Composite resins are commonly used as dental restorative materials. They have improved over time with lower polymerization shrinkage and better bonding to tooth structure. For posterior class 2 cavities, composites can be used when certain criteria are met, such as avoiding heavy occlusal stress areas or sites without isolation. Placement techniques aim to reduce shrinkage stresses, such as multi-directional curing of thin increments and use of matrices.

1. COMPOSITES
FOR CLASS II
CAVITIES
SEMINAR-DEPARTMENT OF
CONSERVATIVE DENTISTRY&
ENDODONTICS
VESTA ENIDLYDIA .R
III BDS
CSICDSR-MADURAI

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Dentalcompositeresins
are types of synthetic resins which are used in dentistry as
restorative material or adhesives.
Synthetic resins evolved as restorative materials since they
were insoluble, aesthetic, and insensitive to dehydration and
were inexpensive.
It is easy to manipulate them as well.
Composite resins are most commonly composed of Bis-GMA
monomers or some Bis-GMA analog, a filler material such as
silica and in most current applications, a photoinitiator.
Dimethacrylates are also commonly added to achieve certain
physical properties such as flowability.
Further tailoring of physical properties is achieved by
formulating unique concentrations of each constituent.

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Historyof use
Initially, composite restorations in dentistry were very prone
to leakage and breakage due to weak compressive strength
In the 1990s and 2000s, composites were greatly improved
and are said to have a compression strength sufficient for
use in posterior teeth.
Today's composite resins have low polymerization shrinkage
and low coefficients of thermal shrinkage, which allows
them to be placed in bulk while maintaining good
adaptation to cavity walls.
The placement of composite requires meticulous attention to
procedure or it may fail prematurely
ADA STATEMENT ON
POSTERIOR RESIN-BASED
COMPOSITES
1.composites used successfully till date in
o CLASS V RESTORATIONS.

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o RESTORINGESTHETICALLYIMPORTANT
AREAS.
o IN PATIENTSALLERGICOR SENSITIVE
TO METALS.
2.other places where composites can be
used are
o PIT AND FISSURESEALING.
o PREVENTIVERESIN RESTORATIONS.
o INITIALCLASS I AND II LESIONS.
 MODERATE-SIZED CLASS I AND II
RESTORATIONS
3.LITERATURE DOES NOT
SUPPORT THE SUCCESFULL
USE IN
o TEETHWITHHEAVYOCCLUSALSTRESS.
o IN SITESTHAT CAN’T BE ISOLATED.
IN PATIENTSALLERGICTO RESIN-BASED
COMPOSITES.

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4.FUTURE RESEARCH IN
COMPOSITESSHOULD
ADDRESS
o REDUCTIONIN POLYMERIZATION
SHRINKAGE.
o IMPROVED DENTIN/ENAMELBONDING
TECHNIQUES.
o IMPROVED PLACEMENT AND
INSTRUMENTATION TECHNIQUES.
o IMPROVED CURING METHODS.
o CONTACT WEAR BEHAVIOR.
o POLYMERIZATIONINITIATORS.
o ALTERNATIVEMATRIX SYSTEMS.
o MORE EXTENSIVERESTORATIONS??
CASE SELECTION
 Cavity preparationdesign
 Locationof margin

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 Locationof restoration
 Sizeof restoration
 OCCLUSIONCONCERNS/ANTAGONISTICCUSP:

o GREATLYAFFECTS DEGRADATION OF
COMPOSITE.
o INCREASEDLOCALIZEDWEAR ON THE
COMPOSITE SURFACE WITHINCREASED
CONTACT AREA.
o INCREASEDGENERALIZED WEARON
THE CONTACT FREEAREA.
o BULK FRACTURE AND MARGINAL
DETERIORATION.
ANTAGONISTICCUSP:
o PRE-OP: USE OF ARTICULATINGPAPER.
o DESIGNOUTLINE FORM TO AVOID
CONTACT AREA.

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o MODIFYTHE OPPOSINGCUSP TO
REDIRECT THE CONTACT AREAAWAY
FROM RESTORATION.
o ENAMELOPLASTYOF OPPOSINGCUSP TO
FLATTENTHE OCCLUSALLOAD OVER A
WIDERAREA.
MATERIAL OPTIONS
 HYBRIDRESIN
 MICROFILL ED RESIN
 HYBRIDRESIN INTERNAL& MICROFILL
RESIN ON OUTER 1 MM.
 PACKABLERESIN
 PACKABLERESINWITHMICROFILLON
OUTER 1 MM.
CLINICAL TECHNIQUE
ISOLATION
RECOMMENDATIONS

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 RubberDam Isolationis Mandatory:
o Failureto maintaina dryfieldwillresultin
clinicalfailure.
o Preventionof moisturecontaminationand
protectionof gingivaltissues is of paramount
importance.
o Selectshadebeforerubberdam application.
 Dentinshadeup to the DEJ level.
 Incisal or enamelshadefor finalincrement.
PRE-WEDGING
 Gains interproximalseparationto facilitatetight
contactarea.
 INITIAL: 90 um movement.
 AFTER 30 SECONDS:
o 30 um is lost.
 90% RECOVERY: within30 seconds
removalof wedge.
CAVITYPREPARATION

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 ADHESIVE PREPARATION FOR POSTERIOR
COMPOSITES
 DIFFERSFROM TRADITIONAL AMALGAM
PREPARATIONSIN MANY WAYS.
 PREPARATION IS SHALLOWER.
 RETENTIONIS PROVIDEDTHROUGH
BONDING
 PREPARATION IS NARROWER:
o 1. LESS OCCLUSALCONTACT AREA.
o 2. REDUCESWEAR.
o 3. DECREASES AFFECT OF
POLYMERIZATION SHRINKAGE.
o 4. IMPROVED MARGINALINTEGRITY.
o 5. LESS CUSPALDEFLECTION.
 PREPARATION HAS ROUNDEDINTERNALLINEANGLES:
o 1. CONSERVES TOOTHSTRUCTURE.

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o 2. DECREASES STRESSCONCENTRATION.
o 3. ENHANCES RESINADAPTATION
DURING PLACEMENT.
 NO EXTENSIONFORPREVENTION:
o 1. OCCLUSALSURFACEIS INVADED
ONLY IF CARIES DICTATES IT.
o 2. TREAT ADJACENT PITSAND FISSURES
WITHSEALANTS.
PROXIMAL BOX
PREPARATIONCONCERNS
 SLOT PREPARATIONS:
o MECHANICALRETENTIONISN’T
IMPORTANT.
o DON’T EXTEND THEPREPARATION
BEYOND THEMARGINAL RIDGEBY
MORE THAN 2 MM.

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GINGIVAL MARGIN
CONCERNS
 SLOT PREPARATION OR CONVENTIONAL CLASSII PREP:
o GINGIVALFLOOR EXTENDED ONLY TO
DEPTHOF CARIOUSLESION.
o CONSERVEENAMELFOR BONDING AND
MICROLEAKAGEPREVENTION.
OCCLUSAL MARGIN OF
PREPARATION
o BEVELED OCCLUSALCAVOSURFACE
MARGIN:
o SIGNIFICANTLYINCREASES THEWEAR
RATE COMPAREDTO CONVENTIONAL
BUTT JOINT CAVOSURFACEMARGINS.
o WHY? THEBU-LIDIMENSION IS
INCREASEDAND INFLUENCES THE
AFFECT OF THE ANTAGONISTICCUSP
PULPAL PROTECTION

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 Postoperativesensitivity concerns:
o effects of polymerizationcontractionand/or
marginalleakagewithbacterialinvasion.
o Hermetically sealthe dentinwithyourchoiceof
dentinbonding agent material.
o Placea light curableresinmodifiedglass ionomer
cement that has the fluoridereleasingproperties
you may desire.
DENTIN/ENAMEL BONDING
 AnotherClinicalDecisionto Make:
o yourchoiceof one of the currently availabledentin
bondingagents followingthe manufacturer’s
instructions.
CRITERIA FOR MATRICES
 RE-ESTABLISHCONTOUR
 FORM POSITIVECONTACT
 SEAL GINGIVALMARGIN
 ALLOW ADEQUATE BULK OF MATERIAL

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 LIMITEDTHICKNESS
 PRODUCESMOOTHSURFACE
CRITERIA FOR MATRICES
 PERMIT NON-DISRUPTIVEWITHDRAWAL
 MUST AVOIDTOOTH DISTORTING
PRESSURES
 MUST BE EASY TO PLACE
 ALLOW FOR A VARIETY OF RESTORATIVE
MATERIALS
COMPOSITE PLACEMENT
TECHNIQUES
 1.SEGMENTALPLACEMENT: < 5.0 MM.

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o 1. FLOWABLERESIN(0.5-1.0MM LAYER)
o 2. DENTINSHADEOF PACKABLERESIN.
NO MORE THAN 3.0-3.5MM
INCREMENTS.
o 3. TINT PLACEMENT (OPTIONAL).
o 4. ENAMELSHADE(UNIVERSAL
HYBRID)
 2.BULKFILLTECHNIQUE:
o A MAJOR CLAIMOF PACKABLE
COMPOSITE MANUFACTURERS.
o Incrementsshouldbe no greaterthan2mm to
obtaina uniformand maximumcure.
o Increasecavitydepthresultedin decreased
effectivenessof polymerizationforall exposure
times.
o Increasedexposuretimeresultedin an increased
hardnessratio and effectivepolymerizationat
depths of 3-4 mm.

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THREE-SITED
LIGHT CURING
TECHNIQUE
 FIRSTINCREMENT:
o CURED THROUGHTHELIGHT-
REFLECTINGWEDGE IN A GINGIVAL-
PROXIMALDIRECTION.
 LARGER 2ND
and 3RD
INCREMENT:
o CURED FROM BUCCALAND LINGUAL.
o ENSURESSHRINKAGE VECTORS
TOWARD THECAVITY MARGINS.
 FINALINCREMENT:

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o ADDED TO THE OCCLUSALASPECT.
FINISHING PROCEDURES
 12-B BLADETO REMOVEINTERPROXIMAL
GINGIVALEXCESS.
 FINE-DIAMOND FINISHINGSTRIPS.
 ALUMINUM OXIDEFINISHINGDISCS.
 CARBIDE FINISHINGBURS.