6. Ceramics in Dentistry Flashcards
we try to mimic natural teeth as close as possible
- One of the things that helps us do that is materials.
- ____
- ____.
composite
ceramics
When it comes to: • \_\_\_\_ • \_\_\_\_ • \_\_\_\_ • \_\_\_\_ Ceramics have some advantages. Must be used for \_\_\_\_ restora?ons. It’s the way to go!
longevity esthetics durability biocompatibility indirect
Ceramics
Term comes from the ____ word.
“of/for ____”
greek
pottery
porcelain - ____, feldspar, ____, kaolin
ceramic - ____ non-metallic solid prepared by the action of ____ (sintering) and subsequent ____
- ____ (= glass) or (partial) ____
The ceramics we use don’t have ____ so he’s doesn’t like the term porcelain.
quartz clay inorganic heat cooling amorphous crystalline clay
ceramic materials
silica-based (____- based, feldspathic porcelain)
high-strength (____-based)
This is why the esthetic features are good:
because they have a high degree of ____
Enamel is almost completely translucent, the shade is determined by the ____ underneath.
glass
oxide
translucency
dentin
Ceramic materials
SILICA
traditions
reinforced feldspathic ceramic
____ glass ceramics
- ____ glass phase
- controlled ____ during firing
SILICA = traditional veneering porcelains.
• Traditional ones are used as veneering porcelain.
• These porcelains or ceramics have a glass phase and a certain crystalline content.
• BUT they’re too ____ to use by themselves
• Normally placed on a ____ or coping to support the ceramics, b/c they aren’t very strong.
polycrystalline amorphous crystallization weak framework
SILICA
feldspar: ____
silic: SiO2 - ____ during firing > provides ____
kaolin: ____; provides ____
• Then we have some metal oxides added to provide opaqueness but also to achieve different colors
• Teeth are not ____, there are translucencies, mamalons and opalescents that we want to
mimic
• That’s why cad cam is helpful but the biggest problem in dentistry is that every tooth is different
• We have to customize it for every patient.
By stacking ____ we can do this
K2O-Al2O3-6SiO2 unchanged stability Al2O3-2SiO2-2H2O opaqueness
monochromatic
porcelain
Silica
raw materials ____ and purified then ____ to form glass
fused glass is “fritted” in water, freezing it in an ____ state
We can:
• ____ it
• mill it from a block of ____
- Ceramic is more ____, not as easy to get the intricacies like translucencies.
- But we don’t stack powders together.
- The ingredients are sintered or melded together then thrown into water < this is Fri$ng
- it freezes it into a amorphous state.
- That frozen amorphous stat ceramic is then crushed in small pieces.
crushed sintered/fused amorphous stack ceramic monochromatic
Silica
ceramic/porcelain powder
- mixed with ____ fluids
- stacked in ____ to mimic tooth
- frit is ground and pigmented with ____ for shade and opacity
- Then they add modifiers and other ingredients like
- ____
- ____ (to provide opacities)
- The ground, pigmented pulverized material can be used to add water or other liquids to provide a slurry that we can stack onto a framework.
- This isn’t the ____ we would ultimately have but a dentist would mix it.
- You can see the base dentin, enamel powders that you mix with water (usually) and stack.
- Once you stack and dry it it goes into a furnace, at a certain temp the mass melts and shrinks.
- It’s a ____ process.
- Not just the shape but the intricacies as well.
water/special
layers
metal oxides
pigments
metal oxides
color
multistep
Ceramic oven/furnace - controlled firing in vacuum
• These are the furnaces and what they look like
• Under a ____ based on the framework and ceramic (they come in different fusing
temperature)
• Ex. Gold alloy (w/ lower melBng T) you can’t use a veneering porcelain that exceeds
that and melts the gold when you fire it.
• This right here, you place the restoraBon on top
• it goes up into the furnace
• Then you program the specific ____ you want for that porcelain to melt under certain
condiBons.
vacuum
heat
Opaque bake
first step creates oxide layer for bonding
- depends on core material
- ____ (precious/non-precious)
- ____ ceramics
Depending on what kind of frame you’re using, for ex.
• Metal > precious or non-precious
• Ceramics (high strength ceramic)
• w/ ____ or zirconium oxide as a core or framework material then to block out the underlying structure (like metal).
• If it’s metal and you didn’t block it out, the metal would shimmer through if porcelain was put on top, it would look grey.
• Step one is to place an ____, then you can recreate natural tooth estheHc parameters.
metal alloys
high-strength
aluminum oxide
opaquer
Selection of veneering ceramic depends on care material
Coefficient of Thermal Expansion (CTE)
____ (e-module)
____
framework design (support!)
Then we can see it looks kind of weird.
• Kind of over “steg?”
• The shrinkage is about 20% so you over build it
• The mammalons are the natural structure of the tooth and dentin so then you fire this
• The selection on the veneering ceramic depends on the core material b/c the CTE has to
match the ____.
• Diff metal alloys have diff CTE that’s why you have to use diff ____.
• If not, they will chip. Read the rest.
• ____ to support the veneering porcelains
• Areas of ____mm of just veneering porcelain it may not be strong enough.
• That’s why we have to design the framework so it can support the porcelain.
modulus of elasticity fracture toughness thermal degree veneering porcelain framework design 3
Dentin bake
- This is what it looks like after the first bake. !
- Now we can make adjustments, like making it not ____.
- Base it on what the pt wants, some ppl like darker teeth or whiter teeth.
- California likes toilet bowl white teeth “
- Check with pt before you give them something they don’t like.
then you do the ____
monochromatic
enamel bake
Silica
High fusing:
2,350 to 2500 F
Medium fusing:
2000 to 2300 F
Low fusing:
____ F
We normally use ____ fusing
1220 to 1950
low
Silica
Polycrystalline glass ceramics
- ____ glass phase
- ____ crystallization during firing
Traditional
Reinforced
Feldspathic
Ceramic
In this group of silica based ceramics we have:
• ____ porcelain (just showed as veneering porcelain)
• ____ reinforced Feldspathic (Empress)
• ____ (IPS e max)
amorphous controlled feldspathic leucite lithium disilicate
SILICA
GLASS BASED CERAMICS: A Simple Graph
• The grey box is the glassy matrix
• During the cooling process, Leucite crystals grow in the ceramic in a ____ manner
• You have a glassy matrix, you fire it, then due to certain (____) chemical components,
crystals grow during the cooling process in the ceramic
• We want to control this
• Want to make sure not too many or too few
• We can do this by changing the ____ component amounts
• This determines how many crystals we have
• they will effect ____ AND ____ properMes.
- Why do we care about more crystals?
- ____ changes and ____ changes
- When a crack happens, it goes through and might be stopped by one.
- So the more crystals, the ____ BUT the less ____.
- The fracture strength isn’t high of the materials.
controlled magnesium chemical optical physical modulus of elasticity fracture stronger translucent
Metal vs. ceramic
E-modulus
brittle ceramics need support
- ____ (metal alloy or high-strength ceramic)
- ____ with composite cement
metal alloys undergo plastic deformation
- ceramics are ____
Modulus of Elasticity (MOE): Huge difference in the fractural behavior in a metal alloy and a ceramic.
• Explained by ____ curve.
• Ex. Metal wire: you can bend ____ times before it breaks.
• Why? b/c metal can undergoes ____.
• What does this mean? It can deform itself before it breaks.
- ____ does not have the physical property of undergoing plastic deformation.
- Ex. Uncooked spaghetti, bend a little and it breaks < just like ceramic. • Why do we care? It effects how the materials act in the oral cavity.
- Ex. We can make metal thin, if you have a heavy bruxer pt you can use ____ and don’t have to worry about it chipping off.
- Ceramic onlay is too thin, it would fracture not to thick!
- Not more than 3mm but normally we use 1-1.5mm.
- Metal alloys undergo plastic deformation but ceramics are ____ < IMPORTANT.
- This is why the brittle ceramics need ____ through a core or resin bonding.
- Resin bonding w/ resin luting agent and pretreatment of tooth and restorative material (ceramic) increases fractural strength.
- Can increase fractural strength of silica ceramic by 50-80% by using adhesive technologies to bond in place.
core
resin bonding
brittle
stress strain
multiple
plastic deformation
ceramics
metal
brittle
support
Ceramic inlays/onlays
Posterior
• We can use them for posterior restora1ons for onlays/inlays.
• As early as possible I want to get you in the mind set of modern den1stry
• For many years there was a direct restora1on of amalgam and composite then we moved into “oh I need
a crown I need a crown” needing a crown.
• But this is trauma1c because we prepare all around the tooth.
• But keep this in mind, our goal is to help people keep their teeth
• Think about alterna1ves, like onlays
• You can s1ll do a crown later on if needed.
• Don’t go the most invasive, and don’t be stupid!
• You can do inlay now and crown later on! More monayy! !!!!
• Think long term, think career, build pt popula1on that will s1ck with you.
• Main reason inlay and onlay aren’t used and taught in this country b/c ____ DOESN’T PAY FOR IT.
Da fuq. “
• That determines the invasiveness of our procedures. “This was totally off topic” mmkthnxbai.
insurance
Ceramic inlays/onlays
Posterior
____% success after 5-7 years
- This could have been a crown in some peoples view
- But no! inalys onlays and consider them later on
- You have to know how do it because the preparaAon and bonding are more complicated
- Don’t just slap a crown on for anything
- We have very high success rates with these
90-100
Silica
leucite reinforced feldspathic “porcelain”
- The next level of ceramics when it comes to strength is Leucite reinforced feldspathic
- Meaning that we change the magnesium content and get more ____ growing in the end during the cooling process.
- All of a sudden we have more ____ available.
crystals
crystals
Silica
leucite reinforced feldspathic “porcelain”
Pressed or milled (CAD/CAM)
• When a crack happens we might be able to stop it
• Could still be brittle but not as much as ____ felspathic porcelain
• At a certain point in time you can’t add more crystals too it
• You can make it as small as you want, this is a good one but typically they are ____, or
milled.
• Normally don’t use the as ____ (veneering porcelain)
• That’s specifically designed for a certain frame.
• Different MOE doesn’t work anymore.
• Empress (brand name) or milled from a block w/ CAD/CAM you can use the block made of
Leucite reinforced feldspathic block.
traditional
pressed
stacking
Ceramic materials
silica
- ____ porcelain (various systems i.e. Nortake, Vita, Ivoclar)
- ____ feldspathic (i.e. IPS empress, ivoclar; C2R press, nortake)
- ____ (IPS e.max, ivociar)
• You can mimic the natural tooth structure with this
• This is a monolithic Leucite-reinforced feldspathic porcelain
• Typically milled or pressed
• Popular product is Emax b/c it’s it in the middle of high strength ceramic and feldceramic
Not for ____ though b/c not strong enough
feldspathic
leucite-reinforced
lithium disilicate
bridges
Ceramic materials
____-infiltrated alumina
densely ____ alumina
____ (procera, lava, katana, zircod, everest, cercon)
GLASS-INFILTRATED ALUMINA
• The glass is not the matrix, but the ____
• Aluminum structure that’s infiltrated w/ glass
• You can’t stack it but you can use as a ____ restoration
• much stronger than conventional ____ based ceramic b/c the alumina is the ____ and the glass is used to fill it in.
glass sintered zirconia filler stand alone silica matrix
Ceramic materials
fracture strength
- Fracture strength is determined by ____ point bending test.
- They see how many mega Pascals it takes to break it.
- ____ is the weakest ~ 104.
- ____ is the strongest.
____
Leucite reinforced feldspathic: Empress
Lithium discilicate: Emax Glass infiltrate alumina Denslicit Alumna? (sp?) ____
3
feldspathic
zirconia
feldspathic
zirconia
ceramic materials
translucency
____ proper$es and the materials go the opposite
• That doesn’t mean that this is never used.
• Doesn’t mean the extremes aren’t ever used (Zirconia vs Feldspathic)
• We use the individual pa
optical translucency
Ceramic mateirals
LEFT: (require \_\_\_\_) high \_\_\_\_ greater \_\_\_\_ lower \_\_\_\_ no \_\_\_\_
RIGHT: (\_\_\_\_) higher \_\_\_\_ greater \_\_\_\_ masking \_\_\_\_ units \_\_\_\_ parts
• Physical proper.es go way beyond fracture strength
• Op.cal proper.es go beyond translucency but these are the most popular.
• Ex. Ask yourself
• Do we need high strength?
• Do we need high translucency?
• W/ out a sub structure the materials on the le# need a resin bonding to get ____.
• The ones on the right are cementable because they are strong enough to retain a ____ without needed anything bond.
• Conven.onal cement is easier b/c you don’t ____ the tooth or the ceramic itself, just
put the glass ionomer, resin modified glass ionomer or self adhesive resin and get good results.
bonding translucency esthetics strength masking
cementable opacity strength multiple implant
support
crown
pretreat
Glass-infiltrated alumina
• This isn’t used much anymore < Glass-infiltrated alumnia
• he added alumina parAcles to his feldspathic silica base ceramic
• At some point it’s saturated and you can’t add more parAcles to it
• Michael Sedune came up with the idea to use an ____
• bring the temperature up to a certain degree to where it’s not completely fluid
and melted but the corners of the parAcles sAck and morph together.
• Making an amorphous mesh.
• Then you have the mesh, infiltrate with a glass and the glass is not the matrix
anymore it becomes a ____.
MUCH STRONGER THAN ____ THAT IS MATRIX
aluminus powder
filler
ceramic
Densely sintered alumina
- Then we had densely sintered alumna where the is no ____ at all
- To fabricate this we needed ____.
- Every ceramic shrinks and the first system that took advantage was…. ____
glass
CAD/CAM
procera
Densely sinter alumina
Procera
scan > design > milling of enlarged die > ceramic powder application > milling
PROCERA PROCESS:
• To use the material as a core (even though it was shrinking so much) they use a trick:
• CAD/CAM scans the die you prepare.
• Scan, then design
• They fabricated an enlarged die
• If you know the ____ it will have when you fire it…make a 20% larger die…apply a powder and fabricate your coping on that.
• Makes sense b/c if you remove the die, fire the coping that’s 20% larger
• it will ____ when you fire it and fit!
• This is called the Procera process
• Then you can put the ____ porcelain on top of it.
volumetric shrinkage
shrink
veneering
Densely sintered alumina
Very high success rates that we can see with this system, but what has happened…
- As we started using ____ (which is stronger) alumina based ceramics went out the door
- This is from 2011 and then PFM was going down, composite not so much
- Lithium Disillicate when up in the lab (no one talked about crown restoraDons)
- Then Full Zirconia has changed how we do things
- The restoraDons we produce are made out full monolithic material of ____ or ____
zirconia
Emax
zirconia
Zirconia
Yttria ____ stabilized zirconium dioxide
Y-TZP = Yttria-____ zirconia polycrystal
- In the beginning we used Zirconia as a framework or coping material
- Instead of the Procera process where you make a large die…you mill them in an ____ stage
- If you use Zirconia (and we don’t use in a green stage) we use in pre-sintered stage when you mill it
- A big huge block of Zirconia is milled out, a framework of pre-sintered Zirconia
- You could do full-sintered but it’s incredibly tough, that’s why we use it in ____-sintered
- It’s like hard chalk but b/c you know it’s going to shrink you make it 20% larger
- After you put in the furnace, you sinter, it shrinks and becomes a fitting restoration
- Then veneered w/ veneering porcelain to the crown.
partially
tetragonal
enlarged
pre
Y-TZP
- Zirconia comes in diff stages and formula3ons
- Typically the par3cles we use are ____-stabilized tegragonic zirconia polycrystal
- We stabilize the tetragonic par3cle with ____.
ytric
ytria
Zirconia
- Once a crack or force from the outside comes into the material, the par5cle changes it’s form into a ____ form that’s slightly larger
- You get a transforma5on of the faces and it will be stopped b/c it is put under compression
- Not really clear how much it changes the fracture strength but this is what we think
- Only happening on the surface in a certain area.
- “Transforma5on toughening or ac5ve crack resis5ng.”
monolithic
Zirconia
Monoclinic
____ Toughening
transformation
No difference between ____ and ____
PFM
PFZ
Bond strength of veneering ceramics to zirconia
- The important point is that the veneering porcelain we use has to be adapted to the material
- We can’t use the same veneering porcelain for ____ alloys that we do for Zirconia.
- ____ Alloys CTE = 12.5-13.
- Zirconia is only 10.
- Veneering porcelain has to be lower than the ____ of the core material that’s why we can’t exchange gold alloy and zirconia.
zirconia
gold
CTE
Fracture toughness of various veneering ceramics
Selecting the ones w/ the right ____ toughness to make sure we’re on the right target
fracture
Zirconia
\_\_\_\_ Fracture toughness coefficient of thermal expansion residual thermal stresses framework design
____ properties and ____ protocols (cooling rate) are key
MoE
veneering material
firing
Zirconia
- ____ is still the most used amongst clinicians
- But in research they can’t find any significant difference b/t PFM and ____ over the years
- The nice thing about it:
- if you want to block out the gold cast and core you use ____ coping that has opacity.
- If you used translucent material the gold would shimmer through.
- So we block out the gold post w/ cast, post and core w/ a less translucent back and stack porcelain on top of it.
- (Shows pictures of gold cast, post and core)
PFM
PFZ
zirconia
METAMERISM:
• Teeth have ____.
• There is an effect called “metamerism” it effects how we see certain teeth.
• You’ll never see fluorescent unless you have a black light at da club. !
• But it effects the ____ of the tooth in natural light.
• Veneering porcelains have certain fluorescents, pigments, and we can modify the ____ to
have more fluorescents
• We also use them for ____ detec2on b/c denEn that’s carious infected does NOT have ____.
• It looks dark when you put the black light on.
fluorescence brightness coping caries fluorescence
PFZ and PFM have the same ____ after 7.4 years
success
Zirconia
Full contour
What has really taken over is Full Contour Zirconia
• This one from Glidewell labs. It goes through the roof when compared to PFM.
• Why? Easier to ____ in CAD/CAM and ____ that PFM.
• Don’t need dental technician to stack the material.
fabricate
cheaper
Zirconia full contour
full-contour zirconia infiltrated with “____” prior to sintering, or “____” with colored glaze (glass), or polished (precolored blanks)
- Not as pretty as stacked in the anterior but certainly for ____ restoration we can use full contour Zirconia restorations.
- You can modify them (NOT by ____ porcelain on top) but by using certain ____ or colorins to get to the nice restoration.
shade modifiers glazed posterior stacking modifiers
High-translucent FCZ
• In the mean)me we are already in the 4th genera)on of Zirconia.
• By changing some of the structure and adding more cubic par)cles we get a more ____
zirconia.
• The increase in zirconia comes at a price, more translucent has a lower ____ than
tradi)onal.
• But light transmission goes up drama)cally w/ the high strength ____ and high ____
zirconia versions we have now.
translucent
fraction strength
ceramic
translucent
Selecting proper ____ and ____ is the first important step…
We have pre-shaded zirconia w/ high translucent version. Shows pictures of teeth. We try to use a monolithic zirconia restoration from a pre shaded blank milled form that to get a roper shade. The size was the problem in this case.
base shade
zirconia blank
CEMENTS
ZOP/GIC RMGIC - full \_\_\_\_ - cast metal/PFM - high-\_\_\_\_ ceramics - \_\_\_\_ bond strength - \_\_\_\_ to use
Self-adhesive resin Composite resin - \_\_\_\_ restorations - retention/seal/strength - \_\_\_\_-based ceramics - \_\_\_\_ bond strength - \_\_\_\_/multiple steps
coverage
strength
low
easy
bonded
silica
high
complicated
