CONTENTSIntroductionHistoryDefinitionIndicationsContraindicationsAdvantagesDisadvantagesClassificationCompositionTypes of compositesRecent advances

• Mode of supply• Curing and curing lamps• Properties• Clinical techniques• Finishing and polishing• Repair of composites• Tunnel restorations• Sandwich technique • Conclusion• References

INTRODUCTIONComposite resins are a class of mature and well

established restorative materials that have their own indication in anterior and posterior teeth.

Dental composites have continued to evolve with the development of smaller particle sizes, better bonding systems, curing refinements and sealing systems. Although composites are now well accepted in general practice, the complex steps involved have hindered their full success.

HISTORICAL DEVELOPMENT During the first half of the 20th century, silicates

were the only tooth coloured esthetic material available for cavity restoration.

Acrylic resins similar to those used for custom impression trays and dentures replaced silicates during the late 1940s and the early 1950s because of their tooth like appearance , insolubility in oral fluids, ease of manipulation and low cost.

In 1956, Dr. R.L. Bowen developed a polymer based on dimethacrylate chemistry.

This polymer was generally known as Bis-GMA or Bowen resin, was made up from the combination of bisphenol – A and glycidyl methacrylate.

1956 - Bowen Resin

1960 - Traditional or Macrofilled composites

1970 - Mircofilled and Light initiated composites

1980 - Posterior composites

1990 - Hybrid, Flowable, Packable, Compomers

2000 - Nanofilled composites

DEFINITIONSKINNER’S

A highly cross linked polymeric material reinforced by a

dispersion of amorphous silica, glass, crystalline or organic

resin filler particles and/or short fibers bonded to the matrix

by a coupling agent.DCNA

A 3 dimensional combination of at least two chemically

different materials with a distinct interface separating the

components.

STURDEVANTIn materials and science word composite refers to

a solid formed from two or more distinct phases that have been combined to produce properties superior to or intermediate to those of individual constituents.

INDICATIONSClass I, II, III, IV, V, VI

core buildups

Sealants and preventive resin

restorations

Esthetic enhancement

procedures

Cements

Veneering metal

crowns/bridges

Temporary restorations

Periodontal splinting

Non carious lesions

Enamel hypoplasia

Composite inlays

Repair of old composite

restoration

Patients allergic to metals

CONTRAINDICATIONSIsolation

Occlusion

Subgingival area/root surface

Poor oral hygiene

High caries index

Habits (bruxism)

Operator abilities

ADVANTAGESEsthetics

Conservation

Less complex

Used almost universally

Strengthening

Bonded to tooth structure

RepairableNo corrosionNo health hazardCheaper then porcelain

DISADVANTAGESPolymerization shrinkage

Technique sensitive

Higher coeff. Of thermal expansion

Difficult, time consuming

Increased occlusal wear

Low modulus of elasticity

Lack of anticariogenic property

Staining

Costly

CLASSIFICATIONSKINNER’S (10th ed)

Traditional composites (Macrofilled) 8-12µm

Small particle filled composite – 1-5µm

Microfilled composite – 0.04 – 0.4 µm

Hybrid composite – 0.6 – 1 µm

• ANUSAVICE (-11th ed)

STURDEVANTClassification of composites based on the filler particle

sizeMegafill- in this one or two large glass inserts 0.5 to 2 mm

in size are placed into composites at points of occlusal contact.

Macrofill- particle size range between 10 to 100 µm in diameter

Midifill - particle size range between 1 to 10 µm in diameter, also called traditional or conventional composites.

Minifill - particle size range between 0.1 to 1 µm in diameter

Microfill - particle size range between 0.01 to 0.1 µmNanofill - particle size range between 0.005 to 0.01 µm

As per filler size

According to CRAIG: TYPE I:

Class 1 – Macrosized particles – 8-25µ Class 2 – Mini size particles – 1-8µ Class 3 – Micro size particles – 0.04-0.2µ Class 4 – Blend of macro and micro – 0.04-10µ

TYPE II Class 1: Macrosized 10-20µm (organic particles

in unreinforced resin matrix). Class 2: Macrosize unreinforced particles 10-

20µ (organic in reinforced resin matrix 0.04-0.2µ organic).

MODE OF PRESENTATION

METHODS OF POLYMERIZATION

COMPOSITION

Resin matrix

Inorganic Fillers

FILLER SHAPESLarge spherical

particlesLarge irregularly

shaped particlesBlends

Filler particles are most commonly produced by grinding or milling quartz or glasses to produce particles ranging in size from 0.1-100um. Submicron silica particles of colloidal size (0.04um),referred to as microfillers, are obtained by a pyrolytic or precipitation process.In these processes a silicon compound is burned in an O2 and H2 atmosphere to form macromolecule chains of SiO2.

Material Used:

Classification of fillersi): Quartz: It is made by grinding or milling quartz, was used in early composites.it is chemically inert.

Because of its hardness it was difficult to grind to a finer size & was difficult to polish, causes abrasion of opposing tooth structure.

ii) SILICA :obtained by a pyrolytic or precipitation process.Apart from reinforcing the composite ,it also helps in high scattering and light transmission.

Forms of silica: Forms of silica: - Pure silica. - Fused silica. - colloidal silica.

iii) GLASSES: Aluminosilicates & Borosilicates.provides radiopacity.

Other fillers: Tricalcium phosphate & Zirconium

dioxide. Recently fluoridefluoride fillers like: Yittrium trifluoride &

Yitterbium trifluoride are introduced. - to ensure acceptable esthetics of composite translucency

of fillers should be similar to tooth structure.

Coupling agents

H2O

Activator-initiator system

HEAT ,LIGHT AND SOME CHEMICALS CAUSES DECOMPOSITION OF BP RESULTING IN FREE RADICALS THAT INITIATE POLYMERISATION .

HENCE IT IS RECOMMENDED THAT COMPOSITE SHOULD STORED IN COOL ,DARK ,CLEAN ENVIORNMENT .

USES-RESTORATIONS AND LARGE FOUNDATION STRUCTURES THAT ARE NOT EASILY CURED WITH A LIGHT SOURCE.

THESE COMPOUND ABSORBS LIGHT(VISIBLE AND UV) AND GENERATE FREE RADICALS .

FOR SYSTEM USING ULTRAVIOLET LIGHT INITATION BENZION ALKYL ESTER IS USED AS INITIATORS.

FOR SYSTEMS USING VISIBLE LIGHT A DIAKETONE SUCH AS CAMPHOROQUINONE (APP.0.2%) IS USED .

CQ ABSORBS BLUE LIGHT (400-500NM),PRODUCES AN EXCITED STATE OF CQ+AMINE FREE RADICALS.

INHIBITORSButylated hydroxytoluene (BHT)-0.01%4 –Methoxy phenol (PMP)Extends storage life and provides sufficient working

time THESE COMPOUNDS ARE USED IN AMOUNTS OF

0.1 % OR LESS

OPTICAL MODIFIERSPigments-metal oxidesOpacifiers-titanium dioxide & aluminum oxide-0.001-

0.007%Darker shade & opacifier-thin layersUV light absorbers

TYPES OF COMPOSITES

TRADITIONAL COMPOSITES

SMALL PARTICLE COMPOSITES

MICROFILLED COMPOSITES

Prepolymerized paricles(organic fillers)+colloidal silica+monomer

microfilled composite paste

HYBRID COMPOSITES

Nanofilled Composites

These particles are extremely small (0.005- 0.01 µm) and virtually invisible.

Their particle size is below range of wavelength of light and thus they do not absorb or scatter visible light.

Nanofiller offers means of incorporating radiopacifiers that do not interfere with esthetic properties

THANK YOU

“The world hates change, yet it is the only thing

that has brought progress.”

-Charles Kettering

FLOWABLE COMPOSITESCreated for special handling properties – Fluid

injectibility.

Introduced in 1996, the flowable composites are characterized by the presence of filler particles that have a particle size similar to hybrid composite but the filler content is reduced which results in viscosity

They were launched to improve handling characteristics of existing composites

PROPERTIES

Filler size 0.6-1 µm Filler content 30-55 wt% Compressive strength 210-300 MPa Elastic modulus 4-8 GPa Flexural strength 70-120 MPa Depth of cure 6 mm

PACKABLE COMPOSITES

Based on newly introduced concept called PRIMM(Polymer rigid inorganic matrix material)

System consist of a resin and a ceramic component Filler phase instead of being incorporated are ground

particles present as a continuous network of ceramic fibers Fibers composed of alumina & silica which are

superficially fused to each other at specific sites to generate a continuous network of small components

Silanization of the fibrous network is done by infiltration with BiSGMA resin

Consistency of PRIMM based composite is similar to freshly triturated mass of amalgam

PROPERTIES Inorganic filler 65-81 wt % Compressive strength 220-300 MPa Flexural strength 85-100 MPa Tensile strength 40-45 MPa Elastic modulus 3-13 GPa Depth of cure 6 mm

Antibacterial Composites

Composites that offer antibacterial properties are promising since several studies have shown that a greater amount of bacteria and plaque accumulate on the surface of resin composite than on the surface of other restorative material / enamel surface.

Imazato et al 1994 incorporated a non-releasing newly synthesized monomer MDPB with anti-bacterial properties into resin composites.

MDPB is methacryloxy decyl pyridinium bromide. It was found to be effective against various streptococci

However, its activity against other important species in plaque formation like Actinomyces still needs to be investigated

Silver has also been added in composites to make it antibacterial

NANOCOMPOSITESInorganic Phase – nanosized – 0.1 to 100 nm.Increased overall filler level.

Are unable to scatter or absorb visible light.

Nanofillers - usually invisible and offer the advantage of optical property improvement

-Mitra e t al. , 2003

ORMOCERS“Organically Modified Ceramics.”

Chemically- Methacrylate Substituted Alkosilanes ie., Organic -Inorganic Copolymers.

Based on organically modified heteropolysiloxanes.Filler particles are incorporated into this cross-

linked inorganic and organic network matrix.

PROPERTIES

Compressive strength: 410 MPa

Filler Content: 77-80%

Polymerization shrinkage: 1.97 Vol. %

Elastic modulus: 13-14 GPa

Polish ability: high gloss

Color stability: no discoloration ISO 4049

COMPOMERSPolyacid modified resins:

Mc Le an & Nicho lso n defined it as:

“Materials that may contain either or both of the essential components of a glass ionomer cement but at levels insufficient to promote the acid-base curing reaction in the dark.”

Compomer monomers contain acidic functional acidic functional groupsgroups that can participate in an acid/base glass ionomer reaction following polymerization of the resin molecule

A resin polymerization takes place resin polymerization takes place with the compomers after the material has set completely. The glass-glass-ionomer reaction(acid/base) may then occurionomer reaction(acid/base) may then occur in the presence of water. In the presence of water from the oral cavity, the acid functional groups, which are attached to the monomer units, and have now become part of the polymerized material are able to react with the base (glass) to stimulate the glass ionomer reaction. Fluoride is released Fluoride is released as a result of this reaction.

Paste containing Ca, Al, F silicate glass filler in dimethacrylate monomers with acrylic acid like molecules.

Set by polymerization & then delayed acid/base reaction. Good strength, biocompatible, low solubility. Have higher wear than composite, lower F release than

conventional GIC.

INDICATIONS:INDICATIONS:Sealing and filling of occlusal pits and fissures.Restoration of deciduous teeth.Minimal cavity preparation or tunnel preparationAs a liner - cariostatic action is required.

Core-build – up.

Repair of defective margins in restorations.

Class V repairs.

Erosion

Retrograde filing materials

GIOMERSHybrid of Glass Ionomers & composites.Advantages of both.Resin based & Contain Pre-reacted Glass Ionomer

particles.Flourosilicate Glass + Polyacrlylic acid & resin.Giomers employ the use of (PRG) technology to form a

stable phase of GIC in the restoration and are also known as PRG composites

Giomers are light polymerized and require bonding system for adherence to enamel and dentin. The bonding system currently available is known as Reactmer bond (Shofu Inc. Kyoto, Japan).

Reactmer bond is the glass ionomer based, tricurable, all-in-one, filled adhesive based on PRG technology and consists of UDMA, HEMA, PRG filler, fluoroaluminosilicate glass, acetone, water and initiator.

SMART COMPOSITES

Ivoclair introduced a material in 1998 named Ariston pHC (pH control).

Releases Fluoride & Ca Hydroxide when the pH in restoration in the material is less than 5.5

Smart composites work based on the newly developed alkaline glass filler which will reduce secondary caries formation at the margin of a restoration by inhibiting bacterial growth. This results in a reduced demineralization and a buffering of the acid produced by caries forming microorganisms

Composition

The paste consists of mixture of different types of dimethacrylate (20.8 wt %),

Inorganic fillers Ba, Al and F silicate glass filler (1 μm)

Ytterbium triflouride

Silicon dioxide

Alkaline Ca silicate glass (1.6 μm) in dimethacrylate monomers.

It is filled 80% by weight and 60% by volume.

CEROMERSCeramic Optimised Resins

Laboratory processed inlays , onlays.

Some manufacturers – with fiber reinforcement for short span bridges

Three-dimensionally loaded fillers in a polymer matrix of which two are fluoride releasing

Material consists of a paste containing

Indications

Class I and II posterior restorations (stress bearing areas) Class III and IV anterior restorations Class V restorations cervical caries, root erosion, abfraction,

wedge-shaped defects Inlays/onlays with extraoral post-tempering

INDIRECT COMPOSITESArt glassBell glass HPClearfil CR inlayColtene inlay systemCristobalSculptureTargisTrue vitality Visio gem

MODE OF SUPPLYFor chemical cure-

syringes/tubsFor light cure-

spills/syringe/compules

CURINGCHEMICAL ACTIVATION

cold curing or self curingAdvantages

Even polymerization-75%

Disadvantages Oxygen inhibition

No control over Working time

LIGHT

ACTIVATIONUV light

Visible light

Advantages Easy to use, single paste

Less porosity

Less sensitive to oxygen

Command polymerization

Colour stability, colors can be optimized

Better mech properties

Setting time –faster cure

– Disadvantages• Increments• Time consuming• Poor accessibility • Variable exposure• Sensitive to ambient light• Shrinkage• Ocular damage• Cost

Comparison Chemical Light cure

Polymerization is central Peripheral

Curing is one phase Is in increments

Sets within 45 seconds Sets only after light activation

No control over working time Working time under control

Shrinkage towards centre of bulk Shrinkage towards light source

Air may get incorporated Less chance of air entrapment

More wastage of material Less wastage

Not properly finished Better finish

DUAL CURING2 light cure pastes-syringes/tubsCombines chemical and light curingDisadvantages- air inhibition,porosityUse-cementation of bulky ceramic inlays

EXTRAORAL CURING

Use- a chemical or light cured composite used to produce an inlay on a tooth or die

CURING LAMPS…

1970’s-”Nuva Light”360-400nm

Types of devices4 sources of light440-490nm

CURING SYSTEMS

UV LIGHT VISIBLE LIGHT

Counter top units

Gun type units-features

Types of devices…

Quartz-Tungsten-Halogen units

CONVENTIONAL HALOGEN CURING LAMPSE.g.: Optilux 500Advantages

Less costSimple, well known

technologyLittle/no heat

DisadvantagesSlow cure timePlug into electricityLarge, cumbersomeDecreased outputReplace lamp

Halogen gas protects filament by:

oxidation re-deposits tungsten

to filament by: Halogen Cycle Light guides

Plasma Arc units

Advantages Curing time-3 sec Short procedure

Disadvantages Heat production High cost Large, bulky

Two tungsten electrodes

Pressurized chamberContains xenon gas

High-voltage sparkIt ionizes xenon gas

Argon laser unitsADVANTAGES

Correct wavelengthDeeper & faster curingBetter mech propertiesDecreased sensitivity to curing tip

distanceLess post-op sensitivity & discomfort

DISADVANTAGES Increased shrinkage, brittlenessMarginal leakage Heat increase on surface ExpensiveBulky equipment

LED units

ADVANTAGES Cordless,light weight Long lasting No heat Moderate curing time Quiet

DISADVANTAGES New technology Slower than PAC Batteries must be recharged Higher cost Low intensity

Narrow emission spectrum440-490 nm

peak at 470 nmnear absorption max activation of camphoroquinoneefficient

First generation high cost low

irradiance < 300

mW/cm2

increase exposure time

Second generation

Single large surfaced emitting LED chips lower costhigher irradiance

> 600 mW/cm2

similar to halogen

High heat production

Third Generation

1 or more low-powered chips that emit a second frequency

Optical Safety Do not look directly at light Protection recommended

glasses Shields

May impair abilityto match tooth shades

Degree of conversion

% of C-C double bonds that have been converted to single bonds to form polymeric resin

Strength, wear resistanceAvg 50-60%, light cure-44-75%Cross linked , pendant, free groupsFactorsLight curing: more shrinkage stress

Staining Sensitivity Secondary caries

polymerization shrinkageValue: 1- 4% , stress: 17MPa

Prevents bonding to dentin-strength required

Causes stress to develop Externally: interface of restoration

& tooth

Internally: between filler and resin

Factors affecting stress developmentRestorative technique

Modulus of resin elasticity

Polymerization rate

Cavity configuration

Cavity configuration [C-FACTOR] BONDED WALLSUNBONDED WALLS

C=

During curing, shrinkage leaves the bonded surfaces in a state of stress, while the free surfaces relax some of the stresses by contracting inward toward the bulk of the material.Use of incremental/layering technique

Two walled cavity Three walled cavityC=

2 Bonded

4 Unbonded

C-FACTORC-FACTOR 0.50.5

CAVITY CLASSCAVITY CLASS IVIV

C=3Bonded

3Unbonded

C-FACTORC-FACTOR 11

CAVITY CLASSCAVITY CLASS IIIIII

Four walled cavity Five walled cavityFour walled cavity Five walled cavity

C=C=

C-FACTORC-FACTOR 22

CAVITY CLASSCAVITY CLASS IIII

4Bonded4Bonded

2Unbonded2UnbondedC=C=

C-FACTORC-FACTOR 55

CAVITY CLASSCAVITY CLASS I I

5Bonded5Bonded

1Unbonded1Unbonded

REDUCTION OF RESIDUAL STRESSReduction in vol contraction by alteration of chemistry

Low shrink monomers

Clinical techniquesCuring rate control

Incremental build-up

Resin based composite systems

Dentin-enamel adhesive systems

Using material which flows

Material with low modulus of elasticity

Introduction of air bubbles

CHARACTERISTIC PROPERTY

Unfilled acrylic Traditional

Small particle Hybrid Micro filled

Size (µm) - 8-12 0.5-3 0.4-1.0 0.04-0.4Inorganic filler (vol

%) 0 60-70 65-77 60-65 20-59Inorganic filler (wt

%) 0 70-80 80-90 75-80 35-67Compressive

strength (MPa) 70 250-300 350-400 300-350 250-350Tensile strength

(MPa) 24 50-65 75-90 40-50 30 -50Elastic modulus

(GPa) 2.4 8-15 15-20 11-15 3-6TEC (ppm/ °C) 92.8 25-35 19-26 30-40 50-60Water sorption

(mg/cm2) 1.7 0.5-0.7 0.5-0.6 0.5-0.7 1.4-1.7Curing shrinkage

(vol%) 8-10-

2-3 2-3 3-4

Radio opacity(mm\Al) 0.1 2-3 2-3 2-4 0.5-2

OTHER PROPERTIES

CLINICAL TECHNIQUE…Local anesthesia

Preparation of operating site

Shade selection

IsolationRubber dam

Cotton rolls

Gingival retraction cord

Preoperative wedging

INITIAL PROCEDURES

Tooth preparationCONVENTIONAL

DESIGN Conventional Tooth Preparation

are those typical for amalgam restoration

walls in butt joint junction (90º) with the restorative material

Indications- i. Preparations located on root

surfaces. ii. Moderate to large class I

or class II restorations.

MODIFIED

Scooped out preparation

Modified preparations are indicated for the initial restoration of smaller, cavitated, carious lesions usually surrounded by enamel & for correcting enamel defects.

This design is indicated when only proximal surface is faulty with no lesion present on the occlusal surface.

• BOX-ONLY •FACIAL/

LINGUAL SLOT

• Design for restoring proximal lesions on posterior teeth.

Shade selectionShade selection

Composite shade is selected by working with a clean, moist tooth prior to placement of a rubber dam.

Shade selection should be done prior to prolonged drying of teeth because dehydrated tooth becomes lighter in shade as result of decrease in translucency.

Samples from the shade guide should be applied parallel with the tooth whose color is being matched, not in front of it (it will appear lighter), and not behind it (it will appear darker)

Shade selected acc. to manufactures shade guide or VITA shade guide.

Natural light is preferable. Shade tab is holded near theteeth to be restored & is partiallycovered with lip or operator thumb.

To choose accurate color - small amt. of selected color shade material is placed on the tooth, in close proximity to the area to be restored & cured.

Isolation of operating fielda) Rubber damb) Cotton rolls with or without retraction cord

RESTORATIVE TECHNIQUERESTORATIVE TECHNIQUE

1. 1. Preliminary steps for enamel & dentin bonding:Preliminary steps for enamel & dentin bonding: Both liquid & gels etchants are available(32 to 37%).

Acid etching is done for 15-30secs.

Following this it has to be thoroughly

rinsed with a water spray for 5-15secs.

Later the surface should be dried with

air or cotton pellets. The etched enamel

appears frosty white.

Bonding Use low viscosity resin which will flow into etched

enamel pores & dentinal tubules to form resin tags. Act as intermediary between tooth and composite.

The bonding agent is applied using a microbrush.

The manufacturer's instructions are followed regarding the no.of coats to be applied and the curing time.(usually 20secs

labially and lingually each) 20 - 30 sec.

Apply ample Apply ample amounts, amounts, leave leave undisturbedundisturbed

Remove Remove solvent with solvent with air-syringeair-syringe

It penetrates the irregularities on enamel and bonds

micromechanically by formation of resin tags.

On dentin, it penetrates the collagen network and the dentinal tubules.

CURING:

Two categories of technique are commonly used in curing polymers:

continuous and discontinuous.

The continuous cure refers to a light-cure sequence in which the light is on continuously.

There are four types of continuous curing: uniform continuous cure, step cure, ramp cure, and

high-energy pulse . Continuous curing is conducted with halogen, arc, and laser lamps.

The discontinuous cure is also called soft cure, which commonly uses a pulse delay.

Distance from a tooth to initiate a cure, and then moving it close to the restoration for the duration of appropriate exposure.

In uniform continuous curing intensity is kept uniform over the time

In step curing intensity is increased in sudden step over the time.

Ramp curing is where the intensity continuously increases over the time

In high energy pulse the high intensity is kept for shorter exposure time.

3. Insertion of composite3. Insertion of composite

Can be inserted with the help of hand instruments or syringe or guns.

Material is inserted in increments in thickness of 1-2mm

Different designs of increment placementDifferent designs of increment placement

1.Three increment design one flat increment at gingival & occlusal wall & two oblique increments both at proximal box occlusal box.1st increment thinner than 1.00mm.2. Horizontal layering designsmall increments placed horizontally one above the other, starting from gingival wall to occlusal wall.

3. Oblique layering design Each increment is placed obliquelystarting from any sides & curing is done from all three sides.

4. U-shaped layering design At base, both gingival & occlusal gingival, U-shaped increment is given

5. Vertical layering techq. Increments are placed in verticalfashion starting from one wall & carried on to another wall & curing is done from behind the wall.6. Layering techq. in the proximal box& curing each increment by insertingthe fiber-optic microtip into composite.

FINISHING &POLISHING OF COMPOSITES

REPAIR OF COMPOSITESOLDER

RESTORATION

Etch, primer,

adhesive, composite

Bond strength- 50%

FRESHLY POLYMERIZEDIf not yet contoured

Directly place composite

If contoured and polished Re-etch, adhesive,

composite

TUNNEL RESTORATIONS

Jinks in 1963 introduced this as a conservative approach for CLASS II.

Hunt & Knight modified the technique

INDICATIONS Pt. with high esthetic demand, low caries rate with

small proximal caries without involvement of the marginal ridge.

CONTRAINDICATIONS Large proximal caries involving marginal ridges. Marginal Ridges under excess occlusal loads. Difficulty in access

Proximal Caries

Tunnel Tunnel Prep. Prep. Round burRound bur

GIC GIC placedplaced ComposiComposi

te over te over GICGIC

ADVANTAGES Marginal ridge is preserved Reduced microleakage Adjucent tooth preserved

DISADVANTAGES Poor visibility & lack of caries removal Marginal ridge may be undermined Prep. may extend closer to pulp than desired

SANDWICH TECHNIQUE Developed by McLean. Laminate or Bilayed technique. Large Class III, IV, V & Class I, II.

COMPOSITECOMPOSITE

GICGIC GIC

COMPOSITECOMPOSITE

In close sandwich the GIC is placed over pulpal floor and axial wall then composite is placed and cured on the GIC

In open sandwich the GIC is placed on the gingival seat and on that

composite is cured till the occlusal level

ADVANTAGES Favourable pulpal response due to biocompatibility of

GIC. Fluoride release minimizes recurrent caries. Less composite, less polymerisation shrinkage.DISADVANTAGES Time consuming. Technique sensitive. Adhesion of composite with GIC is a worry.

CONCLUSION Composites have acquired a prominent place among the

filling materials employed in direct techniques. Their considerable aesthetic possibilities give rise to a variety of therapeutic indications, which continue to grow as a result of the great versatility of the presentations offered.

Nonetheless, it should not be forgotten that they are highly technique-sensitive, hence the need to control certain aspects: correct indication, good isolation, choice of the right composite for each situation, use of a good procedure for bonding to the dental tissues and proper curing are essential if satisfactory clinical results are to be achieved.

REFERENCES…

Phillips’: Science of dental materials Sturdevant : Art and science of operative dentistry Vimal Sikri : Textbook of operative dentistry Marzouk : Operative dentistry - modern theory and practice Craig: Dental marterials Charbeneau : Principles & practice of operative dentistry Goldstein : Esthetics in dentistry