introduction to composite restorations

8/3/2019 Introduction to Composite Restorations

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INTRODUCTION TO COMPOSI

RESTORATIONS

Edited By:

Ahmad Fawzi Ali



CONTENTS-:

1.INTRODUCTION2.CLASSIFICATION

3.TOOTH PREPARATION.

4.RESTORATIVE TECHNIQUE

5.NEWER ADVANCEMENTS.



INTRODUCTION-

A composite is a physical mixture of materials.The parts of mixtu

with the purpose of averaging the properties to achieve intermed

Dental composite indicates a mixture of silicate glass particles in

monomer that is polymerised during an application



COMPOSITION-:

Composite consists of-:

1.Resin Matrix-A plastic resin material that forms a continuous phthe filler particles.

2.Filler particles-reinforcing particles and\or fibres that are disper

matrix.

3.Coupling agents-bonding agents that promote adhesion betwee

resin matrix.



CLASSIFICATION-:

Based on the size of filler particles:

1.Traditional -particle size 8-12 micrometer.

2.Small particle filled-1-5 micrometer.

3.Microfilled composite-0.04-0.4 micrometer.

4.Hybrid composite-0.6-1 micrometer.



INDICATIONS-:

1. Class I,II,III,IV,V,VI restorations

2. Foundation or core buildup.

3. Esthetic enhancement procedures-

Partial veneers and Full veneers.

Tooth contour modifications.

Diastema closure.

4. For temporary restorations.

5. For periodontal splinting.



CONTRAINDICATIONS-:

1.Teeth with heavy occlusal stress.2.If operating site cannot be isolated.

3.Patient allergic or sensitive to composite.



ADVANTAGES-:

1.Esthetic.2.Conservation of tooth structure.

3.Insulative.

4.Bonded to tooth structure.

5.Repairable.



DISADVANTAGES-:

1.May have gap formation.

2. More difficult,time consuming,and costlier.

3. More technique sensitive.

4. May exhibit greater occlusal wear in areas of high occlusal st

5. Higher linear coefficient of thermal expansion resulting in mpercolation.



TOOTH PREPARATION-:

Basically this includes-1. Removing the fault,defect,old restorative material or friable to

2. Creating prepared enamel margins of 90 degree or greater.

3. Creating 90 degree cavosurface margins on root surface.

4. Roughning the prepared tooth structure.



TYPES OF COMPOSITE TOOTH PREPARATION

1.Conventional-

Indications-1.Preparation located on root surface-utilizes butt jo

configuration and retention groove in dentin.

2.Moderate to large classI or II restorations-there may be increa

resistance which is provided by conventional amalgam like pre



2.BEVELED CONVENTIONAL

This design is indicated when a composite restoration is being u

an existing restoration exhibiting a conventional tooth preparatenamel margins or to restore a large area.

This design is most typical more classIII,IV & V restorations.



Advantage of enamel bevel-ends of enamel rods are

effectively etched producing deeper microundercuts

when only the sides of enamel rods are etched.



3.MODIFIED

Indicated for initial restoration of smaller, cavitated, carious le

surrounded by enamel.

For correcting enamel defects. For larger restoration as well(wider bevel or flares &retention

or locks can be given)

Less tooth structure removed compared to beveled preparati



4.BOX ONLY PREPARATION

Indicated when only the proximal surface is faulty with no les

the occlusal surface

Prepared with either an inverted cone or diamond stone held

long axis of tooth crown.

Initial proximal axial depth - 0.2mm inside DEJ.

Neither bevel nor secondary retention required.



5.FACIAL OR LINGUAL SLOT

For restoring proximal lesions on posterior teeth.

Entry is made with a diamond stone at a correct occlusogingivclose as possible to adjacent tooth.

Occlusal,facial and gingival cavosurface margin is 90 degree or



RESTORATIVE TECHNIQUE

Treating the prepared tooth for bonding requires –

1.Etching and then application of an adhesive-if only enamel is in

2.Primer and adhesive –

if both enamel and dentin are involved.STEPS-

1.L.A.

2.Preparation of operative

site.



3.Shade selection- done under natural light.

shade guide used

4.Isolation-rubber dam and cotton rolls used.

.polyester strip applied

before etching to protect

adjacent tooth from inadvertent

Etching.



5.ETCHING

30-40% conc. Of phosphoric used(ideally 37%)

For enamel-30 sec & for dentin 15 sec and then rinsed off.

Available as –

liquid and gel.

Syringe for dispensing gel etchant Applicator tip for liquid

ETCHING ENAMEL



ETCHING ENAMEL-

affects both prism core and prism periphery.

transforms smooth enamel into very irregular surface

When fluid resin is

applied to etched

surface

Resin penetrates etched surface

Forms resin tags

Basis for adhesion of resin to enamel



ETCHING DENTIN-

Affects intertubular and peritubular dentin.

Removes the smear layer and exposes collagen network to

optimal adhesion to the dentinal surface.

After rinsing the surface is kept slightly moistened when dentin

involved because it allows the primer and adhesive material to

effectively penetrate the collagen fibre to form a hybrid layer wbasis for mechanical bond to dentin.



6. PRIMER

Applied to both the surfaces(enamel and dentin)

It contains hydrophillic monomers dissolved in a solvent that e

easily and removes water without need for excessive drying.

Thus,it promotes penetration of adhesive resin in to the expos

network.



7.ADHESIVE RESIN

.Applied to etched and primed surface and cured.

When resin is applied the resin becomes interlocked into the

forming hybrid layer which is the basis for micromechanical r

8.COMPOSITE PLACED.



9.CURING

Two types-1.Self curing. 2.Light curing.

SELF CURING-

not used extensively .

Disadvantages-1.Mixing of two pastes required and it is almost

avoid incorporation of air bubbles.

Air bubble contain oxyge4n that causes oxygen inhibition dupolymerisation.

2.No control of working time.



LIGHT CURING-

Material inserted in tooth preparation in 1-2mm thickness.Th

light to properly polymerise the composite and may render the

polymerisation shrinkage appear along the gingival floor.

ADVANTAGES-

1.Sufficient working time.

2.Not sensitive to oxygen inhibition.

3.Easy placement.

LIMITATION

1.Time consuming

2.Shrink towards the light source.

9 CONTOURING



9.CONTOURING-

Can be initiated immediately after light cured composite have b

3 minutes after the initial hardning of self cured material.

10.POLISHING-Done with fine polishing discs,fine rubber points or cups.



RECENT ADVANCES-1.Flowable composites-

a.New standard for convenience in anterior and posterior restob.Offers smart handling.

c.Flows under pressure but holds its shape in place prior to ligh

d.No oozing,slumping or running.

e.Ideal viscocity and flow suitable for small classI,III,IV and shallo

restoration and as pit and fissure sealant.



2.Packable composites-

promoted as amalgam alternative or conventional universal com

Distinguishing feature-

a.Less stickiness or stiffer viscosity than conventional compositethem to be placed in a manner that somewhat resembles ama

b.Likely to offer better clinical performance than non packable c

But it is not reccomended in deep cavities.

Polymerisation shrinkage similar or higher than non packable co

introduction to composite restorations

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