All ceramics/cosmetic dentistry courses

Dental CeramicsDental Ceramics
Part II
INDIAN DENTAL ACADEMY
Leader in continuing Dental Education
www.indiandentalacademy.com

Contents
All-Ceramics
Types and processing methods
CAD-CAM
Recent advances
Factors affecting the color of ceramics
Important considerations
Adhesive bonding
Chemical attack by fluorides
Abrasiveness of dental ceramics
• Glazing and polishing
Enhancing clinical performance

All-Ceramic SystemsAll-Ceramic Systems

Indian Dental academy
• www.indiandentalacademy.com
• Leader continuing dental education
• Offer both online and offline dental
courses

Classification
(Philips)
Conventional powder- slurry ceramics
Hi ceram – Alumina reinforced porcelain.
Optec HSP – Leucite reinforced porcelain.
Duceram LFC – Hydrothermal low fusing
ceramic
Castable ceramics
Dicor

Pressable ceramics
IPS empress
Optec pressable ceramic
Infiltrated ceramics
In-Ceram
Computer - aided design/computer-aided
milling (CAD/CAM)
Cerec

CAD/CAM with aluminium oxide
coping
Procera
Machinable ceramics
Cerec vitablocks
Celay blocks
Dicor MGC
Cercon and lava

ALL-CERAMIC
Feldsp
ar
Cast
Glass
ceramic
High
leucite
(Optec
)
Low
leucite
Leucite
(Empre
ss)
Mica
(Dicor)

Core Copy-
milled
block
Cerec/Cel
ay
Al2O3 MgO Magnesi
a
moulded
(Ceresto
re)
Alumina
milled
(Procera
)
Alumin
a (PJC)
Slipcast
(In-
ceram)
Feldspat
hic
overlay
ALL-CERAMIC

Features of newer All-
Ceramic materials
Stronger materials that involve better
fabricating techniques.
Can be etched and bonded to the underlying
tooth structure with newer dentin adhesives.
Greater tooth reduction than what was
previously used for PJC’s is carried out

Conventional powder slurry
ceramics
Processing: Sintering
Aluminous porcelain crowns (PJCs)
Mc Lean and Hughes (1965)
E.g. Hi-ceram, Vitadur N
Made with platinum foil backing which is later
removed
Advantages:
• Better esthetics
Disadvantages:
• Inadequate strength for posterior teeth

Optec HSP
Feldspathic composition glass filled with crystalline
leucite
Leucite reinforced porcelain – 50.6%wt
Increased strength
To reduce mismatch: K ions exchanged for Ru or Ce ions
Uses
• Inlays
• Onlays
• Anterior crowns
• Veneers

Advantages
• More translucent than alumina core crowns.
• Good flexural strength – 146Mpa.
• No special processing equipment
• Lack of metal or opaque substructure.
• Can be etched
• Restorations fit accurately
Disadvantages
• High in vitro wear of opposing teeth
• Potential to fracture in posterior teeth.
• Requires a special die material.

Duceram LFC
Low fusing ‘Hydrothermal’ glass
Leucite free
Less abrasive
Self-healing through ion exchange
Uses:
•Ceramic inlays, veneers
•Full crowns

Advantages:
Good flexural strength (110 MPa) and
fracture toughness
Greater density
Low hardness – less abrasive
Disadvantages:
Needs special die material

Castable Ceramic Systems
Processing: casting through lost wax technique
DICOR
Adair and Grossman 1984
Glass ceramic: a ceramic consisting of a glass
matrix phase and at least one crystal phase
that is produced by the controlled
crystallization of the glass
• Philips 11th
ed.
Casting at 1350˚C

Flourmica glass ceramic:
•SiO2.K2O.MgO.Al2O3.ZrO3
•Fluorides for fluorescence
Ceramming: heat treatment that causes
microscopic platelike crystals of
crystalline material (mica) to grow within
the glass matrix.
•Philips 11th
ed.
Tetrasilicic fluormica crystals
•Dicor 55%
•Dicor MGC 70%www.indiandentalacademy.com

Formation of
crystalline phase:
• Crystal nucleation
• Crystal growth
1075˚C – 10 hrs
Functions:
• Create opacity
• Increase strength and
fracture resistance

Mica
Strength : 120-150 MPa

Advantages:
•Increased strength and toughness
•Good marginal adaptation (30-60 µm)
•Ease of fabrication
•Improved esthetics – Chameleon effect
•Minimal processing shrinkage
•Low thermal expansion
•Minimal abrasiveness to tooth structure

Disadvantages:
•Inability to be coloured internally
•Grinding of restoration may leave white area
•Special investing and casting material
•Technique sensitive

Dicor Plus – feldspathic veneer for dicor crowns
Willi’s Glass Crowns – veneer of Vitadur N
aluminous porcelain
Etching with 10% ammonium bifluoride
2 mm occlusal reduction
1.5 mm axial reduction
Uses:
• Inlays, onlays
• Full crowns
• Cores

Pressable Glass Ceramics
Precerammed glass
ingots
Leucite reinforced
Processing: injection
molding

IPS Empress
Higher Leucite: 23.6% and
41.3%
TEC – 15ppm/˚C
1180˚C, over 45 mins
Stained and glazed or
veneered
Advantages:
• Heat pressing gives
better marginal fit
• Good esthetics
• Moderately high flexural
strength
112 MPa

Disadvantages:
•Potential to fracture in posterior areas
•Need for special equipment
Uses:
•Anterior crowns
•Veneers
•Inlays

IPS Empress 2
Lithium dislicate
(Li2Si2O5) – 70%
Lithium orthophosphate
920˚C
Flex. Strength = 350-400
MPa
Veneering with apatite
glass ceramic
Uses:
• All-ceramic bridges
• Anterior and posterior
crowns
Small, interlocking plate like
crystals. Randomly oriented.

Property IPS Empress IPS Empress 2
Flexural strength
(MPa)
112 400
Fracture toughness
(MPa/m2
)
1.3 3.3
TCE (ppm/˚C) 15.0 10.6
Pressing temp. (˚C) 1180 920
Veneering temp.
(˚C)
910 800

Optec OPC (Optimal Pressable Ceramic)
Leucite reinforced
1150˚C
Advantages:
• Good flexural strength
• Translucent and dense
Disadvantages:
• Increased abrasiveness
• Special equipment required
OPC 3G
Lithia disilicate crystals

Glass Infiltrated Ceramics
Sadoun 1989
In-Ceram Alumina
In-Ceram Spinell
In-Ceram Zirconia
All need veneering ceramics

Processing: slip casting
• Process used to form ‘green’ ceramic shapes by applying a
slurry of ceramic particles and water or a special liquid to a
porous substrate (die material), thereby allowing capillary
action to remove water and densify the mass of deposited
particles.
Philips 11th
ed
Firing at 1120˚C for 10 hrs
Porous substructure infiltrated with molten
sodium lanthanum glass (1120˚C for 4 hrs.)
Increases strength
Reduces porosity of final structure
Increases refractive index

In-Ceram Alumina
70% alumina (Al2O3)
30% sodium lanthanum glass
400-600 MPa flexural strength

Advantages:
• High strength
• Good marginal fit as shrinkage is low
Disadvantages:
• Cannot be etched
• Opaque
• Special equipment and long process
• Abrasive to enamel
• Difficult to remove
Uses:
• Anterior and posterior crowns
• Three unit anterior and posterior bridges

Note:
•Occlusal reduction = 2 mm
•Axial reduction = 1.5 mm
•Heavy chamfer = 1.2 mm
•Sufficient thickness and height of connector
4mm height
Large gingival radius of curvature

In-Ceram Spinel
Spinel – MgAl2O4 (MgO.Al2O3)
Advantage:
•More translucent than ICA
Disadvantage:
•Lower flexural strength than ICA (325-400 MPa)
•Cannot be etched
Uses:
•Single anterior and posterior crowns

In-Ceram Zirconia
30 wt% ZrO2
70 wt% Al2O3
Flexural strength = 700-900 MPa
Advantage: high strength (ceramic steel)
Disadvantage:
• High opacity
• Difficult to remove
Uses:
• Posterior crowns
• Posterior bridges (three unit)

Pure Alumina Core
Procera All-Ceram
Tech Ceram
Processing: dry-pressed powder on an
enlarged die, followed by sintering

Procera All-Ceram
Nobel Biocare, Sweden 1993
99.9% pure alumina
15-20% shrinkage
Method:
• Die scanned by Procera scanner and information sent to lab
• Enlarged die fabricated by CAD-CAM process
• Powder dry-pressed
• Sintered (1600-1700˚C)
• Veneered (All-Ceram)- feldspathic porcelain

Advantages:
• High Flexural strength
• High hardness
• Good marginal fit
• More translucent than infiltrated ceramics
Disadvantages:
• Special equipment and computer software
Uses:
• Anterior and posterior crowns
• Inlays and onlays

Cera-One
Ceramic superstructures for single tooth
implants
Tech Ceram
Impression sent to Techceram Ltd. (U.K.)
Alumina deposited on die using thermal gun-
spray technique
Density 80-90%

CAD-CAM Ceramics
Processing: Computer Aided Designing –
Computer Aided Manufacturing ( or
Computer Integrated Manufacturing)
3 parts:
Camera to take picture of the preparation
•Scanning principle (Optical Impression)
Active triangulation (Cerec 1 and 2)
Double triangulation (Cerec 3)
Computer to design the prosthesis
Milling machinewww.indiandentalacademy.com

Active Triangulation
One Angle

Cerec Systems
Cerec 1 (Siemens Ltd.)
1985
Machine tool – diamond disc
Active triangulation principle of scanning
Advantages:
• Ease of use
• Single appointment
• Wide range of shapes could be milled
Disadvantages:
• Large marginal gaps
• Inability to cut concave areas
• Difficulty of extending veneers into areas of missing toothwww.indiandentalacademy.com

Cerec 2
1994
Tool: diamond disc
Depth scale: 6.4mm
Titanium dioxide powder placed
Infra red 3D scan of preparation
• Resolution of 25 µm
32-bit processor
Color screen
Detailed formation of occlusal pits and fissures were
possible.

Cerec 3 (Sirona Corp.)
2000, 2001
3D scanning (Sirocam)
• Double triangulation principle
• Depth scale > 20mm
Better computing power
• Windows NT and 2000
Computer
• Shock protected hard disk
Radio control
• Eliminates cables

Image processing
• Twin grab board
• Provides vertical
orientation

Form grinding unit
• Cylindrical diamond - 1.6 mm
• Cylindrical diamond with 45º taper on tip – 1.6 mm
• Detailed occlusal design
Time: 24 mins

3 modes:
• Replication
(Extrapolation)
• Correlation
• Function (Antagonist
or Database mode)

Advantages:
• Negligible porosity
• No impression
• Single appointment
• No lab charges
• Reduced assistant time
Disadvantages:
• Expensive equipment
• Lack of occlusal adjustment
• Specialized training
• Technique sensitive nature of imaging

Uses:
•Inlays, onlays
•Veneers
•Crowns and bridges
Cerec InLab system
Laser scanner to scan die

Machinable Ceramics
Processing: CAD-CAM or Copy-milling
Types:
Feldspathic porcelains
• Vita Mark I and II
• Celay
Glass ceramics
• Dicor MGC (Machinable glass ceramic)
70% tetrasilicic fluormica
Others: Procera All-Ceram, Vita Blocs Spinell and
Zirconia, Cercon Base

Celay system – feldspathic porcelains
Copy milling
• Direct
• Indirect
Composite resin pattern made
Traced and shape milled on ceramic
Short processing time – 3-18 mins
Advantages:
• More accurate
• Ease of adjustment

Recent AdvancesRecent Advances

Advancements
All-Ceramics
Fluoride-mica glass and castable glass ceramic
Pressable ceramic
Lithium Disilicate ceramics
Infiltrated ceramics
Machineable ceramics
CAD-CAM ceramics
Metal-ceramics
Ultra-Low fusing ceramics
Captek system

Others…
Shrink free ceramics
Injection molded aluminous core
Magnesia ceramics
Hydroxyapatite ceramics
Hybrid ceramics
PSZ –partially stabilized zirconia
Ormocers
Ceromers

Shrink-free Ceramics
CERESTORE system
Alumina substrate – mixed oxides
α-Al2O3and Mag. Aluminate Spinel (final)
Ca and Be
No alkalis
Chemical and crystalline reactions compensate
shrinkage
Injection molding (direct molding or transfer
molding) technique
Heat stable epoxy die
Pellet heated to flow at 160ºC and injected
Sintered www.indiandentalacademy.com

Magnesia Core Ceramics
High TCE of 14.5 ppm/ºC
Modulus of rupture = 131 MPa
Modified Pt foil technique
Lazar, McPhee and O’Brien
2050ºF 15 mins
Veneered with feldspathic porcelains
Anterior porcelain jacket crowns

Hydroxyapatite Ceramic
Castable Apatite Ceramic
(CERA PEARL)
Hobo and Iwata
CaO.P2O5.MgO.SiO2 glass
ceramic similar to HA
Ceramming – oxylapatite
(Ca10(PO4)6O)
Moisture – stable
crystalline HA
CaO
P2O5
MgO
CaO
SiO2
45%
15%
5%
34%
HA crystal
formers
Decrease
viscosity
Matrix
and
refractory

Hybrid Ceramics
Hahn
Organic and inorganic components
Polyvinyl siloxane 50 vol%
Ti 30%
Inert filler (Al2O3) 15%
Titanium boride 5%
Precursors handled like composite
Firing - 1150ºC for 6 hrs
Veneering with feldspathic porcelains

Partially Stabilized Zirconia
Cercon and Lava
ceramics
Tetragonal zirconia
stabilized with Yttria
(Y2O3)
Processing:
• Copy milling of presintered
zirconia blank
• 20% shrinkage
• Sintering at 1350ºC for 6
hrs
• Veneering with Cercon
Ceram S www.indiandentalacademy.com

Advantages:
High flexural strength >900 MPa
High fracture toughness 9 MPa/m2
Disadvantages:
Opaque
Cannot be etched
Uses:
Anterior and posterior crowns
Bridges

Ormocers
Organically Modified Ceramics or Ormosils
Light-cured Organic-Inorganic copolymers
Admira, Definite
Methacrylate substituted alkosilanes
Silica filler is modified organically by adding
methacrylate groups
Hydrolysis to form Si-O-Si chains
Final matrix: polysiloxane bonded to Bis-GMA

Molecular Wt. = 2000-20,000

Advantages:
Low shrinkage due to high molecular wt.
• 1.88%
Good abrasion resistance
Fluoride release
Good esthetics
Condensable
Biocompatible
Uses:
Fillings in anterior and posterior regions

Ceromers
Ceramic optimized polymer
(light cured)
Tetric Ceram
Targis
23 wt% organic resin, 77 wt%
fillers
Matrix: conventional resin –
silylated organic polymers
Fillers (0.04-3 µm):
Ytterbium trifluoride 80%
Barium alumino fluorosilicate
glass
Spherical silica particles
Pyrolytic silica

Advantages:
Good wear resistance
Good strength
Easily contoured without slumping
Adhesive bonding
Fluoride release (Tetric Ceram)
Disadvantages:
Needs complete isolation
Cannot be used in very high stress regions
Preferably supragingival margins
Uses:
Posterior bridge with single pontic
Inlays, onlays
Implant superstructures
Fillings
Repair of ceramics

Colour in CeramicsColour in Ceramics

CIELab system : Hue, Value and Chroma

Fluorescence in UV light
Metamerism:
Variation in color perception with different light
sources
Dispersion of light varies with wavelength
Select in more than 1 source
Deficiencies of shade guides
Thicker
Non-metal backing
Necks higher chroma

Shade Selection
Patient upright
Shade tab wetted with water
Keep tab upright
Under more than one light source
Daylight
Operatory
Select: hue, value, chroma
Value most important
Spend less than 5 secs on each colour
Rest eyes on neutral or blue background
Consult patient and technician

New
Colour prescription
• Digitized shade
selectors
Colour corrected
lights

ImportantImportant
ConsiderationsConsiderations

Adhesive Bonding
Glass phase ceramics can be etched and
bonded to tooth using resin cements and silane
coupling agents
Resin bonded ceramics
High density ceramics cannot be etched
Aluminous porcelain
Pure and infiltrated alumina cores
Zirconia
Glass infiltrated ceramics
Dual-cured or self cured resin

Chemical attack of glass phase
ceramics by APF
1.23% APF and 8% Stannous Fluoride etch
glass-phase ceramics
Leaching of sod. Ions
Disruption of silica network
Within 4 mins
Problems:
Staining
Plaque accumulation
Degradation
Increased abrasion

Prevention:
Avoid use of APF on ceramics and
composites
Substitute with 2% NaF or 0.4% SnF2
When APF gel used, protect surface with
petroleum jelly, cocoa butter and wax.

Abrasiveness of Dental Ceramics
Highly abrasive to enamel
Mechanisms of abrasion:
Adhesion (metals and composites)
Microfracture (ceramics and enamel)
Factor:
Surface roughness
Glazing and Polishing
Polishing + Glazing > Glazing = Polishing
Philips 11th
ed.
Polishing with 3M soflex discs, shofu rubber points
and with 1 µm diamond paste

Polishing
Indications:
When auto-glaze not possible (after adjustment)
Subgingival extensions
Functional occlusal pathways
CAD-CAM inlays or restorations that will not receive
veneering ceramic
Polishing is preferred over glazing as a
procedure to reduce abrasion damage of
enamel
Philips 11th
ed.

Guidelines for minimizing
excessive wear of enamel
Ensure cuspid-guided occlusion
Eliminate occlusal prematurities
Use metal in functional bruxing areas
If occlusion in ceramics, use ultra-low fusing
porcelains
Polish functional ceramic surfaces
Repolish ceramic surfaces periodically
Readjust occlusion periodically if needed
Philips 11th
ed.www.indiandentalacademy.com

Clinical Performance
Adequate reduction
Occlusal and incisal reduction of 2 mm
Axial surfaces atleast 1 mm
Deep chamfer (120º) or shoulder
1.5-2 mm bulk of material
Adequate connector height and thickness
Failure during cementation
Overextended margins
Ceramic particles
Distortion of impressions
Inadequate occlusal or connector thickness

Million Dollar Smile

All ceramics/cosmetic dentistry courses

Recomendados

Recomendados

Mais conteúdo relacionado

Mais procurados

Mais procurados (20)

Destaque

Destaque (20)

Semelhante a All ceramics/cosmetic dentistry courses

Semelhante a All ceramics/cosmetic dentistry courses (20)

Mais de Indian dental academy

Mais de Indian dental academy (20)

Último

Último (20)

All ceramics/cosmetic dentistry courses

Notas do Editor