Matrix Systems for Restorative Dentistry Chapter 49 Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved

Matrix Systems for Matrix Systems for Restorative DentistryRestorative Dentistry

Chapter 49Chapter 49

Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved.

Chapter 49Chapter 49

Lesson 49.1Lesson 49.1


Learning ObjectivesLearning Objectives

Pronounce, define, and spell the Key Terms.Pronounce, define, and spell the Key Terms. Describe the use of matrix systems in class II, Describe the use of matrix systems in class II,

III, and IV restorations.III, and IV restorations. Describe the type of matrices used for posterior Describe the type of matrices used for posterior

restorations.restorations. Describe the purpose and use of a wedge.Describe the purpose and use of a wedge. Discuss alternative methods of matrix systems Discuss alternative methods of matrix systems

used in restorative dentistry.used in restorative dentistry. Assemble a universal retainer and matrix band.Assemble a universal retainer and matrix band.(Cont’d)(Cont’d)


Learning ObjectivesLearning Objectives

(Cont’d)(Cont’d)

Place and remove a matrix band and wedge Place and remove a matrix band and wedge for a class II restoration.for a class II restoration.

Place and remove a matrix band and wedge Place and remove a matrix band and wedge for a class III restoration.for a class III restoration.


IntroductionIntroduction

A matrix system provides a A matrix system provides a

“temporary wall” for the restoration “temporary wall” for the restoration

process in class II, III and IV process in class II, III and IV

preparations. preparations.


Posterior Matrix SystemPosterior Matrix System

Universal retainerUniversal retainer Also referred to as Tofflemire retainerAlso referred to as Tofflemire retainer

Holds the matrix band in positionHolds the matrix band in position Positioned most commonly from the buccal Positioned most commonly from the buccal

surface of the tooth being restored surface of the tooth being restored


Components of Universal RetainerComponents of Universal Retainer


Matrix BandsMatrix Bands

Thin, flexible stainless steelThin, flexible stainless steel Common designsCommon designs

Universal Universal Extension Extension

Guidelines for placementGuidelines for placement Larger circumference: occlusal edgeLarger circumference: occlusal edge Smaller circumference: gingival edgeSmaller circumference: gingival edge


Fig. 49-2 Most commonly used posterior matrix bands.Fig. 49-2 Most commonly used posterior matrix bands.


WedgesWedges

Positioned into the lingual embrasure of a Positioned into the lingual embrasure of a class II preparation after band placementclass II preparation after band placement Positions the matrix band firmly against the Positions the matrix band firmly against the

gingival margin of the preparationgingival margin of the preparation Various sizesVarious sizes

Triangular/round Triangular/round Wood/plastic Wood/plastic


Fig. 49-5 Assortment of precontoured wedges.Fig. 49-5 Assortment of precontoured wedges.


Anterior Matrix Systems Anterior Matrix Systems

Plastic matrixPlastic matrix Also referred to as: Also referred to as: Celluloid matrix Celluloid matrix Mylar stripMylar strip Used in Class III and IV restorationsUsed in Class III and IV restorations


Fig. 49-7 A clear matrix system. Fig. 49-7 A clear matrix system. (Courtesy of Premier Dental Products.)(Courtesy of Premier Dental Products.)


Using an Anterior MatrixUsing an Anterior Matrix

Placed interproximally before the etching and Placed interproximally before the etching and bonding of a tooth.bonding of a tooth.

After the placement of composite material, a After the placement of composite material, a matrix is pulled tightly around the tooth to matrix is pulled tightly around the tooth to help reconstruct its natural contour.help reconstruct its natural contour.

A clear plastic matrix allows curing light to A clear plastic matrix allows curing light to penetrate the material and complete the penetrate the material and complete the curing process. curing process.


Automatrix System Automatrix System

The automatrix system is an alternative to a universal The automatrix system is an alternative to a universal retainer.retainer.

No retainer is used to hold the band in place. No retainer is used to hold the band in place. Preformed bands available in assorted sizes in both metal Preformed bands available in assorted sizes in both metal

and plastic. and plastic. Each band has a coil-like auto-lock loop. Each band has a coil-like auto-lock loop. A tightening wrench is inserted into the coil and turned A tightening wrench is inserted into the coil and turned

clockwise to tighten the band.clockwise to tighten the band. When the band is to be removed, a tightening wrench is When the band is to be removed, a tightening wrench is

inserted into the coil and turned counterclockwise to inserted into the coil and turned counterclockwise to loosen the band.loosen the band.

Removing pliers are used to cut the band. Removing pliers are used to cut the band.


Fig. 49-9 Automatrix system. Fig. 49-9 Automatrix system. (Courtesy of Dentsply Caulk.)(Courtesy of Dentsply Caulk.)


Sectional Matrices Sectional Matrices

A thin, polished palodent-type band and A thin, polished palodent-type band and

tension ring produce tight anatomic tension ring produce tight anatomic

contact for composite resin materials contact for composite resin materials

in class II restorations.in class II restorations.


Fig. 49-10 Sectional matrices. Fig. 49-10 Sectional matrices. (Courtesy of Garrison Dental Solutions.)(Courtesy of Garrison Dental Solutions.)


Matrix Systems for Primary Teeth Matrix Systems for Primary Teeth

T-band T-band When formed, the top portion of the T allows the When formed, the top portion of the T allows the

straight portion to adjust and fit the circumference straight portion to adjust and fit the circumference of the primary molar. of the primary molar.

Spot-welded band Spot-welded band Form-fitted band placed around a prepared tooth; Form-fitted band placed around a prepared tooth;

removed and placed in a smaller form of a welder, removed and placed in a smaller form of a welder, fusing the metal together to make a custom band.fusing the metal together to make a custom band.


Fig. 49-11 Copper T-band used for primary molars.Fig. 49-11 Copper T-band used for primary molars.


Preparing the T-Band Matrix Preparing the T-Band Matrix

The wings of the T-band are bent to form a U-The wings of the T-band are bent to form a U-shaped trough. shaped trough.

The free end of the band is slipped loosely The free end of the band is slipped loosely through the U formation. through the U formation.

The wings are closed, and the free end is The wings are closed, and the free end is pulled to make a small circle of the band. pulled to make a small circle of the band.

Holding the free end toward the facial Holding the free end toward the facial surface, place the band on the tooth to be surface, place the band on the tooth to be prepared. prepared.


Fig. 49-12 Spot welder used for primary molars.Fig. 49-12 Spot welder used for primary molars. (Courtesy of Unitek, Monrovia, Calif.)(Courtesy of Unitek, Monrovia, Calif.)


Preparing a Spot-Welded Matrix Preparing a Spot-Welded Matrix Band Band

Measure ¾ to 1 inch of stainless-steel matrix Measure ¾ to 1 inch of stainless-steel matrix material. material.

Fit the matrix band around the prepared tooth. Fit the matrix band around the prepared tooth. Adapt the band, making sure that the ends of Adapt the band, making sure that the ends of

the matrix material are at the facial surface for the matrix material are at the facial surface for the sake of visibility and control.the sake of visibility and control.

Using Howe pliers, hold the ends tightly and Using Howe pliers, hold the ends tightly and remove the band in an occlusal direction. remove the band in an occlusal direction.

Place the band in the spot welder.Place the band in the spot welder. Spot-weld the matrix at three positions. Spot-weld the matrix at three positions.


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Matrix Systems for Restorative Dentistry Chapter 49 Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved