six years' experience with glass-ionomer-silver cermet cement · 2019. 9. 12. · ketac-silver...

Pediaíric Dentistry

Six years' experience with glass-ionomer-silver cermet cementTheodore P. Croll* / Ralph W. Phillips'

Giass-ionomer-silver cermet cement has been used extetisiveiy for restorations inchiidren and adoiescents since 1984. This work describes handling characteristics,clinical uses, and limitations of the materiai and documents representative examples upto 6 years after placement in the mouth. Observations about giass-ionomer-silvercermet cement in clinical tise are also reported. (Quintessence Int 1991;22:783-793. )

Introduction

In 1986, we reported that if glass-ionotner-silver cer-tnet cement {Ketac-Silver and Chelon-Silver, ESPEGmbH) proved itself in the mouth to be durable andreliiible over a 4- to 7-ycar span, the material could bea worthy alternative to silver amalgam for restoringcertain lesions in primary teeth.' After using Ketac-Silver extensively in primary and permanent teeth fortnore than 6 years, we have discovered the material'sstrengths, weaknesses, advantages, disadvantages, im-portant handling characteristics, and strict limitations.When used properly, within those limitations, glass-ioBomer-silver cermet cement is an excellent dentinaiand euamel replacement restorative material that canlast at least 6 years in the human mouth.

* Private Practice, Pédiatrie Dentistri'. Doyiestown, Pennsylvania:Clinicai Associate Professor, Department of Pédiatrie Dentistry,University of Pennsylvania School of Dental Medicine; AdjunctClinical Professor, Department of Pédiatrie Dentistry, Univer-sity of Texas Health Science Center at Houston (DenialBranch),Deceased,

Address all correspondence to DrT, P. Croll, Georgetown Com-mons, Suite 2, 708 Shady Retreat Road, Doyiestown, Pennsyl-vania 1S9Û1,

Ketac-Silver is a premeasured. encapsulated, inject-able glass-ionomer cement material,^ ^ Its non-predosed counterpart is Chelon-Silver, Although it re-tains characteristics of all glass-ionomer cements, suchas chemical bonding to dentin and enamel, coefficientof thermal expansion similar to that of tooth structure,fluoride release to surrounding tooth structure withoutdegradation of the hardened mass, extremely small di-mensional changes and httle heat production duringthe hardening reaction, good biocompatibility, and in-solubility in oral fluids. Ketac-Silvcr differs from con-ventional glass-ionomer cement systems in key ways.The glass powder in the formula is sintered with ele-rnental silver at 800"C, fusing the two materials into acermet (ceramic/meial) mass. That mass is ground intocermet powder, which, when mixed with the acid com-ponent of the formulation, hardens in the traditionalglass-ionomer cement seiting reaction. Although hard-ened glass-ionomer-silver cermet cement is onlyslightly less brittle Ihan conventional glass-ionomercement restorative materials, tbe addition of silvermakes the cement radiopaque and greatly improveswear resistance,'"*

This paper depicts a typical procedure for place-ment of a Class I glass-ionomer-silver cermet cementlestoration and shows representative restorations andother uses of Ketac-Silver in primary and permanentteeth, up to 6 years after treatment (Figs I to 35), Ourprevious work describes placement of a Class IIKetac-Silver restoration,'

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Pédiatrie Dentistry

Fig 1 Maxillary second primary molar with a Class i cariouslesion in the disto-occiusal (ossa.

Fig 2 Lesion is opened for access with a water-cooled,high-speed bur.

Fig 3 Caries is excavated and preparation completed withinterlocking retention form, similar to preparation for a silveramalgam restoration.

Fig 4 Polyacrylic acid wash is applied for 10 seconds to re-move the smear layer.'*'̂ '

Fig 5 Ketac-Silver capsule is activated, mixed on a high-speed amalgamator, and the material is injected directlyfrom a Centrix syringe tip (Centrix inc].' Cement is slowly in-jected from the bottom of preparation, to prevent air voids.

Fig 6 Materiai is compressed into the preparation with a ballbtjrnisher that has beeti wiped with isopropyl alcohol to pre-vent sticking. The preparation is intentionally overfilled.

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Fig 7 After initial hardening (about 5 to 7 minutes), excessmaterial is carved away with a round bur under water iavage.

Fig a Restoration immediately after placement. No varnishor resin giaze is placed.

Fig 9 Three-month postoperative view. Fig 10a Primary moiar immediately after placement of anamaigam restoration in the mesial fossa and Ketac-Siiver res-toration in the distal fossa.

Rg 10b Restorations shown in Fig 10a, 1 year after treat-ment.

Fig 10c Restorations shown in Fig 10a, 5 years after treat-ment.



Fig 11 Primary second molar with Ketac-Silver restoration,5 years after treatment.

Fig 12 Two giass-ionomer-silver cermet cement restora-tions, 4'/2 years after placement.

Fig 13 Five-year-oid Ketac-Silver restorations. Fig 14 Mandibuiar primary moiars wifh 4-year-oid oeclusalKetac-Silver restorations.

Fig 15 Cermet restorations used to restore nutting-related• caries, 5 years after treatment.

Fig 16 Class II Ketac-Silver restorations, 4 years after treat-ment.


Pédiatrie Dentistrv

Fig 17 Narrow isthmus and shallow preparation resulted ina cermet fracture observed 2 years after restoration place-ment.

Fig 18 Class II cermet restoration was fractured when seen14 months after placement.

Rg 19 Four-year-old Ketac-Silver restoration abuts a previ-ously existing mesio-occlusal silver amalgam restoration.Cavity form, by design, provided a large bulk of cement.

Fig 20a Mesio-occlusal amaigam restoration in a primarysecond molar, 5V? years after piacement. Compare with ttietooth in Fig 20b.

Fig 20b Contralateral molar of ttie patient in Fig 20a.Ketac-Silver restoration, 5̂ /̂ years after placement on sameday as the amalgam restoration.

Fig 21 Two years after pulpotomy was performed and theprimary molar was restored with cermet cement, the tooth ¡sasymptomatic and radiographs showed no evidence ofpathosis.



Fig 22 Two-year-old cermet restoration with marginal Fig 23a Mesio-occlusal tunnel restoration,^*'^'^^^ 4 yearscaries. It is believed that an air bubble was entrapped in the after piacement, following exfoliation of the adjacent prim-region during injection ol the cement. ary molar.

Fig 23b Occlusai aspect of a mesio-occlusal tunnel res-toration, 5 years after placement.

Fig 23c Tunnel extension and restoration of the tooth inFig 23b shown in cross section, after extraction tor or-thodontic purposes.

Fig 24 Failed tunnei restoration, 2 years after piacement. Fig 25 Class III cermet restoration, 5 years after place-ment.



Rg 26 Three years after repair of the occiusai surface of astainless steel crown with Ketac-Silver.

Fig 27a Ketae-Siiver used as a dentinai replacement base,under a Ciass i i amaigam restoration.

Fig 27b Three-year-oid siiver amalgam restoration of the Fig 28a Cermet dentinai repiacement base tor a bondedtooth shown in Fig 27a, after dental prophylaxis and poiish- composite resin reste ration."'^ing.

Fig 28b One-year postoperative view of the tooth shown inFig 28a.

Fig 29 Interim Class I restoration of a deep carious lesionin thisfirstpermanentmolar, 3 years after placement. The res-toration and peripherai enamei were "glazed" with bondedresin sealant immediately after placement.



Fig 30 Three-year-old Class I cermet restoration that hadno varnish or bonded resin glaze placed at the time of treat-ment.

Fig 31 Interim cermet restorations of the buceal andoeclusai surfaces of second permanent molar, VA yearsafter placement. The tooth was just beginning to erupt whenthe restorations were placed.

Fig 32 Four-year-old iarge oeelusobuceal cermet restora-tion of the first moiar, 2-year-oid occiusal cermet restorationof the first premolar, and just-piaced occlusal Ketac-Silverrestoration of the second premolar.

Fig 33 Cermet repair of a stainless steel crown margin in apremolar, 4'h years after the repair.

Fig 34a Lingual cervical caries of a first permanent molar. Fig 34b Three years after restoration of the lesion shown inFig 34a-

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Fig 35a Buccal caries and décalcification of a first perma-nent molar.

Fig 35b Immediately after placement of a Ketac-Silver res-toration.

Fig 35c Restoration of tooth shown in Fig 35a, 4 years afterplacement of the Ketac-Silver.

Discussion

Uses for glass-ionomer-silver cermet cement

The senior author has used Ketac-Silver for more tban6 years in tbese ways:

1. Class I restorarions for primary and permanentteeth.

2. Class II restorations for primary teeth, especiallyfor cases in which the restoration abuts a surface ofa permanent tooth (eg, disto-occlusal restorationof a primary second molar).

3. Interim Class I restorafion for a partially eruptedpermanent tooth with limited access that pre-cludes use of bonded composite resin restoration.

4. Class III restoration of primary canine feeth.

5. Class V restoration of primary and permanentteeth (eg, lingual fossa restoration of primary in-cisors with nursing-related caries).

6. Repair of stainless steel crowns with wear throughthe metal occlusal surface.

7. Denfinal replacement base under composite resinor amalgam restoration.

8. "Tunnel" restorations for Class II carious lesionsin primary and permanent teeth.

9. Repair of prosfhetic crown margins.10. Final restoration in primary molars after pulp-

Otomy in teeth with substantial residual coronalstructure and an expected retention of less than3 years.

11. Direct restoration of carious lesions on mesial sur-faces of first permanent molars. Access may beavailable because of exfoliation of the adjacentsecond primary molar, prior to eruption of the sec-ond premolar. Such lesions, detected on bite-wingradiographs, can also be restored witb cermet ce-ment after disto-occlusal preparation of a secondprimary molar that is not yet ready for exfoliationor extraction.

12. As a core material for restoration of a severelybroken down tooth, prior to preparation for a pre-cision cast crown. Because of the material's brit-tleness and low fracture toughness, however, cer-met eement should not constitute more than 40%of the core^ and fhe cermet-tooth structure bondshould not be relied on for crown retention.

Clinical observations after 6 years

The minor formula change (addition of a small

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amount oí titanium dioxide), which was made iti 1986,has eliminated the problem of black staining ofcavosurfaee margins that resulted from the silverions.-'-'-'

Use of the Centrix syringe is important during injec-tion procedures.' The tiianufacturer's capsule has a tipwith a large-diameter lumL̂ n. That tip is too large forplacement in deep recesses of some preparations, andair bubbles are not compressed out of the mixture dur-ing injection, as they are in a Centrix tip. In addition,great care should be taken during injection uf the ce-ment to avoid entrapment of air bubbles, which be-come voids in the hardened restoration {see Fig 22).

Ketac-Silver has radiopacity almost equal to that ofamalgam.

Parents who request "no-mercury" restorations arepleased to hear about "bonded silver fillings that aremercury free."

The Ketac-Silver capsule should be tapped a fewtimes on a hard surface to loosen up the cermet pow-der for better mixing. Furthermore, when the capsuleactivator is squeezed to compress the acid into themixing chamber of the capsule, squeezing should becontinued for 5 seconds. That assures full expressionof the acid portion. Proper handling of the capsuleand its contents is eritical to successful use of cermeteement.

If Ketac-Silver restorations are initially overfilledand permitted to achieve substantial hardness beforetrimming and finishing (about 5 to 7 minutes after in-jection), no varnish or resin glaze is needed to protectthe freshly hardened surface (see Figs 29 and 30).Trimming and finishing procedures should he per-formed with water coolant, however, to avoid desic-cation of the freshly hardened cermet surface.'

Surface pitting and small eraeks are common in cer-met restorations and are usually shallow, self-limiting,and of no clinieal significance (see Figs lOb. 10c, 12.13, 20b, 23b. and 32).

Class I Ketac-Silver restorations do not show ap-preciably greater wear than do silver amalgam restora-tions within 5 years after placement (see Figs 10a to10c and 20a and 20b).

Ketac-Silver Class II restorations have poor fractureresistance, so tooth preparation should include wideand deep channels (see Figs 16 to 19). In addition,whenever possible, marginal ridges of Class II cermetrestorations should be finished out of occlusion, toavoid fracture from masticatory impact forces.

The effect of fluoride release at cavosurface marginsof eermet restorations seems to be clinically signifi-

cant, because Ihe tooth in Fig 22 is the only posttreat-ment case of marginal caries in an unfractured cermetrestoration that the senior author has been able todocument, despite having performed thousands ofsuch restorations since 1984. In addition, we believethat, because of fluoride ion release at proximal contactsites, a Class II Ketac-Silver restoration that contactsthe axial surface of an adjacent tooth has a beneficialanticaries effect. Such a case would he a disto-occlusalrestoration in a primary second molar that abuts themesial aspect of the permanent first molar. Berg etal have reported this phenomenon''' and the effectof cerment cement on formation of inierproximalStreptococctis mutans.^^

Tunnel restorations work well for permanent molarsand primary second moiars when done carefully andwhere the residual marginal ridge is thick and wellsupported. Tunnel restorations involving distal sur-faces of primary first molars work well for 1 to 2years, and then many of the marginal ridges fracture(Fig 24). We have abandoned tunnel restorations forprimary first molars and restore Class II lesions inthose teeth with silver amalgam, stainless steelcrowns, or, on occasion, bonded composite resin.Stainless steel crown restorations are the treatment ofchoice in young patients because of their great durabil-ity and longevity.'*

Ketac-Silver is an excellent restorative material forpartially erupted first or second permanent molars inwhich Class I earies is detected in grooves exposed tothe oral cavity. In such cases, with the tooth anes-thetized, overlying soft tissue is displaced by seatingan orthodontic band, earies is removed, and a restora-tion is piaced. When the treated tooth is fully erupted,the cermet can be cut to form a dentinal replacetnentbase, and the tooth restored with bonded compositercsin'- (see Fig 31).

Bond strength between eermet cement and enamelor dentin is relatively weak and should not be reliedon for retention of the cement. The ehemieal adhesionof glass-ionomer-silver cermet cement to tooth struc-ture is more important for minimizing eavosurfacemarginal leakage than for retention of the hardenedcermet mass. All principles of mechanical interlockingretention form in cavity preparation should be itn-plemented when a cermet cement restoration isplaced. This is the reason that Ketac-Silver performswell as a restorative material in a bur-cut preparationwith mechanical undercuts, but is easily dislodged orworn away when used as a pit and fissure sealant.

Although we have not performed a controlled scien-



tifie study on the subject, it is our clinical impressionthat glass-ionomer-silver cermet cement restorations,when placed as described, are at least as well toleratedby pulpal tissues as are equivalent silver amalgamrestorations."

References

1, Croll TP. Phillips RW: Glass-ionomer-silver cermet restora-tions fof primary teeth. Quimessence b\t 1986; 17:607-615,

2, McLean JW, Gasser O: Glass-cermet cements. Quintessencehit 1985;16;333-343,

3, McLean JW, Gasser O: Powdered Dental Material and Processforthe Preparation Thereof. US patent No. 4,527,579, 1985.

4, Wilson AD, McLean JWi Glass-ionomer Cement. Chicago,Quintessence Publishing Co, 1988, pp 3(1-33, 204-227, 256-270.

.S Pliillips RW: The Science of Dental Materials, ed 9, Philadel-phia. WB Saunders Co, 1991. chap 24.

b. Mount GJ: An Arias of Glass-ionomer Cements. Philadelphia.BC Decker. Inc. 1990, pp 54-65, 78-1Ü3,

7, Duke ES. Phillips RW, Blutnershine R: Effects of variousagents in cleaning cut dentine. / Oral Rehabil 19B5; 12:295-302,

S. Jinks OM: Fltioride-impregiiiitcd cements and their effect onthe activity of interproximal earies, J Dent Child 1963;3Ü(2n(Jquarte i):S7-.92.

9. Hunt PR: A modified Class II cavity preparation for glass-ionomer restorative materials. Qidmessence Int iy84;10:lOU-lOtH.

It). Croll TP: Gluss-ionomcr-silvcr cermet bonded compositeresin Class 11 tunnel restorations. Quimessence Int I988;19:533-539.

11. Croll TP: Glass-ionomer-silver cermet Class II tunnel res-torations for primary molars. / Dent Child 1988;55:177-182,

12. Croll TP: Replacement of defective Class I amalgam restora-tion with stratified glass.ionomer-eompositc resiti materials,Quimessence Int 1989;20:711-716,

13. Croll TP, Ricsenberger RE, Miller AS: Clinical and histolog-ical observations of Ketac-Silver restorations in six primarymolars. Quintessence Im 19S8;19:911-919,

14, Berg JH, Donly KJ, Posnick WR: Glass-ionomer-silver res-torations: a demineralization-remineralization concept.Quintessence Im 1988;9:639-641,

15, Berg JH, Farrell JE, Brown LR: Class II glass-ionomer-siivercermet restorations and their effect on interproximal growthof mutans streptococci, Pediatr Dent 1990;12:2t)-23,

16, Croll TP, Riescnberger RE: Primary molar stainless steelcrown restoration. Oiiiniessence Im 1986; 17:221-226, D

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six years' experience with glass-ionomer-silver cermet cement · 2019. 9. 12. · ketac-silver...

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