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Restorative Composite Resins
Dr shabeel pn
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 Bis-GMA
– monomer O CH3 O
CH2=C-C-O-CH2CH-CH2O -C- OCH2CHCH2O-C-C=CH2
– initiator CH3 OH CH3 OH CH3
– inhibitors
– pigments
• 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)
CH3
O O
CH2=C-C-O-CH2CH-CH2O -C- OCH2CHCH2O-C-C=CH2
CH3 OH 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 O
CH2=C-C-O-CH2CH-CH2O -C- OCH2CHCH2O-C-C=CH2
CH3 OH CH3 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 % Filler Volume
2
– strength
Fracture Toughness
– abrasion resistance 1.5
– esthetics 1
– handling
0.5
• 50 to 86 % by weight
• 35 to 71% by volume 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 OH
Bis-GMA CH3-C-C-O-CH2-CH2-CH2-Si-OH
Bonds with resin Bonds with filler
O OH
Silane
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
CH3
O O
CH2=C-C-O-CH2CH-CH2O -C- OCH2CHCH2O-C-C=CH2
CH3 OH CH3 OH CH3
Bis-GMA
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 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 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 Ground
polymer with
colloidal
– increases viscosity silica (50 u)
Polymer
• To increase filler loading
matrix
with
colloidal
silica
– filler added to resin
– heat cured
– ground to large particles
– remixed with more resin and filler
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
Silane-coated
silica or glass
• 1 - 5 micron heavy-metal
(1-5 u)
glasses Polymer
matrix
• Fracture resistant
• Polishable to semi-gloss
• Suitable for Class 1 to 5
• Example: Prisma-Fil
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 Polymer
matrix with
• improve handling colloidal
silica
• reduce stickiness
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
Small
Property Traditional Microfilled Hybrid
Particle
Compressive strength
250-300 250-300 350-400 300-350
(MPa)
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
25-35 50-60 19-26 30-40
Expansion (10-6/ºC)
Knoop Hardness 55 5-30 50-60 50-60
Phillip’s Science of Dental Materials 2003
Newer Classification System
• Based on particle size • Most new systems
– megafill – minifillers
• 0.5 - 2 millimeters
– macrofill
• Newest trend
• 10 - 100 microns – nanofillers
– midifill – trimodal loading
• 1 - 10 microns • 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
Placement Types
Composite Brands
• Shaded • Anatomic
– 4 Seasons (Ivoclar Vivadent) – 4 Seasons (Ivoclar Vivadent)
– Esthet-X (Dentsply) – Vitalescence (Ultradent)
– Filtek Supreme (3M ESPE) – Miris (Coltene/Whaledent)
– Point 4 (Kerr)
– Venus (Heraeus Kulzer)
– Renamel (Cosmedent)
– Gradia Direct (GC)
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) 11.37
9.95 10.15 10.21
9.44
8.79 8.9 9
8.49 8.53
7.58
6.3 6.5
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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
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Source: USAF DECS Project 03-024
Surface Hardness
(24 hrs)
Source: USAF DECS Project 03-37
KHN
40
30
20
10
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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 Venus Gradia Premise Gradia
Seasons Ant Post
Horizontal lines connect nonsignificant differences (p<0.05); N=5
Volumetric Shrinkage
Source: USAF DECS Project 03-037
5
4
3
2
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1
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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
1.4
Fracture ALERT
1.2
Toughness Solitare
1
SureFil
0.8
Heliomolar
0.6 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 96.9 96.2
% 91.2
Hardness 85.1
Ratio
80 71.5
70.2 70.3
2 mm
60 55.4
5 mm
41.4
40
22.4
20
0 0
0
Pyr-D Prodigy SureFil Alert Solitaire 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
Percent Filler Loading
– class 1, 3, 5
80
– liner Aeliteflo
Weight Percent
70
• Particle size similar 60
50
FloRestore
to hybrid composites 40 Revolution
30 Ultraseal+
• Reduced filler 20
10 Prodigy
content 0
– 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
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Tolidis JDR 1999
Radiopacity
• Reduced Gray value
250
radiopacity?
– product specific 200
Tetric Flow
– may be more 150
Flow-it
Enamel
difficult to
Revolution
distinguish on 100 FloRestore
radiograph 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 2 2.5
MPa 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 Ceramic CAD/CAM Gold GI
Comp Inlays Inlays Inlays Inlays &
Onlays
Longitudinal 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
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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
– ksvandewalle@nidbr.med.navy.mil
