Extra coronal restoration Flashcards
(130 cards)
1
Q
List some examples of different types of crowns
A
- Full veneer crown (FVC)
- Metal ceramic crown (MCC)
- All ceramic crown (ACC)
2
Q
How much reduction do we do for an FVC
A
Buccal: 0.5mm
Occlusal: 1-1.5mm
Lingual: 0.5mm
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
4
Q
How much reduction do we do for an ACC
A
Buccal: 1mm
Occlusal: 1.5-2mm
Lingual: 1mm
5
Q
What are the advantages of a crown
A
- Protects severely broken down teeth
- Protects remaining tooth tissue
- Improves aesthetic
- Can last longer than direct restorations
- Can be placed on a root filled tooth
- Can be used to replace heavily restored teeth
6
Q
What are the disadvantages of a crown
A
- High biological
- Demanding and easy to mess up
- Difficult to get aesthetics right
- May take several appointments
5, Stripping of enamel can lead to dentine sensitivity
7
Q
How many crowned teeth are non vital
A
20 %
8
Q
List the different crown types from highest bond strength to lowest
A
FVC
MCC
ACC
9
Q
List the different crown types from highest biological cost to lowest
A
FVC
MCC
ACC
10
Q
List the different crown types from most aesthetic to elastic
A
ACC
MCC
FVC
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
12
Q
What are the 4 stages of treatment planning
A
- Establishing a healthy oral environment
2, Corrective - Advanced treatment
- Replace missing teeth
13
Q
What is an indirect restoration
A
A restoration that isn not paced directly in the mouth
14
Q
Hive examples of indirect restorations
A
Crowns
Veneers
Onlays
Inlays
15
Q
Why. might we choose t place an indirect restoration over a direct one
A
- Comfort
- Function (indirect restorations are stronger)
- Stability
16
Q
What must we do to the tooth before placing an indirect restoration
A
We must prep it to make space
17
Q
Why do we need to prepare a tooth for an indirect restoration
A
To create room for an indirect restoration to sit
18
Q
What must we make sure our preparation doesn’t have?
A
An undercut
19
Q
What can happen if our preparation has an undercut
A
Then the crown will be vulnerable to cracking and breaking off
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
21
Q
What are the problems associated with under preparing a tooth
A
- Bulbosity will be seen at that portion of the tooth (PRF)
- There won’t be enough space for the porcelain and metal
- Can put stress on the crown increasing the risk of fracture
22
Q
What are the problems associated with over preparing a tooth
A
Can expose/ damage the pulp
23
Q
What does retention prevent
A
It prevents the removal of the crown along the path of insertion
24
Q
What does resistance prevent
A
It prevents dislodgement by lateral or apical forces under occlusal load
25
How can we improve resistance and retention
BY having an adequate taper
26
The more P_____ the two surfaces are, the better the retention
Parallel
27
What happens to the retention and resistance as the taper increases
Decreases
28
How much is suitable taper
6 degrees
29
Why is it important we achieve a good taper
1. Preserve tooth tissue
2. Provides good resistance and retention
3. Allows a visible finish line
4. Allows for adequate seating of indirect restoration
30
How does surface area affect retention and resistance
The larger the surface area of the tooth, the greater the R & R
31
What can we place on the prep to increase retention and residence
Grooves and boxes
32
Cements can work...
Actively and passively
33
how do passive cements work
They fill the gap between the crown and tooth
34
How do active cements work
They bond to the surface of the tooth to improve adhesion
35
What different material scan we use to make crowns
1. Metal ceramic
2. Gold
3. Non precious metal
4. All ceramic
36
Describe how we want the margin of our crown to look
We want the margin to be:
Crisp
Defines
Accurate
37
Do we want eh margin to be supra or sub gingival?
| Why
Supra so that no one can see the margin
38
What is the biological width
The distance from the depth of sulcus to alveolar crest
39
What must we never do in terms of the biological width
Compromise it
40
Why must we not compromise the biological width
We can create inflammation that can lead to disease
| Makes impressions inaccurate and can lead to recession
41
What is a crown
A restoration designed outside of the mouth to encompass the entire tooth
42
How is a crown different to an onlay
Onlays only cover part of the tooth surface
43
What do we do the excess cement the squeezes from the bottom when we are placing a crown
We MUST remove it before ti sets
44
What do we mean by taper
Degree of convergence of the walls
45
What do we mean by height
Distance from the margin to the occlusal/ incisal prepped surface
46
When can open crown margins occur
Poor impressions or recession occurring over time
47
Which materials can we use to make a full veneer crown
1. Precious metal eg gold
| 2. Non rapacious metal eg cobalt chrome
48
What is another name for all ceramic crowns
Dentine bonded crowns
49
What are some of the advantages of gold crowns
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
50
How do we take an impression for a crown prep
2 different impression material sare used: light and heavy body silicone
51
What are some of the indications for using gold crowns
1. Restoring tooth back to function
2. Posterior crown
3. Tooth with limiting starting height
52
What are some of the advantages of metal ceramic crown
1. Aesthetic
2. Strong
3. Durable
4. Requires little prep palatally
53
What are some of the disadvantages of metal ceramic crown
1. Prorcelain must b ethics to hide underlying metal
| 2. Patent with demanding aesthetics may reject it
54
WHt are some of the indication for an MCC
1. Restoring tooth back to function
2. Posterior crown
3. Tooth with limiting starting height
4. Aesthetics are a concern
55
Why do we need crowns
1. Aesthetics
2. Functionality
3. Strength
4. Sensitivity
5. Prevents plaque retention
56
State the dentinal nubile density
72,000mm^2
57
Why do we need to temporise
to prevent:
1. Dentine sensitivity
2. Bacterial invasion of dentinal tubules
3. Over eruption and drifting of teeth
4. , Overgrowth of gingivae
58
What theory explains pain
The hydrodynamic theory
59
Talk through the hydrodynamic theory
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
4. Odontoblasts start to move, around odontoblasts are sensory nerves that detect movement
60
Do we need to temporise teeth that have been tooth filled? why?
Yes because if we didn’t temporise it acts as a PRF & chance of reinfection are greater
61
Why is it important o temporise teeth in terms of occlusion
As teeth can move between appointments which can result in your crown not fitting
62
Other than preventing problems what is a benefit of temporisation
We can assess aesthetics and occlusion
63
List the main methods of temporary crown manufacture
1. Direct custom made
2. Pre fabricated
3. Indirect lab made
64
How are custom made temporary crowns made
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
Before starting your prep what is it important you take
2 Moulds of the tooth you are preparing
66
Why do we need to take 2 moulds of the tooth we are preparing
1, On mould to see how much reduction has been carried out
| 2. One mould for making the temporary crown
67
What material are direct made crowns made from
bis-acryl composite
68
What is bis-acryl composite
Composite with a bit of acrylic
69
What is bis-acryl composites trade name
Integrity
70
List some properties of direct custom made crowns
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
What is diagnostic wax up
A model made in the lab to produce the ideal tooth shape
72
Name the different types of pre fabricated crowns
1. Polycarbonate (Directa)
2. Aluminium (Ion)
3. Stainless steel
73
When are direct (polycarbonate) pre fabricated crowns used
Anteriorly
74
When are Aluminium (Ion) pre fabricated crowns used
posteriorly
75
When are stainless steel pre fabricated crowns used
posteriorly
76
What are direct crown chosen by
Width NOT length
77
How do we adjust a directa crown
By trimming the margins of the temporary crown to conform to the occlusion
78
What are direct crowns filled with and why
As they are hollow they are filled with integrity
79
When might we need a temporary crown that needs to stay in the mouth for a long time
When the patient is undergoing periods surgery alongside restorations
80
If we need the temporary crown to stay on the tooth fro a long time what might we use
An indirect lab technique using PMMA
81
Why can we make PMMA crowns chair side
As the reaction is highly exothermic and the crown will be too hot to hod
82
How is an indirect temporary CROWN made
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
List the qualities of an ideal temporary cement
1. Strong enough to retain the crown
2. Easily removable
3. Does not adhere to the tooth
84
What do we use to cement temporary crowns
tempbond
85
what is tempbond
Fine zinc oxide eugenol cement
86
What is the trade name for tempbond
Tubiseal
87
If the permeant crown fits perfectly onto our prep why do we need to cement it?
As there is a microscopic gap between the prep and the crown where bacteria can ingress into
88
List some ideal properties of cements
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
What do we mean by cement being easy to use
Has a sufficient working time and is easy to remove any excess
90
Name the different types of cement
1. Traditional cements
2. Glass ionomer cements
3. Resin cements
91
Name the two types of traditional cements
Zinc phosphate & Zinc polycarboxylate
92
How Is zinc phosphate cement packaged
Powder: zinc oxide, Magnesium oxide
Liquid: Phosphoric acid, citric acid
93
What are the properties fo zinc phosphate cement
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
What are the indications for the use of zinc phosphate cement
1. Full crowns
2. Conventional bridges
3. Cast posts
95
What is the trade name for zinc Polycarboxylate
Poly F
96
How Is zinc Polycarboxylate cement packaged
As a powder: zinc oxide and liquid: water
97
List soem of th properties of zinc Polycarboxylate
1. Moderate compressive strength
2. Acceptable low film thickness
3. Chemical adhesion to tooth
4. High solubility
5. Flouride release
98
What are the indacrtiosn fro the use of zinc Polycarboxylate
1. Full crowns
2. Conventional bridges
3. inlays/ onlays
4. Ortho brackets
99
List the two categories of glass ionomer cements
Traditional
| Resin modified
100
What is the trade name for resin modified glass ionomer cements
Fuji plus
101
How is fuji plus packaged
As a capsule that needs to be put in the amalgamator
102
What does RMGIC contain
1. Calcium – aluminio – fluoro – silicate glass
2. Polyacrylic acid
3. HEMA
103
List some of the properties of RMGIC
1. High compressive strength
2. Acceptable low film thickness
3. Chemical adhesion to tooth and base metals
4. Low solubility
5. Floruide release
104
What are the indications fro the use of RMGIC
1. Full crowns
2. Conventional bridges
3. inlays/ onlays
4. Ortho brackets
105
Name the 3 types of resin cements
1. Simple
2. Multi step
3. All in one adhesives
106
What is the trade name fro multi step resin cemtns
Panavia
107
List the different components of
```
Acid etch
Paste A (MDP, Methacrylate’s, CQ, Fillers)
Paste B (NaF, activators)
Liquid A & Liquid B (Bond)
Metal primer & Ceramic primer
Oxyguard
```
108
List some of the properties of panavia
1. Very high compressive strength
2. Very high bond strength
3. Acceptable low film thickness
4. Low solubility
109
List soem of the indications for the use of panavia
1. Crowns
2. Both Bridges
3. onlays/Inlays
4. Veneers
5. Posts
6. Bonded amalgam
110
What is the trade name for all In one resin cemtns
Rely X ultimate
111
Name the 2 components of rely X ultimate
1. Scotch bond universal
| 2. Rely X cement
112
List some of the properties of Rely X ultimate
1. Very high bond strength
2. Acceptable low film thickness
3. Low solubility
113
List some of the indications for Rely X ultimate
1. Crowns
2. Both Bridges
3. onlays/Inlays
4. Veneers
5. Posts
114
Once we have placed the crown what do we check for
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
What is shimstocj
Shimstock is a really thin film of metal foil
116
When do we review the patient following crown placement
2 weeks
117
List some advantages of resin bonded bridges
1. Minimally invasive (no prep or LA)
2. Quick
3. Cheap for lab
4. East
5. High patient satisfaction
118
List some disadvantages of resin bonded bridges
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
When are implants not ideal
In patients who dont have enough space or have too much bone loss
120
List some indications for a resin retained bridge
1. Young patent
2. No bone
3. Shortened dental arch
4. Limited biting surface
5. Following cancer treatment
6. Following recession
121
What questions do we need to ask ourself while picking our abutment tooth
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
In terms of occlusion what should we make sure the pontic is not involved in
Pontic can not be in guidance
123
List the design features of a pontic
1. Minimal ICP contact
2. No excessive contacts on pontic
3. Reduced occlusal table
124
When there is a space gap of 2 teeth which type of bridge should we use
Always do 2 cantilever bridges
125
Should we make a bridge for patients with a large edentulous area
No consider making a denture instead
126
What is the base metal of a retainer usually made up of
An alloy such as cobalt chrome
127
How thick should the base metal be? Why?
0.7mm
| ust rigid enough to resist flexion affecting cement
128
What happens if the base metal is too thick
It can jack the bite open
129
Name the 3 different types of pontic designs
1. Ridge lap
2. Modified ridge lap
3. Ovate
130
How do we cement an resin retained bridge
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
