All-ceramic restorations can be classified into glass-based systems, glass-based systems with fillers, crystalline-based systems with glass fillers, and polycrystalline ceramics. Studies show the 5-year survival rates of all-ceramic single crowns range from 87.5% to 96.4%, which is comparable to porcelain-fused-to-metal crowns. However, all-ceramic fixed dental prostheses have lower estimated survival rates of 88.6% after 5 years compared to 94.4% for PFM fixed dental prostheses, with all-ceramic prostheses also having higher veneer fracture rates.

1. All-ceramic Restorations
Presenter: GR3 黃奕崴
Instructor: 王震乾 副教授
Date: 2013. 03. 01

2. Contents
 Introduction
 Classification
 Survival and complication
 Possible causes of veneering porcelain failure
 Options for intraoral ceramic repair
 Conclusions

3. Introduction

4. Introduction
 Porcelain-fused-to-metal (PFM) restorations
have represented the “gold standard” for
years in prosthetic dentistry, thanks to their
good mechanical properties and to somewhat
satisfactory esthetic results, along with a
clinically acceptable quality of their marginal
and internal adaptation.
Walton TR 1999, Spear FM 2001, Heffernan MJ et al. 2002

5. Introduction
 When fabricating PFM restorations, the gray
metal framework makes it difficult to imitate
natural esthetics, especially in situations with
limited space for the reconstruction.
Pjetursson BE et al. 2007

6. Introduction
 PFM restorations can only absorb or reflect
light, while dental tissues show a high degree
of translucency.
 Furthermore, from an economic standpoint,
the cost of precious metals has markedly risen
over the years.
Raptis NV et al. 2006, Donovan TE 2008

7. Introduction
 Associated with improved microstructure and
physical properties, all-ceramic restorations
have been an alternative treatment for dental
defects.
Pjetursson BE et al. 2007

8. Classification

9. Classification
 Glass-based systems (mainly silica)
 Glass-based systems (mainly silica) with fillers,
usually crystalline (typically leucite or lithium
disilicate)
 Crystalline-based systems with glass fillers
(mainly alumina)
 Polycrystalline ceramics (alumina and zirconia)
Shenoy A & Shenoy N 2010

10. Glass-based systems
 Glasses in dental ceramics derive principally
from a group of mined minerals called
feldspar and are based on silica (silicon oxide)
and alumina (aluminum oxide).
 Feldspathic porcelains belong to a family
called aluminosilicate glasses.
Giordano R 2000

11. Classification
 Glass-based systems (mainly silica)
 Glass-based systems (mainly silica) with fillers,
usually crystalline (typically leucite or lithium
disilicate)
 Crystalline-based systems with glass fillers
(mainly alumina)
 Polycrystalline ceramics (alumina and zirconia)
Shenoy A & Shenoy N 2010

12. Glass-based systems with fillers
 Glass= silica + alumina
 Filler: leucite or lithium-disilicate

13. Leucite-reinforced glass ceramics
 Filler: leucite (SiO2-Al2O3-K2O)
Trade name Indications Manufacturing technique
IPS Empress (Ivoclar Onlays, 3/4 crowns, Heat pressed
Vivadent) anterior crowns
IPS ProCAD (Ivoclar Onlays, 3/4 crowns, Milled
Vivadent) anterior crowns
Conrad HJ et al. 2007

14. Lithium-disilicate glass ceramics
 Filler: lithium-disilicate (SiO2-Li2O)
Trade name Indications Manufacturing technique
IPS Empress 2 (Ivoclar Crowns, anterior FPDP Heat pressed
Vivadent)
IPS e.max Press (Ivoclar Onlays, 3/4 crowns, Heat pressed
Vivadent) crowns, anterior FPDP
Conrad HJ et al. 2007

15. Classification
 Glass-based systems (mainly silica)
 Glass-based systems (mainly silica) with fillers,
usually crystalline (typically leucite or lithium
disilicate)
 Crystalline-based systems with glass fillers
(mainly alumina)
 Polycrystalline ceramics (alumina and zirconia)
Shenoy A & Shenoy N 2010

16. Crystalline-based systems with glass
fillers
 Low glass content
 Filler: alumina, spinel, zirconia (approximately
70%)
Trade name Indications Manufacturing technique
In-Ceram Alumina (VITA Crowns, anterior FPDP Slip-cast, milled
Zahnfabrik)
In-Ceram Spinell (VITA Anterior crowns Milled
Zahnfabrik)
In-Ceram Zirconia (VITA Crowns, posterior FPDP Slip-cast, millled
Zahnfabrik)

17. In-Ceram Alumina
 It has a high strength ceramic core fabricated
through the slip-casting technique.

18. Slip-casting technique
 A slurry of densely packed (70-80 wt%) Al2O3
is applied and sintered to a refractory die at
1120°C for 10 hours.
 This produces a porous skeleton of alumina
particles which is infiltrated with lanthanum
glass in a second firing at 1100°C for 4 hours
to eliminate porosity, increase strength, and
limit potential sites for crack propagation.
Xiao-ping L et al. 2002

19. In-Ceram Spinell
 More translucent than In-Ceram Alumina
 Its flexural strength is lower than that of In-
Ceram Alumina, and, thus, the cores are only
recommended for anterior crowns.
Magne P & Belser U 1997

20. In-Ceram Zirconia
 A modification of the original In-Ceram
Alumina system
 Addition of 35% partially stabilized zirconia
oxide to the slip composition to strengthen
the ceramic
Heffernan MJ et al. 20002

21. Classification
 Glass-based systems (mainly silica)
 Glass-based systems (mainly silica) with
fillers, usually crystalline (typically leucite or
lithium disilicate)
 Crystalline-based systems with glass fillers
(mainly alumina)
 Polycrystalline ceramics (alumina and zirconia)
Shenoy A & Shenoy N 2010

22. Polycrystalline ceramics
 All of the atoms are densely packed into
regular arrays that are much more difficult to
drive a crack through than atoms in the less
dense and irregular network found in glasses.

23. Kelly JR & Benetti P 2011

24. Polycrystalline ceramics
 Polycrystalline ceramics tend to be relatively
opaque compared to glassy ceramics.
 Shrink around 30% by volume when made
fully dense during firing.
 Zirconia

25. Zirconia
 At room temperature and upon heating up to
1170℃, the symmetry is monoclinic.
 The structure is tetragonal between 1170℃
and 2370℃.
 The structure is cubic above 2370℃ and up to
the melting point.
Kisi E & Howard C 1998

26. Zirconia
 The most common method of stabilizing the
tetragonal phase and maintaining zirconia in a
metastable condition at room temperature is
by adding a small amount of yttria to the
zirconia.
 Yttrium-containing tetragonal zirconia
polycrystalline = Y-TZP

27.  Two different approaches are now being
offered commercially for fabrication of
prostheses from polycrystalline ceramics, both
of which create oversized greenware (unfired
part) using 3-D data.

28. Procera
 An oversized die is manufactured based on
app. 20000 measurements taken during the
mechanical scanning of a laboratory die.
 Either aluminum oxide or zirconium oxide is
pressed onto the oversized die and predictably
shrunk during firing to become well-fitting
substructures.
Andersson M & Odén A 1993

29.  Blocks of partially fired (app. 10% complete)
zirconium oxide are machined into oversized
greenware for firing as single- and multiple-
unit prosthesis
Raigrodski AJ 2003

30.  Cercon (Dentsply)
 Lava (3M-ESPE)
 Y-Z (Vita)
 e.max ZirCAD (Ivoclar)

31. Survival and complication
Single crowns

32. Pjetursson BE, Sailer I, Zwahlen M, Hämmerle CH.
Clin Oral Implants Res. 2007 Jun;18 Suppl 3:73-85.

33. Total no. of Mean follow- Estimated Estimated
crowns up years failure rate survival after
5 years
All-ceramic 6006 4.9 1.38 93.3%
crowns
PFM crowns 1765 9.2 0.89 95.6%
Survival was defined as the crown remaining in situ with
or without modification during the entire observation
period.

34. Total no. of Mean follow- Estimated Estimated
crowns up years failure rate survival after 5
years
PFM crowns 1765 9.2 0.89* 95.6%
Densely 729 4.5 0.74 96.4%
sintered
alumina
(Procera)
Reinforced 1683 4.2 0.94 95.4%
glass–ceramic
In-Ceram 1915 3.7 1.13 94.5%
Glass–ceramic 1679 6.9 2.67* 87.5%
Glass-ceramic: Jacket crowns, Cerestore, Hi-Ceram,
Feldspat, and Dicor

35. 5-year survival summary estimate
Anterior Posterior
Densely sintered 96.7% 94.9%
alumina
Reinforced glass– 95.9% 93.7%
ceramic
In-Ceram 96.7% 90.4%
Glass–ceramic 91.4%* 84.4%*

36. Wang X, Fan D, Swain MV, Zhao K.
Int J Prosthodont. 2012 Sep-Oct;25(5):441-50.

37. Included publications
 RCT: 2
 Prospective study: 25
 Retrospective study: 10
 Follow-up time: ≥ 3 years

38. Annual fracture rates
Fracture Anterior Posterior P (anterior Overall
mode vs.
posterior)
All-ceramic Veneer 0.4% 0.5% .614 0.6%
systems
Core 0.2% 0.8% .001 0.5%
excluding
Dicor, Overall 0.6% 1.1% .001 0.9%
Cerestore,
and Hi-
ceram
The annual fracture rates were calculated by dividing the
total number of fractures by the total crown exposure
time.

39.  Procera AllCeram
 In-Ceram Alumina
 In-Ceram Spinell
 Vita Mark II
 IPS Empress
 IPS Empress 2

40. Rinke S, Schäfer S, Lange K, Gersdorff N, Roediger M.
J Oral Rehabil. 2013 Mar;40(3):228-37

42. Survival probability
Metal-ceramic crown: 97.6%
Zirconia crown: 95.2%

43. Success of the veneering ceramic
Metal-ceramic crown: 95.2%
Zirconia crown: 93.3%

44.  3-year survival rates of PFM and zirconia-
based molar crowns did not differ statistically,
demonstrating no increased risk of framework
fracture or endodontic treatments for the
zirconia restoration.

45. Survival and complication
Multiple unit

46. Sailer I, Pjetursson BE, Zwahlen M, Hämmerle CH.
lin Oral Implants Res. 2007 Jun;18 Suppl 3:86-96.

47. Year of publication Meterial Total no. of FDPs
2007 Zirconia 57
2006 Zirconia 13
2005 Zirconia 65
2005 Glass-ceramic 36
2006 Glass-ceramic 31
2004 In-ceram Zi 18
2003 In-ceram Al 42
2001 In-ceram 20
1998 In-ceram 61
343
FDPs: fixed dental prostheses

48. Total no. of Mean Estimated Estimated Estimated
FDPs follow-up failure rate survival veneer
years after 5 fracture
years rate
All-ceramic 343 3.8 2.42* 88.6%* 13.6%*
FDPs
PFM FDPs 1163 8 1.15* 94.4%* 2.9%*

49. Heintze SD, Rousson V.
Int J Prosthodont. 2010 Nov-Dec;23(6):493-502.

50. Inclusion criteria
 Prospective clinical trial at least 2 years
 Report of dropouts
 Details on technical failures (framework
fracture, chipping fracture of the veneer and
its extent by recall period
 Debonding
 Replacements and causes

51.  PFM FDPs study: 0
 Zirconia-based FDPs study: 13
 Both zirconia and PFM FDPs study: 2

52. Distribution of veneer chipping grade
of zirconia FDPs
Grade 1: Fracture surfaces were polished.
Grade 2: Fracture surfaces were repaired with resin-based
composite.
Grade 3: Severe chipping fractures required replacement of
affected prostheses.

53. Zirconia PFM
FDPs (n) 595 127
Core fracture 5 0
Veneer chipping 142 (24%) 43 (34%)
Both zirconia and PFM FDPs study
Zirconia PFM
FDPs (n) 197 127
Veneer chipping 107 (54%) 43 (34%)

54.  An explanation as to why the results of this
study were so different from the others is that
replicas of all FDPs were produced and
examined using scanning electron microscopy.
 Therefore, small chippings that would
otherwise not have been seen during clinical
examination were recorded.

55. Raigrodski AJ, Hillstead MB, Meng GK, Chung KH.
J Prosthet Dent. 2012 Mar;107(3):170-7

56.  Randomized controlled trial: 1
 Prospective cohort studies: 11
 2- to 5-year follow-up

57.  Survival rates ranged from 73.9% to 100%
within the 12 studies.
 Framework fracture: 4/387

58. Possible causes of veneering
porcelain failure

59. Possible causes of veneering porcelain
failure
 Coefficient of thermal expansion
 Thermal conductivity
 Aging
 Framework design
 Veneering method

60. Coefficient of thermal expansion
 Veneering porcelains that have a slightly lower
thermal expansion than that of the zirconia
core might develop compressive stresses in
the porcelain surface, with compensating
tensile stresses developing at the surface of
the framework.
Göstemeyer G et al. 2012

61. Thermal conductivity
 During cooling, residual stresses arise in the
veneering porcelain because of a temperature
gradient between the cool outer surface and
the warm inner surface adjoining the coping.
 As a result, tensile stresses develop in the
depth of the veneering material and
accelerate crack propagation.
Swain MV 2009, Baldassarri M et al. 2012

62. Aging
 This might occur in a manner analogous to
water penetration of yttria-stabilized
tetragonal zirconia polycrystals at moderately
elevated temperatures, which also is known as
low-temperature degradation or aging.
 The aging process also is suspected of being
responsible for a number of severe fractures
of artificial hips made of zirconia.
Chevalier J 2005

63. Framework design
 Copings of standard thickness (that is, 0.5 mm)
do not account for individual anatomical
crown or FDP dimensions, which result in a
wide variation of veneering porcelain
thicknesses and changes in the ratio of the
core thickness to the veneering porcelain
thickness.

64. Framework design
 This variation affected the strength and crack
initiation of veneered oxide-ceramic
structures.
 Several investigators reported that a
consistent veneering porcelain thickness
resulted in a more even distribution of
residual stresses in the material.
Kokubo Y et al. 2011, Rosentritt M 2009

65. Options for intraoral ceramic
repair

66. 1. The easiest way to repair chipped veneering
porcelain is to polish the fractured surface
thoroughly to minimize surface flaws that
could lead to future failure.
2. Reapply the broken piece of porcelain with
resin cement

67. 3. Replace the missing piece of porcelain with
composite resin
4. Prepare the restoration for a new veneer and
adhesively bond the ceramic veneer onto the
existing restoration
Kimmich M & Stappert CF 2013

68. Surface conditioning
 Etching
 Air abrasion
 Chemical bond

69. Etching
 Hydrofluoric acid (HF) is the only acid capable
of dissolving bonds in silicate substances.
 However, intraoral use of hydrofluoric acid is
controversial because of its hazardous
properties.
Magne P et al. 2002

70. Etching
 Metal or oxide-ceramics with low silicate
content (< 15 percent volume) cannot be
etched because no currently available acid is
capable of breaking the metallic bonds or the
bonds of oxide-ceramics.
Della Bona A & Anusavice KJ 2002

71. Air abrasion
 Air abrasion with 50-micrometer aluminum
oxide particles will clean, roughen, enlarge
and activate the surface, leading to a better
wetability and chemical accessibility.
Kern M et al. 2009

72. Air abrasion
 Although this does not harm the metal, in
brittle materials such as dental ceramics,
cracks usually originate from these surface
flaws.
 This occurs even in the strongest ceramic
materials such as zirconia and alumina.
Robin C et al. 2002

73. Air abrasion
 To reduce the detrimental effect of air
abrasion on oxide-ceramic materials, clinicians
can lower the pressure to 0.5 bar without
compromising the bond strength.
Attia A et al. 2011, Yang B et al. 2010

74. Chemical bond
 The chemical bond between the ceramic or
metal surface and the hydrophobic resin is
created by bifunctional molecules such as
silanes or phosphate monomers.

75. Silane
 Silanes (for example, RelyX Ceramic Primer, 3M ESPE, or Monobond-
S,Ivoclar Vivadent) bond to silicate materials via a
condensation reaction between silanol groups
on one end of the silane molecule.
 On the other end of the silane molecule, an
additional polymerization reaction of
methacrylate groups generates a bond to resin.

76.  Metal- and oxide-ceramic materials, which do
not contain silanol groups, also can be bonded
to silanes if they are silicatized in advance.
Heikkinen TT et al. 2007

77.  For intraoral surface treatments, this has
become possible through the development of
a chairside system (CoJet silicate-ceramic surface treatment
system, 3M ESPE). Ozcan M 2006

78. Phosphate monomers
 Phosphate monomers bond to oxides of the
metal or oxide-ceramic surface on one side
and to the resin on the other side.
 They are available as metal or ceramic primers
(for example, Alloy Primer, Kuraray Noritake, Tokyo), which are
used in combination with the corresponding
resin cement.
Kern M & Thompson VP 1995, Uo M et al. 2006

80. Conclusions

81. Conclusions
 The frequency of veneer chipping is higher in
the zirconia FDPs than PFM FDPs.
 There is no evidence to support the universal
application of a single ceramic material and
system for all clinical situations.

82. Reference
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83. Reference
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84. Reference
 15. Pjetursson BE, Sailer I, Zwahlen M, Hämmerle CH. A systematic review of the
survival and complication rates of all-ceramic and metal-ceramic reconstructions
after an observation period of at least 3 years. Part I: Single crowns. Clin Oral
Implants Res. 2007 Jun;18 Suppl 3:73-85.
 16. Sailer I, Pjetursson BE, Zwahlen M, Hämmerle CH. A systematic review of the
survival and complication rates of all-ceramic and metal-ceramic reconstructions
after an observation period of at least 3 years. Part II: Fixed dental prostheses. Clin
Oral Implants Res. 2007 Jun;18 Suppl 3:86-96.
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evaluation of metal-ceramic and zirconia molar crowns: 3-year results. J Oral
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85. Thanks for Your Attention

88. Common contributors to failure
in all-ceramic restorations

89. Common contributors to failure in all-
ceramic restorations
 Porosity
 Machining damage
 Thermal residual stresses

90. Porosity
 Pores are present in most all-ceramic dental
restorations, independently of fabrication
technique or ceramic type.
Denry I 2013

91. Porosity
 Crystals can form and grow towards the center
of the pore, creating sharp interfaces and
flaws.
Denry I 2013

92. Machining damage
 Air abrasion
 Grinding during clinical adjustments
 Polishing is unlikely to fully eliminate the flaws
created by grinding, particularly in a clinical
setting.
Denry I 2013

93. Thermal residual stresses
 A coefficient of thermal expansion (CTE)
mismatch
 Temperature gradients created during rapid
cooling
Denry I 2013

94.  The low thermal diffusivity of Y-TZP results in
higher temperature differences during and
after the ceramic firing process.
 The higher temperature difference causes
increased internal stress for the veneering
material, thus increasing the risk for
microcrack formations
Mainjot AK et al. 2011

95. Glass ceramics
 The conversion process from a glass to a partially
crystalline glass is called ceraming.
 Thus, a glass ceramic is a multiphase solid
containing a residual glass phase with a finely
dispersed crystalline phase.
 The controlled crystallization of the glass results
in the formation of tiny crystals that are evenly
distributed throughout the glass.
 The number of crystals, their growth rate and
thus their size are regulated by the time and
temperature of the creaming heat treatment.

96.  A minimum connector height of 3 to 4 mm
from the interproximal papilla to the marginal
ridge is a guideline for most systems.