All Ceramic Flashcards by Abigail Cook

main reasons to use all ceramics

esthetics
- translucent
color stability
material stability
biocompatibility

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biggest problem

brittle

- dont deform under stress all that much before they catastrophically fracture

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isse with biocompatbility that is over come with all ceramics

mercury free and metal free

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empress is an example of?

low strenght PRESSABLE

- and because of properties it is used more in the anterior

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pressable ceramic examples

empress
OPC
Cerpress
Finesse
Microstar 
Bitapress
Cergo 
Fortress

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improve ceramics through?

MICROSTRUCTURE
- through increase in crystal content

Decreasing the size/ crystal size

network – interconnected materials

phase change – “tranformation toughening”

translucency - chemistry and crystal composition

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empress aka?

flexural strenght and % crystals and dimension

leucite glass ceramic

45% crystal at 10-15 microns with 120 MPa flexural stregth

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emax aka?

flexural strenght and % crystals and dimension

lithium disilicate

70% crystal at 2-7 microns with 380 MPa flexural strength

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Celtra press vs emax and implicaiton

emax= lithium disilicate

celtra press = lithium silicate - reduced crystal size down to /5 microns so improved fracture resistance with 10% wt zirconia reinforced

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*how are esthetics improved with all ceramics?

MORE TRANSLUCENT

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CAD/ CAM stands for?

Computer Aided Design/ Computer Aided Machining

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what is subtractive and what is additive in CAD/CAM components

subtractive –> milling

additive -> printing

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components of CAD/CAM that can affect accuracy

scanner system

bur size

feed rate – milling speed

materials – need to be resistant to damage

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bur size in milling machines?

smaller – more accurate

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two types of chair side cameras

cerec AC bluecam

2. CEREC omnicam

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resolution

ability to distinguish between two points

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shorter wavelength?

HIGHER RESOLUTION

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wavelenght in bluecam

.4 microns - very small

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T/F resolution increases as wavelength decreases?

TRUE

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major differences between omni scan and blue scan

omni = no powder and color

VIDEO
more technique sensitive

blue cam - powder /no color

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why use CAD/CAM

reliable and reproducible *

design 
- virtual 
FABRICATION
material
- NOVEL, GOOD CLINICAN RESULTS

FABRICATION TIME

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implants are placed how? very general and number one rule

restoration driven

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virtually integrated patient?

what we are trying to get to

incooporate a virtual facebow, etc
virtual articulator
basically all scans and movements into one

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TI base restoration options

screw retained full contour one piece

2. screw retained custom abutments with seperate bonded crown

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crew retained custom abutments with separate bonded crown features

flexibility in material combinations / esthetics - compensation for mis-alignment

features of screw retained full contour | how many pieces?

one piece - less steps' - high load bearing capacity - cannot completely adjust for mis-aligned implants

monolithic material definition

formed or composed of material without joints or seams

monolithic material examples

1. feldspathic porcelain 2. glass ceramic 3. composite resin 4. full contour zirconia 5. interpentratingi phase ceramic 6. metals

Q: according to Dr. Giordano the most famous monolith is

A: in 2001: a space odyssey

two examples of poly-crystalline ceramics

1. alumina | 2. zirconia

most dominant material used for CAD/CAM?

Zirconia (at 76%) followed by lithium dislicate with 14%

minimum requirement for four unit posterior with ceramic?

800 MPa

minimum requirement for three unit in posterior with ceramics?

650/ 700 MPa

anterior bridge strength requirement

450 MPa

anterior cemented crowns or posterior cemented crowns strenght requirement

360 MPa?

bonded anterior or posterior crowns strenght requirement

130 MPa

human tooth MPa?

not significant but have great resistance to crack propagation

T/F strength is static

NO -- not static

strength degradation through?

Stress Fluids Foods cement breakdown

*ceramic materials age in the mouth, mechanical properties usually?

DECREASE | - decrease over time

what is the key to success in restorations?

adequate reduction / material thickness requirements maintained

strenght measured in? | fracture resistance measured in?

strength -- MPa Fracture resistance -- Newtons

fracture resistance depends on

size and thickness

ceramic vs concrete in reference to strength vs fracture resistance

ceramic -- stronger (higher MPa) but concrete has higher load / fracture resistance

processing implication

Processing is also a big factor in reliability/reproducibility in the materials that we're using LARGER DEFECTS IN FABRICATED (why CAD/CAM can be seen as an adbvantage) - unavoidalble in fabricated / like hand built

best polished cross section is seen in which processing?

BLOCK - due to the processing is better (vs. pressed or hand built)

crystal re-inforced glass AKA

Dense porcelain blocks

first successful monolithic?

Vita family | - MKII, Triluxe, real life, Feldspathic based

Ivoclar Empres CAD based on?

Empress presable - 45% leucite crystal - improvements in microstructure

first monolithic material

Vita MKII | -developed for Cerec I and used for over 30 years

reduction you likely need for block materials

2mm

describe VITA MKII

over 60 million restorations - feldspathic based - fine crystal reinforced (less than 10 microns) clinical longevity as it resists intra-oral stresses and can be easily polished / glazed --> good finish

flexural strenght of VITA MKII

130-160mpa

challenge with blocks?

they are MONOCHROMATIC - need for enahnced esthetics - so solution would be multi-colored blocks

gradual color change in a block would have what at top / enamel layer and what at bottom / cervical layer

top / enamel layer - low chroma - highest translucency bottom / cervical layer - highest chroma - increased fluoresence (middle/ body is regular chroma)

featuers of Vita Triluxe forte?

four layers with gradual color change

vita "real life" block aims to?

internal dentin and external enamel layer | - layered like a lab crown for improved esthetics

minimum occlusal reduction for MKII empress? use? translucency? bonding? type of material?

2. 0 mm - use for inlay/ onlay/ crown translucency is 70-80 and luted by bonding feldspathic material

how to form conventional glass ceramics

HEAT TREATMENT | - then crystals grow within the glass at the proper crystalizzation temperature

temperature needed to go from metasilicate to disilicate

840 degrees celcius must be held at this temperature long enoiugh to get crystallization

* class ceramic materials like emax require crystallization after machining ??

there might be over-crystallization if the temp is incorrect, tere migt be undercrystallization if the temperature is incorerect, the color might not be correct if the temperature is incorrect ALL OF THESE ARE TRUE!!!

*color change that occurs when you heat treat the block? how?

blue/ purple --> to the tooth color change in electronic status of some of the components - depending on the oxide you are using

what happens if e.max crystallizatoin is not held at teperature for long enough?

needs to be held long enough at 840 degress celcius so you get crystallization IF NOT YOU GET IMPROPER SHADE/ SOLUBLE

use of emax

inlay, onlay,

emax minimum occlusal reduction

1.0 - 1.5

lithium SILICATE is pre-crystal? implication

yes -- so it is a processing advnatage and does not need to be supported

celtra-duo aka lithium silicate minimum thickness? translucency? luting?

1.5 60 translucency lute by bond

emax minimum thickness? translucency? | luting?

1.0 but needs to be bonded translucency - 60

effect of glaze?

better mechanical properties