Restorative Composite Resins
Col Kraig S. Vandewalle
USAF Dental Evaluation & Consultation Service
Official Disclaimer
• The opinions expressed in this presentation are
those of the author and do not necessarily
reflect the official position of the US Air Force or
the Department of Defense (DOD)
• Devices or materials appearing in this
presentation are used as examples of currently
available products/technologies and do not
imply an endorsement by the author and/or the
USAF/DOD
Overview
• Direct restoratives
– composition
– classification
– performance factors
• Flowable
• Packables
Click here for briefing on composite resins (PDF)
Composite
• Material with two or more distinct substances
– metals, ceramics or polymers
• Dental resin composite
– soft organic-resin matrix
• polymer
– hard, inorganic-filler particles
• ceramic
• Most frequently used
– esthetic-restorative material
Leinfelder 1993
History
• 1871 – silicates
– alumina-silica glass &
phosphoric acid
– very soluble
– poor mechanical properties
• 1948 - acrylic resins
– polymethylmethacrylate
– high polymerization shrinkage
Rueggeberg J Prosthet Dent 2002
History
(cont.)
• 1962 – Bis-GMA
– stronger resin
• 1969 – filled composite resin
– improved mechanical properties
– less shrinkage
– paste/paste system
•
•
•
•
1970’s – acid etching and microfills
1980’s – light curing and hybrids
1990’s – flowables and packables
2000’s – nanofills
Rueggeberg J Prosthet Dent 2002
Indications
• Anterior restorations
• Posterior restorations
– preventive resin
– conservative class 1 or 2
Contraindications
• Large posterior
restorations
• Bruxism
• Poor isolation
Advantages
•
•
•
•
•
Esthetics
Conservation of tooth structure
Adhesion to tooth structure
Low thermal conductivity
Alternative to amalgam
Disadvantages
• Technique sensitivity
• Polymerization shrinkage
– marginal leakage
– secondary caries
– postoperative sensitivity
• Decreased wear resistance
Composition
• Resin matrix
–
–
–
–
monomer
initiator
inhibitors
pigments
Bis-GMA
CH3
O
CH2=C-C-O-CH2CH-CH2O
CH3
OH
-CCH3
O
OCH2CHCH2O-C-C=CH2
OH
CH3
• Inorganic filler
– glass
– quartz
– colloidal silica
• Coupling Agent
Phillip’s Science of Dental Materials 2003
Monomers
• Binds filler particles together
• Provides “workability”
• Typical monomers
– Bisphenol A glycidyl methacrylate (Bis-GMA)
O
CH2=C-C-O-CH2CH-CH2O
CH3
OH
CH3
-C-
O
OCH2CHCH2O-C-C=CH2
CH3
OH
CH3
– Urethane dimethacrylate (UEDMA)
CH3
CH3
O
O
O
O
CH2=C-C-O-CH2CH2-O-C-NHCH2CH2CHCH2-C-CH2-NH-C- OCH2CH2O-C-C=CH2
CH3
CH3
CH3
– Triethylene glycol dimethacrylate (TEGMA)
O
O
CH2=C-C-O-CH2CH2-OCH2CH2 OCH2CH2O-C-C=CH2
CH3
CH3
Monomers
• Bis-GMA
– extremely viscous
• large benzene rings
– lowered by adding TEGDMA
•
•
•
•
freely movable
increases polymer conversion
increases crosslinking
increases shrinkage
O
CH3
CH2=C-C-O-CH2CH-CH2O
CH3
OH
-CCH3
O
OCH2CHCH2O-C-C=CH2
OH
CH3
Monomers
• Shrinkage
–2–7%
– marginal gap
formation
Filler Particles
• Crystalline quartz
– larger particles
– not polishable
• Silica glass
–
–
–
–
barium
strontium
lithium
pyrolytic
• sub-micron
Phillip’s Science of Dental Materials 2003
Filler Particles
• Increase fillers, increase
mechanical properties
strength
abrasion resistance
esthetics
handling
• 50 to 86 % by weight
• 35 to 71% by volume
Fracture Toughness
–
–
–
–
% Filler Volume
2
1.5
1
0.5
0
0
28 37 48 53 62
Ferracane J Dent Res 1995
Coupling Agent
• Chemical bond
– filler particle - resin matrix
• transfers stresses
• Organosilane (bifunctional molecule)
– siloxane end bonds to hydroxyl groups on filler
– methacrylate end polymerizes with resin
CH2
Bis-GMA
OH
CH3-C-C-O-CH2-CH2-CH2-Si-OH
Bonds with resin
O
Silane
OH
Bonds with filler
Phillip’s Science of Dental Materials 2003
Inhibitors
• Prevents spontaneous
polymer formation
– heat
– light
• Extends shelf life
• Butylated Hydroxytoluene
Phillip’s Science of Dental Materials 2003
Pigments and UV Absorbers
• Pigments
– metal oxides
• provide shading and opacity
• titanium and aluminum oxides
• UV absorbers
– prevent discoloration
– acts like a “sunscreen”
• Benzophenone
Phillip’s Science of Dental Materials 2003
Visible-Light Activation
• Camphorquinone
– most common photoinitiator
• absorbs blue light
– 400 - 500 nm range
• Initiator reacts with amine activator
• Forms free radicals
• Initiates addition polymerization
O
CH2=C-C-O-CH2CH-CH2O
CH3
OH
CH3
-C-
O
OCH2CHCH2O-C-C=CH2
CH3
Bis-GMA
OH
CH3
Polymerization
• Initiation
– production of reactive free radicals
• typically with light for restorative materials
• Propagation
– hundreds of monomer units
– polymer network
– 50 – 60% degree of conversion
• Termination
Craig Restorative Dental Materials 2002
C=C
C=C
C=C
C=C
C=C
C=C
C=C
C=C
C=C
C=C
C=C
C=C
C=C
C=C
C=C
polymerization
C=C
C=C
C=C
C=C
C=C
C=C
C=C
C=C
C=C
C=C
C=C
C=C
C=C
C=C
C=C
Ferracane
Classification System
• Historical
• Chronological
• Based on particle size
– traditional
– microfilled
– small particle
– hybrid
Phillip’s Science of Dental Materials 2003
Traditional (Macrofilled)
• Developed in the 1970s
• Crystalline quartz
– produced by grinding or milling
– large - 8 to 12 microns
• Difficult to polish
– large particles prone to pluck
•
•
•
•
Poor wear resistance
Fracture resistant
Examples: Adaptic, Concise
Suitable for Class 3, 4 and 5
Phillip’s Science of Dental Materials 2003
Microfills
• Better esthetics and polishability
• Tiny particles
– 0.04 micron colloidal silica
– increases viscosity
• To increase filler loading
– filler added to resin
– heat cured
– ground to large particles
– remixed with more resin and filler
Ground
polymer with
colloidal
silica (50 u)
Polymer
matrix
with
colloidal
silica
Phillip’s Science of Dental Materials 2003
Microfills
• Lower filler content
– inferior properties
• increased fracture potential
• lacks coupling agent
• lacks radiopacity
• Linear clinical wear pattern
• Suitable for Class 3, 5
– exceptions with reinforced microfills
• Class 1 or 2
Click here for table of microfills
Small Particle
• 1 - 5 micron heavy-metal
glasses
• Fracture resistant
• Polishable to semi-gloss
• Suitable for Class 1 to 5
• Example: Prisma-Fil
Silane-coated
silica or glass
(1-5 u)
Polymer
matrix
Phillip’s Science of Dental Materials 2003
Hybrids
• Popular as “all-purpose”
– AKA universal hybrid, microhybrids,
microfilled hybrids
• 0.6 to 1 micron average particle size
– distribution of particle sizes
Silane-coated
silica or glass
• maximizes filler loading
– microfills added
• improve handling
• reduce stickiness
Polymer
matrix with
colloidal
silica
Phillip’s Science of Dental Materials 2003
Hybrids
• Strong
• Good esthetics
– polishable
• Suitable
– Class 1 to 5
• Multiple available
Click here for table of hybrids
Table of Properties
Property
Traditional
Microfilled
Small
Particle
Hybrid
Compressive strength
(MPa)
250-300
250-300
350-400
300-350
Tensile strength (MPa)
50-65
30-50
75-90
70-90
Elastic Modulus (GPa)
8-15
3-6
15-20
7-12
Coefficient of Thermal
Expansion (10-6/ºC)
25-35
50-60
19-26
30-40
Knoop Hardness
55
5-30
50-60
50-60
Phillip’s Science of Dental Materials 2003
Newer Classification System
• Based on particle size
– megafill
• 0.5 - 2 millimeters
– macrofill
• 10 - 100 microns
– midifill
• 1 - 10 microns
• Most new systems
– minifillers
• Newest trend
– nanofillers
– trimodal loading
• prepolymerized
– minifill
• 0.1 - 1 microns
– microfill
• 0.01 - 0.1 microns
– nanofill
• 0.005-0.01 microns
Bayne JADA 1994
Midi -filler 2 um
(beachball)
Mini -filler 0.6 um
(canteloupe)
Microfiller .04 um
(marble)
Nanofiller .02 um (pea)
Relative Particle Sizes
(not to scale)
Nanofill vs. Nanohybrid
• Nanofills
– nanometer-sized particles throughout
matrix
• Nanohybrids
– nanometer-sized particles combined with
more conventional filler technology
Swift J Esthet Restor Dent 2005
Nanofilled Composite
• Filtek Supreme (3M ESPE)
• Filler particles
– filled: 78% wgt
– nanomers
• 0.02 – 0.07 microns
– nanocluster
• act as single unit
– 0.6 – 1.4 microns
Click here for technical profile
Click here for DECS evaluation
Performance Factors
• Material factors
– biocompatibility
– polymerization shrinkage
– wear resistance
– polish mechanisms
– placement types
– mechanical & physical properties
Biocompatibility
• Tolerated by pulp
– with good seal
• Rare allergic reactions
– HEMA
• Cytotoxicity
– short lived
• not a chronic source
• Degree of cure important
– decrease free monomer
Phillip’s Science of Dental Materials 2003
Systemic
• Estrogenic effects seen in cell cultures
– impurities in Bis-GMA-based resins
• Bis-phenol A in sealants
– Olea EHP 1996
» click here for abstract
– however, insignificant short-term
risk
• literature review
– Soderholm JADA 1999
» click here for abstract
Polymerization Shrinkage
• Significant role in restoration failure
– gap formation
• secondary caries formation
• marginal leakage
• post-operative sensitivity
• Counteract
– lower shrinkage composites
– incremental placement
Composite Wear
• Less wear
– small particle size
• less abrasion
– heavier filled
• less attrition
– non-contact areas
• 3 - 5 times less
– less surface area
– anterior location
• premolars vs. molars
Hilton Oper Dentistry: A Contemporary Approach 2001
Composite Wear
• Reduced wear with smaller particles
– less plucking leaving voids
• Higher filler loads for enhanced
properties
– correlations between wear and fracture
toughness and flexure strength
• Higher cure of resin matrix to resist
scratching and gouging by abrasives
Hilton Oper Dentistry: A Contemporary Approach 2001
Polish Mechanisms
• Acquired polish
– clinician induced
• Inherent polish
– ultimate surface
• Microfills
– high acquired, high inherent
• similar resin matrix and fillers wear more evenly
• Hybrids
– high acquired, acceptable inherent
Adept Report 1992
Polish Mechanisms
Small Particle Hybrid
Microfilled Composite
Acquired Polish
Time
Linear wear pattern
Inherent Polish
Adept Report 1992
Shaded vs. Anatomic
Placement
• Shaded
– shade selected from middle
third of tooth
– shade guide gives recipe for
multiple shades
• Anatomic
– highly chromatic dentin
matched to existing dentin
– colorless enamel replaces
existing enamel
Click here for details
Shaded
Anatomic
Dentists
Ceramists
“Create Shade”
“Match Shade”
Trans Enamel
Trans Enamel
A1 Enamel
A1 Dentin
Enamel Value
A3/A4 Dentin
Enamel Value
Placement Types
Composite Brands
• Shaded
–
–
–
–
–
–
–
4 Seasons (Ivoclar Vivadent)
Esthet-X (Dentsply)
Filtek Supreme (3M ESPE)
Point 4 (Kerr)
Venus (Heraeus Kulzer)
Renamel (Cosmedent)
Gradia Direct (GC)
• Anatomic
– 4 Seasons (Ivoclar Vivadent)
– Vitalescence (Ultradent)
– Miris (Coltene/Whaledent)
Jackson PPAD 2003
Composite Selection
• Anterior/stress (Class 4)
– hybrid
• mini- or midi-fill
– hybrid/microfill veneer combo
• Anterior/non-stress (Class 3 or 5)
– hybrid
• mini-fill
– microfill
Composite Selection
• Posterior
– hybrid
• mini- or midi-fill
– reinforced microfill
Selecting a Brand
• Contents of kit
– shades
– bonding agent
– unit-dose compules vs syringes
• Indications
– anterior, posterior, both?
• Cost of kit
– refills
Click here for synopsis of
restorative composite resins
Government Price
($/gm of refill resin)
8.49
8.53
8.79
8.9
9
9.44
11.37
9.95
10.15
10.21
7.58
6.5
4
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as
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sc
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th
et
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Z2
50
Pr
em
i
Su se
pr
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e
6.3
Prices current as of Jan 05
Selecting a Brand
• Results of lab and clinical studies
• Compositional characteristics
– % filler content
– average filler particle size
Click here for synopsis of
restorative composite resins
Radiopacity
(mm of aluminum)
3
2
ISO Requirement
1
De
nt
in
Gr
ad
ia
An
t
Ve
nu
s
Su
pr
em
e
4
Se
as
on
s
En
am
Vi
el
ta
les
ce
nc
Gr
e
ad
ia
Po
st
0
Source: USAF DECS Project 03-024
Surface Hardness
(24 hrs)
Source: USAF DECS Project 03-37
40
30
20
10
Po
in
t4
4
Se
as
on
s
Pr
em
is
G
e
ra
di
a
Po
st
G
ra
di
a
An
t
Ve
nu
s
Es
th
et
-X
0
Z2
50
Su
pr
em
Vi
ta
e
le
sc
en
ce
KHN
Horizontal lines connect nonsignificant differences (p<0.05); N=5
Flexural Strength
(24 hrs)
Source: USAF DECS Project 03-037
160
140
120
100
80
60
40
20
0
Supreme
4
Seasons
Venus
Gradia
Ant
Premise
Horizontal lines connect nonsignificant differences (p<0.05); N=5
Gradia
Post
Volumetric Shrinkage
Source: USAF DECS Project 03-037
5
4
3
2
1
ow
Fl
et
-X
R
en
ew
s
Ve
nu
Z1
00
Pr
em
is
e
4
Se
as
on
s
Es
th
G
ra
di
a
D
ire
ct
0
A
11
0
%
Horizontal lines connect nonsignificant differences (p<0.05); N=5
Composite Variants
• Packable
• Flowable
Packable Composites
• Marketed for posterior use
– increase in viscosity
• better proximal contacts?
• handle like amalgam?
• Subtle alteration of filler
– shape
– size
– particle distribution
• Similar resin chemistry and filler volume
Click here for table of packable composites
Packable Composites
• Mechanical properties
– similar to hybrids
1.8
1.6
Fracture
Toughness
1.4
1.2
1
0.8
0.6
ALERT
Solitare
SureFil
Heliomolar
Z100
0.4
0.2
0
Choi J Esthet Dent 2000
Click here for abstract
Proximal Contact Studies
• Packables similar to hybrids
– diameter and tightness
• Best contacts
– sectional matrix system
Peumans Dent Mater 2001
-click here for abstract
Klein Am J Dent 2002
Packable Composite Resin
Depth of Cure
100
%
Hardness
Ratio
80
96.9
96.2
91.2
85.1
71.5
70.2
70.3
2 mm
5 mm
55.4
60
41.4
40
22.4
20
0
0
Pyr-D
Prodigy SureFil
Alert
Solitaire
0
Pyr-E
Choi J Esthet Dent 2000 Click here for abstract
Packable Vs. Hybrid Composites
•
•
•
•
•
Mechanical properties similar
Wear properties similar
Curing depths similar
Similar proximal contacts
Drier, denser feel
Click here for more details
Choi J Esthet Dent 2000
Peumans Dent Mater 2001
Flowable Composites
• Marketed
• Particle size similar
to hybrid composites
• Reduced filler
content
–
Weight Percent
– class 1, 3, 5
– liner
Percent Filler Loading
80
70
60
50
40
30
20
10
0
Aeliteflo
FloRestore
Revolution
Ultraseal+
Prodigy
reduces viscosity
Bayne JADA 1998
Click here for abstract
Liners Under Direct Composites
• Increased flow
• Increased shrinkage
• Improved marginal integrity?
– laboratory studies equivocal
• most studies show no benefit
– Braga JADA 2003
» click here for abstract
• Reduced post-operative sensitivity?
– no clinical evidence of reduction
– Perdigao Quint Int 2004
» click here for abstract
Polymerization Shrinkage
%
5
4
3
2
1
0
o
Fl
Ae
e
t
li
lu
o
v
e
R
n
it o
W
e
av
ow
l
F
-it
ri
t
Te
c
ow
l
F
rt
e
Al
i
F
re
u
S
l
00
1
Z
li
e
H
ar
l
o
m
o
Tolidis JDR 1999
Radiopacity
• Reduced
radiopacity?
– product specific
– may be more
difficult to
distinguish on
radiograph
Gray value
250
200
150
100
Tetric Flow
Flow-it
Enamel
Revolution
FloRestore
UltraSeal+
50
0
Murchison Quint Int 1999
Click here for abstract
Flowable Composite
• Mechanical properties
– inferior to hybrids
Fracture Toughness
Flexure Strength
Prodigy
Ultraseal +
Revolution
FloRestore
Aeliteflo
0
0.5
1
1.5
MPa
2
2.5
0
50
100
150
200
MPa
Bayne JADA 1998
Click here for abstract
Flowable Composites
• Clinical applications
– preventive resin restorations
– small Class 5
– provisional repair
– composite repair
– liners??
Regular Material Usage*
•
•
•
•
•
•
•
•
•
Civilian Practitioners
Flowable Composite
81%
Hybrid Composite
69%
Amalgam
67%
All-Purpose Composite
53%
Microfill Composite
52%
Resin-modified Glass ionomer 45%
Packable Composite
33%
Compomer
7%
Other
1%
*Multiple responses
DPR 2005
Review of Clinical Studies
(Failure Rates in Posterior Permanent Teeth)
% Annual Failure
8
6
4
2
0
Amalgam
Direct
Comp
Comp
Inlays
Longitudinal
Ceramic CAD/CAM
Inlays
Inlays
Gold
Inlays &
Onlays
GI
Cross-Sectional
Hickel J Adhes Dent 2001
Review of Clinical Studies
(Failure Rates in Posterior Permanent Teeth)
% Annual Failure
15
Standard Deviation
10
Longitudinal and Cross-Sectional Data
5
AR
T
el
Tu
nn
I
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re
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al
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ct
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er
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p
In
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ys
m
ic
In
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ys
CA
D/
CA
M
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st
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0
Manhart Oper Dent 2004
Click here for abstract
Purchasing Considerations
Federal Service
• Universal hybrid systems are suitable for
both anterior and posterior restorations
– may not need to stock packable systems
•
•
•
•
additional expense to maintain
no improvement in mechanical properties
no improvement in proximal-contact formation
no increase in depth of cure
Click here for more details
Purchasing Considerations
Federal Service
• Most cases often only need one shade type
• Complex cases may need multiple shades
applied in layers
– larger Class 4, direct veneers, diastema
closures
• Wide diversity of kits available
– simple kits with only a few shades
– complete kits with multiple shades in various
opacities; bonding agents, dispenser guns,
shade guides
Click here for synopsis of restorative composite resins
Purchasing Considerations
Federal Service
• Simple universal hybrid kit in compact
case for routine individual use in
operatories or suites
– many systems available
• e.g., Prodigy (Kerr)
• More complete universal hybrid kit
for general use by entire facility
or training program
– several systems available
• e.g., 4 Seasons (Ivoclar Vivadent)
Click here for synopsis of restorative composite resins
Future Composites
• Low-shrinking monomers
– expanding spiroorthocarbonates
– epoxy-based resins
– liquid crystal
• Self-adhesive?
Click here for details
Acknowledgments
• Dr. Dave Charlton
• Dr. Jack Ferracane
• Dr. Tom Hilton
Questions/Comments
Col Kraig Vandewalle
– DSN 792-7670
– [email protected]