INTRODUCTION

In the late 1800’s the need for a matrix became apparent

when dentists recognized that the best way to treat a tooth affected

by dental caries on the approximal surfaces was by restoring its

anatomical contour and contacts with adjacent tooth. The matrix

was needed to provide the missing wall or walls and thus contain

the restorative material during the filling of the prepared cavity. Until

the late 1800’s, the rationale for treating carious lesions on the

approximal surfaces of teeth was based on either a restorative or a

prophylactic concept.

EARLY CONCEPTS OF TREATING APPROXIMAL CARIES

Restorative concept

The rationale for restorative treatment was to remove the

caries and fill the cavity with a suitable material. At this time,

however, restoration of the tooth to form and function was not of

general concern.

Prophylactic concept

The rationale for prophylactic treatment was premised on an

early theory of caries, which taught that caries began at the point of

contact between the teeth where pressure damaged the enamel -

the lesion being caused by the action of external corrosive agents.

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The method advocated the creation of a self - cleansing

space by removing diseased or healthy tooth structure from the

approximal surfaces, thereby achieving total and permanent

separation of teeth.

The self - cleansing space was indicated for the prevention of

caries, for the treatment of superficial caries, and to provide access

to deep caries.

The procedure was accomplished by the use of a file, the

oldest method of removing tooth structure.

The procedure as described by HARRIS(1848) required the

removal of one - third or more of the tooth and created a shoulder

at the cervical margin to maintain contact in this area and prevent

the teeth from drifting.

In the posterior regions, the separation was referred to a V -

shaped space. If the teeth required restorations, they were

designed so as not to encroach on the space created.

Even with these improvements however, the results observed

by the general practitioner led to condemnation of the procedure by

the profession at large. The main criticism of this technique, voiced

by patients and the practitioners and patients alike, concerned the

disfigurement of teeth. Not only did patients complain of disfigured

teeth, they also complained of impaction of food on the gingivae

and sensitivity of teeth due to exposed dentin.

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By 1887, the technique was contraindicated.

CONTOURED FILLINGS

Around 1890, practitioners changed the way they restored

teeth that had approximal lesions.

The concept was premised on a new theory of caries, which

taught the caries began below, not at the contact point of the teeth

as with the early theory of caries(MILLER 1904) and advocated the

restoration of the natural, or original contour and contact of the

tooth. As such a contoured filling

1. Would reestablish the proper form of the inter - proximal space

2. Maintain the function of the teeth

3. Ensure no breach in the continuity of the occlural aspect of the

dention.

4. Maintain the length of the arch

5. Prevent impaction of food

6. Maintain and promate the health of the gingivae as well as the

comfort of the patient

Thus BLACK(1890) brought a new and different meaning to

the ‘V - shaped’ space . An additional concept introduced

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concurrently prescribed extending the margins of the approximal

surfaces of the cavity on to facial and lingual surfaces of the tooth.

This concept not only facilitated the placement of contoured

fillings, but also placed the cavity margins within the range of

protective influences, reducing the possibility of recurrent caries.

EARLY MATRICES

The early advocates of contoured fillings included W. H

Atkinson, M .H WEBB and S.H GUILFORD.

They recognized that to fill a prepared cavity and produce a

contoured filling the practitioner required assistance in containing

the filling material without such assistance , over contour at the

cervical level and under contour at the occlusal level resulted.

The assistance came in the form of a matrix, which provided

for the missing walls of the prepared tooth and transformed a cavity

of two, three or more surfaces into a simple one.

In addition the matrix could be molded to assist in re-

establishing the natural contours of the tooth.

Early in its use, the matrix was subject to criticism. Some

believed that when a tooth was to be restored with direct filling gold,

the matrix did not allow for enough contour of gold to compensate

for the subsequent polishing and adapted too closely to the

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margins, thus providing the potential for inadequate condensation

of gold in these areas especially at the cervical area.

ORIGINAL MATRIX

1. JACK MATRIX

2. HUEY MATRIX

3. PERRY MATRIX

4. BRUNTON MATRIX

(A) CUSTOM MATRICES

I. Anatomic matrices II. Tie band matrix III. Continuous loop

matrix

1.Shellac matrix Perry matrix Herbst

2.Herbst matrix Clapp matrix Newkirk modifi

3.Hutchinson matrix Fillebrown matrix Soldred matrix

4.Hand matrix Black matrix Spot welded

5.Woodward matrix Andrews matrix Tinner’s joint

6.Rubber matrices Baker matrix Welded

circumferential

(i) Danforth matrix Abernethy matrix Rivet matrix

(ii) adapto matrix Hallenback matrix Collar / band

modification

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7.Sweeny matrix Markley modification Harrison

8.Ingraham - -----matrix Hampson modification Copper band

9.Sectional matrix with Pinch band

Bi- ting ring

10.Open face matrix

(B) MATRICES WITH RETAINERS

Although the early matrices were intended for use with direct

filling golds, these matrices were also recommended for use with

amalgam which has been introduced to America in 1830’s.

Because of its plasticity amalgam required a matrix for the

condensation and development of proper physical properties,

contour and inter proximal contact.

THE ORIGINAL MATRIX

The first recorded use of a matrix is of that introduced by

DWINELLE(1855). The matrix consisted of a band made from a

broad, thin piece of dense gold. The band was wedged firmly

against the tooth. However it was opened against the cervical

margin of the cavity of the preparation to allow space for

condensation of excess gold.

Although his own personal testimony and that of his peers

(Brophy 1886 , Jack 1887) point Dwinelle as the originator of the

matrix. Later, the original matrix was described as the metal band

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that was wedged against and supported by the adjacent tooth, but

was not attributed to any one inventor.

IMPROVEMENTS ON THE ORIGINAL MATRIX

With the new concept of contoured fillings, the matrix took on

added significance. The earliest matrices incorporating the new

concepts appeared in the late 1800’s and included the JACK,

HUEY, PERRY and BRUNTON MATRICES. As a group, these

matrices used various materials of unspecified thickness for the

band.

The materials included steel, platinum plate or foil, brass,

copper, phosphor - bronze, German silver and tin. Few of these

bands were precontoured.

JACK MATRIX

Jack matrix introduced in 1871, was accepted as the first

matrix to satisfy the concept of contoured fillings. The matrix

consisted of a slight wedge shaped piece of steel hollowed out to

create a depression on its face to correspond to the desired

contour.

The band was made in assorted sizes and shapes and was

put into place with forceps, the Adjacent tooth used for

retention. The band was then wedged with a boxwood wedge.

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MATRICING

Matricing is the procedure whereby a temporary wall is

created opposite to the axial walls surrounding areas of tooth

structure that were lost during tooth preparation.

It is used with restorative materials that are introduced in a

plastic state.

OBJECTIVES

The matrix should

1. Displace the gingivae and rubber dam away from the cavity

margins during introduction of the restorative material.

2. Assure dryness and non-contamination of the details and the

space to be covered with and occupied by the setting restorative

material.

3. Provide shape of the restoration during the setting of the

restorative material i.e band materials should be unyielding to

the enregies of insertion.

4. Maintain shape during the hardening of the materila.

5. Confine the restorative material within the cavity proparation and

predetermined surface configration.

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MATRICES FOR CLASS I CAVITY PREPARATIONS

Double banded Toffelmire for class I.

Turn the large vice moving knob until the slotted vice is about

¼ inch from the inner end of the retainer. Loosen the screw until its

painted end is clear of the slotted vice.

Make a loop out of the universal band creating an edge with a

narrow circumference.

The narrow circumference is placed gingivally and the wide

circumference edge is placed occlusal.

The free ends of the band are inserted into the vice while the

looped end of the band extends away from the retainer.

Always be sure the slotted end of the vice is facing gingivally.

This will facilitate easy occlusal removal of the retainer.

Tighten the vice screw to lock the band in the vice. Guide the

looped end of the band gently over the tooth. The size of the loop

may be increased or decreased by turning the vice moving knob.

With the band in position around the tooth, tighten the vice

moving knob.

Ideally the retainer should be parallel and adjacent to the

facial surfaces of the quadrant of the teeth being operated on.

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An additional small piece of matrix band material is that

contoured to the facial or lingual axial configuration of the

contemplated restoration and inserted between the tooth and the

previously positioned and retained matrix in the area of the facial or

lingual extension of the cavity preparation.

This piece of material should overlap over the margins of the

extension by about 1.5 - 2mm circumferentially.

With a beaver-tail burnisher, create a separation between the

two bands. Select a wedge that will create and maintain the proper

separation between the two bands and thereby enable the

formation of the proper contour facially and / or lingually.

Cover the wedges with softened compounds and insert it

between the two bands and cool to harden.

MATRICES FOR CLASS II CAVITY PREPARATIONS

a) SINGLE-BANDED TOFFELMIRE FOR CLASS II

This is the most practical matrix for class II cavity

preparations. Its use is made universal by the easy application and

removal of the band to and from its holder without disturbing the

condensed material.

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PROCEDURE

The basic steps are repeated from the previously described

double banded arrangement.

If the cavity preparation involves one proximal surface only

and there is a substantial difference between the heights of the

interproximal gingiva on the mesial and distal sides of the tooth, the

matrix band should be trimmed so that it is narrower on the side

where the interproximal gingiva is more occlurally located.

It may also be possible to use matrix bands with only one

gingival projection, which should coincide with the proximal side

where the interproximal gingiva is more apically located.

If the gingival extension of the proximal portion of the cavity

preparation is more apically located than gingival lines facially and

lingually, there is a danger of cutting the gingival tissues facially

and lingually in using a band with a straight gingival edge.

In this situation it is necessary to reduce the occlusal - apical

width of the band facially and lingually or to use a band with apical

projections which coincide and cover the gingival extension of the

proximal portion of the cavity preparation.

In preparation with subgingival margins, especially at the

axial angles or any surface protrusion of the tooth, the edges of the

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band occasionally encounter the gingival margin and become bent

inward, preventing further seating of the band.

For this reason there should be unprepared, exposed tooth

surface apical to the gingival margin of the preparation to support

the band in its apical path and to prevent its inward collapse or

bending. This may necessitate gingival retraction or cutting.

Also in these situations, the band edges should be guided in

their apical path by placing a flat - bladed, blunt instrument between

the band and the adjacent unprepared tooth surface apical to the

gingival margin.

Although it is preferable to put the retainer in the buccal

vestibule, parallel to the adjacent teeth, sometimes, due to shallow

sulcus or sizable buccal involvement of the tooth in a activity

preparation, the retainer is placed on the lingual. This usually

necessitates a contrangled retainer.

However a retainer should never be located at right angle to

the facial or lingual surfaces of the teeth operated upon as this will

drastically change the occluso-apical contour of the band.

As soon as the band is in place and all cavity margins can be

seen inside the matrix, a wedge, comparable to the dimensions of

the future gingival embrassure is chosen and tied(always from the

opposite side of the retainer attachment).

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Using a ball burnisher from within the cavity preparation,

shape the matrix material to create the out line of the contact and

contour of the future restoration.

If the cavity has buccal or lingual extension, repeat the

modifying steps in the double-banded Toffelmire application.

For all Toffelmire applications, after the insertion and initial

hardening and manipulation of the restorative material, the wedges

and secondary band are removed. Then the retainer is loosened

and disengaged. The primary band is bent against adjacent tooth

surfaces and removed from between the teeth in an occlusal

direction, while being pressed against the adjacent tooth.

If the contact area is extremely tight and the band is resistant

to removal, it is a good idea to cut the band on the opposite side of

the retainer, remove the roughened portion of the band and then

pull it buccal-lingually with pressure against the adjacent tooth.

b) IVORY MATRIX NO.1

The band encircles a posterior proximal surface so it is

indicated in unilateral class II cavities.

c) IVORY MATRIX NO.8

The band encircles the entire crown of the tooth so it is

indicated for bilateral class II cavities.

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d) BLACK’S MATRICES

i)Black’s matrix for simple cases is recommended for a majority of

small and medium size cavities

PROCEDURE

Cut a metallic band so that it will extend only slightly over the

buccal and lingual surfaces of the tooth.

To prevent a wrap, around holding ligature from slipping off

the band and the band sliding gingivally. The corners of the gingival

ends are turned up to hold the ligature.

ii) BLACK’S MATRIX with a gingival extension to cover the

gingival margin of a subgingival cavity.

In this form of extension is created in the occluso-gingival

width of a band to cover the gingival margin of a subgingival

cavity. The retaining procedures are the same as for the previous

type of Black’s matrix.

e) SOLDERED BAND OR SEAMLESS COPPER BAND MATRIX

These are indicated for badly broken teeth, especially those

receiving pin retained amalgam restorations, with large buccal and

lingual extension i.e Class II design preparation

PROCEDURE

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A stainless steel band is cut according to the measured

diameter of the crown of the tooth, then the two ends are soldered

together or a seamless copper band is selected so that it barely

clears the diameter of the tooth in the cervical area.

Either the band could be heated in a flame until it glows red

light. It is then quenched in alcohol thus softening the band for easy

handling.

With curved scissors, fasten the band so its gingival periphery

corresponds to the gingival curvature and the CEJ.

The band is then smoothed to remove rough edges cervically

and occlusally. With containing pliers contour the band to produce

the proper shape in the contact area.

Areas of the band in the contact area are reduced to a paper

thinness using a coarse sand paper disc.

Then they are recontoured . Next the band is seated on the

tooth and tightened at the cervical end by pinching a ‘tuck’, using a

flat bladed plier at the gingival edge in the area accessible to the

plier.

To stabilize the band and prevent cervical flashes of

amalgam, wedges are placed gingival to the cervical margin of the

preparation.

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The external portions of the matrix and the wedges are

covered with compound to further stabilize the matrix. A wire is

inserted facio- lingually in the compound to further stabilize it.

Apply a heated ball burnisher from the inside of the cavity to

the band, softening the external compound and insuring the proper

contour, contacts and embrasures.

After condensation and initial covering, the compound is

removed and the matrix is cut at the area of the tuck.

With a plier or hemostat, grip the band at either side of the

scissors, cut and tear through each thinned contact portion to

remove the band without damaging the proximal region of the

amalgam.

f) THE ANATOMICAL MATRIX

This is the most efficient means of reproducing contacts and

contour.

It is entirely hand made and contoured specifically, for each

individual case. It is specially useful in mutilated teeth. It is

indicated for class II designs.

PROCEDURE

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A piece of “0.001 - 0.002” stainless steel matrix band 1/8th in

width is drawn between the handle of a pair of festooning scissors.

This procedure facilitates the adaptation of the free ends of the

matrix to the proximal surface of the tooth.

The matrix is cut to proper length. It must extend well beyond

cavity margins. To obtain a proper length the center’s of the

proximal buccal and proximal lingual cusps are used as a guide.

The matrix band is contoured with contouring pliers. The band is

then trimmed so that the matrix will extend well below the gingival

margin of the cavity and at least 2mm beyond the buccal & lingual

margin of the cavity.

A wedge is selected and shaped to conform to the gingival

embrasures, and it is then placed in warm water to soften it slightly.

Two small cones of compound are warmed in hot water.

These compound cones are forced one at a time, using thumb and

finger pressure into the buccal and lingual embrasures.

The pressure is maintained until the compound has flowed

evenly over the entire buccal and lingual surface of the adjacent

teeth. A wire staple is constructed from a paper clip.

The staple is heated in a flame and forced into the compound

in the buccal and lingual embrasures. This adds to the stability of

the matrix by locking together the 2 pieces of the blacking

compound.

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A warm ball burnisher is used to soften any compound that

has been forced between the matrix and the adjacent tooth. The

matrix is burnished lightly against the contacting tooth.

After initial hardening of the inserted restorative material, the

compound is cracked at its occlusal junctions using a sharp chisel

or knife.

The wedges are removed using a hemostat and the band is

curled backwards against the adjacent tooth and withdrawn

buccolingually, with pressure against the adjacent proximal surface.

g) ROLL - IN - BAND MATRIX (Auto matrix)

h) S - SHAPED BAND

This is used for class II cavity preparations. Procedural

instructions are exactly as described in class III preparations

3)MATRICES FOR A CAVITY PREPARATION FOR AMALGAM RESTORATION ON THE DISTAL OF THE CUSPID

a) The S - shaped matrix

This is an ideal matrix for class III cavity preparation on the

distal of the cuspid, with either a labial or lingual access.

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PROCEDURE

One half to one inch of regular strip matrix 0.001 - 0.002 in

thickness is used. A mirror handle is used to produce the S-shaped

in the strip. The band is contoured over the labial surface of the

cuspid and the lingual surface of the adjacent bicuspid.

With contouring pliers, the strip is contoured in its middle part

to create desired form for the restoration. It is then placed inter

proximally and wedged firmly apical to the gingival margin and

covered with compound at its facial and lingual ends.

The remaining procedure is similar to those of the anatomic

matrix.

4) MATRICES FOR CLASS III DIRECT TOOTH COLOURED RESTORATIONS

These are usually transparent plastic matrix strips. For resin’s

cellophane strips are used. Mylar strips may also be used.

a) Matrix for class III preparations with teeth in normal alignment.

The suitable plastic strip is burnished over the end of a steel

instrument. Eg :- handle of a tweezer , to produce a BELLY in the

strip. This will allow for curvature which if properly contoured and

designed, will reproduce the natural proximal contour of the tooth.

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The strip is cut to allow the belly to be placed where the

contact is desired. In placing a plastic strip between the teeth, it

should be cut as wide as the tooth is long.

The corners of the strip should be trimmed therefore , to allow

for better adaptation to the tooth and to prevent any excess material

from forming on and beyond the facial or lingual margins.

The length of the strip should be just sufficient to cover the

labial and lingual surfaces of the tooth.

A wedge is trimmed and applied to hold the strip in place. For

labial approach use fingers of the left hand for holding the strip

firmly against the lingual surface of the tooth while the material is

being placed in the cavity.

b) Matrix for class III preparation in teeth with irregular alignment

PROCEDURE

A suitable plastic strip is contoured and adopted as described

previously and then removed.

For a labial approach preparation a compound impression is

taken of the lingual surface. The compound is allowed to overlap

the adjacent teeth. It is cooled and then removed.

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The compound impression should show an imprint of the

cavity preparation.

The compound impression is then warmed. The surface is

softened without distorting the form of the entire impression. This

can be done by holding the impression close to the flame only for a

moment.

The strip is then placed into position again, followed by the

compound impression against the strip, assuring perfect adaptation

of the matrix to the cavity on the lingual surface. The material is

then introduced from the labial.

c) MATRIX FOR TWO SMALL PROXIMAL PREPARATIONS IN CONTACT WITH EACH OTHER

An appropriate plastic strip is folded with one end slightly

longer than the other.

A loop ½ inch in diameter is formed in the matrix strip. The

loop is flattened and ceased with a finger, making a T - shaped and

trimmed. The trimmed matrix is then placed between the teeth.

For labial approach preparations, the strip is held over the

lingual surface with the finger while the cavities are filled.

5) MATRICES FOR CLASS IV PREPARATIONS FOR DIRECT TOOTH COLOURED MATERIALS

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a) The plastic strip for inciso proximal cavities

PROCEDURE

A suitable plastic strip is folded at an angle into an L - shaped

then sealed with a plastic cement or any adherence that does not

react with tooth coloured material.

One side of the strip is cut so that it is as wide as the

length of the tooth.

The other side is cut so that it is as wide as the width of

the tooth.

The strip with a wedge in place is adapted to the tooth

b) ALUMINIUM FOIL INCISAL CORNER MATRIX

These are ‘stock’ metallic matrices shaped according to the

proximo - incisal corner and surfaces of anterior teeth. They can be

adapted to each specific case.

PROCEDURE

A corner matrix closest in size and shape of the lost area of

the tooth is selected. It is trimmed gingivally so that it coincides with

the gingival architecture and covers the gingival margin of

preparation.

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As it is readily deformable, shape it with the thumb and first

finger until it fits the mesio distal and labio - lingual dimensions of

the tooth. Loosely place the wedge allowing space for the matrix

band thickness.

Partially fill the preparation and then the corner matrix

preferably after venting the corner.

Apply the partially filled matrix over the partially filled tooth

preparation at its predetermined location between the loosened

wedge and the tooth.

c) TRANSPARENT CROWN FORM MATRICES

These are ‘stock’ plastic crowns which can be adapted to

tooth anatomy.

In bilateral class IV preparations use the entire crown form.

In unilateral class IV cut the plastic crown inciso -

gingivally into two halves and use only the side

corresponding to the location of the preparation.

PROCEDURE

Choose the crown form with the size and shape close to the

tooth to be restored.

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For a unilateral class IV, after cutting the crown from inciso -

gingivally, so that the correct incisal angle of the crown form

matches the last tooth incisal angle. If for bilateral class IV keep the

crown as it is.

Trim the crown form gingivally, so that it coincides with the

gingival architecture and completely covers the gingival margin of

the preparation.

Check the matrix to ensure that it will recreate proper contact

and contour. Then remove the matrix and thin it at its contact area

with a sand paper disc. It should be perforated at the incisal angle.

Completely fill the matrix with the restorative material and

partially fill the preparation with the restorative material.

Place the filled crown form on the tooth in the desired

location. The wedge is then tightened.

d) ANATOMIC MATRIX

Prior to preparing the teeth, study model for the affected tooth

together with at least one intact adjacent tooth on each side is

made.

It is preferable, especially in multiple involvement. The

defective area is restored on the study model in a fairly heat

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resistant material ( plaster, acrylic resin, blacking compound,

plasticine, etc) to the appropriate configuration.

A plastic template is made for the restored tooth on the model

using a comb of heat and suction consequently to draw the

mouldable material onto the study model.

The template is trimmed gingivally to fit the tooth and

adjacent peridontal architecture. It should seal on atleast one

unprepared tooth on each side.

This is the matrix which should be vented by perforating the

corners of its part corresponding to the future restoration.

6) MATRICES FOR CLASS V AMALGAM RESTORATION

a) WINDOW MATRIX

This matrix is formed using either a Tofflemire matrix or

copper band matrix.

PROCEDURE FOR USING THE TOFFLEMIRE MATRIX

The contrangle retainer is applied at the side of the tooth that

does not have the preparation. A window is cut in the band slightly

smaller than the outline of the cavity (perforated windowed bands

are available). Wedges are placed mesially and distally to stabilize

the band.

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PROCEDURE FOR USING THE COPPER BAND

A seamless copper band is selected that is just larger than

the prepared tooth. Fasten and adjust the band to the tooth.

A window is cut coinciding with the cavity but smaller in

diameter. The edges are smoothed.

b) THE S - SHAPED MATRIX

This is usually indicated for a proximal extension of a buccal

or lingual class V preparation.

7) MATRICES FOR CLASS V PREPARATIONS FOR DIRECT TOOTH COLOURED RESTORATIONS

a) Anatomic matrix for non light cured direct tooth colored

materials.

PROCEDURE

The class V cavity may be preliminary filled with inlay wax or

gutta - percha and trimmed to the proper contour. The wax and the

tooth are then coated with cocoa butter or mylar strip and

compound impression is taken of the tooth surface to be restored.

Adjacent surfaces are to be included in the impression. After the

compound has cooled, it is removed and the wax is removed from

the cavity.

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A mix of the restorative material is made and placed into the

cavity, and the compound matrix is placed into position and held

securely in place under pressure until the material sets.

SUMMARY / CONCLUSION

Although there have been very few investigations conducted

on this subject, it is clear that no matrix technique is capable of the

exact replication of normal anatomic contour of restored teeth.

Overall the anatomic matrix procedures must closely reproduce

normal tooth contours.

Wedging is universally imperative in order to eliminate cervical

flash of restorative material.

Some of the clinical significance is the fact that circumferential

matrix bands retained by tightening devices(Toffelmire) have

been shown to deform tooth structures.

Passively inserted matrix bands like anatomic matrix and T -

shaped bands etc have no deformative effect on the remaining

tooth structure.

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