Advances in Materials in Fixed Partial Dentures

Dr.Sivaranjani Gali MDS, PhD
Dept of Prosthodontics
Faculty of Dental Sciences
M.S. Ramaiah University of Applied Sciences
Bangalore
Master Class for Post Graduates
Recent Advances of Materials in Fixed Partial
Dentures (Emphasis on Connector Designs)
20-3-21
Mind Martians-Advances in Materials in FPD-
Dr.Gali

Learning Objectives......to be able to
Discuss Current Problems in Fixed
Partial Dentures (FPD)
Describe Recent Advances In Materials
in FPD
Provide Evidence Based Performance of
the Materials in FPD
20-3-21
Dr.Gali

Contents
Background of Existing Materials in Fixed Partial
Dentures (FPD)
Connecting Problems with Recent Advances in
Materials in FPD
Evidence Based Status of the Recent Advances
in Materials
Emphasis on Connector Designs
20-3-21
Dr.Gali

Timeline of Dental Ceramics
20-3-21
Dr.Gali

Metal-Ceramic Copings with
Feldspathic Porcelains
20-3-21
Dr.Gali

Dental Ceramics
Oxide Ceramics
Low glass content
SilicateCeramics
Glass & Crystalline
Glass Infiltrated
Ex: Infiltrated
Alumina/Zirconia
Polycrystalline
Ex: Zirconia
Alumina
Feldspathic Porcelain
Ex: Feldspar
Glass-Ceramics
Ex: Leucite
Lithium disilicate
Flourapatite
20-3-21
Dr.Gali

Lithium Disilicate Glass-Ceramics (Pressed)
20-3-21
Dr.Gali

Lithium Disilicate Glass-Ceramics (Milled)
20-3-21
Dr.Gali

Zirconia (Milled)
20-3-21
Dr.Gali

Mechanical Properties of All-Ceramic
Systems
Material Modulus
GPa
Hardness
GPa
Toughness
MPa/m1/2
Strength
MPa
Glass Ceramics
Empress esthetic (Leucite)
65 6.2 1.3 160
IPS e.max Press
(lithium disilicate)
95 5.8 2.75 400
IPS e.max CAD
(lithium disilicate)
95 5.8 2.25 360
Alumina
Procera
In ceram Alumina
340
280
17
20
3.2
3.5
695
500
Zirconia
Lava
ZirCAD
210
210
14
13
5.9
5.5
1048
900
Dental Clinics of North America 2011;55:2
20-3-21
Dr.Gali

Layered & Monolithic Ceramics
Layered Ceramic
Monolithic Ceramic
https://www.sciencedirect.com/scie
nce/article/pii/S0022391315006800
20-3-21
Dr.Gali

Framework Designs
 Bi-layered: Adequate Esthetics
Inadequate Strength
 Monolithic: Adequate Strength
Inadequate Esthetics
http://sci-hub.tw/10.1155/2015/418641
20-3-21
Dr.Gali

Material Survival Rates
Crowns Bridges
Lithium DisilicateGlass-Ceramics
IPS Empress 2
(Pressable Layered)
95.5 % 70 %
IPS e.max Press with
Apatite Glass Ceramic Veneer
(Pressable Layered)
96.6%
(3 yrs)
Monolithic
Inlays
100% (4 yrs)
Full Crown Retained
FDP
93% (8 yrs)
88% (10 yrs)
IPS e.max CAD (Milled)
Monolithic/ Bi-layered
Pressable Veneer
Core & Veneers
100% (2 yrs)
Journal of American Dental Assoc 2012;143:234-240
Clinical Oral Investigations 2013;1:275-284
Journal of Oral Rehabilitation 2005 ;32:747
https://onlinelibrary.wiley.com/doi/full/10.1111/j.1600-0722.2010.00767.x
20-3-21
Mind Martians-Advances in
Materials in FPD-Dr.Gali

Material Survival Rates
Crowns Bridges
Zirconia
1. Cercon /Cercon Ceram
(Layered)
2. Lava /Lava Ceram (Layered)
3. Monolithic
• 98% for 2 years
(9 % veneer
fracture)
• 100% for 3
years ( 5%
veneer
fracture)
• 100% survival
rate (3 yrs)
• 86.7% for
crowns (2 yrs)
• 91 % for 5 years with
13 % veneer fracture
• 100 % for 1 year with
3 % veneer fracture
• Connector fractures
• Debonding
• 92% (2yrs)
• 97.4% ( 5 yrs)
Journal of American Dental Assoc 2012;143:234-240
Clinical Oral Investigations 2013;1:275-284
Journal of Oral Rehabilitation 2005 ;32:747
https://onlinelibrary.wiley.com/doi/full/10.1111/j.1600-0722.2010.00767.x
. Dent J (Basel). 2019 Sep 2;7(3):90
20-3-21 Mind Martians-Advances in Materials in FPD-
Dr.Gali

Moisture Assisted Crack Growth
of Zirconia
Ceramic fractures
Opacity of Zirconia
Difficult Etching
of Zirconia
20-3-21
Dr.Gali

Contents
Background of Existing Materials in Fixed Partial
Dentures (FPD)
Connecting Problems with Recent
Advances in Materials in FPD
Evidence Based Status of the Recent Advances
in Materials
20-3-21
Dr.Gali

Addressing Problems
with
Innovations
20-3-21
Dr.Gali

Zirconia Ceramics
20-3-21
Dr.Gali

Problem
Ceramic Fractures in Zirconia
20-3-21
Dr.Gali

Veneer Fractures Core
Veneer
13 % incidence of veneer
fractures in all- ceramic
bilayered restorations in a 3
year follow up
15 % of veneer fractures in a 5
year follow up
Quintessence Int. 2006 Oct;37(9):685-93
Int J Prosthodont. 2007 Jul-Aug;20(4):383-
8
20-3-21
Dr.Gali

Why Veneer Fractures?
Inadequate support of
veneer from the core
Non-uniform thickness of
veneer
Low thermal conductivity of
cores
Low flexural strength of
veneer
20-3-21
Dr.Gali
Low-temperature degradation of Y-TZP ceramics: A
systematic review and meta-analysis. J. Mech. Behav.
Biomed. Mater., 55, 151–163.

Problems of Layering Technique
https://id.cdeworld.com/courses/4663-Classification_of_Dental_Ceramics
Layering technique (Sintering)
Thermal gradients due to
sintering process
Heating and cooling rates
Low thermal conductivity of
zirconia
Presence of residual stresses
20-3-21
Dr.Gali

Veneering Techniques
Layering Technique
Pressing Technique
CAD-on Technique
Rapid Layer
Technology
Dr.Gali

https://id.cdeworld.com/courses/4663-Classification_of_Dental_Ceramics
https://www.ivoclarvivadent.us/explore/ips-emax-cad/VITA Rapid Layer Technology
Layering technique( Sintering) CAD-on technique (Low fusing glass)
Rapid Layer Technology ( Adhesively Bonded technique)

CAD CAM Milled Veneers
Core
Veneer
20-3-21
Dr.Gali

Advances in Veneering Techniques
CAD-on technique (Low fusing glass)
CAD on technique uses
a low fusing glass
between core-veneer
Rapid Layer Technology
is based on adhesive
bonded structures with
resin cement
Rapid Layer Technology
( Adhesively Bonded technique)
20-3-21

Advances in Veneering Techniques
CAD-on technique (Low fusing glass)
Minimise the thermal
and associated residual
stresses of the sintering
technique
Core and Veneer are
CAD CAM milled
Offer uniform thickness
of core-veneer
( Adhesively Bonded technique)
20-3-21

(Adhesively Bonded Technique)
Cleaning zirconia
core
Etching veneer with
HF gel
Silanising the veneer
Applying resin to veneer
Adhesive bonding
Core-veneer
Adhesively bonded
Core-veneer
VITA_1740_VITA_1740GB, Rapid Layer Technology
20-3-21
Dr.Gali

Composite Veneers for
Zirconia
Frameworks
20-3-21
Dr.Gali

Problem
Opacity of Zirconia
20-3-21
Dr.Gali

Birefringence of Zirconia
https://glidewelldental.com/education/inclusive-dental-implant-magazine/volume-2-
issue-4/understanding-zirconia-crown-esthetics-and-optical-properties/
20-3-21

Generations of Zirconia
First
Generation
3 mol % yttria
stabilized
zirconia
High
Strength &
Opaque
Second
Generation
Translucent 3
mol% YZP
Limited alumina
content (<0.05
%)
Third
Generation
4-5 mol % YZP
Highly
Translucent
Aging resistant
& Reduced
Strength
20-3-21
Dr.Gali

First Generation Zirconia
Staining / Dipping Technique
Three generations of zirconia:  From veneered to monolithic. Part I and Part II. Quintessence Int. 2017;48(6):441-450
20-3-21
Dr.Gali

Second Generation Zirconia
• Alumina content reduced to less than 0.05%
• Improved translucency but suitable as monolithic
posterior restorations
• 0.5 mm thickness for tooth reduction due to good
strength
20-3-21
Dr.Gali

Third Generation Zirconia
• 5 mol% YZP with Cubic (53%) and Tetragonal phase
• Higher translucency
• Less prone to Aging
• Low Strength of 400-500 MPa
20-3-21
Dr.Gali

Translucent Zirconia
GENERAL DENTISTRY January/February 2017
20-3-21
Dr.Gali

20-3-21
Dr.Gali

Gradient Technology in Zirconia
20-3-21
Dr.Gali

Gradient Technology in Zirconia
• Larger Particles
• More 3Y Zirconia
• Low Translucency
• High Strength
• Small Particles
• More 5Y Zirconia
• High Translucency
• Low Strength
20-3-21
Dr.Gali

Problem
Moisture Assisted Crack Growth
(Aging/Low Temperature Degradation)
20-3-21
Dr.Gali

Aging of Zirconia
(Low Temperature Degradation)
Chevalier J. What future for zirconia as a biomaterial? Biomaterials. 2006
Feb;27(4):535-43. doi: 10.1016/j.biomaterials.2005.07.034.
Dr.Gali

Chevalier J. What future for zirconia as a
biomaterial? Biomaterials. 2006 Feb;27(4):535-
43. doi: 10.1016/j.biomaterials.2005.07.034.
Moisture Assisted
Degradation
20-3-21
Mind Martians-Advances in Materials in FPD-Dr.Gali

Third Generation Zirconia
• 5 mol% YZP with Cubic (53%) and Tetragonal phase
• Higher translucency
• Less prone to Aging
• Low Strength of 400-500 MPa
20-3-21
Dr.Gali

Zirconia Cementation
20-3-21
Dr.Gali

Dental Ceramics
Acid Sensitive
Ex: Glass-ceramics,
Feldspathics
Acid Resistant
Ex: Zirconia/Alumina
oxide ceramics
20-3-21
Dr.Gali

Adhesion to Zirconia: A Systematic Review of Current Conditioning Methods and Bonding
Materials. Dentistry journal, 7(3), 74.
20-3-21

Tribo-Chemical Silica Coating
3M ESPE Rocatec Bonding
20-3-21

The Magic of MDP to Zirconia
Nagaoka, N. et al. “Chemical interaction mechanism of 10-MDP with zirconia.” Scientific Reports 7 (2017)
20-3-21

Chemistry of Adhesion
http://www.rjor.ro/wp-content/uploads/2011/10/Adhesive-Cementation-Protocol-of-Zirconia-
Restorations.pdf
20-3-21
Dr.Gali

When Should Zirconia Be Bonded?
Suitable for Cementation with Self Adhesive Resin Cement:
• Tooth Preparation with adequate cervical –occlusal height:
h > 3mm
• Tooth Preparation with adequate taper, 2-5 degrees
Guide to Zirconia Bonding Essentials: John M Powers
20-3-21
Dr.Gali

When Should Zirconia Be Bonded?
• Suitable for Cementation with MDP based Adhesive Resin
Cement
• Tooth with short clinical crown h < 3mm
• Tooth with overprepared taper > 5
Guide to Zirconia Bonding Essentials: John M Powers
20-3-21
Dr.Gali

Glass-Ceramics
20-3-21
Dr.Gali

Toughening Glass Ceramics
Celtra DuoTM-Zirconia reinforced lithium silicate
20-3-21
Dr.Gali

Wet Firing Technique
Mill Stain and Glaze Fire Seat
20-3-21
Dr.Gali

Dry Firing Technique
Mill Polish Fire Seat
20-3-21
Dr.Gali

Vita Supranity DC
Zirconia reinforced Lithium
Silicate Glass-Ceramic
0.5 µm
1.5 µm
20-3-21
Mind Martians-Advances in Materials in FPD-Dr.Gali

Polishable Glass-Ceramics
20-3-21
Dr.Gali

Alternative Materials
to
Dental Ceramics
20-3-21
Dr.Gali

Polymer Infiltrated Ceramic
Network
20-3-21
Dr.Gali

Polymer Infiltrated Ceramic
Network (PICN) for FPD
Merits
• Good load resistance
than feldspathic but
lower than lithium
disilicate glass-ceramic
• Low elastic modulus
• Shock absorbing
• Machinable
Demerits
• More evidence
required
• Wear resistance
20-3-21
Dr.Gali

Polyether Ether Ketone (PEEK)
20-3-21
Dr.Gali

PEEK as a FPD Framework
Merits
• Good load resistance
• Low elastic modulus
• Comfort to patient
Demerits
• Low translucency
• Low surface energy
• Inadequate bonding to
veneer
• Requires chemical
treatment with sulfuric
acid
20-3-21
Dr.Gali

Selective Laser Sintering Alloys
20-3-21
Dr.Gali

Selective Laser Sintering for FPD
Merits
• Similar marginal fit
with casting
• Reduced technical
errors
• Reduces time and long
term cost
• Co-Cr alloys
Demerits
• Expensive Machine
• Training
20-3-21
Dr.Gali

Digital Impressions
20-3-21
Dr.Gali

Contents
Background of Existing Materials in Fixed
Partial Dentures (FPD)
Connecting Problems with Recent Advances
in Materials in FPD
Evidence Based Status of the Recent
Advances in Materials
20-3-21
Dr.Gali

Problems of Connector Fractures
Connector Height
(h) & Width (w)
Radius of
Curvature (r)
r
h/w
h x w = Area of Connector Size (mm2)
r = Radius of curvature (Round or Sharp)
e = Embrasures
Embrasures (e)
20-3-21
Dr.Gali

Problems of Connector Fractures
• Why connectors fracture?
• How to prevent connector fractures?
• What is the minimum dimensions of connectors for
all-ceramics to achieve esthetics and strength?
20-3-21
Dr.Gali

Why Connectors Fracture?
• Insufficient connector dimensions
• Framework Grinding caused Damage
• Positioning of Connectors Outside the Arch
20-3-21
Dr.Gali

Pathogenesis of Connector
Fractures
• Origin of fracture at the
Gingival Embrasure
(Junction between the Core
and the Veneer)
• Connectors are the most
loaded parts with tensile
stresses
20-3-21
Dr.Gali

That Radius of Curvature.....
20-3-21
Dr.Gali

That Radius of Curvature.....
Influence of radius of curvature at gingival embrasure in connector designs
J Int Soc Prevent Communit Dent 2019;9:338-48
20-3-21

Preventing Connector Fractures
• A gingival embrasure
with a broader radius of
curvature reduces stress
concentration under
loading and improves
fracture resistance
Influence of radius of curvature at gingival embrasure in connector designs
J Int Soc Prevent Communit Dent 2019;9:338-48
20-3-21
Dr.Gali

Preventing Connector Fractures
Location & Indication Connector Cross Section
Anterior 2 or 3 unit bridges 7 mm2 or more
More than 4 unit
bridges
9 mm2 or more
Posterior 2 or 3 unit bridges 9 mm2 or more
More than 4 unit
bridges
9 mm2 or more
Between Two Pontics 12 mm2
Cantilever Bridge to One Pontic 12 mm2
20-3-21
Dr.Gali

The Future....
• Chair side milling of Dental Zirconia with
Rapid Sintering
• Nano-Zirconia with Better Translucency
• 3D printed Zirconia using Lithography based
Ceramic Manufacturing (LCM) Technology
https://www.aegisdentalnetwork.com/cced/special-issues/2018/10/zirconia-the-
material-its-evolution-and-composition
20-3-21
Dr.Gali

What’s the Evidence?
20-3-21
Dr.Gali

Hierarchy of Evidence
20-3-21
Dr.Gali

Based on PICO
Problem (P)
Intervention (I)
Comparison (C)
Outcome (O)
What’s the Current Problem ?
What are the Innovations ?
Traditional/ Status Quo
What’s the Outcome?
20-3-21
Dr.Gali

Anatomy of a Forest Plot
20-3-21
Dr.Gali

Are Advances in Veneering
Techniques
(CAD-on/RLT technique)
better for
Bi-layered Zirconia?
20-3-21
Dr.Gali

Clinical Implications...
• Fused veneering (CAD-on) appears to be an
appropriate alternative to Y-TZP bilayers
• Pressed veneers on Y-TZP had a failure load and
flexural strength values similar to those of the
hand-layered veneers.
20-3-21
Dr.Gali

Does Aging affect Translucency of
Zirconia?
20-3-21
Dr.Gali

Clinical Implications..
• Meta-analysis on translucency showed no
significant difference in the TP value (Translucency
Parameter) between the non-aged and aged Y-TZP
(P = :73; mean difference ðMDÞ = 0:46; 95%
Confidence Interval (C.I) 2:12 to 3.05)
20-3-21
Dr.Gali

Which is the Effective Method of
Bonding Zirconia?
20-3-21
Dr.Gali

• The combination of mechanical and chemical
zirconia surface pre-treatments contributed to the
durability of the bond of composite cements to
zirconia ceramics.
• The cement choice appeared less critical, as long as
a composite cement was used for adhesive luting of
zirconia ceramics.
20-3-21
Dr.Gali

Which fares Better?
Zirconia or Metal-Ceramic in
Ceramic Chipping
20-3-21
Dr.Gali

• Metal-ceramic fares better than zirconia in ceramic
chipping
20-3-21
Dr.Gali

No Evidence on Effectiveness of...X !
• Gradient Zirconia
• Zirconia reinforced lithium silicate ceramics
• PEEK as Fixed Partial Prosthesis
• Polymer Infiltrated Ceramic Network (PICN)
• No meta-analysis studies on comparing zirconia
with lithium glass-ceramics
• No meta-analysis on Connector fractures
20-3-21
Dr.Gali

Thank You
20-3-21
Dr.Gali

Advances in Materials in Fixed Partial Dentures

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