This is a journal club presentation featuring a recent article in which the authors have attempted a new classification of all ceramic materials. The presentation and all the related material is available on request. Mail me at apurvathampi@gmail.com

1. JOURNAL CLUB
PRESENTED BY :
APURVA THAMPI
1

2. About the Key article….
• New classification system for ceramic and ceramic-like restorationsTitle
• Stefano Gracis, Van P Thompson, Jonathan L Ferencz, Nelson, Silva, Estevam A
Bonfante
Authors
• Narrative reviewType of study
• 2015Year
• International Journal of ProsthodonticsJournal
2

3. Purpose of the study
To propose a new classification system for ceramic and ceramic like
restorations in a an attempt to systematize and include a new class
of materials
3

4. Need for the study
High number
of products
available –
newer
products being
developed
Communicat
ion and
education
Clinically
relevant
information
Where to use?
What type?
How to lute it?
Warrant for continuous
revisions and updates
4

5. Basis of the study
Glass
matrix
Polycry
stalline
Resin
matrix
Criteria : Based on the phase
present in the composition
5

6. Introduction
Ceramics  mainstay
of esthetic dentistry
John Mclean
introduced aluminous
porcelain – mid 1960’s
 continuous
improvements in
strength, esthetics and
methods of fabrication
Selection of material 
strength, translucency,
manufacturing
techniques,
preferences, advertising
6

7. 7
Some of the Previous classification
systems…

8. All ceramics
Composition
Predominantly
composed of glass
Particle filled glass
Polycrstalline
Processing methods
Powder/liquid
building
Slip casting
Hot pressed
ceramic
CAD/CAM
Fusing temperature
High fusing
Medium fusing
Low fusing
Ultra low fusing
Microstructure
Leucite reinforced
Lithium disilicate
Alumina
Zirconia
Translucency Fracture resistance Abrasiveness
8
Drawbacks : it is not
specific and does not
include the most
recent developments

9. All ceramics
Reinforced glass cermic
– leucite reinforced
Lithium disilicate glass
ceramics
Glass infiltrated
ceramics
High strength oxide
ceramics
9
Drawbacks : it is
not specific and
does not include
the most recent
developments

10. All ceramics
Composition category I
Glass based systems
mainly silica
Composition category
II
Glass based systems
with fillers - crystalline
leucite
Lithium disilicate
Composition category
III
Crystalline based
systems with glass
fillers
Alumina
Composition category
IV
Polycrystalline solids
Alumina
Zirconia
10
Drawbacks : Too
general and
impractical

11. All ceramics
Predominantly
glassy materials
Particle filled
glasses
Pollycrystalline
crystals
11

12. Why do we need a new
classification??
12

13. All previous classifications are
general and imprecise
Failure to
recognize
developments in
ceramic technology
13
Previous classifications
do not include resin
matrix materials
Recently coded as
“ceramics” by the ADA –
ceramic like properties

14. New classification 14

15. Glass-matrix ceramics
Feldspathic Synthetic
Leucite based
Lithium disilicate
and derivatives
Fluorapatite
based
Glass infiltrated
Alumina
Alumina and
magnesium
Alumina and
zirconia
15

16. Glass-matrix ceramics
Feldspathic
Composed of:
clay/kaolin,
quartz and
feldspar
Traditional
group 
ternary material
system
16
Potash feldspar
Leucite crystals
• Increases strength
• Suitable for veneering
substructures
Eg: IPS Empress Esthetic, IPS
Empress CAD, IPS Classic,
Vitadur, Vita VMK 68,
Vitablocs, Vident

17. Glass matrix ceramic
Synthetic
Remains less dependent on natural resources
Composed of: silicon dioxide, potassium
oxide, sodium oxide, aluminium oxide
Glass phases combined with
Apatite crystals Leucite crystals Lithium disilicate
17
Apatite
crystals
Leucite
crystals
Thermal expansion
compatibility with
framework
Lithium disilicate
Improves
mechanical
properties
20 x 10-6/֯ C for leucite
12-14 x 10 -6 / ֯C for alloys
- Kelly et al – 2011 Aus Dent J

18. Leucite based
IPS d.sign, Ivovlar
vivadent, vita VM7, VM9
VM13, Vident; noritake
EX-3
Lithium disilicate
and derivatives
3G HS, Pentron
Ceramics, IPS e.max
CAD, IPS e.max Press,
Ivoclar Vivadent;
obsidian Glidewell
laboratories; Suprinity,
Vita; Celtra Duo,
Dentsply
Fluorapatite-based
IPS e.max Ceram,
ZirPress, Ivoclar
Vivadent
18

19. Glass matrix ceramics
Glass infiltrated
1989 – InCeram
Alumina – Slip
casting technique –
lanthanum glass
infiltrated
1994 – InCeram
Spinell – Slip
casting technique –
porous magnesium
aluminate
InCeram Zirconia –
Slip-casting –
stabilised zirconia
oxide
19
Large elongated grains
(10-12μm long and 2.5
to 4 μm wide)
Faceted particles
(1-4μm)
Spherical grains
(<1μm diameter)

20. Polycrystalline ceramics
Fine grain
crystalline
structure
Provides
strength and
fracture
toughness
Limited
translucency
Absence of glass
phase – difficult
to etch with
hydrofluoric acid
20
• Formed by powders –
packed to 70% of
theoretical density
• Shrink by 30% by vol  fully
dense
- Kelly et al 2011 Aus Dent J

21. Polycrystalline ceramics
Alumina
First introduced by Nobel Biocare in 1990 – core material for fabrication with
High hardness (17-20 GPa) and high strength
High elastic modulus (300 GPa) – vulnerable to bulk fractures
Decreased use
21
Eg: Procera AllCeram, Nobel Biocare,
InCeram Al

22. Polycrystalline ceramics
Stabilized zirconia
22
Monoclinic Tetragonal cubic1170 ֯C 2370 ֯C
Produces shear strain
and 4% increase in
volume Stabilised by alloying
pure zirconia with
oxides

23. Fully stabilized
zirconia
• Cubic form
• Contains more
than 8mol%
yttrium oxide
Partially stabilized
zirconia
• Nanosized
tetragonal or
monoclinic
particles in cubic
matrix
Tetragonal zirconia
polycrystals
• Tetrgonal phase
stabilized with
yttria or ceria
23Polycrystalline ceramics
Stabilized zirconia

24. Polycrystalline ceramics
Zr-toughened Al and Al toughened Zr
 1976 – Claussen – interaction between crack front and the second phase
+ interatom between crack front an pre existing micro cracks  increased
fracture toughness of alumina
 ZTA - >50% by wt of Al
 ATZ - >50% by wt of Zr
 Latest – nanoparticles – resistance to low temperature degradation,
higher strength and higher fracture toughness
24
ZrO2 - 67.9mass% ,
Al2O3 -21.5 mass%;
CeO2 -10.6 mass%,
MgO -0.06 mass%
TiO2- 0.03 mass%

25.  Graded Al and graded Zr – variations of polycrystalline materials
 Glass infiltrated onto the surface – more damage resistant and esthetic
system
 Low stiffness glass to high stiffness core
 ZR + silicate glass – 100% to 0% across a 120 μm interphase – varying
elastic modulus
25Polycrystalline ceramics
Zr-toughened Al and Al toughened Zr

26. Resin –matrix cearmics
 Organic matrix highly filled with ceramic particles
 ADA - pressed fired polished or milled materials containing
predominantly inorganic refractory compounds – including porcelain
glasses, ceramics and glass ceramics - 2015
 >50% by wt
26
EM more
close to
of dentine
Easier to
mill
Facilitate
repair or
modify

27. Resin matrix ceramics
Resin nanoceramic
Highly cured resin matrix reinforced
with 80% by wt nanoceramic
particles
Silica nanoparticles (20nm) +
zirconia nanoparticles (4-11 nm) +
zirconia silica nanoclusters
Reduces interstitial
spacing of filler
particles  high
nanoceramic content
27
Eg : Lava Ultimate, 3M ESPE

28. Resin matrix ceramics
Glass ceramic in a resin penetrating matrix
Dual network
Feldspathic ceramic
network + polymer
network
28
SiO2 58 – 63%
Al2O3 20-23%
Na2O 9-11%
K2O 4-6%
B2O3 0.5-2%
Zr2O and CaO <1%

29. Resin matrix ceramics
Zr – Si ceramic in a resin interpenetrating
matrix
Different organic matrices
eg: UDMA. TEGDMA. Microfumed silica, pigments
85% ultrafine Zr-Si ceramic particles (0.6μm) embedded in a polymer
of bisphenol A glycidylmethacrylate, TEGDMA and a patented ternery
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30. Discussion
Materilas available have increased significantly
Classification help in material selection
Criteria used to differentiate ceramic systems – phase or phase in the chemical composition
Techniques of fabrication
• Freehand layering
• Hot pressing of an ingot nto a mold
• Slip casting technique
• CAD/CAM of a block or disc
30

31. 31

32. 32

33. Use of material –
core/veneer
Etchability is important
Indications for adhesive
cementation (Ghert et al
2013)
Abutment height
less than 4mm
Angle of
convergence
>10degrees
33
Hydrofluoric acid
topography modifies
topography of the
substrate – micro
retentions (9.5% at
25 ֯C for 1 hour)
Etching removes
surface damages
caused by sand
blasting

34. 34

35. Conclusion
 Compared to the previous classification, this system of classification
provides amore logical and precise method of classification.
 Includes the latest advancements in the field of ceramics
35

36. References 36
 Helvey et al. classifying dental ceramics: numerous materials and
formulaions available for indirect restoration. Compend Contin Educ Dent
2014 35:38-43
 Guess et al. all ceramic systems laboratory and clinical erformance. Dent
clin nirth am 2011. 55:333-352
 Shenoy et al. dental ceramics: an upstae. J Coserv Dent 2010. 13:195-203
 Giordano et al. ceramics overview: classification by microstructure and
processind methods Compend Conting Educ Dent 2010 :31:6282-684,
686,688

37.  Martin et al. material and clinical consideration for full coverage indirect
restoreation. Com[end contin educ dent 2012 ; 33:2-5
 Kelly et al. ceraic material sin dentistry-historical evolution and current
practice Aus dent J 2011;56:84-96
 Nakamura et al. current status of zirconia restration. J prosthodont Res
2013 57-236-261
 Fischer et al. range of indication for ranslucnet zirconia modification;
clinical and technical aspect. Quintescence int 2013;44:557-566
 Kim et al. effects of sintering conditions of dental zirconia ceramics on the
grain sizr and translucency. J Adv Prosthodnot 2013; 5:161-166
37

38.  Quinn et al. Fractographic failure analysis of a procera all ceram crown
using stereo and scanning electron microscopy. Dent Mater 2008;24:1107-
113
 Piconi et al. zirconia as a ceramic biomaterial. Biomaterial 1999;20:1-25
 Chevalier et al. tetragonal-monoclinica transformation in zirconia: lessons
learnt and future trneds. J am ceram soc 2009;82:1901-1920
 Abi et al. microstructure and mechanical properties of MgO stabilizied
Zro2-Al2O3 dental composite. J Mech behave biomed mater 2013; 18:123-
131
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39.  Gehrt et al. clinica results of lithium disilcate crowns after upto 9 years of
service. Clin oral investing 2013; 17:275-284
 Giordano 2nd R. A comparison of all-ceramic restorative systems: Part 2.
General dentistry. 1999 Dec;48(1):38-40.
 Kelly JR. Ceramics in restorative and prosthetic dentistry 1. Annual Review
of Materials Science. 1997 Aug;27(1):443-68.
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40. THANK YOU!
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