Restorative Dentistry

The atraumatic restorative treatment (ART) approachfor the management of dental cariesRoger J. Sinales, MDS, DDScVHak-Koiig Yip, BDS, MEd, MMedSc, PhD^

There is woridwide interest in and increasing usage of the conservative atraumatic restorative treatmenttechnique or approach for tiie restoration of primary and permanent teeth. However, most pubiished dataon the ciinicai performance of the newer, high-strength esthetic conventional glass-ionomer restorativecements marketed for the procedure have been derived from short-term studies. There have been veryfew reports comparing different types of restorative materiais and methods of cavity preparation, inprimary teeth, after 1 year, success rates have been approximateiy 80% to 95% for Ciass i and Class Vsingie-SLJfface restorations, 55% to 75% for Ciass ii muifisurface resfcrations, and 35% to 55% for Class iiiand Ciass iV restorations, in permanent teeth, after 2 to 3 years, success rates have been approximately90% for Class i and Class V singie-surface restorations, but iittie data have been reported for otherrestorafion ciasses. Faiiures tjsuaiiy result from restoration iosses, fractures, and wear. Further improve-ments in the design of hand instruments and in the mechanicai properties of the newer glass-ionomercements are required. Currently, use of fhe atraumatic restorative treatment approach shouid be restrictedto restoration ot singie-suriace caries lesions, especiaiiy in permanent teeth, and to seaiing of occlusalfissures in selected teeth, (Quintessence Int 2002:33:427-432)

Key words: atraumatic restorative treatment, dentai caries, giass-ionomer cement

The atraumatic restorative treatment (ART) tech-nique or approach is an innovative, largely pain-free, minimal intervention approach for treating cari-otis teeth, particularly in countries where highlytrained dental personnel and the electricity needed forclinical equipment are not readily available or afford-able.' However, the method is also suitable for thedental treatment of apprehensive children and disad-vantaged groups in more developed countries, becauselocal anesthetic and dental handpieces are usually notrequired .^ -^

The ART approach was developed in Tanzania inthe mid-1980s; only hand instruments are used toremove carious tooth substance before the cavity isrestored and any adjacent enamel fissures are sealed,tisually with a conventional, self-hardening glass-ionomer cement (GIC).'' The minimally invasive pro-

'Visiling Research Feliow, Denial School, Faculty of Health Sciences,Adeiaide Universily. Adelaide, South Australia. Australia.

'Associale Professor, Department of Oral Diagnosis, Faculty of Denlistry,Prince Piiilip Dental Hospital. Hong Kong Special Administrative Region,China.

Reprint requests: Dr Kevin H.-K. Yip, Department ol Oral Diagnosis,Faculty of Dentistry, Prince Philip Dental Hospital, 34 Hospital Road. HongKong Speciai Adrrinistrative Region, China. E-mait: hkyip@ni

SmslesA'ip

TABLE 1 Survival rates (%) of atraumatic restorative treatment restorations andsealants in permanent teeth

StudyFrencken et a l " ='

Phantumvanitet al^ ='^ 6

Mallow et al'"Limanowska-Shaw

et a l "Holmgren et aPMandan et al^

Ho et aP

Smith et al='

Peng et al

TrialField

Field

FieldField

FieldField

Clinic

Field

Clinic

Time(V)3

3

33

32

2

1

t

Material

ChemFil SupFuji iX-ChemFil [lAmalgamFuji IIFuji IX*

Ketac-MolarFuji IIAmaigamCliemFil SupFuji IX-Metal-GICsAmalgamFuji IX GP-Ketac-Molar'Amalgam

Class 1 and Vsingle-surface

Sur viva i85(69-96)

887ta5

61,6793

77-92969289939799100100100

Caries2.2NR8.68.8NRNR

1.5NRNR4.41.80.00.00.00.00.0

Sealant (fuSurvival

50 (26-fi9)7150NRNRNR

72NRNR5871NRNR9497NR

Glass-ioromer cements specifically marketed tor tfie airaumatic restorative treatment approacti.NR ^ not reported.

, partial)Caries

8.43.7NRNRNRNR

2.0NRNR4.85.7NRNR0.00.0NR

RESTORATIONS

Survival rates

Most of the puhlishcd ART studies of the newer high-strength esthetic conventional GfCs placed in primaryteeth have heen short term. After 1 year, success rateshave been approximately 80% to 95% for Class I andClass V single-surface restorations, 55"/o to 75% forClass II multisurface restorations, and 32''/o to 55% forClass fll and Class IV restorations.i'-" After 2.5 years,one follow-up study reported success rates of approxi-mately 75% for Class I and Class V restorations, 54%for Class II restorations, and 14% for Ciass Ilf andCiass IV restorations.'^' Two other studies reportedthat, after 3 years, success rates were 100% for single-surface and 55% for multisurface restorations'*" andapproximately 94% for Class 1 and Class II restora-tions and 15% for Class III restorations.'^ Generally,the success rates for earlier generation GICs placed inconventional Class H preparations in primary molarshave been very low, and amalgam restorations haveperformed better.^"-"

The newer GICs marketed specifically for the ARTapproach appear to he promising for the restoration ofsingle-surface caries lesions in permanent teeth (Table1). After 2 to 3 years, the success rate reported by

most studies is approximately 90% for Class I andClass V single-surface restorations; the rate for recur-rent caries is approximately 2%. One recent 3-yearstudy reported higher survival rates for small restora-tions (92%) than for large restorations (77%),^ ' Studiesinvolving earlier formulations of GIC showed slightlylower success rates (with higher caries}, as did restora-tions placed in children and in occlusal rather thannonocclusal surfaces."''^ '^s statistically significantoperator difterences have also been reported. "^ ^^ ^

Very few studies have reported the success rates forClass II multisurface restorations in permanent teeth.After 2 years, one study '^ of an earlier GIC reported asuccess rate of 69%. After 3 years, a much smallerstudy'^ of Fuji IX (GC) used in a mixed age populationreported a very high success rate of 93%. Anotherrecent study of Ketac-Molar (ESPE) found that eightof 14 Class II restorations were successful after 3years."

Almost nothing is known of the success rates forClass III and Class IV preparations in permanentteeth. One study of Class III restorations after 3 yearsfound one surviving Fuji II restoration (GC} of fourassessed.'"

Only a few studies have compared the survival ratesof GIC restorations placed with the ART method andamalgam restorations placed with the conventional

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SmalesA'ip

method in the same subjects or in similar populations.Both 1- and 2-year studies have reported very highand similar success rates for the two materials whenplaced in single-surface occiusai preparations in per-manent teeth.^ *-^ *'-'^ A 3-year study, however, foundthat resuits were significantly better for amalgamrestorations,^ ^ Slightly better, but not significantly dif-ferent, restilts have been reported for conventionalamalgam restorations than for ART method GICrestorations placed in primary molars, both in Ciass Ipreparations after I year'' and in Class II preparationsafter 2 years,"

The newer high-strength GICs appear suitable forthe restoration of single-surface lesions in both pri-mary and permanent teeth. However, the success ratesfor GIC restorations in Class III and Class IV lesionsin primary teeth have been very poor, and insufficientsttidies of the success of the ART method for other^es of restorations have been reported,

Occiusai wear

Little information is available on the occlusal wear ofthe newer high-strength esthetic GICs, One recentstudy of restored primary molars reported cumuiativenet mean wear rates after 1 year of 66,5 40.4 pm forFtiji IX GP and 70,3 48-2 pm for ChemFlex(Dentsply/DeTrey),'* These wear rates were higherthan those found for similar occlusal restorations inthe permanent teeth of the same subjects, and higherthan the threshold wear of 50 pm per year recom-mended by the American Dental Association's guide-lines for posterior resin composites," After 1 year, thetiet mean wear of permanent molar occlusal restora-tions was 774 47.0 pm for Fuji IX GP and 82,5 50,9 pm for Ketac-Molar.^" A similar study reportedtiet mean wear values of 61.4 38,9 pm after 1 year,and 83,1 + 67.3 jmi after 2 years, for Fuji IX.^

These high and widely variahle wear rates may besignificant for the long-term clinical success ofocclttsal restorations in permanent teeth.

Cavity preparations

Few studies have investigated the successes of difter-ent methods of cavity preparation for the newerGiCs, either in the primary'^ or the permanent^*-'"'^ 'dentitions.

After 1 year, the success rates for Class I prepara-tions in primary molars were approximately 92% forboth conventional rotary and ART instrumentationmethods; for Class II preparations, however, the suc-cess rates were 87% for the conventional techniqueand 79% for the ART method.'^ Faiiures occurredfrom restoration losses because of inadequate reten-

tion and the poor physical properties of the GICs.Lack of retention is also commonly found in Class IIIand Class IV ART preparations'^'-"' and where thecements are used to restore shallow occiusai prepara-tions and to seal occlusal pits and fissures,^ It is some-times difficult to achieve space for adequate hulk ofcement and macromechanical retention form whenthe ART hand instruments are used,'^

In permanent molars, no failures of Class I GICrestorations were found for either conventional rotaryor ART methods of cavity preparation after 1 year,'" Inanother study of Class I GIC restorations over 2 years,no statistically significant differences were found inthe success rates of conventional, modified-conven-tional, or ultraconservative preparation methods. Thelast technique involved the use of Caridex CRS (Medi-Team) and hand instnoments,^ ^

In all instances, the cavity preparation times forGIC restorations are longer when ART hand instru-ments are used than when conventional rotary instru-ments are used (Table 2),

Although little information is available, failure ofsome GIC restorations appears to be a combinationof inadequate cavity preparation with hand instru-ments to provide sufficient bulk and macromechani-cal retention and inadequate physical properties ofthe materials to resist occlusal forces. Inadequate GICadhesion may also result from salivary contaminationand incomplete removal of dentin caries,^ ahhough anin vitro study found that satisfactory caries excavationis possible with ART instruments,'' These problemsmay lead to loss of retention of the restorations, bulkfractures, and brittle fatigue wear

Early, rapid occlusal wear results in liftle surfaceand marginal staining and usually only minor mar-ginal discrepancies.^ '^ ''^ '"^ A progressive color shift forseveral of the newer conventional GICs over time hasalso heen observed, but the clinical significance of thischange is not known,""

PIT AND FISSURE SEALANTS

The use of GICs as fissure sealants placed with theART approach has heen studied in permanent teeth inboth field trials"^""' and clinical trials,''""' Early,rapid losses of GIC sealant material were observed;after 2 to 3 years, retention (full and partial) was usu-aliy approximately 50% to 70% and the rate of fissurecaries was approximately 4% to 8% (see Table 1).These results appear to be better than those obtainedin earlier comparable studies of conventional GICs,'"''^

in vitro investigations have demonstrated the abil-ity of the high-strength GICs to penetrate successfullyand to seal the occlusal fissures of molar teeth when

Quintessence Inti 429

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TABLE 2 Mean ( SD) times (min) for cavity preparation and tnaterialplacetnent

Study

Frencksn et a i ' '

Lo et a l "

Smaies et a i ^ "

Hong et aP^i

Fang'5

Details

Permanent teeth,one surface

Primary teethPermanent teethPrimary moiars.one surface

Permanent molars,one sjr tace

Permanent molars,one surface

GIC = g lass, ionomer cement.NA = not applicable.No chairside assistance.'Preparation limes on'No local analgesia u

y, for small cavilies.Bed.

Atraumaticrestorative

treatment GIC22.t (19.8-23.6)

t0.54,010.8 3,69.1 2.1

2.1 0.3

11 9 3.2

ConventionalGIC

NA

NANAe.1 2.0

0.9 0.3

NA

ConventionalamalgamNA

NANA4.8 1.7

1.1 0.3

6.5 1.9

the finger-press technique is used. '^ Two field studiesof the ART approach have also shown the effective-ness of GIC sealants in preventing fissure caries inselected teeth compared to unsealed teeth in the samepopulation." ^ ^ Although the bulk of the cement maybe lost, remnants may remain in the depths of the fis-sures, and this, together with fluoride on uptake intothe adjacent enamel, may confer some protectionagainst enamel caries, at least over the short term.*-

RECOMM EN DATIONS FOR FUTURE EVALUATIONS

Several items from the preliminary research agendafor minimal intet^/ention techniques for caries'*"' havebeen or are being addressed."^ ^ Although the results arepromising, short-term clinical studies have revealedless than ideal restoration and sealant survival ratesfor the GICs currently used with the ART approach.There is a lack of long-term randomized ciinical trialsinvolving comparisons of techniques, restorative mate-rials, and different at-risk population groups, to enableaccurate cost-effective analyses in terms of restorationand sealant successes and teeth retained.

Alternative treatment methods could include theuse of topical fluorides for shallow, nonretentive cavi-ties*^ "*^ combined with other preventive measures.''^Glass-ionomer cements with further improvedmechanical and adhesive properties are also needed,as is the development of restorative materials toactively promote remineralization and destroy cario-genic acid-producing microorganisms.

Exfoliated and extracted teeth that have been

restored through the ART approach require detailedexamination of the restorations and the restoration-tooth interfaces to assess the adequacy of cariesremoval and the ability of the materials to adaptclosely and to sea! the cavity walls.^ ^ Recently, theimportance of these factors in preventing caries pro-gression has again been emphasized.^' The use of handinstruments with larger, more ergonomie handles mayreduce operator finger and wrist fatigue'* and therebyimprove cavity preparation and caries excavation.

The criteria used to assess ART restorations andsealants in field and clinical trials often differ fromstudy to study, making it difficult to compare findings;more use should be made of the well-known USPublic Health Service {Ryge} method for direct clini-cal observations."'^''''^-^' Indirect clinical evaluationsshould also be considered in clinical trials when moreobjective assessments are required. Life table statisticsshould be used for survival estimates to allow morevalid comparisons among studies.'''

CONCLUSION

Although newer, high-strength GICs are marketed bymanufacturers as definitive restorative materials foruse with the ART approach, some clinical problemshave become apparent over the short term. Theseinclude the early loss of sealant material, the loss ofrestorations from shallow and nonmacromechanicallyretentive preparations, and bulk fracture of multi-surface restorations. Further improvements in themechanical and adhesive properties of the newer

430 "02

Smales/Yip

GICs are required to ensure their optimal long-termclinical performance.

There is a need for long-term randomized clinicaltrials involving different treatment techniques, restora-tive materials, and at-risk populations and both directand indirect assessment methods. Exfoliated andextracted teeth require detailed examination to assessthe adequacy of the restorative procedures, includingthe effects of leaving residual caries. Until furtherstudies are avaiiabie, it is recommended that the ARTapproach he restricted to restoration of single-surfacecaries lesions, especially in permanent teeth, and tosealing of occlusal fissures in selected teeth.

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