ultraconservative and cariostatic sealed restorations

JADA, Vol. 129, January 1998 55

The traditional treatment forcarious lesions was outlinednearly a century ago by G.V.Black.1 This treatment consistsof the removal of the carious le-sion, including all demineral-ized dentin and unsupportedenamel rods. Tooth preparationthat follows these guidelinesmust also provide sufficientroom for placement of a restora-tive material, based primarilyon the physical properties of thematerial itself. Furthermore,the preparations are extendedto include pits and fissures thatmay at some future date be-come carious (extension for pre-vention). Finally, cavity prepa-ration, according to Black,requires the removal of toothstructure to prepare a specifi-cally dictated outline form aswell as an internal form thatprovide for mechanical reten-tion of the restoration.

Adherence to these tradition-al guidelines results in removalof sound tooth structure, howev-er. The net result is that thefinal preparation for a very lim-ited carious lesion can involveextensive loss of healthy enameland dentin.

In 1969, Keyes2 described thethree groups of causative fac-tors (illustrated as overlappingcircles) essential in the etiology

the sugars in the host’s diet).All three groups of causative

factors must interact simultane-ously for caries to occur orprogress. Thus, it is reasonableto expect that if the source ofnutrition for the cariogenic bac-teria could be eliminated, theorganisms would die, thus ar-resting the carious process.Therefore, a bonded and sealedcomposite restoration placedover a frank cavitated lesioncould form a physical barrieragainst nutrients from the oralcavity. Without these nutrients,the cariogenic organisms withinthe sealed lesion would notthrive, leading to a halt in thecarious process. The substratecircle that Keyes describedwould be prevented from inter-acting with the other two cir-cles, although the host and bac-teria circles would still overlapbecause the bacteria would re-main inside the host’s tooth.

The success of enamel etch-ing and resin bonding in greatlyreducing or virtually eliminat-ing microleakage at the inter-face between the etched enameland resin is well documented.3,4

Resin tags penetrate into theetched enamel, forming a physi-cal barrier at the microscopiclevel against the entry of bacte-ria and nutrients from the oral

ULTRACONSERVATIVE AND CARIOSTATIC SEALED RESTORATIONS:RESULTS AT YEAR 10EVA J. MERTZ-FAIRHURST, D.D.S.; JAMES W. CURTIS JR., D.M.D.; JANET W. ERGLE, C.D.A.; FRED A.RUEGGEBERG, D.D.S., M.S.; STEVEN M. ADAIR, D.D.S., M.S.

Changes in restorative tech-

niques and the development of

newer restorative materials have

allowed for the use of more con-

servative cavity preparations.

This 10-year study evaluated

bonded and sealed composite

restorations placed directly over

frank cavitated lesions extend-

ing into dentin vs. sealed conser-

vative amalgam restorations and

conventional unsealed amalgam

restorations. The results indi-

cate that both types of sealed

restorations exhibited superior

clinical performance and longevi-

ty compared with unsealed amal-

gam restorations. Also, the bond-

ed and sealed composite

restorations placed over the

frank cavitated lesions arrested

the clinical progress of these le-

sions for 10 years.

A B S T R A C T

RESEARCH

of caries: da susceptible host;dcariogenic microflora;da suitable substrate (mainly

Copyright ©1998-2001 American Dental Association. All rights reserved.

lars be paired only with perma-nent molars and premolars withpremolars. There were 131molar pairs and 25 premolarpairs. The procedures, possiblediscomforts or risks, and possi-ble benefits were explainedfully to subjects, and their in-formed consent was obtainedbefore the investigation.

Lesion characteristics. Wescreened patients who had atleast two clinically obvious cavi-tated lesions with bitewing ra-diographs to confirm that eachlesion extended into the dentinbut was no deeper than halfwayinto it. The judgment that a le-sion on a radiograph was halfwayinto dentin was estimated ashalf the distance between thedentinoenamel junction, orDEJ, and the pulp chamber orbetween the DEJ and the near-est pulp horn. We did not acceptlesions confined to the enameland we excluded teeth withproximal caries.

Restorations. Conventionalamalgam restorations. At base-line, 123 patients (43 males, 80females), aged 8 to 52 years (themedian age was 23 years), re-ceived either a localized sealedamalgam, or AGS, restorationthat was not extended for pre-vention or an unsealed amal-gam, or AGU, restoration thatwas prepared using the tradi-tional principles for Class I cav-ity form in which the preparationwas extended into noncarious fis-sures to prevent future caries ac-tivity. We completely removedsoft demineralized dentin andchalky white demineralizedenamel for both types of amal-gam preparations. We did notremove dentin or enamel thatwas stained and hard.

Conservative amalgamrestorations. For the AGSrestorations, the dentist opera-

cavity. Thus, a properly placedbonded and sealed Class Irestoration has the potential topreclude the progression of acarious lesion sealed within thetooth.

The purpose of this con-trolled clinical study was to usetwo modalities to evaluate theeffectiveness of treating frankcavitated lesions:dsealed composite restorationsplaced over the carious lesion;dremoval of the carious lesionand placement of ultraconserva-tive, localized sealed amalgamrestorations without an exten-sion for prevention.

We then compared these twomodalities with the traditionalunsealed Class I amalgamrestoration, including the exten-sion-for-prevention cavity out-line form. This article summa-rizes the observed results foreach of the three restorative ap-proaches over a 10-year clinicaltrial period.

MATERIALS ANDMETHODS

The materials and methodsused in this study have been de-scribed elsewhere,5-10 but de-scriptions of the patient selec-tion criteria, lesions, proceduresand materials follow. All opera-tors and evaluators were den-tists. The operators were trainedregarding the specific restora-tive techniques and the evalua-tors were calibrated to enhanceinterexaminer reliability.

Patient selection criteria.To be included in the study,each person must have had atleast two Class I lesions in pre-molars or permanent molars,and the carious lesions musthave been clinically and radio-graphically obvious.

The selection of study lesionsrequired that permanent mo-

tor removed all soft demineral-ized dentin only in the localizedarea of the carious lesion, butthe preparation was not extend-ed into unaffected fissures andgrooves. If two separate occlusallesions were present, they werenot combined into a single largeramalgam restoration. Instead,two small localized cavity prepa-rations were made, except whenthe distance between the twocavity preparations would beless than 0.5 millimeters. Afterthe amalgam was placed, theoperator applied sealant overthe restoration and all pits andfissures of the tooth.

Cariostatic sealed compositerestorations. For each patient,we paired one of these amalgamrestorations with a bonded andsealed composite, or CompS/C,restoration placed over caries,for a total of 156 pairs of studyteeth, or a total of 312 teeth.Treatment assignment(CompS/C and AGS or AGU)was statistically randomized foreach study tooth.

The only preparation for theCompS/C restorations consistedof placing a 45- to 60-degreebevel in the enamel surround-ing the frank cavitated lesion.This occlusally divergent bevelhad to be at least 1 mm wideand placed in sound enamel. Weremoved all of the crumbly,opaque demineralized enamelwith a bur until we reachedtranslucent sound enamel. Wedid not remove underminedenamel or caries below thebevel.

During the operative proce-dures at baseline, if the opera-tor inadvertently removed all ofthe soft dentin, the potentialstudy tooth was disqualified forthe CompS/C restoration be-cause a carious layer of softdentin had to remain below the

56 JADA, Vol. 129, January 1998

RESEARCH


bevel to qualify the tooth for theCompS/C restoration. The deepsoft portions of the cavity re-mained untouched. After place-ment of the bevel, we frequentlyobserved shreds of cariousdentin or other material hang-ing below the bevel toward thesoft and wet pulpal floor of thecavity.

After placement of the bevel,the operator washed the cavityand dried the bevel. Some of thepreviously observed hangingshreds were washed out, butothers remained. A layer of softand wet-looking dentin in thepulpal area of the cavity re-mained intact, and there wasabsolutely no instrumentationbelow the enamel bevel. The op-erator next thoroughly driedand etched the bevel and theadjacent enamel for 60 seconds.The bonding agent was placedon the bevel and the adjacentetched enamel. The operatorthen used hand instruments toplace a self-curing compositematerial.

After a final shaping of theocclusal anatomy with rotaryinstruments, the operator thenetched all of the occlusal, buccaland lingual pits and fissures for60 seconds, washed the etchantthoroughly and applied a chem-ically cured sealant. Thesealant, which was applied withan applicator supplied in thesealant kit, was placed over theentire restoration and adjacentetched enamel as well as overall of the pits and fissures of thetooth.

When the sealant was set inthe mixing well, the operatorwaited another 30 seconds toensure that the sealant wasalso set on the tooth. The opera-tor then wiped the sealed toothwith a wet cotton roll, dried itwith an air syringe and inspect-

ed it to ensure that all of thepits and fissures and the entirerestoration with the adjacentenamel were completely sealed.If they were not completelysealed, the area or areas inquestion were re-etched for 30seconds and resealed. The rub-ber dam was removed and thedentist made necessary occlusaladjustments.

Materials. The materialsused included Delton yellow-tinted, chemically cured pit andfissure sealant (L. D. Caulk,Dentsply Division [at the timeof the study, the sealant wasmanufactured by Johnson &Johnson Dental Products Co.]),radiopaque chemically curedMiradapt composite restorativematerial (Johnson & JohnsonDental Products Co. [the mate-rial is no longer manufactured])and Dispersalloy amalgam (L. D. Caulk, Dentsply Division[at the time of the study, theamalgam was manufactured byJohnson & Johnson DentalProducts Co.]).

Study design. The study de-sign was four-celled, as shownin the box (“Four-Celled StudyDesign”). This type of design al-lowed us to compare the four

groups of restorations, with theadded advantage that Group 1(n = 77) and Group 2 (n = 79)CompS/C restorations couldalso be combined into aCompS/C study cell consistingof 156 CompS/C restorations.This double-sized CompS/C cellrepresented the greatest devia-tion from the traditional ap-proach to treating pit and fis-sure caries and was designed totest not only the clinicallongevity of service but also tomonitor any progression of thecarious lesions under the sealedcomposite restorations.

Criteria for clinical evalu-ation. The three types of studyrestorations were evaluatedclinically according to the modi-fied Ryge criteria10 and accord-ing to further subcategories ofthe marginal integrity, or MI,criteria.8 The Ryge criteria,ranging from the best rating tothe worst, are as follows: dOscar is excellent; dAlfa is very good; dBravo means a defect is pres-ent but the restoration is stillclinically acceptable and doesnot require replacement; dCharlie is a clinical failure ofthe restoration involving ex-


RESEARCH

FOUR-CELLED* STUDY DESIGN.GROUP 1

Teeth with bonded andsealed composite restora-tions over caries (CompS/C) (n = 77)

GROUP 2

Teeth with bonded andsealed composite restora-tions over caries (CompS/C) (n = 79)

GROUP 3

Teeth with sealed amalgam(AGS) restorations (n = 77)

*Groups 1 and 3 and groups 2 and 4 were compared directly in the same patients. Different patients in Group 1 were compared with different patients in Group 2. Likewise, different patients in Group 3 were compared with different patients in Group 4.

GROUP 4

Teeth with unsealed amal-gam (AGU) restorations(n = 79)


posed dentin or base and re-quires immediate attention; dDelta implies a clinical fail-ure so extensive that therestoration is mobile, fracturedor missing and also requires im-mediate attention.

All examiners used a mirrorand an explorer, without the aidof magnification, during theclinical evaluations.

RESULTS

Figure 1 shows standardized ra-diographs of two teeth withCompS/C restorations. Figures 2and 3 are intraoral photographsof each of these CompS/C teeth.The lack of progress of the cari-ous lesions under the CompS/Crestorations in these two teeth istypical for the CompS/C group.

Table 1 shows the study re-sults at baseline and at year 10.Of the original 156 pairs of studyteeth, 85, or 54 percent, wereevaluated at year 10; there were85 CompS/C, 44 AGS and 41AGU study restorations.

Partial and completeretention of sealant overrestorations and the occur-

rence of openmargins. Anopen margin isdefined as a vis-ible crevice de-tectable by anexplorer tip,which is drawnlightly and gen-tly back andforth across allmargins of the restoration in acontinuous motion perpendicularto the cavosurface margin. TheRyge criteria for MI in this studypertain not only to the status ofthe margins but also include thedegree of sealant retention overthe sealed restorations.

Table 1 shows the clinicallyacceptable MI ratings of thestudy restorations. The columnslabeled Oscar, Oscar/Alfa andAlfa refer to restorations thathad no open margins. At year10, 16 percent of the CompS/Crestorations and 25 percent ofthe AGS restorations exhibitedcomplete sealant retention.Fifty-four percent of theCompS/C restorations and 57percent of the AGS restorations

showed partial sealant reten-tion with no open margins. Twopercent of the AGS restorationsbut none of the CompS/Crestorations fell into the Alfacategory, in which there was nosealant retention but also noopen margins. Fifty-six percentof the AGU restorations had noopen margins.

The number of restorationswith completely sealed marginsin the CompS/C and AGSgroups tended to decrease,whereas the number of partlysealed restorations without anyopen margins increased steadilyover the 10-year observation pe-riod. These two patterns repre-sented some wear of the sealantover the CompS/C and AGS


RESEARCH

Figure 1B. At year 6, there is no evidence ofprogress of the lesions shown in Figure 1A.Figure 1A. Preoperative radiograph of the mandibu-

lar right first and second molars (teeth no. 30 and31) of a 26-year-old woman showing a rather large le-sion in the central pit area of tooth no. 30 and a sep-arate, barely visible lesion in the mesial pit of thistooth. There is also a barely visible lesion in the cen-tral pit of tooth no. 31. These teeth were randomlyassigned to receive bonded and sealed compositerestorations over caries (amalgam restorations wereplaced in other teeth).

Figure 1C. At year 10, the lesions in Figure 1A arewell-delineated and not progressing, the distance be-tween the carious lesions and the pulp is not de-creasing and the pulp is not in danger in either toothno. 30 or 31.


restorations.Other subcategories of MI

among the sealed restora-tions. As of the third year ofthe study, we subdivided theRyge MI criteria into additionalsubcategories to better differen-tiate the marginal status of thesealed restorations.8 Among thesealed restorations, the largest

subcategory(Oscar/Alfa)consisted of

restorations that remainedpartly sealed; that is, more than50 percent of the margins re-mained sealed and there wereno open margins. This subcate-gory had a wide range ofsealant retention (that is, 51 to99 percent of margins remain-ing sealed) over restorationmargins. At year 10, 36 percentof the CompS/C restorationsand 45 percent of the AGSrestorations were in this largestsubcategory.

At year 10, the percentage ofremaining sealed restorationsthat had no open margins andvarying amounts of sealant (rat-ings of Alfa, Oscar/Alfa, Oscar)was 70 percent for the CompS/Crestorations and 84 percent forthe AGS restorations. As shownin Table 1, only 56 percent ofthe AGU restorations had theAlfa rating at year 10.

Open margins. Althoughthe margins of the restorationswere never forcibly probed, theexplorer tip would perceptiblydrop into the defect as it wasmoved across the margin. Once

the explorer tip encountered acrevice, the explorer tip enteredit and then was blocked fromcontinuing in either direction(that is, from the tooth to therestoration or from the restora-tion to the tooth). Table 1 showsthe percentage of open marginsfor the CompS/C and AGSrestorations that remained insingle digits after 10 years.

According to the Ryge crite-ria, some restorations with openmargins are clinically accept-able; that is, they require obser-vation rather than replacement.Seven percent of CompS/Crestorations and 9 percent ofAGS restorations had openmargins that remained partlysealed after 10 years. In addi-tion, 1 percent of CompS/Crestorations lost all of thesealant and had an open mar-gin (Bravo MI), which meansthat a total of 8 percent ofCompS/C restorations had anopen margin. Thus, 8 percent ofCompS/C, 9 percent of AGS and29 percent of AGU restorationshad open margins at year 10.Because the percentage of openmargins in the sealed restora-tions remained in single digits,


RESEARCH

Figure 2A. Clinical photograph of a mirror image oftwo preparations (bevels in the central and mesialpit areas) of tooth no. 30 shown in Figure 1. Therewas no excavation of soft caries below the bevels.Part of the mesiolingual aspect of the tooth is cut off in this photograph.

Figure 2B. Tooth no. 30 immediately after therestorative procedure.

Figure 2C. Tooth no. 30 at year 10.


their clinical degradation over10 years was usually limited tominor transitions from Oscar toOscar/Alfa, thus representingonly superficial sealant wear.

In contrast with the infre-quent and minor degradation ofMI seen in the sealed restora-tions, the development of openmargins (Bravo MI) of the AGUrestorations reached 43 percentat year 5 and then declined to29 percent at year 10, as shownin Table 1. This apparent de-cline in the percentage of openmargins was offset by the AGUgroup’s large shift resultingfrom clinical failures, all ofwhich were due to caries. Sevenof these AGU failures were ob-served through year 10.

Thus, the high occurrence ofopen margins in the AGU grouppeaked at year 5, and then theopen margin ratings (Bravo MI)deteriorated to ratings of eitherCharlie (denoting softness andopacity of enamel or dentin) orDelta (denoting such extensive

caries aroundthe restorationthat the studyrestoration ismobile, frac-tured or miss-ing). One of theseven AGU fail-ures receivedthe Delta cariesrating, and theremaining sixAGU failuresreceived theCharlie cariesrating.

We shouldnote, as shownin Table 1, thatat the begin-ning of thestudy, 4 per-cent of CompS/C and 6 percentof AGS restorations had onlypartial sealant coverage; also,10 percent of CompS/C and 4percent of AGS restorations hadno sealant at all at the begin-ning of the study. At baseline,

this absence of sealant or thepresence of only partial sealantcoverage over the CompS/C andAGS restorations was usuallydue to occlusal adjustment ofthe sealant after the operatorremoved the rubber dam.


RESEARCH

Figure 3A. Clinical postoperative photograph of toothno. 31, which was shown in the radiographs ofFigure 1.

Figure 3B. Tooth no. 31 at year 6.

Figure 3C. Tooth no. 31 at year 10.


Statistically, there was nosignificant difference throughyear 10 in the number of openmargins, compared with thenumber of closed margins, forthe AGS and CompS/C groupsof restorations (χ2 = 0.0133,P = .91). The AGS group had asignificantly lower number ofopen margins than did the AGUgroup (χ2 = 6.8356, P = .009).The CompS/C group alsoshowed a significantly smallernumber of open margins thanthe AGU group (χ2 = 8.6189,P = .003). These findings dem-onstrate that the traditionalAGU restorations fared theworst of the three groups withregard to the occurrence of openmargins.

Clinical failures of studyrestorations. Over the 10-yearperiod, there were 25 clinical

failures, including five failuresthat were unrelated to the study.Clinical failures of restorationsthrough year 9 have been de-scribed elsewhere.7-10 Table 2shows the number of failures perrestoration type. The cumula-tive number of clinical failuresat year 10 that were related tothe study included 12 in thedouble-sized CompS/C group,one in the AGS group and sevenin the AGU group.

Caries. Over the 10-year pe-riod, caries occurred at the mar-gin of only one CompS/Crestoration and one AGSrestoration. However, carieswas the only reason that theseven AGU restorations failed.As shown in Table 2, the clini-cal failures in the AGU groupstarted to appear in year 4 ofthe study and continued to

occur in subsequent years.(Years 7 and 8 of the study wereunsupervised, so no data areavailable for that period.)

Sealant failure. We definedsealant failure as occlusal pitand fissure caries that occurredat a site other than the marginof a study restoration. Throughyear 10, three sealant failureshad occurred in the CompS/Cgroup. The first was observed atyear 2; the second and thirdwere observed at year 9. In theAGS group, there were twosealant failures, one of whichwas observed at year 3 and theother at year 9.

Restoration failure. Forthe AGU restorations, develop-ment of occlusal caries that wasnot at the margin of the studyrestoration was considered afailure of the extension-for-pre-


RESEARCH

TABLE 1

CLINICALLY ACCEPTABLEMARGINAL INTEGRITY RATINGS

(% OF TEETH)

CLINICALFAILURES

(% OF TEETH)

YEAR NO. OFTEETH

Oscar/Alfa‡

Oscar/Bravo**

Alfa§ Bravo††Oscar†

RESTOR-ATIONTYPE*

UNRELATEDFAILURES

(% OF TEETH)

OTHERS(% OF TEETH)

RESULTS AT BASELINE AND AT YEAR 10.

Base-line

10

156

77

79

85

44

41

86

90

NA‡‡

16

25

NA

4

6

NA

54

57

NA

10

4

100

0

2

56

0

0

NA

7

9

NA

0

0

0

1

0

29

0

0

0

4

2

0

0

0

0

5

4

0

0

0

0

13

0§§

15

Comp-S/C

AGS

AGU

Comp-S/C

AGS

AGU

* CompS/C: bonded and sealed composite restoration over caries; AGS: sealed amalgam restoration; AGU: unsealed amalgam restoration.

† Restoration, including all margins, is completely sealed. ‡ Restoration is partly sealed and has no open margin—that is, the restoration has no visible crevice and either the explorer does not catch or

it catches only one way.§ There is no sealant but no open margin.

** The restoration is partly sealed and there is an open margin (a visible v-shaped crevice at the margin or one determined by an explorer catch in both directions), but no dentin or base is exposed. (The terms open margin and crevice are interchangeable.)

†† There is no sealant and there is an open margin.‡‡ NA: not applicable.§§ There was a single clinical failure in the group that received the bonded and sealed amalgam restorations. The failure occurred at year 4, but

the patient did not come for an evaluation at year 10.


pain or othersymptoms.The AGStooth of onepatient wasavulsed in acar accident.At year 10, wesaw some ofthese pa-tients, andagain four (5percent) of the80 CompS/Crestorationsthat remainedand two (4percent) of the50 AGSrestorationsthat remainedcould not beevaluated.

Wear.Table 4 shows the anatomicform, or the modified Ryge cri-teria for wear of restorations(one criterion, Hotel, was devel-oped by one of the authors). Atyear 10, 10 percent of the AGUrestorations showed clinicallyacceptable wear (Bravo). Wesaw this same level of wear inonly 3.5 percent of the CompS/Crestorations and in none of theAGS restorations.

The CompS/C restorations intwo patients had abnormallyhigh occlusal stresses andshowed a complete loss ofsealant and generalized wear.Once the entire enamel bevelwas completely exposed, thesetwo CompS/C restorations losttheir bond to enamel and weremissing at the next evaluation(Delta anatomic form failures).Thus, the dentist evaluators didnot see the Charlie anatomicform, in which dentin is exposedas a result of wear. We shouldnote that these two CompS/C

vention concept, and, therefore,it was a restoration failure. Oneof these was observed in anAGU restoration at year 9.

Unrelated clinical fail-ures. Five clinical failures un-related to the study occurred.Three intact study restorationshad to be removed to achieveaccess to unrelated proximalcaries, and two teeth were even-tually extracted as a result ofunrelated gingival (Class V) le-sions.

Restoration survival. Weused Wilcoxon’s test to analyzethe survival of the restorationsto determine the homogeneity ofthe survival curves of the mate-rials.11 Table 3 shows the re-sults of this analysis. We foundthat the longevity of therestorations in the AGU andCompS/C groups was the same.Furthermore, the longevity ofthe restorations in the AGSgroup, which recorded only oneclinical failure related to the

study, was significantly betterthan the longevity of therestorations in the other twogroups.

Others. At year 9, six (8 per-cent) of the 75 CompS/Crestorations that remained andtwo (5 percent) of the 40 AGSrestorations that remainedcould not be evaluated becauseof circumstances that could notbe controlled during the unsu-pervised years 7 and 8 of thestudy. During that period, fourCompS/C restorations had beenreplaced for unknown reasons(probably because they had ap-peared radiographically unusu-al to dentists who were unfamil-iar with this study).

In addition, one CompS/Cstudy restoration and one AGSrestoration had been placed inthird molars that were extract-ed between years 6 and 9 of thestudy. Neither patient knewwhy the teeth were extractedsince neither had experienced


RESEARCH

TABLE 2

NO. OF FAILURESTIME

Bonded and SealedComposite Restorations

Over Caries(n = 156 at Baseline)

Sealed AmalgamRestorations

(n = 77 at Baseline)

Unsealed AmalgamRestorations

(n = 79 at Baseline)

OCCURRENCE OF CLINICAL FAILURES OF RESTORATIONS THROUGH YEAR 10.

Six months-two years

Three years

Four years

Five years

Six years

Nine years

Ten years

Cumulativefailures throughyear 10

1

3 + 1 U*

4

1

0 + 1 U*

3 + 2 U*

0

12 + 4 U*(14%)† (n = 85)

0 + 1 U*

0

1

0

0

0

0

1 + 1 U*(2%)† (n = 44)

0

0

2

1

1

2

1

7(17%)† (n = 41)

* U: clinical failure unrelated to the study.† The percentage is calculated by dividing the number of cumulative failures related to the study by the number of

restorations evaluated at year 10.


study teeth had previously beenmisclassified as Delta MI fail-ures.8,9

DISCUSSION

Since the introduction of pit andfissure sealants into clinicalpractice, dentists have beenconcerned that undetectedsmall carious lesions couldprogress under a sealant. This10-year study might help to al-leviate such fears regardingsealed-in lesions. These resultsmay have contributed to anunderstanding of the behavior ofthe carious process in that afrank cavitated lesion can bearrested both clinically and radio-graphically over a long (10-year)period by means of bonded andsealed composite restorations. Itis highly probable that once theyhave been arrested, these dor-mant lesions have stabilized andwill not progress. As long asetched enamel is present aroundthe periphery of the lesion, abonded and sealed restorationwill cut off the nutrients from theoral cavity to the cariogenic bac-teria in the lesion and preventany further progress of the cari-ous process.

This study confirms Keyes’concept of caries etiology.2 A pre-vious clinical study,12,13 which in-cluded microbial sampling andan evaluation of bacterial viabili-ty in sealed carious lesions,showed that such lesions becamesterile and clinically inactive.

The use of a pit and fissuresealant to protect amalgammargins was not a commonpractice when we began thisstudy. Because this appeared tobe a logical extension of sealantuse, a scanning electron micro-scopic study was conducted14 toevaluate the extent of sealantpenetration into the interfacialgap between the margins of the

amalgam and the cavity walls.The results of that studyshowed that deep penetration ofsealant did occur; hence, we in-corporated the technique intothis study.

Sealants highly success-ful. The results indicate thatusing sealant as a means ofmaintaining MI is highly suc-cessful and should be adoptedas an improved technique forplacing Class I amalgamrestorations. Moreover, suchminimal localized cavity prepa-ration and sealing of the re-maining occlusal pits and fis-sures result in an amalgamrestoration that prevents thedevelopment of caries and isless invasive.

When conducting long-termstudies on arresting caries withsealants or with bonded andsealed restorations placed overcaries, investigators should pro-vide operative treatment forteeth that are not part of thestudy to prevent dentists unfa-miliar with the research designfrom interfering with the studyteeth. Except for the period cov-

ering years 7 and 8, we provid-ed free-of-charge operative carefor teeth not included in thestudy. (Patients also received anominal annual fee to encour-age their continued participa-tion in the study.)

After the unsupervised two-year interval, a total of eightstudy teeth could not be evalu-ated at year 9, because the orig-inal study restorations hadbeen replaced or the study teethhad been extracted or avulsedin an accident. This inability toevaluate all of the study teethdid not occur at any other year.

Occlusal enamel underminedby caries may be stronger thanwhat has been believed in thepast. Only one of the CompS/Crestorations appeared to cave in(the enamel, which was verythin, fractured at the edge of anintact CompS/C restoration).This single fracture of under-mined enamel may have beendue to an operator’s error dur-ing the bevel preparation atbaseline, which then resulted ina failure to reach the 1 mm ofsound enamel that the protocol


RESEARCH

TABLE 3

COMPARISON GROUP P-VALUE

SURVIVAL ANALYSIS USING WILCOXON’S TEST AT YEAR 10.

77 Bonded and sealedcomposite restorations overcaries (CompS/C) vs. 79CompS/C restorations*

77 CompS/C restorationsvs. 77 sealed amalgam(AGS) restorations†

79 CompS/C restorationsvs. 79 unsealed amalgam(AGU) restorations†

77 AGS restorations vs. 79AGU restorations*

0.8990 (Not significant)

0.0322 (Significant difference;AGS is superior)

0.8320 (Not significant)

0.0242 (Significant difference;AGS is superior)

* Comparison of two groups of restorations in different patients.† Direct comparison of restorations in the same patient.


dictated. We observed no thin-ning of undermined enamelaround any other CompS/Crestorations on the radiographs.

Dental caries is a globallyprevalent symptom of an infec-tious bacterial disease transmit-ted in early childhood (as soonas primary teeth start erupting)from parents or caretakersthrough an exchange of saliva,

such as that which occurs wheneating utensils are shared.15-18

Historically, dental caries hasbeen treated by surgical exci-sion. Sound tooth structure hadto be sacrificed to make up forthe shortcomings in the physi-cal properties of variousrestorative materials.

Medical model of treatingcaries. With the advent of ad-

hesive dentistry, prevention ofcaries and greater conservationof tooth structure are possible.19

Even more important, there isevidence that a shift in philoso-phy from the traditional surgi-cal model of excision to a moremodern medical model of treat-ing caries may be occurring.20-26

Edelstein27 said that this reori-entation advances the dentist to


RESEARCH

TABLE 4

YEAR NO. OFTEETH

RESTORA-TION TYPE*

ALFA† ANDHOTEL‡

(% OF TEETH)

OTHERFACTORS

(% OFTEETH)

DELTA**(% OF

TEETH)

BRAVO§

(% OFTEETH)

CLINICAL FAIL-URES OTHER

THAN ANATOMICFORM

(% OF TEETH)

UNRELATEDFAILURES

(% OF TEETH)

MODIFIED RYGE CRITERIA10 FOR ANATOMIC FORM (WEAR).

Base-line

1

2

3

4

5

6

9

10

1567779

1266363

1195960

1286563

1236261

1166056

1005149

754035

854441

000

100

1 A††

00

1 B‡‡

32

023

302

004

003

3.5010

000

000

000

1 A00

2 A, B00

2 A, B00

2 A, B00

3 A, B00

2.4 A, B00

100100100

100100100

99100100

959598

939593

889793

909692

689180

70.690.973

000

100

100

300

723

825

928

16217

14.12.317

000

020

020

020

020

120

220

520

4.72.30

000

000

000

000

000

000

000

850

4.74.50

CompS/CAGSAGU

CompS/CAGSAGU

CompS/CAGSAGU

CompS/CAGSAGU

CompS/CAGSAGU

CompS/CAGSAGU

CompS/CAGSAGU

CompS/CAGSAGU

CompS/CAGSAGU

* CompS/C: bonded and sealed composite restoration over caries; AGS: sealed amalgam restoration; AGU: unsealed amalgam restoration.

† Restoration is neither undercontoured nor discontinuous.‡ Restoration is neither undercontoured nor discontinuous, and it remains completely sealed.§ Restoration is undercontoured and discontinuous, but neither the dentin nor the base is exposed.

** Restoration is mobile, fractured or missing as a result of the amount of material that has been lost to wear.†† A: At year 2, loss of sealant and generalized wear below the cavosurface margin of the bevel (Bravo anatomic form), followed by loss of the

CompS/C restoration (Delta anatomic form) at year 3. (The patient had abnormally heavy occlusion, as described elsewhere.8,9)‡‡ B: At year 3, generalized wear (Bravo anatomic form), followed by loss of the CompS/C restoration (Delta anatomic form) at year 4.

(The patient had abnormally heavy occlusion, as described elsewhere.8,9)

Copyright ©1998-2001 Amer ican Dental Association.All rights reserved.

a new role as clinical cariolo-gist. He also discussed one ofthe barriers to an informationtransfer, which could be relatedto a lack of shared language be-tween scientists and clinicians.Even the word caries is useddifferently by scientists andclinicians; scientists refer to aprocess and clinicians use it toidentify the lesions that resultfrom that process.

Other investigations.Many investigators28-32 have sug-gested altering traditional diag-nostic techniques and ceasing touse a sharp explorer to examinethe enamel for evidence of cari-ous changes. A sharp explorermight destroy the enamel over-lying the initial surface lesion,thus jeopardizing the possibilityof remineralization. A sharp ex-plorer might also carry cario-genic microorganisms from aninfected to a noninfected site.Thus, a dentist who is perform-ing a dental examination withan explorer may be inoculatingthe sound teeth of the patientwith infectious cariogenic bacte-ria. In summarizing presenta-tions given by several speakersat a 1993 symposium, Baderand Brown33 suggested thatthere is no overall improvementin diagnostic accuracy when anexplorer is used compared witha detailed visual examinationinvolving careful drying of thetooth.

Wenzel34 discussed newermethods of diagnosing caries,such as direct digital radiogra-phy, fiber-optic transillumina-tion and electrical resistancemeasurements. However, thesetechnologies need to be evaluat-ed further before they are rou-tinely adopted in clinical prac-tice.

During a joint symposium atthe 1993 meeting of the

International Association forDental Research and theAmerican Association of DentalSchools, Brown35 stressed theneed for a longitudinal clinicalrisk assessment to discriminatebetween progressive and remin-eralized lesions. He stated thattreating caries restoratively in-volves the probability of morecostly retreatment, and thatovertreatment of caries is possi-bly the norm.

Hume36 stated that dentistsshould modify their 200-year-old philosophy that cariesshould be treated like gangreneby extracting or excavating andfilling. He advocated a treat-ment approach based on thestructure and behavior of thecarious lesion. He further notedthat carious lesions in dentinand cementum are reversible tosome degree and recommendedthat clinicians include nonsur-gical healing of these lesions inthe treatment plan.

Bader and Brown33 reportedthat the prevalence of carieshas decreased and that cariouslesions may progress more slow-ly. These changes in diseasepatterns make it important todetermine the activity status ofa carious lesion and its poten-tial for remineralization andsealing. Anusavice37 providedinsight into the decision-makingprocesses related to restorativedental care.

Pitts38 suggested that forproper treatment decisions, itmay be logical to differentiate“LANIMA” (that is, lesions forwhich appropriate noninvasivemanagement is advised) cariesfrom “LOCA” (that is, lesionsfor which operative care is ad-vised) caries.

Perhaps in the future, re-search might focus on the possi-bility of remineralization of the

carious dentin as a precursor torestorative procedures.

CONCLUSIONS

Bonded and sealed compositerestorations placed over frankcavitated lesions (CompS/C) ar-rested the progress of these le-sions over a period of 10 years.Caries at the margin occurredin only one CompS/C restora-tion and one AGS restoration.All failures of the AGU restora-tions occurred as a result ofcaries at the margin. Because ofthe high occurrence of openmargins leading to caries at themargins of AGU restorations,we recommend that Class Iamalgam restorations be sealedimmediately after they havebeen placed.

At year 10, 10 percent of theAGU restorations, 3.5 percentof the CompS/C restorationsand none of the AGS restora-tions showed wear. Insofar asthe literature has reported wearin composite restorations, weconclude that the unfilledsealant used in this study pro-tected the posterior compositerestorations from any clinicallyobvious wear, as evaluated ac-cording to modified Rygeanatomic form criteria.

The sealed restorations weresuperior to the unsealed restora-tions in conserving sound toothstructure, protecting margins,preventing recurrent caries andprolonging the clinical survivalof the restorations. ■

Dr. Mertz-Fairhurst is professor emerita,Department of Oral Rehabilitation, MedicalCollege of Georgia, School of Dentistry,Augusta.

Dr. Curtis is an associate professor,Department of Oral Rehabilitation, MedicalCollege of Georgia, School of Dentistry, 1120Fifteenth St., Augusta, Ga. 30912-1260.Address reprint requests to Dr. Curtis.

Ms. Ergle is a research assistant, Departmentof Oral Rehabilitation, Medical College ofGeorgia, School of Dentistry, Augusta.


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Dr. Rueggeberg is an associate professor,Department of Oral Rehabilitation, MedicalCollege of Georgia, School of Dentistry,Augusta.

Dr. Adair is an associate professor andchairman, Department of Pediatric Dentistry,Medical College of Georgia, School ofDentistry, Augusta.

The first six years of this investigation weresupported financially by NIH/NIDR grant No.DE 06112; years 9 and 10 were supported bythe NIH/NIDR Shannon award. Additional fi-nancial support and clinical supplies wereprovided by Johnson & Johnson DentalProducts Co., New Windsor, N.J.

The authors gratefully acknowledge the sig-nificant contributions of the following peoplein conducting this research: W. FrankCaughman, D.M.D., M.Ed.; Gene L.Dickinson, D.D.S., M.S.; I. Kin Hawkins,D.D.S., Ph.D.; J. Rodway Mackert Jr.,D.M.D., Ph.D.; Norris L. O’Dell, D.D.S.,Ph.D.; E. Earl Richards, D.D.S., M.P.H.; CarlM. Russell, D.M.D., M.S., Ph.D.; Deirdre R.Sams, D.D.S., M.S.; George S. Schuster,D.D.S., M.S., Ph.D.; Jack D. Sherrer, D.D.S.;C. Douglas Smith, D.D.S.; and J. EarlWilliams, D.D.S., Dr.P.H.

The authors also thank Dr. S. Julian Gibbsof Vanderbilt University, Nashville, Tenn., forhis assistance as a radiology consultant in thedesign of the study and Mr. Warren Twiggsfor designing the computer database inputand report formats.

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ultraconservative and cariostatic sealed restorations

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