2. 22
Matrix ?Matrix ?
A matrix is defined as a properlyA matrix is defined as a properly
contoured piece of metal or othercontoured piece of metal or other
material used to support and give form tomaterial used to support and give form to
the restoration during its placement andthe restoration during its placement and
hardening.hardening.
The art and science of operative dentistry,1995: Mosby-Year Book,Inc.
3. 33
IntroductionIntroduction
Unfortunately, dentistry does not have a trulyUnfortunately, dentistry does not have a truly
satisfactory manufactured matrix for directlysatisfactory manufactured matrix for directly
placed restorations.placed restorations.
Most matrices available to the profession haveMost matrices available to the profession have
some good qualities but do not meet all thesome good qualities but do not meet all the
requisites.requisites.
The primary function of the matrix is to restoreThe primary function of the matrix is to restore
anatomical contours and contact areas.anatomical contours and contact areas.
4. 44
Why do we need matrices ?Why do we need matrices ?
Gingival floor of a class IIGingival floor of a class II
cavity is the mostcavity is the most
vulnerable area wherevulnerable area where
overhang of restorativeoverhang of restorative
material can take place.material can take place.
There is no method toThere is no method to
control the placement andcontrol the placement and
contour of restorationcontour of restoration
without a matrix wall.without a matrix wall.
5. 55
Characteristics of a good matrixCharacteristics of a good matrix
Rigidity.Rigidity.
Establishment of proper anatomical contour.Establishment of proper anatomical contour.
Restoration of correct proximal contact relation.Restoration of correct proximal contact relation.
Easy adaptation to the tooth.Easy adaptation to the tooth.
Ability to be contoured.Ability to be contoured.
Prevention of gingival excess.Prevention of gingival excess.
Strength to offer resistance to condensation.Strength to offer resistance to condensation.
pressure.pressure.
Easy removal from the tooth.Easy removal from the tooth.
6. 66
Functions of matrixFunctions of matrix
Provision of aProvision of a temporary walltemporary wall of resistanceof resistance
to the pressure necessary for amalgamto the pressure necessary for amalgam
insertion.insertion.
Provision of shape and contour to theProvision of shape and contour to the
restoration.restoration.
Maintenance of form during placementMaintenance of form during placement
and set of the amalgam/composite.and set of the amalgam/composite.
7. 77
ClassificationClassification
On the basis of chemistryOn the basis of chemistry
On the basis of thicknessOn the basis of thickness
On the basis of rigidityOn the basis of rigidity
On the basis of circumferenceOn the basis of circumference
9. 99
Circumferential TypeCircumferential Type
The band encircles the tooth and isThe band encircles the tooth and is
secured by the retainer on the buccal orsecured by the retainer on the buccal or
lingual aspect.lingual aspect.
Band may be straight, curved orBand may be straight, curved or
contoured.contoured.
Advantage: this type can be firmly adaptedAdvantage: this type can be firmly adapted
to the tooth.to the tooth.
11. 1111
DimensionsDimensions
The non-contoured bands are available inThe non-contoured bands are available in
two thicknesses, 0.05mm and 0.038mm.two thicknesses, 0.05mm and 0.038mm.
Contoured matrices may have variableContoured matrices may have variable
dimensions (depending upon thedimensions (depending upon the
commercial product).commercial product).
12. 1212
Tofflemire matrix bandTofflemire matrix band
The Tofflemire matrix assembly consistsThe Tofflemire matrix assembly consists
of the following:of the following:
Matrix bandsMatrix bands
Matrix retainerMatrix retainer
WedgeWedge
17. 1717
WedgesWedges
Anatomical (triangularAnatomical (triangular
wedges) arewedges) are
recommended for deeperrecommended for deeper
and / or wider proximaland / or wider proximal
preparations.preparations.
Rounded wedges areRounded wedges are
recommended forrecommended for
shallower and / orshallower and / or
narrower proximalnarrower proximal
preparations.preparations.
Sturdevant JR et al: Conservative preparation designs for class II
amalgam restorations, Dent Mater 3:144, 1987.
18. 1818
Role of wedgeRole of wedge
It should hold the matrix band firmly in positionIt should hold the matrix band firmly in position
cervically.cervically.
It should not be of such a height that it preventsIt should not be of such a height that it prevents
the formation of a contact point.the formation of a contact point.
Another function is to separate the teeth slightlyAnother function is to separate the teeth slightly
so that when it and the matrix are finallyso that when it and the matrix are finally
removed, the teeth return to their originalremoved, the teeth return to their original
positions, closing the small space left by thepositions, closing the small space left by the
thickness of the matrix band.thickness of the matrix band.
21. 2121
TechniqueTechnique
Either precontoured the matrix materialEither precontoured the matrix material
before placing on the tooth.before placing on the tooth.
Matrix band can be contoured after beingMatrix band can be contoured after being
adapted on the tooth with the help of anadapted on the tooth with the help of an
egg-shaped burnisher, back side of theegg-shaped burnisher, back side of the
blade of 15-8-14 spoon excavator or bladeblade of 15-8-14 spoon excavator or blade
of a Hollenbeck carver.of a Hollenbeck carver.
23. 2323
Modification of matricesModification of matrices
All matrices require modification when:All matrices require modification when:
proximal surface is a guide plane for tooth/proximal surface is a guide plane for tooth/
tissue supported partial denture.tissue supported partial denture.
Adjacent tooth has a flatter contact.Adjacent tooth has a flatter contact.
Adjacent proximal contours are notAdjacent proximal contours are not
normal.normal.
25. 2525
Wedges for compositeWedges for composite
Light reflecting wedges along with clearLight reflecting wedges along with clear
matrices are recommended for compositematrices are recommended for composite
restorations.restorations.
Alternatively, ultra thin (0.013mm) metalAlternatively, ultra thin (0.013mm) metal
matrices can be used for composites.matrices can be used for composites.
26. 2626
PrewedgingPrewedging
Placement of wedge prior to toothPlacement of wedge prior to tooth
preparation is helpful especially in case ofpreparation is helpful especially in case of
composite restorations.composite restorations.
It allows greater separation of the teethIt allows greater separation of the teeth
and more space to build a contact.and more space to build a contact.
27. 2727
AutomatrixAutomatrix
It’s a retainer less matrix system withIt’s a retainer less matrix system with
four types of bands, designed to fit allfour types of bands, designed to fit all
teeth regardless of circumference.teeth regardless of circumference.
Narrow regular (4.7mm), (0.05mm)Narrow regular (4.7mm), (0.05mm)
Wide regular (7.9mm), (0.05mm)Wide regular (7.9mm), (0.05mm)
Medium thin (6.2mm), (0.038mm)Medium thin (6.2mm), (0.038mm)
Medium regular (6.2mm), (0.05mm)Medium regular (6.2mm), (0.05mm)
28. 2828
Sectional matricesSectional matrices
Studies have shown that use of sectionalStudies have shown that use of sectional
matrices for composite restorations are onmatrices for composite restorations are on
a rise.a rise.
Sectional matrices do not only result inSectional matrices do not only result in
tighter anatomical contacts but also aretighter anatomical contacts but also are
dentist friendly.dentist friendly.
Lowe RA. The use of sectional matrix systems in class II direct composite
restorations. Dent Today. 2004 Oct;23(10):108, 110-2
30. 3030
Apical flap matrix ?Apical flap matrix ?
Restoring a class II cavity with deeplyRestoring a class II cavity with deeply
placed proximal gingival floor orplaced proximal gingival floor or
restoration of root caries in proximalrestoration of root caries in proximal
surfaces with composite is a restorativesurfaces with composite is a restorative
challenge for the dentist.challenge for the dentist.
The feature of apical flap in the design ofThe feature of apical flap in the design of
sectional has solved the issue tosectional has solved the issue to
considerable extent.considerable extent.
A conservative technique for restoring a tooth affected by interproximal
root caries. J Prosthet Dent. 2003 Feb;89(2):221-2.
32. 3232
Questions ?Questions ?
Is the matrix band stable ?Is the matrix band stable ?
Does the matrix band fit at the cervicalDoes the matrix band fit at the cervical
margin ?margin ?
Has the band beenHas the band been burnishedburnished in thein the
contact area so that the contact point cancontact area so that the contact point can
be restored ?be restored ?
Is the height of the band sufficient ?Is the height of the band sufficient ?
Is the cavity clean and dry ?Is the cavity clean and dry ?
39. 3939
Other methods for tighter contacts.Other methods for tighter contacts.
Use of PTFE tape.Use of PTFE tape.
Use of composite inserts.Use of composite inserts.
Incremental composite placement.Incremental composite placement.
Continuous pressure against proximalContinuous pressure against proximal
wall.wall.
Class transition technique.Class transition technique.
Dunn WJ, Davis JT, Casey JA. Polytetrafluoroethylene (PTFE) tape as aDunn WJ, Davis JT, Casey JA. Polytetrafluoroethylene (PTFE) tape as a
matrix in operative dentistry. Oper Dent. 2004 Jul-Aug;29(4):470-2matrix in operative dentistry. Oper Dent. 2004 Jul-Aug;29(4):470-2
40. 4040
Are matrices reusable ??Are matrices reusable ??
A survey of the use of matrix bands and theirA survey of the use of matrix bands and their
decontamination in general dental practicedecontamination in general dental practice..
Lowe AH, Burke FJ, McHugh S, Bagg J.Lowe AH, Burke FJ, McHugh S, Bagg J.
The University of Birmingham School of DentistryThe University of Birmingham School of Dentistry..
CONCLUSIONS:CONCLUSIONS: The Siquveland matrix band is the mostThe Siquveland matrix band is the most
popular among the study group of dental practitioners. Re-usepopular among the study group of dental practitioners. Re-use
of matrix bands is common. Guidelines for the safe re-use ofof matrix bands is common. Guidelines for the safe re-use of
matrix bands are requiredmatrix bands are required
41. 4141
ConclusionConclusion
The role of matrices in operative dentistryThe role of matrices in operative dentistry
is irreplaceable.is irreplaceable.
Without a matrix there is no other way (inWithout a matrix there is no other way (in
a directly placed restoration) to producea directly placed restoration) to produce
contours and contacts.contours and contacts.
No matrix band is ideal, almost allNo matrix band is ideal, almost all
proximal cavities need a matrix dependingproximal cavities need a matrix depending
on the requirements of the specific case.on the requirements of the specific case.
Goldstein MB.It's all in your contacts! A Class II matrix roundup. Dent Today.Goldstein MB.It's all in your contacts! A Class II matrix roundup. Dent Today.
2003 Sep;22(9):60-5.2003 Sep;22(9):60-5.
42. 4242
Mullejans R, Badawi MO, Raab WH, Lang H. An in vitroAn in vitro
comparison of metal and transparent matrices used forcomparison of metal and transparent matrices used for
bonded class II resin composite restorations. Oper Dent.bonded class II resin composite restorations. Oper Dent.
2003 Mar-Apr;28(2):122-6.2003 Mar-Apr;28(2):122-6.
El-Badrawy WA, Leung BW, El-Mowafy O, Rubo JH,El-Badrawy WA, Leung BW, El-Mowafy O, Rubo JH,
Rubo MH. Evaluation of proximal contacts of posteriorRubo MH. Evaluation of proximal contacts of posterior
composite restorations with 4 placement techniques. Jcomposite restorations with 4 placement techniques. J
Can Dent Assoc. 2003 Mar;69(3):162-7.Can Dent Assoc. 2003 Mar;69(3):162-7.
43. 4343
Rada RE. Achieving anatomic proximal contacts withRada RE. Achieving anatomic proximal contacts with
direct composite resin restorations.Dent Today. 2000direct composite resin restorations.Dent Today. 2000
Mar;19(3):46-50.Mar;19(3):46-50.
Klein F, Keller AK, Staehle HJ, Dorfer CE.. ProximalKlein F, Keller AK, Staehle HJ, Dorfer CE.. Proximal
contact formation with different restorative materials andcontact formation with different restorative materials and
techniques. Am J Dent. 2002 Aug;15(4):232-5 .techniques. Am J Dent. 2002 Aug;15(4):232-5 .
