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Dental Materials Second Half Sem > Ceramics > Flashcards

Ceramics Flashcards

1
Q

What are some applications of ceramics?

A

-inlay/onlay
-veneers
-crowns
-bridges

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2
Q

what are ceramics composed of?

A

metal-oxygen atoms with ionic bonds (strongest):
* Example: Zirconium (ZrO2) and Aluminum (Al2 O3)

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3
Q

The metals and oxygen form arrays in what arrangement?

A

three-dimensional crystalline lattice

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4
Q

what are glassy ceramics?

A

-Mostly used for esthetics
-Veneers
-not super organized, not much crystaline (esthetic over strength)

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5
Q

what are glass-dominated ceramics?

A

-Better esthetic (translucency)
-Better strength

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6
Q

what are crystalline dominated esthetics?

A

-70% crystalline
-Improved strength
-More opaque
-Cores for anterior
posterior crowns
-Some inlay/onlay

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7
Q

what are crystalline ceramics?

A

-Strongest
-Opaque
-Any dental restoration
(crowns/bridges)
(more strength, opaque)

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8
Q

what are common compounds in the crystal phase?

A
  • Leucite
  • Fluoroapatite
  • Spinel
  • Zirconia
  • Alumina
  • Lithium Disilicate
  • Lithium Silicate/Phosphate
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9
Q

what are some ways to manufacture ceramics?

A
  • Stacking
  • Pressing
  • Milling
  • Additive manufacturing
  • Slip casting
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10
Q

what are common compounds in the glassy phase?

A

Silica (Quartz, Silicone Oxide)

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11
Q

what ways can you manufacture a glassy ceramic?

A

stacked or pressed

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12
Q

what ways can you manufacture a crystaline ceramic?

A

infused or machined

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13
Q

what is stacking?

A

have ground ceramic, add heeat making boarders of ceramic fuse so it comes together making fused ceramic

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14
Q

what is glass infusion?

A

there is spaces between the ground ceramic in fused ceramic so you can add glass to fill the voids made

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15
Q

what is hot pressing?

A

like molding, start with negative mold, push ceramic into the mold to create desired shape

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16
Q

what is CNC milling?

A

have a highspeed burr and following computer rendering shapes the ceramic to desired tooth shape

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17
Q

what is additive manufacturing?

A

have a ceramic and lasers and you imprint the geometry you want onto the ceramic

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18
Q

examples of a resin-ceramic material?

A
  • Matrix: Bis-GMA, UDMA, TEGDMA
  • Fillers: Zr-Si, Silica, Zirconia, Alumina
19
Q

why use a resin-ceramic material?

A
  • Easier to fabricate (milling - CAD/CAM)
  • Properties closer to dentin
  • Easier to repair
20
Q

what are the mechanical properties of ceramics?

A
  • High compressive strengths and moduli
  • Low tensile strengths and elongation
  • Stiff and brittle relatively to alloys and polymer
21
Q

The hardness of most glassy or glass-dominated and crystalline ceramics is _______ than enamel

A

substantially higher

22
Q

how can you minimize wear to the enamel surface in antagonist teeth?

A

smooth restoration surface

23
Q

what is CTE?

A

The coefficient of thermal expansion (CTE) is a measure of how much a material expands
per unit length if heated 1C

24
Q

Changes in material temperature results in ________ changes

A

dimensional changes (expansion/contraction)

25
Q

The CTE is important when a ceramic is ______ to another material since can cause ______

A

bonded, failure

26
Q

why is proper CTE matching required between bonded
materials

A

Not all alloys are compatible with all ceramics

27
Q

what is the difference between glassy and crystalline optically?

A

*Glassy phase allows light to pass thru
*Crystalline phase reflects the light (absorbs and
reflects)

28
Q

what is value of ceramics?

A

(amount of lightness of
darkness) is the most critical
parameter to match color

29
Q

what is the corrosion layer of ceramics?

A

loss of mass during service isolates ceramic vs bone

30
Q

what is the difference between all ceramic and porcelain fused metal?

A

metal has metal inside

31
Q

what are the layers of ceramic alloy restoration?

A

alloy, alloy oxide, opaque, gingival ceramic, incisal ceramic

32
Q

what is the purpose of Opaque Porcelain?

A
  • Masks the darkness of the oxidized metal
    framework
  • Establishing Metal-Ceramic bond
33
Q

what is the Gingival and Incisal Ceramics?

A
  • Overlap of ceramics gives natural tooth color
  • Final buildup of dentin/enamel porcelain
34
Q

Alloys are formulated to have an ____ layer

A

oxide layer

35
Q

The bond between ceramic and alloy is a result of chemisorption by diffusion between the surface _______ and _______

A

oxide layer on the alloy and the ceramic (covalent bond)

36
Q

what increased the bond strength between metal and ceramic?

A

roughening the surface (increasing wetting area for porcelain, micromechanical retention)

37
Q

what are some causes for failure of ceramic-Alloy bonding?

A
  • Inadequate oxide layer (too thick, not existing)
  • High thermal residual stresses (large difference in
    thermal expansion coefficients between ceramic and
    alloy)
38
Q
  • Majority of re-treatments are due to biological failures are:
A
  • Secondary caries
  • Tooth failure
  • Periodontal disease
39
Q

All-Ceramic restorations do not have ____ layer

A

oxide (just ceramic core and ceramic veneer layer)

40
Q

the core of an All-Ceramic materia has:

A

Core (replaces alloy):
* High strength ceramic
* Crystalline or crystalline-dominated ceramics formed by
pressing or machining
* Opaque due to crystallinity

41
Q

the outer or veneering ceramic has:

A
  • Glassy or glass-dominated
  • Commonly custom-stacked onto the core in a manner similar
    to that used for ceramic–alloy
  • Great esthetic nature (translucent)
42
Q

All-Ceramic are still relatively _____ materials

A

brittle (Could fracture more often than ceramic–alloy
restorations)

43
Q
A
43
Q

High ceramics have
* ______ thickness required
* _____ cementation compared to PFM
* ____ hardness
* ____ of clinical evidence on the success

A

Greater, complex, high, lack

Dental Materials Second Half Sem (6 decks)

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