Class III, IV, V Direct Composite (2)

7/28/2019 Class III, IV, V Direct Composite (2)

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Because Classes III and IV Restorations

involve only anterior teeth, an esthetic

material such as composite is indicated .


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Likewise, Class V Restorations on

anterior teeth usually require esthetic

restorations.


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Although esthetic considerations are valid

for posterior restorations, many patients are

not as concerned with esthetic in posterior

teeth as they are in anterior teeth .


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However, the use of composite for anyrestoration provides benefits rather than

improved esthetics.


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Pertinent Material Qualities and

Properties


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The specific material qualities or properties

that make composite the best material for

most Classes III, IV, and V Restorations

relate to esthetic.


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These include adequate strength and the

benefits of being able to bond thecomposite to tooth structure often resulting

in less tooth structure removal during tooth

preparation.


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Indications


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Almost all class III and Class IV restorations

are appropriately restored with composite.


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Most Class V restorations that are in estheticprominent areas are also appropriately

restored with composite or other tooth-

colored material.


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Contraindications


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The contraindications for use of composite for

these classes of restorations include:


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1- an operating area that cannot be

adequately isolated.


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2- some class V restorations in areasthat are not esthetically critical .


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3- some restorations that extend onto

the root surface.


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Clinical Technique for Direct Class III

Composite Restorations


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Initial Clinical Procedures


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Some information about procedures

necessary before beginning restoration:


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(1) Anesthesia may be necessary for patientcomfort, and if used, will help decrease the

salivary flow during the procedures.


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(2) Occlusal assessments should be made to

help in properly adjusting the restorations

function and in determining the tooth

design.


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(3) The shade must be selected before thetooth dehydrates and experiences

concomitant lightening .


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(4) The area must be isolated to permit

effective bonding.


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(5) If the restoration is large (including all ofthe proximal contact), inserting a wedge in

the area will assist in the re-establishment ofthe proximal contact with composite .


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Tooth Preparation


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Class III tooth preparations, bydefinition, are located on the proximal

surface of anterior teeth .


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Because the bond of composite to enameland dentin is so strong, most Class IIIcomposite restorations are retained only by

the micromechanical bond from acid

etching and resin bonding, so no additional

preparation retention form is usually

necessary.


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Using diamond stones for the toothpreparation leaves the prepared surfaces

rougher, increasing the surface area and

the micromechanical retention.


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Sometimes a groove or cove may benecessary for Class III restorations that

either extend onto the root surface or are

very large .


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The advantages of restoring theproximal lesion from the lingual

approach include:


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1- The facial enamel is conserved for

enhanced esthetics.


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2- Some unsupported, but not friable,enamel may be left on the facial wall of

Class III or Class IV preparation.


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3- Color matching of the composite is

not as critical.


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4- Discoloration or deterioration of the

restoration is less visible.


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Indications for a facial approach include

the following:


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1- The carious lesion is positioned faciallysuch that facial access would significantly

conserve tooth structure.


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2- The teeth are irregularly aligned, making

lingual access undesirable.


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3- An extensive carious lesion extends onto

the facial surface.


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When the facial and lingual surfaces areinvolved, the approach that provides the

best access for instrumentation should be

used.


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It is expeditious to prepared and restore

approximating carious lesions or faulty

restorations on adjacent teeth at the same

appointment.


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Conventional Class III ToothPreparation


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The primary indication for this type ofClass III preparation is for the restoration of

root surface.


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Beveled Conventional Class III

Tooth Preparation


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The beveled conventional tooth

preparation for composite restoration is

indicated primarily for replacing an

existing defective restoration in the crownportion of the tooth.


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The axial line angles may or may not beof uniform pulpal depth, varying as the

thickness of the enamel portion of the

external walls varies.


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Once the outline form and initial axial walldepth have been established, the initial

tooth preparation stage is completed and

the final stage of tooth preparation begins.


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Remove all remaining infected dentin usinground burs or small spoon excavators or

both.


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Some undermined enamel can be left innonstress areas, but very friable enamel

at the margins should be removed .


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Remaining old restorative material on theaxial wall should be removed if any of the

conditions presented earlier are present.


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Apply a calcium hydroxide liner only ifindicated .


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If restoration features (grooves or coves)

are indicated (and usually they are not),

Prepare them along the gingivoaxial line

angle and, sometimes, the incisoaxial lineangle with a No.1/4 bur .


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Occasionally retention may be provided

by undercuts left from caries removal.


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Particular care must be exercised not toweaken the walls or incisal angles that are

subject to masticatory force.


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Any necessary incisal retention cove is

prepared with the No.1/4 bur at theaxioincisal point angle with the bur

oriented in similar angle, 0.2mm inside the

DEJ, and 0.25mm deep.


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It is extended slightly into the facioaxial line

angle where it fades out.


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The placement of incisal retention is not

always as easy in mouth as illustratedbecause of handpiece size and angulation

problems caused by the anatomy of themaxilla and tooth positions.


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Modified Class III Tooth

Preparation


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A modified tooth preparation is the mostused type of Class III tooth preparation.


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It is indicated for small and moderatelesions or faults and is designed to be as

conservative as possible.


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The preparation design is dictated by the

extent of the fault or defect and is prepared

from a lingual approach when possible, with

an appropriate size round bur or diamondinstrument.


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No effort is made to produce preparationwalls that have specific shapes or forms

other than external angle of 90 degrees

or greater.


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Weakened, friable enamel is removed

while preparing the cavosurface margins in

a beveled or flared configuration with the

round diamond.


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Usually no groove (or cove) retention form

is indicated because the retention of the

material in the tooth will result from the

bond created between the compositematerial and the etched peripheral enamel.


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Begin the preparation from a lingual

approach (if possible) by making an opening

a round carbide bur or diamond instrument.


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Documents

Class III, IV, V Direct Composite (2)