DENTAL CERAMICS Dental Porcelain All-CERAMIC RESTORATIONS dental material

1. DENTAL CERAMICSDENTAL CERAMICS
GenerallyGenerally the wordthe word ceramicceramic is used to name any materialis used to name any material
having bothhaving both metallicmetallic andand non-metallicnon-metallic ions in itsions in its
compositional formulacompositional formula
e.g. cements, gypsum, porcelain and glassese.g. cements, gypsum, porcelain and glasses

2. DENTAL PORCELAINDENTAL PORCELAIN
Dental Porcelain = an early type of dental
ceramics that has been modified to improve
its properties
APPLICATIONS OF PORCELAIN
1. Porcelain denture teeth
2. Porcelain jacket crown
3. Porcelain inlay
4. Porcelain veneer
5. Porcelain fused to metal prosthesis
6. Implant material

3. COMPOSITIONCOMPOSITION
OFOF DENTALDENTAL PORCELAINPORCELAIN
A. Feldspathic porcelain
Fired material is composed of
1. Glassy phase (Vitreous matrix made of feldspars)
 Feldspars are mixture of Anhydrated alumino-silicates
of both…. Potash feldspar = K2O. Al2O3. 6 SiO2 And
.… Soda feldspar = Na2O. Al2O3. 6 SiO2
2. Dispersion of crystalline phase (mineral phase including
silica and other oxides)
Main characters
• Void of kaolin
• Technically it is a glass rather than true porcelain
• They are translucent

4. COMPOSITIONCOMPOSITION
DENTAL PORCELAINDENTAL PORCELAIN
B. Aluminous porcelain
The porcelain material contains 40-50% alumina
crystals (Al2O3) in a low-fusing glass matrix.
High-Ceram
– The dispersed alumina particles are much stronger with
higher modulus of elasticity and coefficient of thermal
expansion than those of the glassy matrix.
– Presence of alumina makes the material opaque. (used
only as coping beneath regular porcelain)
In-ceram alumina
– It is not only a kind of infiltrated glass ceramic, but
also considered as one of the aluminous porcelains.

5. Classification of Dental PorcelainClassification of Dental Porcelain
A. According to their fusion temperatures
1- High-fusing (1300-1400o
C)
2- Medium-Fusing (1100-1300o
C)
3- Low-Fusing (850-1100o
C)
4- Ultra-Low- Fusing (< 850o
C)
1 & 2 are used for denture teeth production
3 & 4 are used for crown and bridge construction
B. According to the method of their firing
1- Atmospheric firing
2- Vacuum firing (lower % of porosity)

6. C. According to their clinical applications
1. Core porcelain:
Used to form the basal layer of jacket crown
2. Dentine or Body porcelain:
More translucent, used to build the body of crowns
3. Enamel porcelain:
The most translucent, used to form the incisal edges
Classification of Dental PorcelainsClassification of Dental Porcelains
Manipulation Of Dental PorcelainManipulation Of Dental Porcelain
(Powder-slurry technique)(Powder-slurry technique)  Watch the videoWatch the video

7. CHARACTERSCHARACTERS OF DENTAL PORCELAINOF DENTAL PORCELAIN
1. Biological Properties:
• Inert has no interaction with surrounding soft tissue
(biocompatible)
2. Interfacial Properties:
• Not adhere chemically to dental cements
3. Chemical properties:
• Not soluble in oral fluids and resist acid attach
• Both hydrofluoric acid and stannous fluoride can cause
an increase in surface roughness
4. Mechanical Properties:
• Brittle
• Low DTS and fracture toughness
• Hard, can cause wearing of opposing dentition

8. CHARACTERSCHARACTERS OF DENTAL PORCELAIN (Cont.D)OF DENTAL PORCELAIN (Cont.D)
5. Thermal Properties:
• Low thermal diffusivity
• Coefficient Of thermal expansion similar to that of
enamel and dentine
6. Esthetic properties:
• Excellent esthetic, and color matching
• Difficult to be stained
7. Practicability:
• Sensitive manipulation technique, Requiring skilled
operator and Special equipments
• Firing shrinkage is always, So operator should build up
the restoration to a bigger size that allows shrinkage

9. Metal-ceramic restorations

10. These restorations are composed of; Metal substructure
(Coping) supporting a ceramic veneer those are chemically
and mechanically-bonded together
Metal-Ceramic RestorationsMetal-Ceramic Restorations
Metal
substructure Opaque
porcelain
Body (dentine)
porcelain
Incisal (enamel)
porcelain

11. Benefits and drawbacks of the metal-ceramicBenefits and drawbacks of the metal-ceramic
restorationsrestorations
Advantages:
1. Stronger than porcelain crowns
2. Can be used for constructing long-span bridges
3. Good esthetic and less liable to staining
4. High wear resistance
5. Long term clinical durability (2.3-7.5 years)
6. Less preparation is required in comparison to all-
ceramic restorations
Disadvantages:
1. Sufficient metal bulk (0.3 mm) is required for proper
rigidity
2. Metal display could result at the thin marginal area
3. Using opaque porcelain is essential to overcome the
metal color
4. Special properties of the metal coping are required for
proper results (see the next section….)

12. Requirements of the metal copingRequirements of the metal coping
1. Has melting temperature higher than the porcelain firing temp. (to
avoid sagging at the time of porcelain firing)
2. Able to form an oxide layer that provides the chemical bond to
porcelain (presence of indium or tin in high noble alloys is essential
for that purpose. e.g gold alloys)
3. Has coefficient of thermal expansion a little bite higher than that
of porcelain (to provide higher mechanical bond)
4. Has no greening effect on the porcelain color
5. High high elastic modulus (E) to resist the bending and the
cracking of porcelain under masticatory force.

13. Bonding of porcelain to the metal copingsBonding of porcelain to the metal copings
1. Mechanical bonding:
- Infiltration (flow) of the fused
ceramic into the surface irregularities
of the metal coping.
- Sandblasting of the metal surface or
using plastic beads during waxing
are important for this issue.
Metal
Porcelain
Oxide layer
Irregularities

14. Bonding of porcelain to the metal copingsBonding of porcelain to the metal copings
2. Chemical bonding:
- Ionic bond between the metal oxide layer and the opaque
porcelain.
- Metal degassing is important for oxide formation, removing the
surface contaminants and greases.
- Thin oxide layer (in case of noble alloys) provides stronger
bond than the thick one (in case of base metal alloys).
3. Coeff. of thermal expansion mismatch:
As a result of higher metal contraction on cooling ,
- The fused porcelain will be sucked (attracted) more strongly
into the metal surface irregularities.
- Residual compressive stresses will developed in and strengthen
the porcelain.

15. 4. Application of a special bonding agent:
Certain metal system (electro-forming) requires the application
of specific bonding paste before building-up the porcelain.
Bonding of porcelain to the metal CopingsBonding of porcelain to the metal Copings

16. Production of Metal copingsProduction of Metal copings
A. Casting of pure metals or metallic alloys
1- Commercially-pure titanium (CP Ti)
2- High gold alloy 3- Gold-palladium alloy
4- Palladium-silver alloy 5- High palladium alloys
6- Nickel- chromium alloy
B. Burnishing and heat treating metal foils on a die
1- Platinum foil 2- Gold foil 3- Captek system
C. Electro-deposition of metal on a duplicate die
D. CAD-CAM processing of a metal ingot

17. All-CERAMIC RESTORATIONSAll-CERAMIC RESTORATIONS

18. Advantages ofAdvantages of
all-ceramicall-ceramic
restorationsrestorations
 Biocompatibility
 Superior esthetic (No metal display)
 Good bonding (cohesion) between the ceramic coping
and the porcelain veneer
 Acceptable mechanical properties
 Superior hardness that provides the restoration its
wear resistance
 Resist the degradation in oral fluids
 Low thermal diffusivity
 Most systems could be used for constructing inlays,
onlays and crowns

19. Disadvantages of all-ceramicDisadvantages of all-ceramic
restorationsrestorations
 High cost of the materials and
the processing equipments
 Excessive tooth reduction is
needed
 Most systems utilize feld-
spathic porcelain coating to
provide the desired color and
contour
 Most systems are not suitable
to construct long span bridge

20. 1. Powder-slurry ceramics
2. Castable ceramics
3. Machinable ceramics
4. Pressable ceramics
5. Infiltrated galss ceramics
Families of all-ceramicFamilies of all-ceramic
restorationsrestorations

21. 1.1. Powder-slurry ceramicsPowder-slurry ceramics
The material presents as powder to be mixed
with liquid forming a slurry that is used to build
the restoration up
e.g. (1) Optec HSP, (2) Duceram systeme.g. (1) Optec HSP, (2) Duceram system

22. 2. Castable ceramics2. Castable ceramics
Ceramic ingot is fused and cast in a
refractory (investment) mold made
by the lost wax technique
e.g. (1) Dicor, (2) Dicor Plus, (3) Castable Apatitee.g. (1) Dicor, (2) Dicor Plus, (3) Castable Apatite

23. 3. Machinable ceramics3. Machinable ceramics
CAD- CAM technology
 The prepared tooth is optically impressed (pictured
using intra-oral camera). The restoration is design over
that image by the aid of computer……Then
 Ceramic blocks are carved into restorations by the aid
of computer-controlled milling machine
e.g. (1) Cerec Vitablocks-mark I, (2) Cerec Vitablocks-mark II,e.g. (1) Cerec Vitablocks-mark I, (2) Cerec Vitablocks-mark II,
(3) Dicor MGC Blocks(3) Dicor MGC Blocks

24. CAD-CAM Technology

25. 3. Machinable ceramics3. Machinable ceramics
Copy-Milling technology
 The prepared tooth is impressed poured in gypsum
to form a die.
 A wax pattern is built over the die……Then Ceramic
blocks are carved into restorations by the aid of
computer-controlled milling machine that is guided by
the constructed wax patter
e.g. (1) Celay blocks (2) Lava Zerconia, (3) Cercone.g. (1) Celay blocks (2) Lava Zerconia, (3) Cercon

26. Copy-milling Technology

27. 4. Pressable ceramics4. Pressable ceramics
Ceramic ingots are softened by heat and
pressed into a refractory mold using
special alumina injector
e.g. (1) Optec Pressable Glass Ceramic, (2) IPS Empress ,(3) Empress 2,e.g. (1) Optec Pressable Glass Ceramic, (2) IPS Empress ,(3) Empress 2,
(4) IPS e.max press(4) IPS e.max press

28. 5. Infiltrated glass ceramics5. Infiltrated glass ceramics
A porous crystalline slip is
formed by fusion of
Metallic particles at high
temperature.
A Glass coat is then fused
over the porous slip to
infiltrate into the pores and
strengthen the structure.
Veneering porcelain is then
required to provide the
desired shade and contour
e.g.(1) In-Ceram Alumina, (2) In-Ceram Spinel, (3) In-Ceram Zerconiae.g.(1) In-Ceram Alumina, (2) In-Ceram Spinel, (3) In-Ceram Zerconia