Extra coronal restoration Flashcards

1
Q

List some examples of different types of crowns

A
  1. Full veneer crown (FVC)
  2. Metal ceramic crown (MCC)
  3. All ceramic crown (ACC)
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2
Q

How much reduction do we do for an FVC

A

Buccal: 0.5mm
Occlusal: 1-1.5mm
Lingual: 0.5mm

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3
Q

How much reduction do we do for an MCC

A

Buccal: 1.2-1.5mm
Occlusal: 1.5-2.5mm
Lingual: 0.5mm

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4
Q

How much reduction do we do for an ACC

A

Buccal: 1mm
Occlusal: 1.5-2mm
Lingual: 1mm

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5
Q

What are the advantages of a crown

A
  1. Protects severely broken down teeth
  2. Protects remaining tooth tissue
  3. Improves aesthetic
  4. Can last longer than direct restorations
  5. Can be placed on a root filled tooth
  6. Can be used to replace heavily restored teeth
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6
Q

What are the disadvantages of a crown

A
  1. High biological
  2. Demanding and easy to mess up
  3. Difficult to get aesthetics right
  4. May take several appointments
    5, Stripping of enamel can lead to dentine sensitivity
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7
Q

How many crowned teeth are non vital

A

20 %

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8
Q

List the different crown types from highest bond strength to lowest

A

FVC
MCC
ACC

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9
Q

List the different crown types from highest biological cost to lowest

A

FVC
MCC
ACC

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10
Q

List the different crown types from most aesthetic to elastic

A

ACC
MCC
FVC

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11
Q

For a patient with group function which crown would you recommend and why

A

FVC is better as patients with group function will grind on their back teeth and metal is kinder to opposing teeth

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12
Q

What are the 4 stages of treatment planning

A
  1. Establishing a healthy oral environment
    2, Corrective
  2. Advanced treatment
  3. Replace missing teeth
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13
Q

What is an indirect restoration

A

A restoration that isn not paced directly in the mouth

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14
Q

Hive examples of indirect restorations

A

Crowns
Veneers
Onlays
Inlays

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15
Q

Why. might we choose t place an indirect restoration over a direct one

A
  1. Comfort
  2. Function (indirect restorations are stronger)
  3. Stability
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16
Q

What must we do to the tooth before placing an indirect restoration

A

We must prep it to make space

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17
Q

Why do we need to prepare a tooth for an indirect restoration

A

To create room for an indirect restoration to sit

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18
Q

What must we make sure our preparation doesn’t have?

A

An undercut

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19
Q

What can happen if our preparation has an undercut

A

Then the crown will be vulnerable to cracking and breaking off

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20
Q

How can we correct any undercuts we may create on our preparation

A

We may need to full the space with lining/ filling material

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21
Q

What are the problems associated with under preparing a tooth

A
  1. Bulbosity will be seen at that portion of the tooth (PRF)
  2. There won’t be enough space for the porcelain and metal
  3. Can put stress on the crown increasing the risk of fracture
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22
Q

What are the problems associated with over preparing a tooth

A

Can expose/ damage the pulp

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23
Q

What does retention prevent

A

It prevents the removal of the crown along the path of insertion

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24
Q

What does resistance prevent

A

It prevents dislodgement by lateral or apical forces under occlusal load

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25
Q

How can we improve resistance and retention

A

BY having an adequate taper

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26
Q

The more P_____ the two surfaces are, the better the retention

A

Parallel

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27
Q

What happens to the retention and resistance as the taper increases

A

Decreases

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28
Q

How much is suitable taper

A

6 degrees

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29
Q

Why is it important we achieve a good taper

A
  1. Preserve tooth tissue
  2. Provides good resistance and retention
  3. Allows a visible finish line
  4. Allows for adequate seating of indirect restoration
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30
Q

How does surface area affect retention and resistance

A

The larger the surface area of the tooth, the greater the R & R

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31
Q

What can we place on the prep to increase retention and residence

A

Grooves and boxes

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32
Q

Cements can work…

A

Actively and passively

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33
Q

how do passive cements work

A

They fill the gap between the crown and tooth

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34
Q

How do active cements work

A

They bond to the surface of the tooth to improve adhesion

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35
Q

What different material scan we use to make crowns

A
  1. Metal ceramic
  2. Gold
  3. Non precious metal
  4. All ceramic
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36
Q

Describe how we want the margin of our crown to look

A

We want the margin to be:
Crisp
Defines
Accurate

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37
Q

Do we want eh margin to be supra or sub gingival?

Why

A

Supra so that no one can see the margin

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38
Q

What is the biological width

A

The distance from the depth of sulcus to alveolar crest

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39
Q

What must we never do in terms of the biological width

A

Compromise it

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40
Q

Why must we not compromise the biological width

A

We can create inflammation that can lead to disease

Makes impressions inaccurate and can lead to recession

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41
Q

What is a crown

A

A restoration designed outside of the mouth to encompass the entire tooth

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42
Q

How is a crown different to an onlay

A

Onlays only cover part of the tooth surface

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43
Q

What do we do the excess cement the squeezes from the bottom when we are placing a crown

A

We MUST remove it before ti sets

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44
Q

What do we mean by taper

A

Degree of convergence of the walls

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45
Q

What do we mean by height

A

Distance from the margin to the occlusal/ incisal prepped surface

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46
Q

When can open crown margins occur

A

Poor impressions or recession occurring over time

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47
Q

Which materials can we use to make a full veneer crown

A
  1. Precious metal eg gold

2. Non rapacious metal eg cobalt chrome

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48
Q

What is another name for all ceramic crowns

A

Dentine bonded crowns

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49
Q

What are some of the advantages of gold crowns

A
  1. Strong
  2. Durable
  3. Similar hardness to enamel
  4. Inert
  5. Accurate fitting on tooth margins
  6. Minimal reduction required
  7. Manufacturing proces sis easy
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50
Q

How do we take an impression for a crown prep

A

2 different impression material sare used: light and heavy body silicone

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51
Q

What are some of the indications for using gold crowns

A
  1. Restoring tooth back to function
  2. Posterior crown
  3. Tooth with limiting starting height
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52
Q

What are some of the advantages of metal ceramic crown

A
  1. Aesthetic
  2. Strong
  3. Durable
  4. Requires little prep palatally
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53
Q

What are some of the disadvantages of metal ceramic crown

A
  1. Prorcelain must b ethics to hide underlying metal

2. Patent with demanding aesthetics may reject it

54
Q

WHt are some of the indication for an MCC

A
  1. Restoring tooth back to function
  2. Posterior crown
  3. Tooth with limiting starting height
  4. Aesthetics are a concern
55
Q

Why do we need crowns

A
  1. Aesthetics
  2. Functionality
  3. Strength
  4. Sensitivity
  5. Prevents plaque retention
56
Q

State the dentinal nubile density

A

72,000mm^2

57
Q

Why do we need to temporise

A

to prevent:

  1. Dentine sensitivity
  2. Bacterial invasion of dentinal tubules
  3. Over eruption and drifting of teeth
  4. , Overgrowth of gingivae
58
Q

What theory explains pain

A

The hydrodynamic theory

59
Q

Talk through the hydrodynamic theory

A
  1. Dentinal tubules are full of fluid
    2, Odontoblasts project the processes into tubule
    3, Fluid movies in response to changes in temp/osmotic potential
  2. Odontoblasts start to move, around odontoblasts are sensory nerves that detect movement
60
Q

Do we need to temporise teeth that have been tooth filled? why?

A

Yes because if we didn’t temporise it acts as a PRF & chance of reinfection are greater

61
Q

Why is it important o temporise teeth in terms of occlusion

A

As teeth can move between appointments which can result in your crown not fitting

62
Q

Other than preventing problems what is a benefit of temporisation

A

We can assess aesthetics and occlusion

63
Q

List the main methods of temporary crown manufacture

A
  1. Direct custom made
  2. Pre fabricated
  3. Indirect lab made
64
Q

How are custom made temporary crowns made

A

Chairside
1. Make a mould of the tooth using alginate/silicate
2. Do the crown prep
3 .Use the mould to do make the crown prep

65
Q

Before starting your prep what is it important you take

A

2 Moulds of the tooth you are preparing

66
Q

Why do we need to take 2 moulds of the tooth we are preparing

A

1, On mould to see how much reduction has been carried out

2. One mould for making the temporary crown

67
Q

What material are direct made crowns made from

A

bis-acryl composite

68
Q

What is bis-acryl composite

A

Composite with a bit of acrylic

69
Q

What is bis-acryl composites trade name

A

Integrity

70
Q

List some properties of direct custom made crowns

A
  1. Adequate strength
  2. Accurate fit
  3. No mining required
  4. Has a granular finish but acceptable aesthetics
  5. Comes in a variety of shades
  6. Can be prepared with composite
  7. Poor stain resistance
71
Q

What is diagnostic wax up

A

A model made in the lab to produce the ideal tooth shape

72
Q

Name the different types of pre fabricated crowns

A
  1. Polycarbonate (Directa)
  2. Aluminium (Ion)
  3. Stainless steel
73
Q

When are direct (polycarbonate) pre fabricated crowns used

A

Anteriorly

74
Q

When are Aluminium (Ion) pre fabricated crowns used

A

posteriorly

75
Q

When are stainless steel pre fabricated crowns used

A

posteriorly

76
Q

What are direct crown chosen by

A

Width NOT length

77
Q

How do we adjust a directa crown

A

By trimming the margins of the temporary crown to conform to the occlusion

78
Q

What are direct crowns filled with and why

A

As they are hollow they are filled with integrity

79
Q

When might we need a temporary crown that needs to stay in the mouth for a long time

A

When the patient is undergoing periods surgery alongside restorations

80
Q

If we need the temporary crown to stay on the tooth fro a long time what might we use

A

An indirect lab technique using PMMA

81
Q

Why can we make PMMA crowns chair side

A

As the reaction is highly exothermic and the crown will be too hot to hod

82
Q

How is an indirect temporary CROWN made

A
  1. Technician starts with a pre – op plaster model of the tooth
  2. A minimal prep is carried out (a crown prep) on the model & crown is made with PMMA
  3. Crown returned to clinician who preps tooth and modifies the lab made temp to make it fit
83
Q

List the qualities of an ideal temporary cement

A
  1. Strong enough to retain the crown
  2. Easily removable
  3. Does not adhere to the tooth
84
Q

What do we use to cement temporary crowns

A

tempbond

85
Q

what is tempbond

A

Fine zinc oxide eugenol cement

86
Q

What is the trade name for tempbond

A

Tubiseal

87
Q

If the permeant crown fits perfectly onto our prep why do we need to cement it?

A

As there is a microscopic gap between the prep and the crown where bacteria can ingress into

88
Q

List some ideal properties of cements

A
  1. Prevents micro leakage
  2. High compressive strength
  3. Low solubility
  4. Retentive to tooth and restoration
  5. Low film thickness
  6. Biocompatible
  7. Ease of use
89
Q

What do we mean by cement being easy to use

A

Has a sufficient working time and is easy to remove any excess

90
Q

Name the different types of cement

A
  1. Traditional cements
  2. Glass ionomer cements
  3. Resin cements
91
Q

Name the two types of traditional cements

A

Zinc phosphate & Zinc polycarboxylate

92
Q

How Is zinc phosphate cement packaged

A

Powder: zinc oxide, Magnesium oxide
Liquid: Phosphoric acid, citric acid

93
Q

What are the properties fo zinc phosphate cement

A
  1. Long record of clinical success
  2. High compressive strength
  3. Acceptable low film thickness
  4. 6 min working time
  5. No adhesive property, (macro mechanical retention only)
  6. High solubility & prone to dissolution
94
Q

What are the indications for the use of zinc phosphate cement

A
  1. Full crowns
  2. Conventional bridges
  3. Cast posts
95
Q

What is the trade name for zinc Polycarboxylate

A

Poly F

96
Q

How Is zinc Polycarboxylate cement packaged

A

As a powder: zinc oxide and liquid: water

97
Q

List soem of th properties of zinc Polycarboxylate

A
  1. Moderate compressive strength
  2. Acceptable low film thickness
  3. Chemical adhesion to tooth
  4. High solubility
  5. Flouride release
98
Q

What are the indacrtiosn fro the use of zinc Polycarboxylate

A
  1. Full crowns
  2. Conventional bridges
  3. inlays/ onlays
  4. Ortho brackets
99
Q

List the two categories of glass ionomer cements

A

Traditional

Resin modified

100
Q

What is the trade name for resin modified glass ionomer cements

A

Fuji plus

101
Q

How is fuji plus packaged

A

As a capsule that needs to be put in the amalgamator

102
Q

What does RMGIC contain

A
  1. Calcium – aluminio – fluoro – silicate glass
  2. Polyacrylic acid
  3. HEMA
103
Q

List some of the properties of RMGIC

A
  1. High compressive strength
  2. Acceptable low film thickness
  3. Chemical adhesion to tooth and base metals
  4. Low solubility
  5. Floruide release
104
Q

What are the indications fro the use of RMGIC

A
  1. Full crowns
  2. Conventional bridges
  3. inlays/ onlays
  4. Ortho brackets
105
Q

Name the 3 types of resin cements

A
  1. Simple
  2. Multi step
  3. All in one adhesives
106
Q

What is the trade name fro multi step resin cemtns

A

Panavia

107
Q

List the different components of

A
Acid etch 
Paste A (MDP, Methacrylate’s, CQ, Fillers)
Paste B (NaF, activators)
Liquid A & Liquid B (Bond)
Metal primer & Ceramic primer
Oxyguard
108
Q

List some of the properties of panavia

A
  1. Very high compressive strength
  2. Very high bond strength
  3. Acceptable low film thickness
  4. Low solubility
109
Q

List soem of the indications for the use of panavia

A
  1. Crowns
  2. Both Bridges
  3. onlays/Inlays
  4. Veneers
  5. Posts
  6. Bonded amalgam
110
Q

What is the trade name for all In one resin cemtns

A

Rely X ultimate

111
Q

Name the 2 components of rely X ultimate

A
  1. Scotch bond universal

2. Rely X cement

112
Q

List some of the properties of Rely X ultimate

A
  1. Very high bond strength
  2. Acceptable low film thickness
  3. Low solubility
113
Q

List some of the indications for Rely X ultimate

A
  1. Crowns
  2. Both Bridges
  3. onlays/Inlays
  4. Veneers
  5. Posts
114
Q

Once we have placed the crown what do we check for

A
  1. Check to see if the crown is high using Shimstock
  2. check to see the margins are fully seated
  3. Check to see if the crown is fully seated
115
Q

What is shimstocj

A

Shimstock is a really thin film of metal foil

116
Q

When do we review the patient following crown placement

A

2 weeks

117
Q

List some advantages of resin bonded bridges

A
  1. Minimally invasive (no prep or LA)
  2. Quick
  3. Cheap for lab
  4. East
  5. High patient satisfaction
118
Q

List some disadvantages of resin bonded bridges

A
  1. Need to use abutment tooth
  2. Limited life span compared to conventional bridges
  3. Difficult to get tooth/ alignment right
  4. Can be adjusted once put on
  5. Causes grey out of abutment tooth
119
Q

When are implants not ideal

A

In patients who dont have enough space or have too much bone loss

120
Q

List some indications for a resin retained bridge

A
  1. Young patent
  2. No bone
  3. Shortened dental arch
  4. Limited biting surface
  5. Following cancer treatment
  6. Following recession
121
Q

What questions do we need to ask ourself while picking our abutment tooth

A
  1. What is the periodontal status
  2. Are there any biting forces on the tooth
  3. Root morphology
  4. Is the abutment heavily restored
122
Q

In terms of occlusion what should we make sure the pontic is not involved in

A

Pontic can not be in guidance

123
Q

List the design features of a pontic

A
  1. Minimal ICP contact
  2. No excessive contacts on pontic
  3. Reduced occlusal table
124
Q

When there is a space gap of 2 teeth which type of bridge should we use

A

Always do 2 cantilever bridges

125
Q

Should we make a bridge for patients with a large edentulous area

A

No consider making a denture instead

126
Q

What is the base metal of a retainer usually made up of

A

An alloy such as cobalt chrome

127
Q

How thick should the base metal be? Why?

A

0.7mm

ust rigid enough to resist flexion affecting cement

128
Q

What happens if the base metal is too thick

A

It can jack the bite open

129
Q

Name the 3 different types of pontic designs

A
  1. Ridge lap
  2. Modified ridge lap
  3. Ovate
130
Q

How do we cement an resin retained bridge

A
  1. Check the prescription
  2. Pumice rinse and dry the prep
  3. Try in the retainer for fit and extension
  4. Assess the aesthetics
  5. Resandblast
  6. Cement