance:

E) ____ of all line angles

A

A) 0.3-0.5 mm
B) as little as 0.5mm
C) 6-10 dgrees
D) 1.0-1.5 mm
E) Rounding

104
Q

Label the various tooth preparations: (left to right)

A

Metal or All-Zirconia
PFM
All-Ceramic

105
Q

A relatively new material that is tooth-colored and ceramic-like:

106
Q

Zirconia is considered _____ free

107
Q

Zirconia can have similar properties to:

108
Q

Zirconia can be described as:

A

very hard and tough

109
Q

Compare the appearance of zirconia to natural teeth:

A

less translucent

110
Q

What material is seen in the following crown?

111
Q

The original zirconia that was very tough and very ugly:

112
Q

Why have new iterations of zirconia been created?

A

to make zirconia more esthetic

113
Q

What is the problem with making new iterations of zirconia that is more esthetic?

A

In order to make them more esthetic, the strength of zirconia is reduced

114
Q

Depending on the type of zirconia crown, the preparation can be:

A

as minimal as a full metal crown prep or as extensive as all ceramic crown prep

115
Q

Zirconia is rapidly changing still so what is extremely important?

A

knowing which kind of zirconia your lab is using so you can prep appropriately

116
Q

The more esthetic your zirconia is, the more ____ will be needed

Fixed Prosthodontics I (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions