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Operative Dentistry
The "sandwich" technique as a base for reattachment of
dentalfragmentsLuiz Narciso Baratieri* / Sylvio Monteiro, Jr* /
Mauro Amaral Caldeira de Andrada*
Esthetics and function were restored to a fractured maxillary
central incisor by reat-taching the tooth fragment with the
"sandwich" technique (glass-ionomer cement andcomposite resin).
After 3 years, the toolh showed optimal fragment rehydration,
pres-ence of pulped vitality, absence of sensitivity, and a
di.screte color alteration in the ¡inebetween the fragment and tlie
dental remnant. (Quintessence Int 1991:22:81-85.)
Introduction
The "sandwich" technique, first advocated by McLeanet al,' has
been widely discussed and accepted foruse iu various clinical
situations.'"™ Tbe techniquecombines the favorable properties of
glass-ionomercements—adhesion to dental structures, release of
flu-oride ions to the dental structures adjacent to the
res-toration (anticaries action), better biologic compati-bility,
and responsiveness to acid etcbing—witb thefavorable properties of
composite resins—superiorwear resistance, greater cohesive
strength, and bettertranslucency.' The combined restoration thus is
moreesthetic and offers better-sealed margins.'
Tbe fact that glass-ionomer cements are responsiveto add
etching,''"'" through which a porous surfaceis created by a
selective wearing of its matrix,' is im-portant to the
physicoehemical bonding between com-posite resins and the dental
structures, particularly ifthe enamel of the cervical margin is of
a poor qualityor nonexistent.^ Mechanical te,sts have shown that
thebond strengtb between composite resin and acid-etched
glass-ionomer cement is greater tban thecohesive strength of the
cement by itself.'•''•*•"
Associate Professor. Department of Operative Dentistry,
FederalUniversity of Santa Catarina. School of Dentistry, Av
OsmarCunha, No. 15 Bloco A Conjunto 4Ü2, 88000 Florianópolis,Santa
Catarina, Brazil.
Several techniques, including the
acid-etching/fluidresin/composite resin technique, have been
suggestedto enhance the stability and/or to improve the
estheticresults of the reattachment of a tooth fragment to
afractured anterior tooth.-* '̂'-"" This paper presents aelinical
case in which a tooth fragment was reattachedto the coronal remnant
with the sandwich technique.The advantages and limitations of the
procedure willalso be discussed.
Case report
A 20-year-old woman hit her maxillary incisorsagainst a
windowsill. fracturing tootb 11. Tbe patientlooked for a dentist
itnmediately after the accident,taking the tooth fragment (not in
water) with her. Shewas seen by a practitioner who carried out
emergencytreatment, applying a calcium hydroxide cement plusa zinc
oxide-eugenol cement to the dentin for pro-tection. The dentist
referred the patient to us tn thatcondition (Fig 1). Shestillhad
the tooth fragment withher. and it was still not in water (Fig
2).
Wben tbe patient came to our office, 1 day after thefracture had
occurred, our ftrst action was to immersethe fragment in ajar of
water. A routine examinationwas performed, and a periapical
radiograph was takento evaluate the possibihty of root involvement
(theroot was not involved). Next, the emergency dressingwas removed
to evaluate the extent of the fracture.The fragment was
repositioned against the tooth rem-nant to check its adaptation.
Loss of facial tooth
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Operative Dentistry
Fig 1 Incisai view ot a wide coronai fracture. The emer-gency
coating (calcium hydroxide cement and zinc oxide-eugenoi cement]
has aiready begun to separate.
Fig 2 (left) Paiatai view ol the dental fragment reveals
theexposure of the inner surface of enamei. (right) Facial viewot
the dental fragment shows the white incisai region, thearea hit by
the patient.
Fig 3 Once the fragment is back in its piace, loss of
faciaidental structure is found, particulariy near the cervical
mar-gin.
Fig 4 Once the fragment is back in its place, no loss otpalatai
dentai structure is found. The fragment has sufferedfrom
dehydration, so it is whiter than the coronai remnant
Figs The giass-ionomer cement coating, after the fieldwas
isolated and the exposed dentin was cleaned with 25%poiyacrylic
acid for 10 seconds, washed with an air-waterspray, and air
dried.
Fig 6 Phosphoric acid gei is applied to the surface of
theglass-ionomer cement, to the inner enamel, and to ap-proximately
2 mm of surface enamei (30-second etch).
82 Quintessence international Voiume 22, Number 2/1991
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operative Dentistry
Fig 7 Phosphoric acid gel is appiied to the inner surfaceof the
fragment and to approximately 2 mm of the externaisurtace
|30-second etch).
Fig 8 Enamei and glass-ionomer cement after acid etch-
structure next to the cervical margin (Fig 3) and goodpalatal
adaptation (Fig 4) were verified.
The field was tsolated wtth a rubber dam, prophy-laxis of enamel
was performed with a slurry of pumiceand water, and the exposed
dentin was cleaned withair-water spray and air dried. Exposed
dentin was thencoated with a film of fast-setting glass-ionotner
ce-meut (Ketac-Boud, ESPE GtnbH) (Fig 5). After 8minutes of
dentinal protection with the glass-ionotnercement, the fragment was
again positioned andchecked for adaptation. To restore the
adaptation be-tween the fragment and the coronal remnant, part
ofthe inner dentin of the fragment had to be groundaway with a
spherical diamond bur.
Approximately 2 mm of surface enamel, all the frac-tured enamel,
and the glass-ionomer cernent surfacewere acid etched with a
phosphoric acid gel for 30seconds (Fig 6). The tooth remnant was
rinsed withan air-water spray for 1 minute and air-dried. Boththe
outer and inner surfaces of the fragment receivedthe same
treatrnent (Fig 7). The enamel of the frag-ment and the coronal
remnant offered, following acidetching, a dull, white aspect (Figs
8 and 9)-
The fragment was then bonded to the tooth rem-nant. A thin layer
of fluid resin (Concise Enamel BondSystem, 3M Dental Products Div)
was first applied tothe etched enamel of the fragment and to the
surfaceof the glass-ionomer cement, as well as to the etchedenamel
of the coronal remnant. Before the fluid resinset, the fragment was
loaded with a paste-paste com-posite resin system (Concise) and
attached to the co-ronai remnant- Excess resin was removed with an
ex-
ploratory probe. The fragment was held in positionwith a
gutta-percha rod for 8 minutes.
The dam was removed and the occlusion checked.Finishing and
polishing of exposed composite resin atthe facial region was
carried out with flexible sequen-tial disks. The patient was
cautioned about a possiblefragment detachment, and instructed not
to allowforceful incisor function.
Results
Immediate results (Fig 10) indicated that there wouldbe
long-term success. Clinical exatnination 60 daysafter the
reattachment revealed a totally rehydratedfragment, acceptable
esthetics and satisfactory func-tion (Fig 11). The 3-year
examination revealed thatesthetics and function had been maintained
(Fig 12).Pulpal vitality was observed both at the initial
andsubsequent exarns. No kind of sensitivity was reportedby the
patient pos tope ratively. Radiographs indicatedapical
normality.
Discussion
The possibility of employing the sandwich technique'for the
reattachment of a dental fragment representsa breakthrough in the
art and science of such resto-rations, particularly for those cases
in which enamelis nonexistent or minimal at the cervical margin.
Acidetching of the glass-ionomer cement surface favors theformation
of microporosities,"''"-^ which lead to astrong union between the
composite resin and the ce-
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Operative Dentistry
Fig 9 Internal surface ot the fragment after acid etching,Tbe
fragment is field in place with a gutta-percha rod.
Fig 10 Clinical view immediately following reattacfimentoftbe
fragment and removal of tbe rubber dam, Tbe degreeof debydration of
restored tooth can be noticed when it iscompared to the opposing
teetb.
Fig 11 Clinical view 6 months after reattachment Fig 12 Clinical
view 3 years after reattachment.
,17 jfjj. strength of this union is greater thanthe cohesive
strength of the cement itself.'"" The pro-cedure also allows,
indirectly, the chemical bonding ofthe composite resins to the
dental strticture,' thus re-sulting in better-sealed margins.
The reported case shows the possibihty of applymgthe sandwich
technique to the reattachtnent of a dentalfragment. However, there
are possible difficulties, suchas the requirement that the cement
layer have a min-imal thickness of 0,5 mm to favor the formation
ofmicro porosities.' To produce that effect, a greateramount of
dentin will have to be ground from thefragment, to compensate for
the thickness of the ce-ment layer and make possible the
readaptation of thefragment to the dental remnant. This could be
detri-mental to the iong-tenn esthetics of the restoration,'
Another criticism of the technique is the need towait at least
20 minutes after agglutination before acidetching the surface of a
glass-ionomcr cement. Un-timely etching might cause an exaggerated,
nonselec-live wearing of the cement matrix,' ' Such a delay,
nec-essary for the maturation of the cement matrix, couldrender the
technique unproductive, because a dentist'stime is usually precious
and, thus, substantially ex-pensive. Nevertheless, "sacrificing"
such time to pro-duce a better-sealed, more esthetic, and
longer-lastingrestoration would be fully justified.
At the time we decided to proceed with the reat-tachment as
described above, we were not aware oftbe work by Smith,'' which
indicated that the etchingof glass-ionomer cernent surfaces must
not exceed 20seconds. Nevertheless, it is our behef thiu »i-c
suppos-
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Operative Dentistry
edly excessive (30-second) etching of the glass-ionornercement
has not apparently affected the efficacy ofeither the protection
offered by the cement or the reat-tachment bond. The tooth has
shown vitality at recallexaminations, the patient has not reported
any sen-sitivity, and the fragment has not been dislodged.
When bond strength between a glass-ionomer ce-ment and a
composite resin is studied, silane couplingagents should also be
considered because these"primers" might produce a clinical reaction
hetweenthe two materials,'* Recently, new formulations
ofglass-ionomer cements have been introduced, in whicha resin
matrix forms an essential part of the compo-sition. It is claimed
that these materials require noetching to achieve a bond with
composite resins,'^Such materials could improve, in the near
future, thestability of sandwich restorations.
The decision not to adopt any kind of chamfer oneither the
fragment or tooth remnant is due to a recentwork by Dean et al,-°
in which they concluded thatthere were no differences in the
fracture strengths ofFragments that received no mechanical
preparationand those prepared with a 45-degree chamfer
beforereattachment.
The final esthetics of such restorations might changefrom case
to case, particularly beeause of differencesin the degree of
dehydration presented by the frag-ment, the loss of dental
structure, the number of frag-ments, and the technique employed in
preparing andreattaching the fragment,' In the majority of
patients,the fragment will be totaUy rehydrated within 1
weekfollowing reattachment; nevertheless, rehydrationmight take a
few months,'^ or might not even happenat all.̂
References
1, McLean JW, et al; The use ofglass-ionomer cements in
bondingeomposite resins to dentin, Br Dem J 1985;158:41[Mt4,
2, Banitieri LN, et al; Dental adhesives: clinical
CQn,sideriition Torthe use of dentin adhesives and cnamel/detltin
adhesives. RevGaucha Odontol 1987;35;2l7-22t,
3, Baratieri LN. et al: Operative Denti.iîry: Préventive and
Resto-ralive Procedures. Sao Paulo, Quintessence Publ Co. 1989,
4, Croll TP; Dentin adhesive bonding: new applications, 1,
Quin-tessence Im I984;15:]O21-1O27,
5, Garcia-Godoy E; Gluss ionomer materials in Class II
compositeresin restorations: to elcli or not to etch? Quinles.sence
Im1988;19:241-242,
6, Garcia-Godoy F, Malone WEP: The effect of acid etching onIwo
glass-ionomer lining cements. Quintessence Inl Í986;17:621-623,
7, Garcia-Godoy E, Draheim RN. Titus HW: Shear bond strengthof a
posterior composite resin (o glass ionomer bases. Quin-tessence Im
1988; 19:357-359,
8, Hinomura M, et al: Tensile bond strength between glass
ionom-er cements and composite resins, J Am Dem Assoc
1987;ii4:167-172,
9, Smith GE: Surface détérioration of glass-ionomer cement
dur-ing acid etching: an SEM evaluation, Oper Dent 198S;13;3-7,
to Hunt PR; A modified Class II cavity preparation for
glass-ionomer restorative materials, Quitiiessence Im
1984;15:1011-tO18,
11, Wesler G, Beech DR: Bonding of a composite restorative
ma-terial to etched glass-ionomer cement, Au.il Dent J
1988;33:313-318.
12, Simonsen RJ; Traumatic fractured restorations; an
alternativeuse of acid etch technique, Quimessence Int
1979;10:t5-21,
13, Simonsen RJ: Restoration of a fractured central incisor
usingoriginal tooth fragment. J Atn Dent Assoc
1982;105:646-648,
14, Amir E, et al; Restoration of fractured immature
maxillarycentral incisors using the crown fragments, Pediatr
Dent1986;8:285-288,
15, Busato ALS, et al: Tooth fragment attachment:
Heterogeneousattachment in fractured anterior teeth with metallic
reinforce-ment by palatal. Rev Caucha Odomoi ]985;33:326-328,
16, Chin YH, Tyas MJ: Adhesion of composite resin to etched
glassionomer cement, Ausl Dem J Í988;33:87-9O.
17, Sneed WD. Looper SW: Shear bond strength of a compositeresin
to an etched glass-ionomer. Dent Muter li'85;l:127-128,
18, Culler SR. et al: Investigations of silane priming solutions
torepair fractured porcelain crowns, J Dem Res 1986:65
(specialissue);191 (abstr No, 193),
19, Subrata G, Davidson CL; The effect of various surface
treat-ments on the shear strength hetween composite resin and
glass-ionomer cement. J Dem l989;i7;28-32,
20, Dean JA, el al; Attachment of anterior tooth fragments,
PedtalrDent 1986;8;139-142, D
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