6. Intro to ceramics Flashcards

1
Q

LOs

A
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2
Q

Main applications of ceramics

A

•Inlays
•Onlays
•Veneers
•Crowns
•Implant components
•Fixed partial prostheses
•Denture Teeth

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3
Q

Why’re ceramics so popular

A
  • Used widely because of their optical similarities to teeth
  • can mimic shade, translucency and lustre of tooth structure better than other materials
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4
Q

Disadvantages of ceramics

A

•Brittle in nature (can undergo very little deformation before they fail)

microstructure and defects/flaws play a major role in determining strength

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5
Q

1
Ceramics definition

2
Eg of ceramic materials

A
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6
Q

Type of bonding involved in ceramics

A
  • ionic
  • covalent
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7
Q

Are porcelain and ceramics the same

A

Porcelain is a ceramic but not all ceramics are porcelains

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8
Q

Main types of ceramics used in dent?

A
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9
Q

Key properties of dental ceramics?

A
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10
Q

Recap differences between glassy and crystalline states

A
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11
Q

1
What does it mean by the fact that ceramics are brittle?

2
What factors are do ceramics mechanical strength depend on?

A
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12
Q

1
What is fracture toughness

2
What is ceramics relative fracture toughness

3
Why is the theoretical tensile strength so high for ceramic compared to the actual tensile strength?

4
Tensile strength varies depending on?

A
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13
Q

Feldspathic Ceramics (Porcelain)

1
Overall structure

2
Main component in it?

A

1
- type of ceramic
-mainly glassy
–minor crystalline component

2

Feldspar is main component, KAlSi3O8

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14
Q

Feldspathic Ceramics (Porcelain)

1
When melted it forms

2
What happens when it cools

A
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15
Q

Feldspathic Ceramics (Porcelain)

1
Relative flexural strength?

2
Why is it used in aesthetics?

3
Is it mechanically strong?

A

1
typically 60-80MPa
- relatively weak

2
- Translucent in nature
- Can closely match the shade, translucency and luster of natural dentition

3
- But is low strength and prone to mechanical failures
- Addition of other crystal phases (e.g. fluorapatite) in contemporary materials increases mechanical performance

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16
Q

1
How may mechanical toughening of glassy cements be done

2
What condition must be met for this to be effective

3
EG

A
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17
Q
A
  • subtle changes to crystalline component of ceramics is used to produce materials with different properties
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18
Q

Eg of different ceramic microstructures

A
19
Q
  • ceramic manufacturing methods
A
  • can classify diff ceramic materials not only by their structure but also by their manufacturing methods
20
Q

1
What is sintering of dental ceramics?

2
What are the 2 main types of crystalline reinforced sintered dental ceramics?

A
21
Q

SINTERED ALL-CERAMIC RESTORATION:
ALUMINA-BASED MATERIALS

1
Is it still used?

2
Alumina formula and % added?

A

1
Rarely used system now – but many functioning crowns out there

2
•Alumina is an aluminum oxide, Al2O3
•Typically added in levels of up to 40-50% by weight

22
Q

SINTERED ALL-CERAMIC RESTORATION:
ALUMINA-BASED MATERIALS

Key problems with it?

A
  • shrinkage during sintering leading to dimensional inaccuracies
  • During sintering procedure shrinkage between 10-20% can occur
  • opacity of core necessitates veneering with glassy material to achieve esthetics
23
Q

SINTERED ALL-CERAMIC RESTORATION:
ALUMINA-BASED MATERIALS

1
Good bond with glass phase?

2
How is it formed? Temp?

3
Flexural strength? What does this depend on?

A
24
Q

SINTERED ALL-CERAMIC RESTORATION:
ALUMINA-BASED MATERIALS

1
Good bond with glass phase?

2
How is it formed? Temp?

3
Flexural strength? What does this depend on?

A
25
Q

SINTERED ALL-CERAMIC RESTORATION:
ALUMINA-BASED MATERIALS

1
Good bond with glass phase?

2
How is it formed? Temp?

3
Flexural strength? What does this depend on?

A
26
Q

SINTERED ALL-CERAMIC RESTORATION:
LEUCITE-REINFORCED MATERIALS

1
Compound made of?

2
Flexural strength?

3

4
What happens during cooling

5
Positives

A
27
Q

HEAT-PRESSED ALL-CERAMIC RESTORATIONS

1
What is it?

2
What happens during the process? Pressure? Temp?

3
Why was it introduced?

A
28
Q

HEAT-PRESSED ALL-CERAMIC RESTORATIONS?

1
Why is Heat pressing is typically used over classical sintering?

2
What is the final step for final-heat pressed ceramics?

3
Ceramic materials used in heat pressing?

A
29
Q

HEAT-PRESSED ALL-CERAMIC RESTORATIONS:
LEUCITE-REINFORCED MATERIALS

1
Properties?

2
Final porosity % vol?

3
Final flexural strength

4

A
30
Q

HEAT PRESSED CERAMICS:
LITHIUM DISILICATE MATERIALS

1
Properties

2
final porosity by % vol?

3
Flexural strength

A
31
Q

SLIP-CAST ALL-CERAMIC RESTORATIONS

1
What is it

2
How is it formed

3
Types of materials used

4
Commonly used today?

A
32
Q

CAD-CAM All-Ceramic Restorations

1
What does it stand for?

2
What happens

3
Disadvantages

4
Common method?

A
33
Q

CAD-CAM All-Ceramic Restorations

1
Bulk ceramics are either (make q)

2
2 main types of machining?

3
What is hard machining

4
Advantages of hard machining

5
Limits of hard machining

6
What is soft maching

A
34
Q

CAD-CAM All-Ceramic Restorations:
Fully Sintered Materials

1
Three types of materials are currently used in the fully sintered state in CAD-CAM restorations?

A
35
Q

CAD-CAM All-Ceramic Restorations:
Fully Sintered Materials

1
Feldspar

2
Leucite-reinforced (K[AlSi2O6]):

3
Lithium disilicates:

MAKE Qs

A
36
Q

CAD-CAM All-Ceramic Restorations:
Partially Sintered Materials

1

Partially sintered materials used in CAD-CAM restorations include:

A

•Alumina
•Spinel (see slip-cast)
•Zirconia

37
Q

CAD-CAM All-Ceramic Restorations:
Partially Sintered Materials

Make Qs

A
38
Q

Mechanical Toughening of Zirconia

Make Qs

A
39
Q

CERAMIC-METAL RESTORATION

1
What is it?

2
What are the layers?

A
40
Q

CERAMIC-METAL RESTORATION

1
What happens after the additional layers are added?

A
41
Q

Ceramic-Metal Restoration: Ceramic-Driven Requirements

A
42
Q
A
43
Q

Not in lecture but in ppt doc

A
44
Q

Qs in lecture

A