Walser Matrices

8/9/2019 Walser Matrices

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Class II (interproximal) decayand/or a failing restoration that involvesa posterior proximal surface is still a com-mon finding in most dental patients.Many of these problems can be handledby using directly placed restorative mate-rials. The challenge for the dentist alwayshas been to create contact with the adja-cent tooth and, at the same time, restoreproper interproximal anatomic form giventhe limitations of conventional matrixsystems. The thickness of the matrix bandand the ability to compress the peri-odontal ligaments of the tooth beingrestored as well as the one adjacent to itcan sometimes make the restoration ofproximal tooth contact arduous at best.

THE MORPHOLOGY OF THEPROXIMAL SURFACE OFPOSTERIOR TEETHAnatomically, the posterior proximal sur-face is convex occlusally and concavegingivally. The proximal contact is ellip-tical in the buccolingual direction andlocated approximately 1 mm apical to theheight of the marginal ridge. As thesurface of the tooth progresses gingival-ly from the contact point toward the

cementoenamel junction, a concavityexists that houses the interdental papilla.Conventional matrix systems are made ofthin, flat metallic strips that are placedcircumferentially around the tooth tobe restored and affixed with some sort ofretaining device. While contact with theadjacent tooth can be made with a cir-cumferential matrix band, it is practical-ly impossible to re-create the naturalconvex/concave anatomy of the posteri-or proximal surface because of the inherent

limitations of these systems. Attempts toshape or burnish matrix bands withelliptical instrumentation may help cre-ate non-anatomic contact, but only dis-torts or indentsthe band and does notre-create complete natural interproximalcontours. Without the support of toothcontour, the interdental papilla may notfill the gingival embrasure completely,leading to potential food traps and areasfor excess plaque accumulation. DirectClass 2 composite restorations can pres-ent even more of a challenge to place forthe dentist because of the inability of resinmaterials to be compressed against a ma-trix to the same degree as amalgam.

This article describes the use of an inno-vative sectional matrix system (Walser,Vi-dent, Brea, CA) and instrumentation de-signed to facilitate placement of these ma-trices to assure maximal results, both inphysiologic contact and anatomic form.When using this system with the latest incomposite resin technology, direct Class 2tooth-colored restorations can be placedthat exhibit natural anatomic proximal formand have predictable proximal contact.1-3

TOOTH PREPARATION AND

MATRIX ARMAMENTARIUMClass 2 preparations that need a matrixband for restoration require rebuilding ofthe marginal ridge, proximal contact, andoften a large portion of the interproximalsurface. The goal with composite place-ment is to do so in a way that the amount ofrotary instrumentation for contouring andfinishing is limited. This is especially truefor the interproximal surface. Because ofthe constraints of clinical access to theproximal area, it is extremely difficult to

sculpt and contour this surface of therestoration correctly. Proper reconstruc-tion of this surface is based largely on theshape of the matrix band and the accuracyof its placement.4 After removal of cariesand old restorative material, the outlineform of the cavity preparation is assessed.If any portion of the proximal contactremains, it does not necessarily need tobe removed. As much healthy, unaffect-ed tooth structure as possible should beconserved. If the matrix band cannot bepositioned through the remaining con-tact easily, the contact can be lightenedusing a Gateway 30-m diamond strip(Brasseler USA, Savannah,GA).

A sectional matrix system, such asWalser, is an excellent choice for Class 2composite restorations for many reasons.

The matrix band is anatomiand the unique design of the for the proper restoration of ianatomy as described. Alsmatrix designs in the Waallow for accurate matrix fitClass 3 and 4 restorationsmolars, and adjacent (baproximal surfaces as well.

CASE REPORT: A CLADIRECT COMPOSITERESTORATIONThe patient presented with 2 composite that had decaygual aspect of the proximathe restoration (Figure 1). Aof the restorative materiadecay, and preparation of t

Sectional Matrices and the Restoration ofClass II Direct Composite RestorationsRobert A. Lowe, DDS

Robert A. Lowe, DDS

Diplomate

American Board of Aesthetic Dentistry

Private Practice

Charlotte Center for Cosmetic Dentistry

Charlotte, North Carolina

Figure 4 Using placement forcematrix (No. 6 for small bicuspid

around the prepared tooth.If the

easily slip through the proximal ar

contact with a 30-m diamond st

wedge helped seal the gingival flo

mal box tightly against the cavosu

Figure 3 An ET 3 (Brasseler USA) was usedto contour the adjacent restoration before the

placement of the matrix on tooth No. 5.

Figure 2 After isolation, the def

tion was removed,and the preparified to remove the recurrent carie

overcontouring of the composite r

tooth No. 4 and how this helped t

cavity in the distoproximal of the

Figure 1) that is now to be replaced

Figure 1 Preoperative occlusal view of tooth

No. 5, which had recurrent caries in the lingual-proximal area of a 10-year-old composite resin

restoration.


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cavity form, the operative area was iso-lated with a rubber dam (Figure 2). Noticethe overcontoured proximal restorationin the adjacent tooth. This surface wasrecontoured and polished before place-

ment of the matrix to create an idealproximal contact for the restoration thatis being placed (Figure 3).

The Walser sectional matrix systemwas chosen for this case to aid in theanatomic restoration of the mesial-prox-imal tooth morphology of this maxillaryfirst premolar (Figure 4).The appropriatematrix band was chosen that best corre-sponded anatomically to the tooth beingrestored and also to the width and heightof the proximal surface. The height ofthe sectional matrix should be no higherthan the adjacent marginal ridge whenproperly placed. Because of the concaveanatomic shape when applied, the proxi-

mal contact was located approximately 1mm apical to the height of the marginalridge. Next, the gingival portion of theband was stabilized and sealed againstthe cavosurface margin of the preparationusing the appropriate size FlexiWedge

(Common Sense Dental Products, Inc,Spring Lake, MI). The size of the flexiblewedge should be wide enough to holdthe gingival portion of the matrix bandsealed against the cavosurface of thepreparation, while the opposite side ofthe wedge sits firmly against the adjacent

tooth surface.If openings exist around theisolated teeth after rubber dam placement,a light-cured liquid dam(OraSeal Ultra-dent Products, Inc, South Jordan, UT)can be used to seal the area(s) and pre-

vent salivary contamination.After the Walser matrix was properlywedged and in place,the restorative processbegan. A 15-second total-etch technique(10 seconds on enamel margins and 5seconds on dentin surfaces) was per-formed using a 37% phosphoric etch(Figure 5). The etchant then was rinsedoff for a minimum of 15 to 20 seconds toensure complete removal (Figure 6). Thepreparation was then air-dried and rewetwith Acqua Seal G desensitizer (Acqua-Med Technologies, Inc, West Chicago, IL)to disinfect the cavity surface, create amoist surface for bonding, and begin ini-tial penetration of hydroxyethylmethacry-

late (HEMA) into the dentinal tubules(Figure 7). A fifth-generation bondingagent (OptiBond Solo Plus, Kerr Cor-poration, Orange, CA) then was placedon all cavity surfaces (Figure 8).The sol-vent was evaporated by spraying a gentlestream of air across the surface of thepreparation. The adhesive was light-curedfor 20 seconds.

The first layer of composite was placedusing a flowable composite (Beautifil

FlowF10, Shofu Dental Corp, San Marcos,CA) toa thickness of about 0.5 mm (Figure

9). The flowable composite flowedintoall the irregular areas of the preparationand created an oxygen-inhibited layer tobond subsequent layers of microhybridmaterial. After light-curing for 20 sec-

onds, the next step was to layer themicrohybrid composite material. First,using a unidose delivery,the first incrementof composite resin (Beautifil II, ShofuDental Corp) was placed into the proximalbox of the preparation. Beautifil II isdescribed by the manufacturer as anano-hybrid composite with fluoriderelease and recharge. A smooth-endedcondensing instrument (Goldstein Flexi-Thin Mini 4, Hu-Friedy, Chicago, IL)was used to adapt the restorative materi-al to the inside of the sectional matrixand preparation.A contact-forming instru-ment, such as the Trimax compositeinstrument (AdDent Inc, Danbury, CT),

can be used to aid in the creation of acomposite bridge to hold the matrixagainst the adjacent tooth and to create aproximal contact, if necessary (Figure 10).Each increment of composite materialshould be no more than 2 mm thick. Thebuccal increment was placed into thefacial portion of the preparation (Figure11), including the facial portion of themarginal ridge. The cuspal projectionswere sculpted and the depressions betweenwere created using the FlexiThin Mini 4.A No. 2 Flat Keystone brush (Patterson

Dental, St. Paul, MN) wasin resin, dried thoroughlyin sponge, and used to fearial toward the margins (smooth the surface of t

The palatal increment ocomposite (Beautifil II) wsame manner as previou(Figure 13 and Figure 14).Aof the composite placemmatrix removal, the restorcured using an LED curingPower Blue, Heraeus Kmonk, NY) (Figure 15 and

The occlusion was checulation paper after remober dam and adjusted as needle-shaped compositemond (Brasseler USA).composite materials usingtechnique, very little finis

required, except at the mRubber polishing abrasivepolish the adjusted areasond etch of the restorativ37% phosphoric acid (Fsurface sealant (ClearChDental Corp) was placed Flat Keystone brush,air-thicured for 20 seconds. Surfato seal microscopic margtions that may remain aftand polishing process. Figuocclusal view of the com

Figure 6 The etchant was rinsed for at least

15 seconds (a longer rinse time can be used).

Then, the preparation was air-dried thoroughly,removing all moisture.

Figure 5 A total-etch technique was used with

a 15-second total-etch time of enamel and

dentin. Start with the application of etchant onthe enamel only, then continue to dentin, which

requires only 5 seconds of etching.

Figure 8 A fifth-generation a

(OptiBond Solo Plus) was appl

the enamel and dentinal surfac

Figure 7 A desensitizer was placed to rewet

the enamel and dentin surfaces and gain initial

penetration of HEMA and fluoride into the denti-nal tubules to aid in formation of the hybrid

zone.

Figure 10 A composite-contact forming

instrument (Trimax composite instrument) was

used to help push the matrix and adapt the

composite firmly against the adjacent proximalsurface.The composite then was cured in place,

forming a composite bridge that guarantees a

strong contact on removal of the matrix.

Figure 9 A thin layer of flowable composite

(Beautifil Flow F10) was placed no thicker than

0.5 mm then, using an explorer tip, was spread to

cover the dentin and fill all the geometric line andpoint angles of the restoration.The goal was to

create a uniformly thin layer of resin in intimate

contact with the cured adhesive, eliminating the

possibility for voids between the composite and

adhesive layer.Also, on curing, the oxygen-inhibit-

ed layer will form a sticky surface onto which the

successive layers of composite resin will be adapt-

ed more easily with less chance of pull back.

Figure 12 A No. 2 Flat Keyst

used to smooth and adapt the

marginal area.This will help to

amount of rotary finishing need

Figure 11 A FlexiThin Mini 4 was used to

place the facial increment of composite

(Beautifil II) in the preparation.


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composite restoration. Notice the beauti-

ful chameleon effect that was achievedusing one shade of composite (Beautifil II)and how well the restorative materialblends with the adjacent tooth structure.5,6

CONCLUSIONA technique has been described using asectional matrix system (Walser) and asso-ciated armamentarium and a nanofilledmicrohybrid composite (Beautifil II) tocreate an anatomically precise Class 2posterior composite restoration.The inter-proximal surface was re-created with nat-ural anatomic contour and elliptical contactwith the adjacent tooth.With proper oc-clusal and proximal form, this invisible

direct composite restoration will servicethe patient for many years to come.7

REFERENCES1. Christensen GJ. Remaining challenges with

class II resin-based composite restora-

tions. J Am Dent Assoc. 2007;138(11):

1487-1489.

2. Boer WM. Simple guidelines for aesthetic

success with composite resinpart 2:

posterior restorations. Pract Proced Aesthet

Dent. 2007;19(4):243-247.

3. Shuman I. Excellence in class II direct com-

posite restorations. Dent Today. 2007;26(4):

102-105.4. Brackett MG, Contreras S, Contreras R, et

al. Restoration of proximal contact in direct

class II composites. Oper Dent. 2006;31(1):

155-156.

5. Lopes GC, Vieira LC, Araujo E. Direct com-

posite resin restorations: a review of some

clinical procedures to achieve predictable

results in posterior teeth. J Esthet Restor

Dent. 2004;16(1):19-32.

6. Lowe RA. Recreating nature using todays

composite materials. Restorative Quarterly.

2000;3(1):3-10.

7. Lowe RA. Morphologic and esthetic preci-

sion in the placement of class II direct

composites. Contemporary Esthetics and

Restorative Practice. 2004;8(5):28-30.

Figure 18 Occlusal view of the completed res-

toration after light-curing of the surface sealant.

Figure 17 After checking occlusion, adjusting

where necessary, finishing, and polishing the

restoration,a 5-second etch was performed to

clean the marginal area, then copiously rinsed

with water and air-dried.

Figure 14 The FlexiThin Mini 4 was used to sculpt

the lingual (palatal) surface of the restoration.

Figure 13 With the facial increment placed

and sculpted, the lingual increment is about to

be placed.

Figure 16 Occlusal view of the completed

restoration before removal of the matrix and fin-

ishing procedures were performed.

Figure 15 The lingual increment was light-

cured for 30 seconds.

EsTHetics

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Walser Matrices