microsoft powerpoint - composites [compatibility mode]
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Restorative Composite ResinsRestorative Composite Resins
Dr Dr AmalAmal EzzEzz El Din El Din FahmyFahmy
AssisAssis Prof. Dental Biomaterials Department Prof. Dental Biomaterials Department Faculty of Dentistry Alexandria UniversityFaculty of Dentistry Alexandria University
Objectives• Historical back ground
• Ideal requirements of restorative materials
•• Indications, contraindications and Uses of Indications, contraindications and Uses of
Composites [ applications] Composites [ applications]
•• CompositionComposition
•• Classification based on the fillers particle Classification based on the fillers particle
size size
•• Classification based on the mode of curingClassification based on the mode of curing
•• Light curing units Light curing units
•• Properties of composites Properties of composites
•• Acid etch techniqueAcid etch technique
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IDEAL REQUIREMENTS OF RESTORAIVE IDEAL REQUIREMENTS OF RESTORAIVE
MATERIALSMATERIALS
••ExcellentExcellent physicalphysical andand mechanicalmechanical propertiesproperties
••HighHigh glossgloss ,polish,polish abilityability ,color,color stabilitystability
••BiocompatibilityBiocompatibility toto pulp,pulp, gingivalgingival tissuestissues
••RadioRadio opacityopacity
••GoodGood adhesionadhesion toto enamelenamel andand dentinedentine
••MinimalMinimal dimensionaldimensional changeschanges uponupon settingsetting
••GoodGood abrasionabrasion &fracture&fracture resistanceresistance
••NoNo mismatchmismatch inin CoefficientCoefficient ofof thermalthermalexpansionexpansion betweenbetween thethe fillingfilling andand toothtooth ..
••NoNo waterwater sorptionsorption oror solubilitysolubility
Restorative Materials for Anterior teeth
1. Silicate cements (not used anymore)
2. Glass Ionomer Cements
3. Polymeric Restorative Materials
a) Type I (Acrylic Unfilled Resin):
b) Type II (Composite Resin, Filled Resin)
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History
• 1871 – silicates
– alumina-silica glass & phosphoric acid
– very soluble
– poor mechanical properties
• 1948 - acrylic resins
– polymethylmethacrylate
– high polymerization shrinkage
Rueggeberg J Prosthet Dent Rueggeberg J Prosthet Dent 20022002
• Disadvantages:
– Monomer penetrates DT
causing pulpal irritation.
– Poor mechanical
properties
– Staining
– Higher TEC than tooth
causing Marginal
Percolation Phenomenon
– High polymerization
shrinkage causing
marginal gap,
Microleakage and
recurrent caries..
POWDER
PMMA + INITIATOR (BENZOYL
PEROXIDE)
LIQUID
MMA + ACTIVATOR (TERTIARY
AMINE)
N.B: NO FILLERS
UNFILLED SELF CURING ACRYLIC RESINSUNFILLED SELF CURING ACRYLIC RESINS
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MICROLEAKAGE PROBLEMSMICROLEAKAGE PROBLEMS
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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 Rueggeberg J Prosthet Dent 20022002
Indications Indications
Contraindications Contraindications
and Uses of and Uses of
Composite ResinsComposite Resins
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Indications
• Anterior restorations
• Posterior restorations
– preventive resin
– conservative class 1 or 2
Contraindications
• Large posterior
restorations
• Bruxism
• Poor isolation
• Patients with bad oral
hygiene (composite not anticariostatic)
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BLACK’S CLASSIFICATIONS OF CAVITY BLACK’S CLASSIFICATIONS OF CAVITY PREPARATIONSPREPARATIONS
Class I Class I
Class II Class II
Class IV Class IV Class III Class III Class V Class V
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Uses of Composites Uses of Composites Uses of Composites Uses of Composites Uses of Composites Uses of Composites Uses of Composites Uses of Composites
Class IIIClass III
Peg lateralPeg lateral
Uses of Composites Uses of Composites Uses of Composites Uses of Composites Uses of Composites Uses of Composites Uses of Composites Uses of Composites
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Uses of Composites Uses of Composites Uses of Composites Uses of Composites Uses of Composites Uses of Composites Uses of Composites Uses of Composites Uses of Composites Uses of Composites Uses of Composites Uses of Composites Uses of Composites Uses of Composites Uses of Composites Uses of Composites
Diastema closureDiastema closureDiastema closureDiastema closureDiastema closureDiastema closureDiastema closureDiastema closure
Veneers Veneers Veneers Veneers Veneers Veneers Veneers Veneers
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Uses of Composites Uses of Composites Uses of Composites Uses of Composites Uses of Composites Uses of Composites Uses of Composites Uses of Composites
Bonding of orthodontic brackets and bandsBonding of orthodontic brackets and bandsBonding of orthodontic brackets and bandsBonding of orthodontic brackets and bandsBonding of orthodontic brackets and bandsBonding of orthodontic brackets and bandsBonding of orthodontic brackets and bandsBonding of orthodontic brackets and bands
Uses of Composites Uses of Composites Uses of Composites Uses of Composites Uses of Composites Uses of Composites Uses of Composites Uses of Composites
Fissure Fissure Fissure Fissure Fissure Fissure Fissure Fissure
sealant sealant sealant sealant sealant sealant sealant sealant
Core Core Core Core Core Core Core Core
buildupbuildupbuildupbuildupbuildupbuildupbuildupbuildup
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5/16/201221
Sealants 22. Apply sealant. Apply sealant
11. Etch enamel. Etch enamel
Courtesy of Courtesy of 33M DentalM Dental
ProductsProducts
33. Light cure. Light cure
Composite Restorative ResinsComposite Restorative ResinsComposite Restorative ResinsComposite Restorative ResinsComposite Restorative ResinsComposite Restorative ResinsComposite Restorative ResinsComposite Restorative Resins
••ByBy definition,definition, aa compositecomposite isis aa combinationcombination
ofof twotwo chemicallychemically differentdifferent materialsmaterials withwith aa
distinctdistinct interfaceinterface betweenbetween them,them, andand havinghaving
propertiesproperties whichwhich couldcould notnot bebe achievedachieved byby
anyany ofof thethe componentscomponents alonealone..
••DentalDental compositescomposites areare highlyhighly crosscross--linkedlinked
polymericpolymeric materialsmaterials reinforcedreinforced byby aa
dispersiondispersion ofof glass,glass, crystalline,crystalline, oror resinresin fillerfiller
particlesparticles and/orand/or shortshort fibersfibers boundbound toto thethe
matrixmatrix byby silanesilane couplingcoupling agentsagents..
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COMPOSITE RESINSCOMPOSITE RESINSCOMPOSITE RESINSCOMPOSITE RESINSCOMPOSITE RESINSCOMPOSITE RESINSCOMPOSITE RESINSCOMPOSITE RESINS
•• DevelopedDeveloped 19601960ss composedcomposed ofof twotwo oror
moremore distinctdistinct phasesphases
•• CombinationCombination ofof inorganicinorganic fillerfiller particlesparticles
bondedbonded toto aa softsoft dimethacrylatedimethacrylate polymerpolymer
•• AdvantagesAdvantages:: improvedimproved mechanicalmechanical
propertiesproperties –– easyeasy toto useuse –– estheticsesthetics
•• UsedUsed inin classclass IIIIII,, IVIV andand VV asas wellwell asas aa inin
conservativeconservative posteriorposterior restorationrestoration
Composition of Composition of
composite resinscomposite resins
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CompositionCompositionCompositionCompositionCompositionCompositionCompositionComposition
•• OrganicOrganic polymerpolymer phasephase (resin(resinmatrix)matrix)
•• InorganicInorganic phasephase (dispersed(dispersed phase/phase/fillers)fillers)
•• InterfacialInterfacial phasephase (coupling(coupling agent)agent)
•• InitiatorsInitiators andand activatorsactivators
•• PigmentsPigments
•• InhibitorsInhibitors
Filled Composite Resin:
Composition
Resin Matrix
(Organic Phase)
Bis-GMA
(Bowen’s resin)
UDMA
TEGDMA
DEGDMA
Fillers
(Inorganic Phase)
Silica(quartz)
Glass Fibers
Lithium
Barium
Strontium
Coupling agent
(Interfacial Phase)
Silane
Gamma methacryloxypropyl silane
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Organic Polymer Organic Polymer
PhasePhase
•• DifunctionalDifunctional dimethacrylatedimethacrylate monomermonomer
•• BISBIS--GMAGMA oror UDMAUDMA
•• DiluentsDiluents asas DEGDMADEGDMA oror TEGDMATEGDMA
•• 7575%% BISGMABISGMA ++ 2525%% DiluentDiluent
•• FunctionFunction ofof organicorganic matrixmatrix::
––ProtectProtect thethe disperseddispersed phasephase toto retainretain it’sit’s
strengthstrength
––CementCement thethe fillersfillers intointo bundlesbundles
––TransferTransfer externallyexternally appliedapplied loadload toto thethe fillersfillers
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Organic polymer phase
•Bis-GMA : extremely viscous
large benzene rings
lowered by adding TEGDMA
freely movable
increases polymer conversion
increases cross linking
increases in diluents increase shrinkage
CHCH22=C=C--CC--OO--CHCH22CHCH--CHCH22OO --CC-- OCHOCH22CHCHCHCH22OO--CC--C=CHC=CH22
CHCH33 CHCH33
CHCH33
CHCH33OHOH OHOH
OO OO
5/16/201230
Most common dental resins
triethylenetriethylene glycol glycol dimethacrylatedimethacrylate
BisphenolBisphenol A A glycidylglycidyl dimethacrylatedimethacrylate
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••Lower polymerization Lower polymerization
shrinkageshrinkage
Lower coefficient of Lower coefficient of
thermal expansionthermal expansion
Harder and stronger Harder and stronger
cross linked polymercross linked polymer
Less water sorption Less water sorption
UDMA IS LESS UDMA IS LESS
VISCOUSVISCOUS--LESS LESS
WATER SORPTIONWATER SORPTION
•• High viscosity which High viscosity which require thinning by require thinning by diluent monomersdiluent monomers
•• High water sorptionHigh water sorption
•• Air inhibition of Air inhibition of polymerizationpolymerization
Organic Polymer PhaseOrganic Polymer Phase
First increment 1.5
AIR
Second increment
Composition & Structure:Resin matrix
•Oligomers (2Monomers)–Monomer:Methylmethacrylate (MMA)
•Dimethacrylate(Bis-GMA)
•Urethane dimethacrylate(UDMA)
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Filled Composite Resin:
Composition
Role of each constituent
Resin Matrix
(Organic Phase)
1. Protect Fillers
2. Cushion transferring loads to
strong fibers
3. Hold fillers together
Responsible for:
Physical Properties
Fillers
(Inorganic Phase)
1. Strength
2. Hardness
3. Abrasion resistance
Responsible for:
Mechanical properties
Coupling agent
(Interfacial Phase)
Bond matrix to fillers
Responsible for:
Filler to matrix bond
Filled Composite Resin:
Composition (cont’d)
Initiators
Chemically Activated
(benzoylperoxide)
Light Activated
(Diketone)
(Camphor Quinone)
Activators
Chemically Activated
(Tertiary amine)
Light Activated
(Light)
Inhibitors
Hydroquinone
Hydroquinone
BHT
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Inorganic phase ( dispersed Inorganic phase ( dispersed
fillers)fillers)
•• ImproveImprove thethe mechanicalmechanical propertiesproperties ii..eecompressivecompressive strengthstrength.. ModulusModulus ofofelasticityelasticity andand hardnesshardness andand wearwearresistanceresistance..
•• ReduceReduce polymerizationpolymerization shrinkageshrinkage
•• ReduceReduce thethe coefficientcoefficient ofof thermalthermalexpansionexpansion
•• ImprovesImproves thethe abrasionabrasion resistanceresistance
•• ImprovesImproves opticaloptical propertiesproperties
Inorganic phase ( Inorganic phase (
dispersed fillers)dispersed fillers)
•• Shape:Shape: spherical OR splintered OR spherical OR splintered OR colloidalcolloidal
•• Size:Size: macrofillersmacrofillers
•• --microfillersmicrofillers
•• --hybridhybrid
•• --finefine
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Types of fillersTypes of fillers
••QuartzQuartz: : advantagesadvantages translucent, hard irregularly translucent, hard irregularly
shaped particles, inert shaped particles, inert disadvantagedisadvantage Very difficult Very difficult
to finish and polish high thermal diffusivityto finish and polish high thermal diffusivity
•• PyrogenicPyrogenic silica (silica (aerosilaerosil): ): prepared from silicon prepared from silicon
compounds have very large surface areacompounds have very large surface area
••Barium/Barium/ strontiumstrontium aluminosilicatealuminosilicate glassesglasses
RadiopaqueRadiopaque,, softersofter thanthan quartz,quartz, moremore easilyeasily
polishedpolished developdevelop basicbasic surfacesurface inin waterwater whichwhich
compromisecompromise resinresin fillerfiller bondbond..
••BetaBeta eucryptiteeucryptite
•• ytterbiumytterbium tritri flourideflouride
•• ZirconiumZirconium
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••MACROFILLERS:MACROFILLERS: quartz, quartz,
lithium, lithium, aluminoalumino silicate silicate
glass, barium or glass, barium or
strontiumstrontium
•• Particle size= Particle size= 00..1 1 –– 100 100
microns average microns average 88--1212µµµµµµµµ
•• 7070--80 80 % by weight% by weight
•• MICROFILLERSMICROFILLERS
•• Hydrolyzed silica Hydrolyzed silica
((pyrogenicpyrogenic silica)silica)
•• Average particle size Average particle size
00..0404--00..4 4 µµµµµµµµ 3535--6767%wt.%wt.
•• PrepolymPrepolym microfillermicrofiller. .
ComplexesComplexes
•• HYBRID (BLENDED HYBRID (BLENDED
FILLERS) averageFILLERS) average
•• Fine fillers Fine fillers 00..44--1 1 µµµµµµµµ + +
00..04 04 µµµµµµµµ -- 6060% wt. + % wt. +
microfillersmicrofillers 00..04 04 m. m.
1515% wt% wt 7575--8080% by % by
weightweight
FINE (SMALL FINE (SMALL
PARTICLE)PARTICLE)
Particle size reduced to Particle size reduced to
00..55--33µµµµµµµµ ((11--6 6 µµµµµµµµ))
8080--9090% by wt.% by wt.
Types of Fillers according to Types of Fillers according to
particle size particle size Type of composite resinType of composite resin::By fBy filler sizeiller size
backback
macrofilledmacrofilled
microfilledmicrofilledSP filledSP filled
HybridHybrid
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Micro fillers
• Pyrogenic silica
•Homogenous
• Pre polymerized particles not purely inorganic
Heterogeneous
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Current pattern microfill Current pattern microfill
compositecomposite
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Classification Based on Filler Classification Based on Filler
Particle SizeParticle SizeCLASS of composite
Particle size Filler content W%
Clinical use
Traditional( macro filled)
1-50µmGlass ,quartz
70-80 High stress area
MicrofilledA) HomogenousB) Heterogenous
0.04µm pyrogenicsilica 0.04 µm pyrogenicsilica& prepolymerized resin containing silica
35-4545-79
Low stress & sub gingivalarea requiring high luster and polish
Small Particle filled SPF
1-6 µm glass& 0.04 µm silica
80-90 Moderate stress areaclass III,IV
HYBRID 0.4-1 µm glass and +0.04 µm silica
75-80 High stress areaclass I,II,III, IV
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Surface Roughness Before and After Surface Roughness Before and After Surface Roughness Before and After Surface Roughness Before and After Surface Roughness Before and After Surface Roughness Before and After Surface Roughness Before and After Surface Roughness Before and After
Finishing Finishing Finishing Finishing Finishing Finishing Finishing Finishing Interfacial Phase Interfacial Phase Interfacial Phase Interfacial Phase Interfacial Phase Interfacial Phase Interfacial Phase Interfacial Phase (Coupling Agent)(Coupling Agent)(Coupling Agent)(Coupling Agent)(Coupling Agent)(Coupling Agent)(Coupling Agent)(Coupling Agent)
•• ProvidesProvides aa chemicalchemical bondbond betweenbetween thethe fillerfillerparticlesparticles andand thethe resinresin matrixmatrix
•• SilanesSilanes areare usedused ee..gg.. triethoxytriethoxy vinylvinyl silanesilane•• MoreMore recentlyrecently gammagamma methacryloxymethacryloxy propylpropyl silanesilaneisis usedused..
•• LackLack ofof adequateadequate bondbond------ dislodgmentdislodgment ofof fillers,fillers,andand penetrationpenetration ofof waterwater alongalong thethe fillerfiller--matrixmatrixinterfaceinterface..
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CHEMISTRY OF COMPOSITESInterfacial Coupling Agents
Inhibitors
• Prevents spontaneous
polymer formation
– heat
– light
• Extends shelf life
• Butylated Hydroxytoluene
Phillip’s Science of Dental MaterialsPhillip’s Science of Dental Materials 20032003
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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 MaterialsPhillip’s Science of Dental Materials 20032003
Classification:
• According to the curing mode:
– Chemically activated composite resin.
– Light activated composite resin
• According to the size of fillers:
– Macrofilled composite resin.
– Microfilled composite resin.
– Hybrid composite resin.
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Classification according to Classification according to
Polymerization TechniquesPolymerization Techniques
II-- CHEMICALLYCHEMICALLY ACTIVATEDACTIVATED (two(two pastepastesystem)system)
•• InitiatorsInitiators ––benzoylbenzoyl peroxideperoxide
•• ActivatorActivator ––tertiarytertiary amineamine ((dihydroxyldihydroxyl ethylethylpp--toluidinetoluidine))
IIII–– LIGHTLIGHT ACTIVATEDACTIVATED (single(single pastepaste systems)systems)
a)a) ultraultra violetviolet lightlight
b)b) visiblevisible lightlight
IIIIII-- DUALDUAL CUREDCURED COMPOSITECOMPOSITE
ChemicallyChemically andand lightlight togethertogether..
Chemical activated resin
• Two pastes– Initiator Activator
:Benzoyl peroxid :Tertiary amine
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Mode of SupplyMode of Supply
•• TwoTwo pastepaste systemssystems
•• TwoTwo jarsjars aa basebase pastepaste +a+a catalystcatalystpastepaste
•• SingleSingle pastepaste systemssystems
•• DisposableDisposable syringessyringes
•• CompulesCompules withwith colorcolor codedcoded tipstips
•• NN..BB:: aa compositecomposite kitkit maymay alsoalso bebesuppliedsupplied withwith anan acidacid etchantetchant andand aabondingbonding agentagent
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2 2 Jars of composite Jars of composite
pastespastes2 2 Bottles bondBottles bond
Acid EtchantAcid Etchant
Manipulation
1. Etching: 37% phosphoric acid Micro-irregularities
2 .Washing and drying
3.Bonding: Mix drops from 2 bottles of bonding agent mixed
and applied to tooth surface with brush then air dried.
4.Application of composite resin:• Use Plastic spatula
• Bulk or pressure pack tech.
• Celluloid strip
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Disadvantages of chemically
Activated composite:
• Short working time
• Polymerization is inhibited by air.
• Voids: Due to bulk technique
• High polymerization shrinkage
• One Shade
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•• A)A) ULTRA VIOLET ULTRA VIOLET
RADIATIONRADIATION
•• PHOTO INITIATOR=PHOTO INITIATOR=
•• BENZOIN METHYL BENZOIN METHYL
ETHERETHER
•• DISADVANTEGES DISADVANTEGES
•• Limited depth of cureLimited depth of cure
•• HazardsHazards--skin (cancer) skin (cancer)
eye (retinal damage)eye (retinal damage)
•• Intensity fades with time Intensity fades with time
•• B)B) VISIBLE LIGHT VISIBLE LIGHT
(BLUE LIGHT (BLUE LIGHT 468468nm)nm)
•• PHOTO INITIATOR=PHOTO INITIATOR=
•• DIKETONE (E.G DIKETONE (E.G
CAMPHOR QUINONE)CAMPHOR QUINONE)
•• DEAEMA (activator)DEAEMA (activator)
•• ADVANTAGESADVANTAGES
•• Greater depth of cureGreater depth of cure
•• The intensity of the light The intensity of the light
bulb remains constant bulb remains constant
until it failuntil it fail
LIGHT ACTIVATED COMPOSITESLIGHT ACTIVATED COMPOSITESLight Activated Composite Resin:
• Supplied in the form of:
• Single paste system or Compules
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A A Shade guide Shade guide is supplied to determine the shade of the is supplied to determine the shade of the
tooth, hence the composite.tooth, hence the composite.
Manipulation:
– Single component for each step
– Bonding agent is light cured
– Composite resin is applied
incrementally, each increment is
max. 2mm thick. Each increment
is light cured separately with blue
light. This decreases the
polymerization shrinkage of the
composite.
Same as chemical cured composite except for:Same as chemical cured composite except for:
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Advantages of light cured composite
resin Vs Chemical cured one.
• Light Cured
• Easy application No Mixing-
Command cure
– Different shades.
– Incremental application
– Less Polymerization
shrinkage (Incremental
application)
– Less voids, hence higher
strength.
– Long working time.
– Higher color stability.
�� Chemical CuredChemical Cured�� Needs mixing Needs mixing
�� Single shade.Single shade.
�� Bulk Technique applicationBulk Technique application
�� Higher Polymerization Higher Polymerization shrinkage (Bulk tech)shrinkage (Bulk tech)
�� More voids, hence lower More voids, hence lower strength.strength.
�� Difficult applicationDifficult application
�� Short working time.Short working time.
�� Less color stability due to Less color stability due to discoloration caused By discoloration caused By NN,P NN,P toluidinetoluidine
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Polymerization Polymerization
ReactionReaction•• DimethacrylateDimethacrylate
++
•• InitiatorInitiator (peroxide(peroxide OROR diketonediketone ++ blueblue light)light)
++
•• AcceleratorAccelerator (amine)(amine) ++ silanesilane treatedtreated particlesparticles
DentalDental compositecomposite
•• PolymerizationPolymerization isis incompleteincomplete (degree(degree ofofconversionconversion isis 6060 --7575%%
C=CC=C
C=C C=C CC=C=C
C=C C=C CC=C=CC=C C=C CC=C=C
C=C C=C CC=C=C
C=C C=C CC==CCC=C C=C CC=C=C
C=C C=C CC=C=C
C=C C=C CC==CC
C=CC=C
C=CC=C
C=CC=CC=CC=C
C=CC=C
C=CC=C
C=CC=C C=C C=C CC==CCC=C C=C CC==CC
C=CC=C
C=CC=C
polymerizationpolymerization
PolymerizationPolymerization
MonomerMonomer
PolymerPolymer
FerracaneFerracane
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Factors Affecting Depth of Factors Affecting Depth of Factors Affecting Depth of Factors Affecting Depth of Factors Affecting Depth of Factors Affecting Depth of Factors Affecting Depth of Factors Affecting Depth of
CureCureCureCureCureCureCureCure
•• LightLight intensityintensity isis inverselyinversely proportionalproportional
toto thethe distancedistance fromfrom thethe lightlight sourcesource
•• ExposureExposure timetime (not(not lessless thanthan 4040 secs)secs)
•• ShadeShade andand opacityopacity ofof thethe compositecomposite
•• ThicknessThickness 22--22..55mmmm
•• FillerFiller particleparticle sizesize;; thethe smallersmaller particlesparticles
causecause dispersiondispersion ofof lightlight——thereforetherefore
needsneeds longerlonger exposureexposure timetime asas inin
microfilledmicrofilled compositescomposites
Degree of Conversion ( DC)Degree of Conversion ( DC)Degree of Conversion ( DC)Degree of Conversion ( DC)Degree of Conversion ( DC)Degree of Conversion ( DC)Degree of Conversion ( DC)Degree of Conversion ( DC)
•• TheThe percentagepercentage ofof carboncarbon––carboncarbon
doubledouble bondsbonds thatthat havehave beenbeen convertedconverted
toto singlesingle bondsbonds toto formform aa polymericpolymeric
resinresin..
•• HigherHigher DC=DC= HigherHigher strengthstrength ..
•• DCDC dependdepend onon::
••ResinResin compositioncomposition..
••ConcentrationConcentration ofof initiatorinitiator andand inhibitorinhibitor..
••TransmissionTransmission ofof lightlight..
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Degree of Conversion ( DC)Degree of Conversion ( DC)Degree of Conversion ( DC)Degree of Conversion ( DC)Degree of Conversion ( DC)Degree of Conversion ( DC)Degree of Conversion ( DC)Degree of Conversion ( DC)
••TransmissionTransmission ofof lightlight ..
Dental Curing LightsDental Curing Lights
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New Types ofNew Types of
Light SourcesLight Sources
•• Traditional Halogen lightTraditional Halogen light
•• Argon beam laserArgon beam laser
•• Plasma arcPlasma arc
•• Light emitting Diode (LED)Light emitting Diode (LED)
TYPES OF LIGHT SOURCES
• Quartz halogen
Tungstun halogen
lamp produces blue
light radiation at468
nm. After filtering
both IR and UV .
Irradiation is
transmitted through a
fiber optic tip
• Light emitting diodes
(LED)
• Junctions of doped
semi conductors (p-n)
junctions are used for
generation of light
instead of a hot
filament.the spectral
output is within the
absorption of CQ
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WAVELENGTH (nm)WAVELENGTH (nm)
UVUV VisibleVisible IRIRCQCQ
INTRAPULPAL HEAT,INTRAPULPAL HEAT,GINGIVAL IRRITATIONGINGIVAL IRRITATION
INTENSITY
INTENSITY
UV
UV
band
band--pass
pass
filter
filter
IRIR band
band--pass
pass
filter
filter
•• Power SupplyPower Supply•• Cycle Timer (Circuit Board)Cycle Timer (Circuit Board)•• BulbBulb / Reflector/ Reflector•• FilterFilter•• FanFan•• FiberFiber--Optic TrainOptic Train
Advantages and Disadvantages of
Other Light Sources
Argon Laser and Plasma Arc•More specific to the absorption of CQ Shorter exposure times •Higher intensities ( 1000 mW )and shorter curing times 1-3 seconds Disadv: early termination of polymerization reaction lead to less chain length is less average mol w
LED •Developed to overcome problems of QTH •They are light in weight Cable free (Cordless)•NO bulb fails•Higher efficiency than QTH •No need for filters to filter unwanted UV and infra red radiation •No noisy fan and less heat generated •Ergonomic design
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Acid Etch TechniqueAcid Etch TechniqueAcid Etch TechniqueAcid Etch TechniqueAcid Etch TechniqueAcid Etch TechniqueAcid Etch TechniqueAcid Etch Technique
•• BunocoreBunocore 19551955
•• AimAim:: toto overcomeovercome thethe problemproblem ofof micromicroleakageleakage.... ToTo provideprovide aa goodgood bondbondbetweenbetween thethe resinresin andand tooth,tooth, improvesimprovesmarginalmarginal seal,seal, reducereduce marginalmarginal stainingstaining
•• MechanismMechanism:: 3737%% phosphoricphosphoric acidacid liquidliquidoror gelgel givesgives opaqueopaque whitewhite chalkychalkyenamelenamel
•• EtchEtch ((3030secssecs forfor enamelenamel 1515 forfor dentinedentine))--washwash ((4545secs)secs)--drydry ((1515secs)secs) applyapply
Mechanism of Acid EtchingMechanism of Acid EtchingMechanism of Acid EtchingMechanism of Acid EtchingMechanism of Acid EtchingMechanism of Acid EtchingMechanism of Acid EtchingMechanism of Acid Etching
•• RemovesRemoves surfacesurface debrisdebris
•• SelectiveSelective dissolutiondissolution ofof enamelenamel prismsprisms------roughrough porousporous surfacesurface
•• IncreasesIncreases thethe surfacesurface energyenergy ofof enamelenamelandand helpshelps wettingwetting byby thethe adhesiveadhesive
•• IncreasesIncreases thethe surfacesurface areaarea ofof enamelenamel
•• EnamelEnamel bondingbonding agentagent (diluted(diluted BISBIS--GMA)GMA) cancan flowflow andand fillfill thethe producedproducedirregularitiesirregularities bondbond byby mechanicalmechanicalinterlockinginterlocking ResinResin TagsTags
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٤٠٤٠
ETCHETCHETCHETCHETCHETCHETCHETCH
Wash & Wash & Wash & Wash & Wash & Wash & Wash & Wash &
drydrydrydrydrydrydrydry
ApplyApplyApplyApplyApplyApplyApplyApply
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How does composite resin bond to
tooth enamel and dentin?1. Etchant 37% phosphoric acid produces micro-
irregularities in enamel, and opens DT removing the smear layer.
Etched EnamelEtched Enamel
Etched DentinEtched Dentin
••Mechanical Mechanical propertiesproperties
••Polymerization Polymerization shrinkageshrinkage
••Water sorptionWater sorption
••Thermal propertiesThermal properties
••# coefficient# coefficient
••# conductivity# conductivity
••Color stabilityColor stability
••Radio opacityRadio opacity
•• CompressiveCompressivestrengthstrength
•• TensileTensile strengthstrength
•• ModulusModulus ofof elasticityelasticity
•• HardnessHardness
Properties of CompositesProperties of CompositesProperties of CompositesProperties of CompositesProperties of CompositesProperties of CompositesProperties of CompositesProperties of Composites
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٤٢٤٢
Compressive and tensile strengths and E.modulusCompressive and tensile strengths and E.modulus
•• CompressiveCompressive strengthstrengthisis higherhigher forfor finefine andandhybridhybrid duedue toto higherhighervolumevolume fractionfraction ofof fillersfillers
•• LowLow tensiletensile strengthstrengthreflectsreflects brittlebrittle behaviorbehaviorofof compositescomposites
•• ModulusModulus ofof elastictyelasticty forformicrofilledmicrofilled CompositesComposites
•• IsIs ¼¼ thatthat ofof finefineparticlesparticles
••DependsDepends onon thethe amountamount ofof fillersfillers
••ModulusModulus ofof elasticityelasticity ofof microfilledmicrofilled
compositecomposite isis ¼¼ 00rr ½½ thatthat ofof finefine particleparticle
compositecomposite
••HighHigh modulusmodulus isis essentialessential inin highhigh stressstress
bearingbearing areasareas toto minimizeminimize wearwear
••HARDNESSHARDNESS:: relatedrelated toto thethe fillerfiller contentcontent
ratherrather thanthan thethe hardnesshardness ofof thethe fillersfillers
themselvesthemselves
••CanCan bebe measuredmeasured usingusing microindentationmicroindentation
teststests
Modulus of ElasticityModulus of ElasticityModulus of ElasticityModulus of ElasticityModulus of ElasticityModulus of ElasticityModulus of ElasticityModulus of Elasticity
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Polymerization Shrinkage
• Significant role in restoration failure
– gap formation
• secondary caries formation
• marginal leakage
• post-operative sensitivity
• Counteract
– lower shrinkage composites
– incremental placement
– Construct composite inlay
Polymerization ShrinkagePolymerization ShrinkagePolymerization ShrinkagePolymerization ShrinkagePolymerization ShrinkagePolymerization ShrinkagePolymerization ShrinkagePolymerization Shrinkage
Chemically Chemically Chemically Chemically Chemically Chemically Chemically Chemically
activated activated activated activated activated activated activated activated
LightLightLightLightLightLightLightLight
activated activated activated activated activated activated activated activated
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٤٤٤٤
Physical properties
•Polymerized shrinkage–Microhybrid : 1.5-2%
––. . %%22--44 Microfilled :
–Polymerized stress :high as MPa
Self cure Light cureSelf cure Light cure
••Leads to marginal Leads to marginal micro leakagemicro leakage
••To overcome:To overcome:
••Place composite Place composite incrementally ORincrementally OR
••Construct Construct composite composite inlaysinlays either direct either direct (chair side (chair side technique) or technique) or indirectindirect
•• InlaysInlays areare subjectedsubjected totoadditionaladditional curingcuring byby
•• VisibleVisible lightlight
•• VisibleVisible lightlight andand heatheat
•• HeatHeat andand pressurepressure (at(at120120 OOCC andand 66 barbarpressurepressure forfor 1010 minmin..
•• CementationCementation:: dualdualcurecure resinresin cementcement
Polymerization ShrinkagePolymerization ShrinkagePolymerization ShrinkagePolymerization ShrinkagePolymerization ShrinkagePolymerization ShrinkagePolymerization ShrinkagePolymerization Shrinkage
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••ConductivityConductivity ofof resinresin compositecomposite ss isis
muchmuch lowerlower thanthan metallicmetallic fillingfilling
materialsmaterials
••TheyThey provideprovide goodgood thermalthermal insulationinsulation toto
thethe pulppulp
••ExpansionExpansion ::thethe higherhigher thethe amountamount ofof
organicorganic matrixmatrix phasephase thethe higherhigher thethe
expansionexpansion
Thermal Conductivity & Thermal Conductivity & Thermal Conductivity & Thermal Conductivity & Thermal Conductivity & Thermal Conductivity & Thermal Conductivity & Thermal Conductivity &
Thermal ExpansionThermal ExpansionThermal ExpansionThermal ExpansionThermal ExpansionThermal ExpansionThermal ExpansionThermal Expansion
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••TheThe organicorganic matrixmatrix isis responsibleresponsible forfor
thethe absorptionabsorption ofof waterwater whichwhich isis
accompaniedaccompanied byby swellingswelling ofof compositecomposite
howeverhowever itit isis notnot effectiveeffective inin
counteractingcounteracting thethe effecteffect ofof
polymerizationpolymerization shrinkageshrinkage..
••ThisThis phenomenonphenomenon isis inin partpart responsibleresponsible
forfor discolorationdiscoloration ofof compositecomposite byby waterwater
solublesoluble stainsstains..
Water SorptionWater SorptionWater SorptionWater SorptionWater SorptionWater SorptionWater SorptionWater Sorption
••NotNot allall compositescomposites appearappear radioradio
opaqueopaque inin dentaldental radiographsradiographs..
•• ItIt mustmust containcontain heavyheavy metalmetal elementselements
suchsuch asas bariumbarium ,strontium,,strontium, zirconiumzirconium
toto bebe radioradio opaqueopaque inin dentaldental
radiographicradiographic filmsfilms..
Radio OpacityRadio OpacityRadio OpacityRadio OpacityRadio OpacityRadio OpacityRadio OpacityRadio Opacity
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Factors Contributing to Wear
••PorosityPorosity
••Filler content and filler particle sizeFiller content and filler particle size
••Degree of polymerizationDegree of polymerization
••HardnessHardness
•• Interfacial bondingInterfacial bonding
••Position of tooth in the dental archPosition of tooth in the dental arch
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Properties of CompositesProperties of CompositesProperties of CompositesProperties of CompositesProperties of CompositesProperties of CompositesProperties of CompositesProperties of Composites
Property Property MicrofineMicrofine Hybrid Fine Hybrid Fine MacrofilledMacrofilled
•• Filler Filler 2020--55 6055 60--65 6065 60--77 5077 50--6565
Content Content
VolVol %%
•• PolymPolym. . 22--4 14 1..55--4 14 1--11..7 17 1--11..77
Shrink %Shrink %
•• Coefficient Coefficient 5050--68 2068 20--40 1940 19--38 1738 17--3535
Thermal expThermal exp
OCxOCx101066
•• Water Water sorpsorp 11..22--22..2 02 0..55--00..7 07 0..33--00..6 06 0..33--00..77
mg/cmmg/cm22
..
..
..
..
PropertiesClassification
Hard, rough surfaces over time,
abrades enamel and poor wear
resistance; difficult to polishMacrofilled (Traditional)
Poor mechanical properties (use
in low stress areas), excellent for
polishing, decreased shrinkage,
increased wear resistance but
debatable
Microfilled
Good mechanical properties,
better polishes than macrofilled,
better
wear resistance than microfilled
Hybrid
Better polish, mechanical
properties similar to hybrids.
Continuum filled Better polish,
mechanical properties similar to
hybrids
Micro-Hybrid
Good mechanical properties,
excellent polishNanofilled.
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Applications: (uses)Applications: (uses)
-- AsAs anan anterioranterior restorativerestorative materialmaterial forfor classclass IIIIII &&classclass IVIV (especially(especially microfilledmicrofilled composites)composites)
-- HybridsHybrids cancan nownow bebe usedused inin smallsmall classclass IIII andandclassclass II (especially(especially radiopaqueradiopaque types)types)
-- AsAs corecore buildbuild upup materialsmaterials
-- AsAs laminatelaminate veneersveneers << facialfacial && labiallabial surfacessurfaces ofofnaturalnatural teeth)teeth)
-- ForFor cementationcementation ofof resinresin bondedbonded bridgesbridgesmarylandmaryland && rochetterochette typestypes
-- DiastemaDiastema closureclosure
-- CementationCementation ofof orthodonticorthodontic bracketsbrackets
-- PitPit && fissurefissure sealantssealants
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٥٠٥٠
UnfinishedComposite Surface Finished
Composite SurfaceEnamelSurface
EtchedEnamel Rods
Voids atMargins
SilicateReinforcing Filler
CrosslinkedResin Matrix
COMPOSITE
INTERFACEINTERFACE INTERFACE
INTERFACE
INTERFACE
DEFINITION OF COMPOSITEPhases and Interfaces
50 v/o filler = 75 w/o filler
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Different Types of Composites according to Filler Different Types of Composites according to Filler Different Types of Composites according to Filler Different Types of Composites according to Filler Different Types of Composites according to Filler Different Types of Composites according to Filler Different Types of Composites according to Filler Different Types of Composites according to Filler
Particle SizeParticle SizeParticle SizeParticle SizeParticle SizeParticle SizeParticle SizeParticle Size
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٥٢٥٢
Different Types of Composites according to Filler Different Types of Composites according to Filler Different Types of Composites according to Filler Different Types of Composites according to Filler Different Types of Composites according to Filler Different Types of Composites according to Filler Different Types of Composites according to Filler Different Types of Composites according to Filler
Particle SizeParticle SizeParticle SizeParticle SizeParticle SizeParticle SizeParticle SizeParticle Size
MEGAFILL MACROFILL MIDIFILL MINIFILL MICROFILL NANOFILL
Not
Shown
Not
Shown
DifferentFiller Particle
Sizes
HYBRID(MIDIFILL)
HYBRID(MINIFILL)
MixturesOf FillerSizes
Hetero-geneousMIDIFILL
Hetero-geneousMINIFILL
Hetero-geneousMICROFILL
Not
Shown
Not
Shown
MixturesOf Pre-Cured
Pieces ofComposite
FILLER PARTICLESSchematic Examples
HOW DO YOU MAKE FILLERS?• Crushing, Grinding, Sieving
• Vapor Phase Condensation
• Sol-Gel Precipitation
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••FlowableFlowable::
••Reduced filler level to Reduced filler level to allow the material to flow allow the material to flow readily and adapt readily and adapt intimately to cavity wall.intimately to cavity wall.
••More susceptible to wear More susceptible to wear
••Lower strengthLower strength
••Used as liner and in class Used as liner and in class V cavitiesV cavities
••Packable :Packable :
••Contain elongated fibrous Contain elongated fibrous filler particles(filler particles(100 100 micron in micron in length which may be length which may be textured to resist flow and textured to resist flow and interlock with the resininterlock with the resin
••Sculpt able and non Sculpt able and non slumping similar to slumping similar to amalgam in placement amalgam in placement techniquetechnique
••Less sticky Less sticky
••Used in large posterior Used in large posterior restorations to establish restorations to establish contact areas and occlusal contact areas and occlusal anatomy.anatomy.
Packable and Packable and Packable and Packable and Packable and Packable and Packable and Packable and FlowableFlowableFlowableFlowableFlowableFlowableFlowableFlowable CompositesCompositesCompositesCompositesCompositesCompositesCompositesComposites
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Coupling agent
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Visible-Light Activation
• single paste in an opaque syringe
• Photo-initiator (camphorquinone ) reacts
with amine activator
• Forms free radicals
• Initiates addition polymerization
– monomer
• Bis-GMA
••Direct viewing will Direct viewing will
damage the eyedamage the eye
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TYPES OF LIGHT SOURCES
• PLASMA ARC
• A xenon short arc lamp is used for curing
• DC. Discharge is passed between two electrodes in a gas which become ionized producing a combination of electrons &+ve ions
• ARGON LASER
• Beams of photons
emitted in phase. The
emission wave length
corresponds to the
absorption spectrum
of CQ
Methods of CuringMethods of Curing
•• SoftSoft startstart oror RampedRamped:: 11stst stepstep (initial(initialcure)cure) slowslow irradiationirradiation atat lowlow energyenergy ee..gg..atat 150150mW/mW/ cmcm22 toto reducereduce earlyearly stiffeningstiffeningandand contractioncontraction stressstress buildbuild upup andandpromotepromote marginalmarginal integrityintegrity
•• 22ndnd stepstep (final(final cure)cure) prolongedprolonged irradiationirradiationatat higherhigher energyenergy 650650 mWmW/cm/cm22 toto achieveachievebetterbetter physicalphysical andand mechanicalmechanicalpropertiesproperties
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Methods of Curing (cont.)Methods of Curing (cont.)
PulsePulse delaydelay::•• InitialInitial curecure atat 200200mW/mW/ cmcm22 forfor 33 secssecs..33 minutesminutes RESTREST..
•• FinalFinal curecure atat 500500--600600mW/mW/ cmcm 22 forfor 3030secssecs..
Visible light source
• The radiation beam is transmitted to the
tooth surface by a quartz rod.
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Photo-initiator
• Camphorquinone (CQ)
– most common
photo-absorbing material
– maximum sensitivity
• blue range (465 nm)
Aim of Light Curing
1. Short irradiation time.
2. Low shrinkage stress.
3. Uniform degree of
conversion of polymer
throughout the whole
mass of composite.
4. To overcome the problems of chemical
activation, such as air incorporation in the mix
leading to porosity and oxygen inhibition of
polymerization and uncontrolled working time.
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Advantages of Light Cure Advantages of Light Cure
Vs . Chemical CureVs . Chemical Cure
•• CompleteComplete controlcontrol overover workingworking timetime
(command(command cure)cure)
•• NoNo mixingmixing–– lessless voidsvoids withinwithin thethe massmass
•• LessLess finishingfinishing timetime
•• MoreMore colourcolour stablestable andand wearwear resistantresistant
•• DisadvantagesDisadvantages extraextra costcost ofof lightlight curingcuring
unitunit--depthdepth ofof curecure dependsdepends onon shadeshade andand
opacityopacity--highhigh intensityintensity …… hazardhazard toto thethe eyeeye
Manipulation of Chemically Activated Manipulation of Chemically Activated Manipulation of Chemically Activated Manipulation of Chemically Activated Manipulation of Chemically Activated Manipulation of Chemically Activated Manipulation of Chemically Activated Manipulation of Chemically Activated
CompositesCompositesCompositesCompositesCompositesCompositesCompositesComposites
SelectSelect properproper shadeshade..
InIn deepdeep cavitiescavities placeplace calciumcalcium hydroxidehydroxide oror glassglass ionomerionomercementcement..
NeverNever useuse eugenoleugenol containingcontaining cementscements asas theythey inhibitinhibitpolymerizationpolymerization ofof compositescomposites..
AvoidAvoid crosscross contaminationcontamination (double(double--endedended plasticplasticspatula)spatula) avoidavoid metalmetal spatulasspatulas
TwoTwo pastespastes systemsystem:: equalequal volumesvolumes areare mixedmixed onon paperpaperpadpad mixingmixing timetime 2020--3030 secssecs
WorkingWorking timetime 11..55--22 minmin–– settingsetting ==33--55 minmin
AvoidAvoid trappingtrapping voidsvoids;; bulkbulk packpack techniquetechnique
ContourContour:: celluloidcelluloid ((mylarmylar)) stripstrip
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Light Activated Light Activated Light Activated Light Activated Light Activated Light Activated Light Activated Light Activated
Systems ManipulationSystems ManipulationSystems ManipulationSystems ManipulationSystems ManipulationSystems ManipulationSystems ManipulationSystems Manipulation
•• SelectSelect properproper shadeshade..
•• InIn deepdeep cavitiescavities placeplace calciumcalciumhydroxidehydroxide oror glassglass ionomerionomer cementcement..
•• NeverNever useuse eugenoleugenol containingcontainingcementscements asas theythey inhibitinhibit polymerizationpolymerizationofof compositescomposites..
•• PlacePlace compositecomposite inin incrementsincrements 22mmmm..EachEach curecure forfor 2020--4040 secssecs..
•• AfterAfter 22--66minmin.. StartStart finishingfinishing andandpolishingpolishing..
INCREMENTAL PLACEMENT TECHNIQUESINCREMENTAL PLACEMENT TECHNIQUES
•• ObliqueOblique incrementalincremental
•• LateralLateral incrementalincremental
•• Directional curing Directional curing technique(light technique(light transmitting wedges and transmitting wedges and transparent matrices)transparent matrices)
•• AimAim ::minimizingminimizing adverseadverseeffecteffect ofof polymerizationpolymerizationshrinkageshrinkage
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