1. CERAMICS
By:
DR. BHARTI DUA
PG IST YEAR1

2. CONTENTS
1.INTRODUCTION
2.HISTORY
3.CLASSIFICATION
4.COMPOSITION
5. STRENGTHNING MECHANISM OF CERAMIC
6. PROPERTIES
7. SHADE MATCHING GUIDELINES
2
8. METAL CERAMIC SYSTEMS

3. 9.ALL CERAMIC SYSTEM
10.CRITERIA FOR SELECTION AND USE OF
DENTAL CERAMICS
11.RECENT ADVANCES IN CERAMIC
12. REFERENCES
13.CONCLUSION
3

4. INTRODUCTION
4

5. DEFINITION1
Ceramics : compounds of one or more metals with a
nonmetallic element, usually oxygen. They are formed of
chemical and biochemical stable substances that are
strong, hard, brittle, and inert nonconductors of thermal
and electrical energy1 – G.P.T-8
5

6. PORCELAIN1
 A ceramic material formed of infusible elements joined
by lower fusing materials. Most dental porcelains are
glasses and are used in the fabrication of teeth for
dentures, pontics and facings, metal ceramic restorations
including fixed dental prostheses, as well as all-ceramic
restorations such as crowns, laminate
veneers, inlays, onlays, and other restorations.G.P.T-8
6

7. HISTORY
7

8. HISTORY2,3,4
 Historically, three basic types of ceramic materials were
developed;
 Earthernware, Stoneware, & Whiteware.
8

9.  In 700 B.C. the Etruscans made teeth of ivory and bone
that were held in place by a gold framework.
 By the 10th century A.D, ceramic technology in China
had advanced to a highly sophisticated stage.
 As trade with the far east grew, this infinitely superior
material came to Europe from China, during the 17th
9
century.

10. HISTORY
 In 1717, a Jesuit missionary Father d’Entrecolles
leaked the secret of Chinese porcelain and passed it on to
M. de Reamer
 1728 – Pierre Fauchard, a French dentist first proposed
the use of porcelain in dentistry.
 By 1825- Samuel Stockton began fabrication of fused
porcelain teeth in Philadelphia. 10

11. HISTORY
 A significant improvement in the fracture resistance
of porcelain crowns was reported by Mc1ean and
Hughes in 1965 when a dental aluminous core
ceramic was used.
 1983-84 – the first castable glass ceramic was introduced
by Grossman and Adair called DICOR
 1985 – CAD/CAM technique was developed by
Mormann and Brandestini
11

12.  The future of dental ceramics is bright because the
increased demand for tooth-colored restorations will
lead to an increased demand for ceramic- based
restorations.
12

13. CLASSIFICATION
13

14. CLASSIFICATION OF DENTAL
CERAMICS2
According to use:
 Anterior bridges
 Posterior bridges
 Crowns
 Veneers
 Post and cores
 FPDs
 Stain ceramic
 Glaze ceramic
14

15. According to composition:
 Pure alumina
 Pure zirconia
 Silica glass
 Leucite-based glass ceramic
 Lithia-based glass ceramic
15

16. According to processing methods:
 Sintering
 Casting
 machining
16

17. According to translucency:
 Opaque porcelain
 Dentin porcelain
 Enamel porcelain
17

18. Acccording to firing temperature.3,5
1. High-fusing: 1,290 to 1,370°C
2. Medium-fusing: 1,090 to 1,2600C
3. Low-fusing: 870 to 1,065oC
OR2
1. High fusing 13000C
2. Medium fusing 1101-1300oC
3. Low fusing 850-11000C
4. Ultra-low fusing - <8500C 18

19. STRUCTURE AND
COMPOSITION
19

20. STRUCTURE AND COMPOSITION
Porcelain :
 Refer to specific range of ceramic materials made by
mixing
kaolin quartz feldspar
20

21. COMPOSITION OF FELDSPATHIC
PORCELAIN2,3,5
1. Feldspar - 60 to 80% - Basic glass former
2. Kaolin - 3 to 5% - binder
21

22. 3. Quartz - 15 to 25% - Filler
4.Oxides of Na, K,Ca - 9 to 15% -Fluxes
(glass modifiers)
22

23. 7. Alumina - 8 to 20% - Glass former and flux
8. Metallic pigments - <1% - Color matching
Ferric oxide, platinum Grey.
Chromium oxide, copper oxide Green
Cobalt salts Blue
Ferrous oxide,nickel oxide Brown
Titanium oxide Yellowish brown
Manganese oxide Lavender
Chromium tin, Chromium alumina Pink 23
Indium Yellow, ivory

24. 9.Opacifying agents
The common metallic oxides used are –
• Cerium oxide,
• Titanium oxide,
• Tin oxide, and
•Zirconium oxide (ZrO2)
24

25.  The typical high-fusing porcelain is composed of
feldspar (70% to 90%),
quartz (11% to18%),
kaolin (1% to 10%)
Medium fusing porcelain has 64.2% silicon dioxide
19% aluminium oxide
Low fusing porcelain has 69.4% silicon dioxide
8% aluminium oxide
25

26. STRENGTHENING MECHANISM
OF CERAMICS 2
26

27. ( Development of residual compressive
stress)
 Ion exchange
 Thermal tempering.
 Thermal compatibility
And
( Interruption of crack propagation )
 Dispersion of crack propagation 27
 Dispersion of crystalline phase

28. Ion Exchange
 The ion-exchange process is sometimes called chemical
tempering.
 When a sodium containing glass article is placed in a bath
of molten potassium nitrate, potassium ions in the bath
exchange places with some of the sodium ions in the
surface of the glass article and remain in place after
cooling.
28

29. THERMAL TEMPERING
 It is done by rapidly cooling (quenching) the surface
of the object while it is hot and in the softened
(molten) state.
 As the molten core solidifies, it tends to shrink, but
the outer skin remains rigid.
 The pull of the solidifying molten core, as it
shrinks, creates residual tensile stresses in the core
and residual compressive stresses within the outer
surface.
29

30. THERMAL COMPATIBILITY
 Ideally the porcelain should be under slight
compression in the final restoration.
 Select an alloy that contracts slightly more than the
porcelain on cooling to room temperature.
30

31. DISPERSION OF CRACK
PROPAGATION
 Ceramic can be reinforced with a dispersed phase
of a different material that is capable of hindering a
crack from propagating through the material.
31

32. DISPERSION OF CRYSTALLINE
PHASE
 When a tough , crystalline material is added to
glass, the glass is toughned and strengthened
because the crack can not penetrate the added
crystalline particle.
32

33. PROPERTIES
33

34. STRENGTH3
Alumina based ceramic
Flexural Strength-139 MPa
Shear Strength -145 MPa
Leucite-reinforced feldspathic porcelain
Flexural Strength-104 MPa
34

35. ABRASION RESISTANCE2
 Natural tooth - 343 KHN
 Porcelain 460 – KHN
Hence , it causes wearing
of natural tooth and metal
restorations
35

36.  Enamel wear by ceramics may adversely affect maintenance
of the vertical dimension of occlusion and can increase the
potential for thermal sensitivity.
 Based on the literature, it can be concluded that material
factors, their proper handling, and control of the patient's
intrinsic risk factors related to wear are critically important for
the reduction of enamel wear by dental ceramics.
Oh WS, Delong R, Anusavice KJ.Factors affecting enamel
and ceramic wear: A literature review.J Prosthet Dent
2002 Apr;87(4):451-9 36

37. SHRINKAGE3
 Volumetric shrinkage – 28-37% - low fusing porcelain
28-34% - high fusing porcelain
 Linear shrinkage - 14 % - low fusing porcelain
11.5%- high fusing porcelain
37

38. COEFFICIENT OF THERMAL EXPANSION (CTE)3
 CTE should match tooth structure to minimize
shrinkage .
 CTE should be slightly lower than that of the casting
alloy keeping the porcelain in residual compression
upon cooling from firing temperatures.
 CTE: 12-13X 10-6/oC
38

39. Properties necessary for use of ceramics in the
fabrication of dental
restorations5
1. Low fusing temperature
2. High viscosity
3. Resistance to devitrification
39

40. COLOUR STABILITY
 Ceramics are the most stable tooth coloured materials .
 The metallic oxides used as colorants do not undergo
any change in shade after firing is complete .
40

41. SHADE MATCHING GUIDELINES 2,4
 Three factors upon which color is dependent:
(1)the observer,
(2) the object,
(3) the light source.
41

42.  The selection of tooth or restorative shades should be
done at the start of a clinical session before the
operator’s eyes become fatigued.
 Have the patient remove lipstick, heavy makeup or large
jewelry that may influence the color perception.
 Do not use operatory light for shade selection.
42

43.  Ideally the clinician should use illumination of northern
light from a blue sky.
 Sunlight near the window can be used.
43

44. CRISTOPHER CK.SHADE SELECTION.AUST
DENT PRAC. 2007;116-119
44

45.  Hold the appropriate shade tab near the tooth to be restored
, party covered with the patient’s lip.
 Shade selection should be done quickly within 30 seconds
45

46.  Try to select the basic hue of the tooth by matching the
shade of the patient’s canine, usually the most highly
chromatic tooth in the mouth.
 With the correct hue group selected, work within the
group on the shade guide to obtain the proper match.
46

47.  Another factor that is important to the aesthetic
qualities is the cementing medium.
 For example, an opaque material such as zinc
phosphate cement, can change the shade of a
translucent crown because of its light absorption and
its color.
47

48. CRISTOPHER CK.SHADE SELECTION.AUST
DENT PRAC. 2007;116-119
48

49. DENTAL CERAMICS:
METAL CERAMICS ALL CERAMIC
49

50. METAL CERAMICS
Mechanical properties Esthetic properties
Metal Ceramic

51. REQUIREMENTS FOR A METAL-
CERAMIC SYSTEM 2
 High fusing temperature of the alloy.
Low fusing temperature of the ceramic.(difference should
not be more than 100oC.)
 The ceramic must wet the alloy readily .
 Adequate stiffness and strength of alloy core.
 An accurate casting metal coping is required.
 Adequate design of restoration is critical.
51

52. REQUIREMENTS2
 Ceramic must have coefficient of thermal
contraction closely matching to that of alloys.
The optimum difference between the two
should not be greater than 1 x 10-6/°C.
 Metal oxide is necessary to promote bonding .
 High melting ranges for gold alloys are necessary
to prevent sag, creep, or melting of the coping
during porcelain firing cycle. 52

53. M E TA L C E R A M I C A L L O Y S
53

54. BONDING PORCELAIN TO METAL2
 Success of a metal ceramic restoration is the
development of a durable bond between the
porcelain and the alloy.
Theories of
metal ceramic
bonding :
Mechanical Chemical
interlocking bonding
54

55. Bond failure classification: O’Brien
Type I: Metal porcelain:
• When the metal surface is totally depleted of oxide
prior to firing porcelain, or
• When no oxides are available
• Also on contaminated porous surface.
Type II: Metal oxide- porcelain:
• Base metal alloy system.
• The porcelain fractures at the metal oxide surface
leaving the oxide firmly attached to the metal.

56.  Type III: Cohesive within porcelain:
• Tensile fracture within the porcelain when the bond
strength exceeds the strength of the porcelain.
 Type IV: Metal- metal oxide:
• Base metal alloys
• Due to the overproduction of Ni and Cr oxides
• The metal oxide is left attached to ceramic.
56

57. 5.Type V: Metal oxide- Metal oxide
•Fracture occurs through the metal because of the
overproduction of oxide causing a sandwich between
porcelain and metal
6. Type VI :Cohesive within metal
•Unlikely in individual metal ceramic crowns.
•Connector area of bridges.

58. FABRICATION OF A METAL CERAMIC
RESTORATION2,3,4
58

59. METAL PREPARATION 4 –
 Sharp angles or pits on the veneering surface of metal-
ceramic restoration should be avoided .
 Convex surfaces and rounded contours should be
created so that the porcelain is supported without
development of stress concentration.
 The intended metal-ceramic junction should be as definite
( 90 0 ) and as smooth as possible.
 The metal framework should be sufficiently thick to
prevent distortion during firing.( min 0.3 mm for noble
metals & 0.2 mm for base metals)
59

60.  Metal Preparation
To establish a chemical bond between
metal and porcelain , a controlled oxide
OXIDIZING layer must be created on the metal
surface.
The oxide layer is obtained by placing the
substructure on a firing tray , inserting it
into the muffle of a porcelain furnace and
raising the temperature to a specified
level that exceeds the firing temperature
of porcelain.
60

61. CONDENSATION
 The process of packing the powder particles together and
removing excess water is known as condensation.
 During this step , the porcelain powder is mixed with
distilled water or any other liquid binder and applied on the
metal substrate in subsequent layers.
61

62. METHODS OF CONDENSATION
 VIBRATION Method
 SPATULATION Method
 BRUSH Method
 ULTRASONIC Method
 GRAVITATIONAL Method
62
 WHIPPING Method

63. CERAMOSONIC CONDENSER
ULTRASONIC CONDENSING UNIT FOR PORCELAIN
BUILD-UP
63

64. Condensing porcelain
 1. Build up porcelain using a brush or spatula and
set the tweezers against the vibrating platform
intermittently. Remove the moisture leaking up out
of the porcelain with a tissue paper.
64

65. CONDENSATION
 Opaque porcelain application
Opaque porcelain is applied first to mask the metal, to give the
restoration its basic shade, and to initiate the porcelain-
metal bond.
65

66.  No attempt should be made to thoroughly mask the metal with
this initial application.
 It is intended to completely wet the metal and penetrate the
striations created by finishing.
 The coping is dried and fired under vacuum
 The second application of opaque porcelain should mask the
metal .
 The powder and liquid are mixed to a creamy consistency and
applied to the coping with a brush in a vibrating motion.
 opaque porcelain is condensed to a thickness of O.3mm and
fired.
66

67. Dentin and Enamel Porcelain Application
 Mix dentin porcelain to a creamy consistency with
distilled water or the manufacturer's recommended
liquid.
 Then apply it over the opaque with a sable brush or
small spatula, starting at the gingivofacial of the
coping, which is seated on the working cast.
67

68.  First develop the full contour of the crown in dentin
porcelain with a brush. Vibrate the porcelain to
condense it, absorbing the liquid with tissue.
 The completed buildup should be over contoured .
 When the porcelain is condensed and dried to a
consistency of wet sand, carve the dentin back to allow
the placement of the enamel porcelain.
68

69.  Apply the enamel porcelain to restore the full
contour of the restoration.
 When completed, the restoration should be slightly
larger incisally to compensate for the shrinkage .
 Overall, make the crown about one-fifth larger than
the desired size to compensate for the 20%
shrinkage that will occur during firing .
69

70. FIRING
 Firing is carried out for fusing (sintering) the porcelain.
 The compacted mass is placed on a fire clay tray and inserted
into the muffle of the ceramic or porcelain furnace.
PREHEATING
 It is first placed in front of the muffle of a preheated furnace and
later inserted into the furnace(5 min)
 If placed directly into the furnace, the rapid formation of steam
can break up the condensed mass. 70

71. TYPES OF FIRING
 AIR FIRING
 VACCUM FIRING
 GAS FIRING
71

72. HOW VACUUM FIRING REDUCES POROSITY 2 –
 When the porcelain is placed in the furnace , the powder
particles are packed together with air currents around
them.
 As the air pressure inside the furnace muffle is reduced to
about one-tenth of atmosphere pressure by vacuum pump,
the air around the particles is also reduced to this
pressure.
 As the temperature rises, the particles sinter together, and
closed voids are formed within the porcelain mass.
 The air inside these closed voids is isolated from furnace
atmosphere.
72

73.  At a temperature of about 55OC, below the upper
firing temperature, the vacuum is released and the
pressure inside the furnace increases a factor of
10, from 0.1 to 1 atm.
 Because the pressure is increased by a factor of
10, the voids are compressed to one-tenth of their
original size, and the total volume of porosity is
accordingly reduced.
 Not all air can be evacuated from the furnace
, therefore a few bubbles are present in vacuum
sintered porcelains, but they are markedly smaller
than the ones obtained by air firing. 73

74. TEMPERATURE TIME
OXIDATION 9300C 15 MIN
BASE PASTE 960OC 19 MIN
SHADE PASTE 975OC 16 MIN
74

75. TEMPERATURE TIME
DENTINE 9350C 19 MIN
ENAMEL 935OC 19 MIN
GLAZE 930OC 11 MIN
75

76. COOLING
 Too rapid cooling of outer layers may result
surface crazing or cracking; this is also
called thermal shock.
 Slow cooling is preferred, and is
accomplished by gradual opening of the
porcelain furnace.
76

77. PORCELAIN SURFACE TREATMENT 5
 Once the desired contours and occlusion have been
achieved, the restoration must receive a surface
treatment i.e glazing
GLAZING -
 After firing, Porcelains are glazed to a glossy surface.
 It enhances strength, esthetics and hygiene.
 Glazed porcelain is much stronger than unglazed.
 The glaze is also effective in reducing crack
propagation.
77

78. TYPES OF GLAZE –
1. Self glaze
 Porcelains can be self glazed by heating under controlled
condition, i.e. it is heated to its fusion temperature and
maintained for 5 minutes.
 it causes only the surface layer to fuse and flow over the
surface to form a vitreous layer called glaze.
 Chemical durability of self glaze is better than over-glaze.
2. Over glaze
 The glaze powder is mixed with liquid, applied over the
smoothened crown and fired at temperature lower than
that of body.
 But it should be avoided because it gives -
 Unnatural appearance
 Loss of contour and shade modification
78

79. ALL CERAMIC SYSTEM 79

80. Classification of all ceramic systems.
GLASS CERAMICS
SINTERED CERAMICS
SLIP CASTING CERAMICS
HOT PRESSED/INJECTION MOLDED
MACHINABLE CERAMICS

81.  CASTABLE/ GLASS CERAMICS
81

82. Glass Ceramics.
Mica based: Dicor
Hydroxyapatite based: Cerapearl
Lithia based: Experimental.
82

83. Glass ceramic: Is a ceramic consisting of a glass
matrix phase and at least one crystal phase that is
produced by the controlled crystallization of the glass.
These ceramics are supplied as ceramic ingots which
are used to fabricate the restoration using a lost wax
and centrifugal casting technique.
DICOR was the first commercially available castable
ceramic material for dental use.
This has a glassy matrix and a crystalline phase.

84. MICA BASED GLASS CERAMICS
DICOR
Developed by The Corning works and marketed by
the Dentsply.
International Term DICOR is the combination of the
manufacturer's names.
DICOR is a castable polycrystalline fluoride
containing tetrasilic mica glass ceramic
material, initially cast by lost wax technique and
subsequently heat treated resulting in a controlled
crystallization to produce a glass ceramic material.

85. COMPOSITION
 SiO2-45-70%
 K2O- 20%
 MgO- 13-30%
 55% vol of tetrasilicic flourmica crystals
increased strength and toughness
increased resistance to abrasion
thermal shock resistance
chemical durability
85
decreased translucency

86. Supplied as –
 DICOR castable ceramic cartridges
 Special DICOR casting crucibles each contain a 4.1 gm DICOR
ingot
 and DICOR shading porcelain kit.
EQUIPMENT REQUIRED –
1. DICOR Casting machine
2. DICOR Ceramming furnace with ceramming Trays.
86

87. FABRICATION OF CASTABLE CERAMICS RESTORATION
CONSISTS OF MAINLY 2 STEPS –
1. CASTING –
The glass liquefies at 13700C to such a degree that it can
be cast into a mold using lost-wax and centrifugal casting
techniques.
The wax pattern of the proposed restoration made on the
model/die is invested in Castable ceramic investment in a
double line casting ring and burned out in a conventional
burnout at 9000C for 30 minutes.
87

88.  Glass ingots of castable ceramic material is
placed in a special zirconia crucible and
centrifugally cast in a electronically controlled
DICOR casting machine maintaining the spin
pressure for upto 4 minutes and 30 seconds.
 Transparent glass casting obtained is
amorphous and fragile.
88

89. 2.CERAMMING –
The cast glass material is subjected to a single –step
heat treatment called as “Ceramming” to produce
controlled crystallization by internal nucleation and
crystal growth of microscopic plate like mica crystals
within glass matrix.
89

90. METHOD –
Transparent casting is embedded in castable
ceramic embedment material ( gypsum-based ) and
placed in a Ceramming tray in the DICOR
Ceramming furnace.
CERAMMING CYCLE –
6500C-10750C for 1.5 hrs and sustained upto 6 hours.
90

91. Difference between Dicor and Dicor
MGC(machinable glass ceramic)
Dicor Dicor MGC
55%vol of tetrasilicic 70% vol of tetrasilicic
fluoramica crystals. flouramica crystals which are
2 µm in diameter
Crystallization done by the Higher quality product that is
technician. crystallized by the
manufacturer and provided
as cadcam blanks or ingots.
Mechanical properties Less translucent than Dicor.
similar.

92. Advantages of Dicor:
1) Uniformity and purity of the material.
3) Minimal processing shrinkage.
4) Good fit.
5) Low CTE equal to that of the tooth structure.
6) Minimal abrasiveness to the tooth structure.
7) Radio opacity like dentin.
8)Moderately high flexural strength.(152 MPa)

93. Disadvantages of DICOR
• OPAQUE due to the presence of mica: Chamaleon
effect
the transparent crystals scatter the incoming light. The light
and also its color, is distributed as if the light is bouncing
off a large number of small mirrors that reflect the light and
spread it over the entire glass-ceramic.this property is called
CHAMALEON effect.
•Low tensile strength.
•Inability to be colored internally
•Labour intensive
•High cost
Indications
Inlays, Onlays ,partial tooth coverage

94. HYDEROXYAPETITE BASED CASTABLE GLASS
CERAMICS :
Cerapearl
COMPOSITION
 CaO- 45%
 P2O5- 15%
 Mg2O- 5%
 SiO2- 35%
94

95. PROPERTIES OF CERAPEARL –
 CASTING SHRINKAGE is 0.53%
 COEFFIECIENT OF THERMAL EXPANSION is
11.0 X 10-6/0C
 Melts at 14600C and flows like a melting glass.
 The cast material has an amorphous microstructure
when reheated at 8700C forms crystalline
Hydroxyapetite.
 Biocompatible: Crystalline structure similar to
enamel.
 Modulus of rupture :150 Mpa. 95

96. S
SINTERED ALL-CERAMIC
MATERIALS2,3
96

97. SINTERED CERAMICS
Leucite- reinforced feldspathic porcelain: Optec
HSP
Aluminous based porcelain( Pt foil):
Vitadur- N TM core
Alumina based porcelain: Hi ceram
Magnesia based feldspathic porcelain(
Experimental)
Zirconia based porcelain: Mirage II
Hydrothermal low fusing Ceramics:
Duceram LFC.

98. SINTERED ALL-CERAMIC MATERIALS2,3
 Supplied as powders which can be mixed with
water to form a slurry.
 This slurry can be built up in layers on a refactory
die to form the restoration.
 The powders are avaliable in different shades and
translucencies.
 These sintered ceramics are thus similar to the
conventional feldspathic porcelains in their method
of fabrication.
 However they are stronger as they are reinforced
by crystalline phases.
98

99. Alumina-Based Ceramic
Mclean and hughes (1965)
developed Alumina
reinforced porcelain core
99
materials

100. ALUMINOUS CORE CERAMICS
 They advocated using aluminous porcelain, which is
composed of aluminum oxide (alumina) crystals dispersed in a
glassy matrix.
 The technique devised by McLean used an opaque inner core
containing 50% by weight alumina for high strength.
 This core was veneered by a combination of esthetic body and
enamel porcelains with 15% and 5% crystalline
alumina, respectively and matched thermal expansion.
10
0

101.  The resulting restorations were approximately 40%
stronger than those using traditional feldspathic
porcelain.
Why Alumina?
 Good Mechanical properties.
 Interfacial region between alumina and porcelain
virtually stress free.
 Crystals rather than fine powdered alumina used.
 High modulus of elasticity( 350 Gpa)
 High fracture toughness( 3.5 to 4 Mpa).
 Significant strengthening of the core.
10
1

102.  Advantages of aluminous porcelains:
 Increased flexural strength,
 Increased elasticity and toughness.
 Disadvantages of Aluminous porcelain
 Extensive reduction, dentin preparation.
 Bonding is limited.
 High failure rates.
10
2

103. LEUCITE REINFORCED FELDSPATHIC PORCELAIN
 In this type , the leucite crystals ( Potassium aluminium
Silicate) are dispersed in a glass matrix.
 The leucite and glass components are fused together
during baking process at 10200C.
 Leucite concentration 50 % wt.
 Eg .Optec HSP( Jeneric/ Pentron)
 Higher modulus of rupture and compressive strength.
 Does not require core unlike aluminous PJC.
10
3

104. Lack of metal or opaque substructure,
Good translucency compared to alumina
crowns.
Advantages: Moderate flexural strength( 146 Mpa),
Ability to be used without special laboratory
equipment.
Can be etched.
Marginal inaccuracy caused by sintering
shrinkage.
Disadvantages: Potential to fracture in posterior teeth.
Increased leucite content :relatively high
invitro wear of opposing teeth.
Requires a special die material.
Uses: Inlays, onlays, crowns for low stress areas and
veneers

105. Magnesia based core ceramic 6
•High expansion core material.
•CTE :magnesia 13.5 x10-6/0C.
Strengthening:
Dispersion strengthening by the magnesia crystals
in a vitreous matrix.
Crystallization within the matrix.( Precipitation of
fosterite crystals.)

106. Magnesia based core porcelain 6
Advantages High CTE:
Same body and enamel porcelains used for
PFM crowns can be used for all ceramic
Flexural strength of magnesia core :131
Mpa
Twice as high as feldspathic porcelain( 65
Mpa).
Esthetics superior to PFM.
Disadvantages Not used for fixed partial dentures.

107. Zirconia based feldspathic porcelains ( Sintered) 6
Mirage II( Myron International, Kansas
City).
Tetragonal Zirconia fibers
Advantages –
•Fracture toughness
•Thermal shock resistance
Disadvantages:
Properties such as translucency and fusion
temperature can be adversely affected.

108. 108

109. Slip Cast Ceramics
Alumina based( In- Ceram)
In – Ceram Spinell
In – Ceram Zirconia
In- Ceram 2000.
109

110. SLIP CAST ALL CERAMIC MATERIALS2
Slip-casting involves the condensation of an
aqueous porcelain slip on a refractory die. The
porosity of the refractory die helps condensation by
absorbing the water from the slip by capillary
action.
110

111. SLIP CASTING _
 Is a process used to form “green” ceramic shapes by
applying a slurry of ceramic particles and water or a
special liquid to form a porous substrate( such as die
material), thereby allowing capillary action to remove
water and densify the mass of deposited particles.
Green state –
 refers to an as- pressed condition before sintering.
11
1

112.  The starting media in slip-casting is a slip that is an aqueous
suspension of fine alumina particles in water with dispersing
agents.
 The slip is applied onto a porous refractory die, which
absorbs the water from the slip and leads to the condensation
of the slip on the die.
 The piece is then fired at high temperature (1150° C).
 The refractory die shrinks more than the condensed
slip, which allows easy separation after firing.
11
2

113.  The fired porous core is later glass-infiltrated, a
unique process in which molten glass is drawn into
the pores by capillary action at high temperature.
 Materials processed by slip-casting tend to exhibit
lower porosity and less processing defects than
traditionally sintered ceramic materials.
113

114. In ceram is provided as one of the three core ceramics
 In-ceram spinel (ICS)
 In-ceram alumina(ICA)
 In-ceram zirconia (ICZ)
 Core of ICS- MgAl2O4
 Core of ICA- 70wt% alumina infiltrated with 30wt%
sodium lanthanum glass
 Core of ICZ- 70wt% alumina and 30wt% zirconia. 114

115. INDICATIONS2
 ICS-anterior single unit inlays, onlays, crowns and
veneers
 ICA-anterior and posterior crowns and anterior
three unit FPD’s
 ICZ-posterior crowns and posterior FPD’s
115

116. LABORATORY PROCEDURE
 In-Ceram – is based on slip-casting of an alumina
core with its subsequent glass infusion.
 An impression of the master cast preparations is
made with an elastomeric impression material.
 A special gypsum supplied with In-Ceram is then
poured into the impression to produce the die onto
which In-Ceram alumina is applied. 116

117.  Alumina powder(38 g) is mixed with 5ml of deionized
water supply.
 One drop of a dispersing agent is added to help create a
homogenous mixture of alumina in the water.
 one-half of the alumina is added to a beaker containing
the water/dispersant and then sonicated for 3 minutes in
a vitasonic.
 This initiated the Dispersion process.
 A second quantity of powder equal to one-half of the
remaining amount is then added to the beaker and
sonicated again for 3 minutes. 11
7

118.  The remaining powder may be added and sonicated for
7 minutes , during the last minute, a vacuum is applied
to remove air bubbles – this solution of alumina is
referred to as “ SLIP” ,which is then painted onto the
gypsum die with a brush.
 The alumina core is then placed in the furnace and
sintered using program 1 – slow heating of approx
2OC/min to 120OC to remove water and the binding
agent.
118

119.  Second stage of sintering involves a temperature
rise of approx 20OC/min to 1120OC for 2 hours to
produce approximation of particles with minimal
shrinkage of the alumina.
119

120. Advantages of the glass infiltrated systems:
 High flexural strength and fracture toughness.
In-ceram alumina(ICA); STRENGTH- 600 MPa ,TOUGHNESS- 6
In-ceram zirconia (ICZ); STRENGTH-900 MPa , TOUGHNESS-9
 Esthetics.
 Biocompatibility.
 Ability to be used with conventional luting cements.
12
0

121. Disadvantages of glass infiltrated
systems.
 High chemical solubility > 1000micro gms/cm2
 Technique sensitive
 High cost.
 Long time period for fabrication(15-16 hrs for single
crown)
12
1

122. Contraindication –
 If functionally appropriate design of the restoration is not
ensured:
 Inadequate preparation
 Bruxism.
 Severe discoloration of prepared teeth.
12
2

123. 123

124. Hot pressed, injection molded
Leucite based: IPS Empress
Spinel based: Alceram
12
4

125. HOT-PRESSED CERAMICS (Leucite based) –
IPS Empress and Optec OPC.
 Hot-pressed ceramics are becoming increasingly popular
in dentistry.
 The restorations are waxed, invested, and pressed in a
manner somewhat similar to gold casting.
 Marginal adaptation seems to be better with hot-pressing
than with the high-strength alumina core materials.
125

126.  Most hot-pressed materials contain leucite as a
major crystalline phase, dispersed in a glassy
matrix.
 The crystal size varies from 3 to 10 µm,
leucite content is 35%
Glass65%
 Leucite is used as a reinforcing phase due to the
tangential stresses it creates within the porcelain.
126

127. IPS Empress 6
Uses a leucite (40 – 50 %) reinforced feldspathic
porcelain.
 LEUCITE CRYSTALS ARE USED BECAUSE –
they improve
fracture toughness &
strength.
 Conventional lost wax technique is used
,except that it uses special investment and a
prolonged burn out cycle.
12
7

128. Advantages: Lack of metal.
Translucent ceramic core
Moderately high flexural strength
Excellent fit
Excellent esthetics.(
Translucence, flouroscence and
opalescence)
Minimal shrinkage:
Only shrinkage that occurs is during
cooling, that can be controlled with an
investment having an appropriate
expansion.

129. DISADVANTAGES
Potential to fracture in the posterior areas.
Need to use resin cement to bond the crown
micromechanically to the tooth structure.
Expensive equipment.
129

130. LABORATORY PROCEDURE
FOR IPS EMPRESS 6

131. 1. DIE PREPARATION
 The Cergo die spacer
(one layer of
approximately 15 μm in
thickness) or the colored
die spacer (two layers of
approximately 15 μm in
thickness) is used as a
placeholder for the
cementing gap. In the
case of crowns, a special
spacer fluid is applied to
within 1 mm of the
preparation margin on
the die.
131

132. 2. WAX MODELING
 Use only wax materials
that burn out without
residue.
 Use Isolit isolating liquid.
 For anterior teeth, the
wall thickness of the wax
model must be at least
0.7mm.
 Thickness of the
framework should be
more than 50% of the
thickness of the veneer in
the case of pressable
ceramics
132

133. 3. SPRUEING
 The wax models are
sprued with wax sprues
(5– 6 mm long for the
Cergo press ceramic
furnace, 2 – 3 mm for the
Multimat Touch&Press).
For smaller inlays and
copings, the
recommended sprue
diameter is 3.0 mm, while
it is 3.5 mm for more
voluminous restorations.
133

134. 4. INVESTING TECHNIQUE
 Place the muffle ring on
the muffle former.
 Mix the investment
material (Cergo fit or
Cergo fit SPEED) as per
the manufacturer’s
instruction. Vibrate lightly
into the muffle, avoiding
bubble formation, until all
objects are completely
covered with investment.
Top off the muffle without
vibrating.
134

135. 5. PRE-HEATING
 When using Cergo fit
SPEED
investment, you may
place the muffle directly
into the oven pre-
heated to 850 ºC after
a setting period of 15
minutes.
135

136. 6. PRESSING
Maximum of 2 ingots can be used.
If wax weight is less than 0.6 gms---- use one ingot
If wax weight is 0.61gm-1.4gms------ use two ingots
136

137. BURNOUT PROCEDURE
 After the investment has set for 15 to 20 min
place the ring in 8500C
45 min for small ring
60 min for large ring
137

138. 7. DIVESTING
 Make a deep cut into the
investment
compound, preferably
using a diamond-covered
and sintered large
carbide disc or(less
costly) a carbide disc for
metal castings.
 Separate the part of the
muffle containing the
alumina pressing die
from the rest of the muffle
using a plaster knife
or, preferably, by turning
in opposite directions.
138

139. 7. DIVESTING
 Use a jet polisher (50 μm, 4
bar) or glass beads to
remove the investment all the
way to the pressed objects.
 Once the objects have
become visible, continue
abrading across the area
using reduced pressure (2
bar).
 Clean the alumina pressing
die using alumina abrasive
and rinse.
 Do not use alumina for air-
abrading. Do not
concentrate the air-
abrading force on small
areas.
139

140. Lithium Silicate based 6
 IPS Empress 2 is a recently introduced hot-pressed ceramic.
 The major crystalline phase of the core material is a lithium
disilicate.( 85%)
 The material is pressed at 920° C (1690° F) and layered with
a glass containing some dispersed apatite crystals .
 The initial results from clinical trials seem quite promising
and may have application for anterior three-unit fixed partial
dentures.
14
0

141. Property IPS Empress IPS Empress II
Flexural strength 112±10Mpa 400±40
Fracture 1.3±0.1 3.3±0.3
toughness MPa/
m1/2
Thermal 15±0.25 10.6±0.25
Expansion
coefficient(ppm/
0C)
Veneering 9100C 8000C
temperature
Chemical 100-200 50
durability(μg/
cm2

142. 142

143. 143

144. 144

145. COMERCIALLY AVAILABLE CAD-CAM SYSTEMS –
 Procera
 Celay
 Sopha’
 Cicero
 Cerac
 Dux
 Denticard
 The japanese system
 The dens system (CERCON)
145

146. CEREC SYSTEM –
 1988: CEREC 1( Brains, Zurich, Switzerland)
 1994: CEREC 2( Siemens, Benshelm, Germany)
 2000: CEREC 3( Sirona, Bensheim, Germany)
 CEREC 3D
146

147. The equipment consists of
a computer integrated
imaging and milling
system, with the
restorations designed on
the computer screen.
 At
least three materials can
be used with this system:
 Cerac Vitablocs mark 1
 Cerac vitablocs mark 2
 Dicor MGC
14
7

148. CERAC system consists of –
 1. A 3D video camera
 2.An electronic image processor with memory unit
 3.A digital processor ( computer) connected to
 4.A miniature-milling machine ( 3-axis machine)
148

149. CEREC1 6
Fabrication of simple inlays.
Very sharp internal angles of the restorations
could not be administered.
Large grinding wheels associated with the
original CEREC system.
The occlusal surface cannot be fabricated with
CEREC 1.

150. CEREC 2 6
CEREC2 was significantly
improved.
Addition of a further cylindrical
grinder
Allowing the addition of occlusal
pits and fissures.
Concave and biconvex contouring
of veneers.
Occlusal surface can be ground
with CEREC2

151. CEREC 3 6
Radiocontrolled operating
system whereby the design and
milling chamber units can be
deployed separately.
Data acquisition and milling to be
carried out simultaneously.
The milling unit of CEREC 3 is
also equipped with laser scanner
A cylindrical floor and wall and a tapered cylindrical rotary diamond
milling tool( coated with 64 µm-grit diamonds)
The angle of taper, which is 450, which is used to shape the occlusal
surface of the restoration.
Simplifies occlusal and functional registration

152. CEREC 3D6
latest version.
allows a 3D view of the preparation and proposed
restoration.
“ Self Adjusting Crown”
automated occlusion tool.
Superior marginal fit.
Precise Proximal
Contacts.

153. Celay System
 uses a copy milling
technique to
manufacture ceramic
inlays or onlays.
A resin pattern is
fabricated directly on the
prepared tooth or on a
master, the pattern is
used to mill a porcelain
restoration.
15
3

154.  As with the Cerec system, the starting material is a
ceramic blank available in different shades
 This material is similar to Vita Mark II
ceramic, used with the Cerec 2 system.
 Marginal accuracy seems to be good, a little better
than the Cerec 2 system.
154

155. Procera AllCeram System6 -
 The Pro cera AllCeram system involves an industrial CAD/
CAM process.
 The die is mechanically scanned by the technician, and the
data are sent to a work station where an enlarged die is
milled using a computer-controlled milling machine.
 This enlargement is necessary to compensate for the
sintering shrinkage.
 Aluminum oxide powder is then compacted onto the die, and
the coping is milled before sintering at very high temperature
(>1550° C).
15
5

156.  The coping is further veneered with an aluminous
ceramic with matched thermal expansion.
 The restorations seem to have good clinical
performance and marginal adaptation, provided the
scanning is done skillfully.
 They may be suitable for posterior crowns and
FPDs, although long-term data are needed. 15
6

157. Lava System 6 –
 In a Lava System , a CAD/CAM procedure is used for
the fabrication of zirconia frameworks all ceramic
systems.
 The preparations are scanned and frameworks are
milled from presintered zirconia blanks.
Non contact optical scanner LAVA THERM
Lava milling unit
15
7

158. Lava System 6–
 The size of the frameworks is precisely increased to
allow for the shrinkage that occurs during sintering.
 Once a framework has been sintered, it is veneered with
layered esthetic porcelains in a manner similar to that
for the metal ceramic technique.
Non contact optical scanner LAVA THERM
Lava milling unit
15
8

159. CERCON
 Master models are prepared
in the same way as when
fabricating crowns and
bridges using precious
dental alloys.
 DeguDent Cergo die spacer
(Order no. 6590 0001) is
ideal as a spacer. One coat
(thickness approx. 15 μm)
of the die spacer is applied
to the preparation surface of
the die to approx. 1mm
short of the preparation
margin to allow a gap for
the cement.
159

160.  Single crowns in the
anterior region
should have 0.3 mm
wall thickness with a
0.2 mm marginal
edge.Single crowns
in the posterior
region should 0.4
mm wall thickness
with a 0.2 mm
marginal edge.
 Secure the pattern in
the model frame. 160

161. Powdering
 Remove the model
frame from the spindle.
 Cover the pattern and
sticks with scanning
powder.
161

162. THE TECHNIQUE –
Cercon eye
Means of data acquisition-Scanner
162

163. 163

164. 164

165. LIMITATION
 Three sizes of blanks are available
12,30 and 38mm
So it can not be used for bridge longer than 38mm.
165

166. RECENT ADVANCES 166
IN CERAMICS

167. SINGLE VISIT CROWN (CAD/CAM) –
Using CERAC 3D
 CEREC 3D uses CAD/CAM technology, incorporating a
camera, computer and milling machine in one instrument.
 The dentist uses a special camera to take an accurate picture of
the damaged tooth.
 This optical impression is transferred and displayed on a color
computer screen, where the dentist uses CAD technology to
design the restoration. Then CAM takes over and automatically
creates the restoration while the patient waits.
 Finally, the dentist bonds the new restoration to the surface of the
old tooth.
167
www.drsimonrosenberg.com
www.dentsply.com

168. Before After
What Are the Advantages CEREC 3D Offers?
•The dentist performs the restoration in a single session,
usually in about one-two hour(s).
•No need for the dentist to make an impression and send it to
a lab
•No return visits for the patient
•The restoration is natural looking, as it is made out of tooth-
colored ceramic material
168

169. Before After
What Are the Advantages CEREC 3D Offers?
•Ceramic material is biocompatible, high-
grade, anti-abrasive and plaque-resistant.
•Metal-free -- no silver-colored fillings.
•Allows dentist to save more of the healthy
tooth
•Extremely precise
169

170. CONCLUSION
 The difference with & without Ceramics is self
evident

171. REFERENCES
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2005; 94(1):62
2)Kenneth J. Anusavice; PHILLIPS’ SCIENCE OF
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3) Robert G. Craig & John M. Powers; RESTORATIVE
DENTAL MATERIALS; 12TH edition; Page 430-500.
4)Rosenstiel, Contemporary Fixed Prosthodontics; Third
Edition, Mosby Elsevier India; page 740-804. 171

172. 5. Herbert T. Shillingburg, Jr, Fudamentals of Fixed
Prosthodontics;Third Edition, Quintessence
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6. www.dentsply.com
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173. 9. Rosenstiel. Apparent fracture toughness of metal
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174. 12 .Denry il. Recent advances in ceramics for dentistry.
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15. Dentsply. Crown and bridge laboratory training guide.
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175. 17.Conrad H,Seong W ,and Pesun I. Current ceramic
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20.Hench L L.Bioceramics: From Concept to Clinic. J.Am.
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175

176. THANK YOU
176