two-year clinical evaluation of a packable resin-based composite

Background. Packable resin-based com-posites were introduced in 1998,but few clinical studies havebeen conducted to eval-uate them. The authorsconducted a clinical studyto determine the two-yearperformance of SureFil(Dentsply DeTrey GmbH,Konstanz, Germany) packable posterior resin-based composite in Class Iand II restorations.Methods. An operator (L.S.T.) restored55 cavities in 36 patients (16 Class I restorations and 39 Class II restorations).After cavity preparation, she etched theenamel with 34 percent phosphoric acid,applied Prime & Bond NT (DentsplyDeTrey GmbH) to dentin and etchedenamel for 20 seconds and then cured it for20 seconds. She restored the cavity using 3-to 5-millimeter increments of SureFil. Inde-pendent examiners assessed the restora-tions after placement and at six months,one year and two years for color matching,marginal discoloration, marginal adapta-tion, secondary caries, surface texture,anatomical form and postoperative sensi-tivity, using the Ryge criteria.Results. The authors assessed thechanges in the parameters during the two-year period using a software program withFriedman test analysis with a Bonferroniadjustment at significant level of P = .05. Atbaseline, 31 restorations were graded asBravo for color match. At the six-month andone-year recall periods (n = 55), 53 restora-tions remained unchanged. Two restora-tions from the same patient fell out afterone month. After two years (n = 50), therewere five Bravos for surface staining andthree for marginal adaptation (P < .05).Conclusion. After two years of clinicalservice, SureFil packable resin-based com-posite had a success rate of 96 percent, andthe authors considered it successful inClass I and II restorations.Clinical Implications. SureFil pack-able resin-based composite can be suc-cessful in clinical situations with limited-sized cavities and proper application ofrestorative techniques.

Two-year clinicalevaluation of a packable resin-basedcompositeL. SEBNEM TÜRKÜN, D.D.S., Ph.D.; MURATTÜRKÜN, D.D.S., Ph.D.; FERIT ÖZATA, D.D.S., Ph.D.

Recent advances in resin-based adhesives andrestorative materials, as well as increasedpatient demand for esthetic restorations,have stimulated an increase in the use ofresin-based composites in posterior teeth.1

Many clinicians have been using posterior resin-basedcomposites successfully during the lastfive to 10 years.2 At the time of theirintroduction three decades ago, how-ever, the performance of these materialswas poor due to inadequate wear resis-tance, leakage, secondary caries andlack of appropriate proximal contact.3

Today, the cause of these problems hasbeen identified and, to a great extent,resolved.

The technique for placing these resin-based composites is focused mainly onreducing polymerization shrinkage byadding material incrementally andcuring successive layers of compositeone at a time. When this material isplaced in bulk, it shrinks away from thecavosurface marginal areas, leading topotential bacterial infiltration andrecurrent caries. Furthermore, whenthese materials are pushed with a con-

densing instrument, there is no resistance to the forceplaced on the material; the material does not move thecomposite in the direction of the force but merely pushesthrough it.4

It is more difficult to obtain proper contour and

A B S T R A C T

JADA, Vol. 134, September 2003 1205

Choosing limited-sizedcavities and

paying meticulous

attention to the restorativetechnique areessential for

achievinglonger-term

clinical successwith posterior

resin-basedcomposite

restorations.

JA D

AC

ON

TI

NU

I N G E D UC

AT

IO

N

✷✷

R E S E A R C H

ARTICLE2

¸

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Copyright ©2003 American Dental Association. All rights reserved.

allow clinicians tocomplete resin-basedcomposite restorationsin less time than inthe past. The manu-facturers marketedpackable resin-basedcomposites as havingannual wear ratesequal or superior tothose of amalgam, lowpolymerizationshrinkage, close coeffi-cient of thermalexpansion to the toothand similar modulus ofelasticity toamalgam.8,9 Althoughearly laboratorystudies of packableresin-based compositessupport these claims,

recently performed in vitro investigations demon-strated that their physical properties do not differfrom the hybrid resin-based composites.1,10,11

The claims that packable resin-based composites solve many of theclinical problems associated withcurrent resin-based composites usedin posterior restorations are attrac-tive. Controlled independently per-formed clinical studies are the onlybasis for manufacturers makingdependable clinical claims. However,clinical studies to test these proper-ties with packable resin-based com-posites have not been longitudinal12-15

because the material was introduced to themarket in 1998. Therefore, we conducted thisstudy to determine the two-year performance ofSureFil (Dentsply DeTrey GmbH, Konstanz, Ger-many) packable resin-based composite in Class Iand II restorations.

MATERIALS AND METHODS

We included in this study 36 patients (22 womenand 14 men) who came to the Department ofRestorative Dentistry, School of Dentistry, EgeUniversity, Izmir, Turkey, and who demonstratedgood oral hygiene. We obtained the subjects’written consent at the start of the project, and thestudy protocol was approved by Ege University’shuman ethical research committee. We placed 55

achieve adequate proximal contact in larger ClassII cavity preparations with conventional resin-based composites than it is with amalgam,because conventional resin-basedcomposites are not packable.5 Toimprove ease of manipulation, theideal resin-based composite shouldhave a viscosity stiff enough tofacilitate placement withoutadhering to the condensing instrument.6

There is a belief among dentiststhat posterior resin-based compos-ites should be condensed or packedinto the preparation to get a good adaptation,and, therefore, “condensable” or “packable” resin-based composites would be required by the profes-sion.7 As a result, since 1998, highly viscous,packable resin-based composites have been avail-able to dental practitioners. They are character-ized by a stiffer and less sticky consistency thatallows them to be packed more easily than hybridcomposites. According to the manufacturers, theyare good for stress-bearing posterior restorationsand have improved handling properties.1,8,9 Thenew packable resin-based composite stays inplace, regardless of the time required forsculpting before light-curing.1 The material is lesstechnique-sensitive and can be inserted and con-densed using procedures familiar to clinicians.Slight modifications in procedural techniques

1206 JADA, Vol. 134, September 2003

R E S E A R C H

TABLE 1

PROPERTIES OF STUDY MATERIAL.*PROPERTIES OF SUREFIL (DENTSPLY DETREY GMBH, KONSTANZ, GERMANY)

Lot Number

Composite Type

Resin Type

Filler Type

Filler Particle Size (Micrometers)

Filler Content Per Weight (%)

Young‘s Modulus (Gigapascals)

Barcol Hardness (Kilograms PerSquare Millimeter)

Compressive Strength (Megapascals)

981116

Packable resin-based composite (high-densityposterior resin-bonded composite)

Urethane-modified bisphenol glycidyldimethacrylate

Barium fluoroalumino borosilicate glasses and fumed silica

0.04-10 (average: 0.8)

82

11.44

103

331

* Source: Dentsply UK.9

Since 1998, highly viscous, packable

resin-based composites have been

available to dentalpractitioners.


restorations (approximately one to two restora-tions per subject) in 34 molars and 21 premolars.Seventy-one percent of the cavities (39) wereClass II restorations and 29 percent (16) wereClass I restorations. We used the packable resin-based composite SureFil to restore the teeth. Theproperties of this material are shown in Table 1.

An operator (L.S.T) recorded the teeth’s vitalitytest scores and then prepared, restored and fin-ished 55 cavities, following standard proceduresand the manufacturer’s directions. She performedadhesive cavity design with no beveling for previ-ously unrestored teeth, as well as for restoredteeth that required modifications of the cavity.The cavosurface margins of all restorations termi-nated on the enamel. Forty-nine restorationswere small to moderate, and six were large. Thesmall-to-moderate restorationsextended between one-quarter andone-third of the way up one or moreof the cuspal slopes. The proximalportion of the Class II cariesextended into the interproximalembrasures, but the margins didnot end above the cementoenameljunction. The operator prewedgedthe proximal area of the cariousteeth with an anatomically con-toured interdental wedge beforeClass II cavity preparation.

After the preparation was com-pleted, the operator placed a hard-setting calcium hydroxide cementover the deepest dentin part of thecavity to protect the pulpal tissues.She then etched the cavosurface margins of theenamel for 15 seconds and the dentin for 20 sec-onds with 34 percent phosphoric acid gel, washedthem for 15 seconds and dried them with oil-freeair. She immediately applied a thin layer ofbonding resin (Prime & Bond NT, Dentsply DeTreyGmbH) over the entire surface of the acid-etchedpreparation for 20 seconds, dried it gently andlight-cured it for 20 seconds. The light from thelight-activating unit was tested before each place-ment to ensure an output in excess of 400 wattsper square millimeter. Before restoring the ClassII caries, a thin stainless steel matrix band held ina Tofflemire retainer was adapted and firmlywedged in the proximal area to closely adapt thematrix to the gingival margin of the preparationand to achieve a degree of tooth separation to fa-cilitate the restoration of the contact area.

The operator placed the restorations in bulk of5 mm in the proximal box of Class II prepara-tions, per the manufacturer’s recommendations,and in 3-mm increments on the other sides of thecavities; each increment was cured for 40 seconds.Contouring and finishing of the restorations werecompleted using water-cooled microfine diamondfinishing burs followed by abrasive aluminumoxide disks. The operator used articulating paperto establish appropriate occlusal morphology andcontacts.

CLINICAL EVALUATION

The restorations were rated by independentexaminers with mirrors and probes using themethod developed by Ryge, which also is knownas the U.S. Public Health Service criteria.16

Evaluation parameters includedcolor-matching ability, marginaladaptation, anatomical form, cavo-surface marginal discoloration, sec-ondary caries, surface texture andpostoperative sensitivity. For eachof the criteria, we used a score ofAlfa to indicate the highest degreeof clinical acceptability, and weused scores of Bravo, Charlie andDelta to indicate progressively lessening degrees of clinical accept-ability (Table 2).

Each restoration was evaluatedby two clinicians who did not per-form the clinical procedures andwho were calibrated before thestudy by a joint examination of 20

resin-based composite restorations each. Whenthere was disagreement during an evaluation, thetwo clinicians made the decision by consensus.They assessed the restorations at baseline, sixmonths, one year and two years. Periapical radio-graphs for secondary caries detection were taken,vitality tests were recorded and color photographswere taken at every recall period for two years.

We regarded all restorations scored as Charlieor Delta or those that had been replaced at thetwo-year recall period as having failed. Thechanges in the parameters during the two-yearperiod were assessed using a statistical softwareprogram with Friedman test analysis, which isthe nonparametric analysis of variance. We com-pared the baseline scores with those at the recallperiods using Wilcoxon signed rank test withBonferroni adjustment. We tested the influence of


R E S E A R C H

¸

Evaluation parametersincluded color-

matching ability,marginal adaptation,

anatomical form,cavosurface marginal

discoloration, secondary caries, surface texture

and postoperativesensitivity.


the teeth and restoration type on the restorationperformance with Fisher exact test. The signifi-cant level was set at P = .05.

RESULTS

At the two-year follow-up examination, we exam-ined 50 of the 55 restorations (91 percent) (Table3). The five missing restorations preliminarilywere due to patient dropout, and two restorationsin the same patient had to be replaced after onemonth due to his occlusion. These two failed res-torations were included in the number of the 50rated restorations.

The vitality of the restored teeth did notchange during the two-year period. None of thepatients complained about postoperative sensi-tivity at any time during the study. There was no

evidence of secondary caries in any of the restora-tions according to the bitewing radiographs thatwere taken. After the two-year recall period, weclassified surface texture as Alfa for all restora-tions (P > .05). Figures 1 and 2 (page 1210)showed restorations classified as Alfa after thetwo-year period. Relative to marginal adaptation,three restorations showed evidence of a slightcrevice along the marginal interface (Figure 3,page 1210) after two years (P < .05). One restora-tion had marginal discoloration at the one-yearrecall period (Figure 4, page 1210) and fourothers had marginal discoloration at the two-yearrecall period (P < .05). Two restorations had beengraded Bravo for anatomical form since the one-year recall period (P > .05). The color match of 31restorations (n = 55) was scored as Bravo at the


R E S E A R C H

TABLE 2

RYGE‘S DIRECT (U.S. PUBLIC HEALTH SERVICE) EVALUATION CRITERIA.

CRITERIA TEST PROCEDURE RYGE SCORE*

Color Match

Cavosurface Margin Discoloration

Marginal Adaptation(Occlusal and Proximal)

Secondary Caries

Surface Texture

Anatomical Form(Occlusal and Proximal)

Postoperative Sensitivity

Visual inspectionwith mirror at 18inches

Visual inspectionwith mirror at 18inches

Visual inspectionwith explorer andmirror, if needed




Ask patients

A. The restoration matches the adjacent tooth structure incolor and translucencyB. Light mismatch in color, shade or translucency betweenthe restoration and the adjacent toothC. The mismatch in color and translucency is outside theacceptable range of tooth color and translucency

A. No discoloration anywhere along the margin between therestoration and the adjacent toothB. Slight discoloration along the margin between the restoration and the adjacent toothC. The discoloration penetrated along the margin of therestorative material in a pulpal direction

A. No visible evidence of crevice along the marginB. Visible evidence of a crevice along the margin into whichthe explorer will penetrateC. The dentin or the base is exposedD. The restoration is fractured, mobile or missed

A. No evidence of cariesB. Evidence of caries along the margin of the restoration

A. The restoration surface is as smooth as the surroundingenamelB. The restoration surface is rougher than the surroundingenamelC. There is a crevice and fracture on the surface of the resto-ration

A. The restoration is continuous with existing anatomicalformB. The restoration is discontinuous with existing anatomicalform, but the material is not sufficient to expose dentin orbaseC. Sufficient material lost to expose dentin or base

A. No postoperative sensitivity at any time during therestorative process and the study periodB. Experience of sensitivity at any time during the restorative process and the study period

* A: Highest degree of clinical acceptability; B, C and D: progressively lessening degrees of acceptability.


baseline examinations.This criterion had notchanged during the two-year period (Figure 4, page 1210).

We found no statisti-cally significant differencebetween Class I and ClassII restorations (P > .05).Similar results wereobtained when we com-pared the findings of pre-molar and molar restora-tions (P > .05).

DISCUSSION

The color match, surfacetexture and absence of sec-ondary caries remainedunchanged during the two-year period for SureFilpackable resin-based com-posite restorations. At thetwo-year recall period,there were five Bravos forsurface staining and threeBravos for marginal adap-tation. These scorechanges were statisticallysignificant; however, asrestorations scored asBravo are not consideredto be clinically unaccept-able, we concluded thatthe SureFil packableresin-based composite didfulfill the ADA acceptancecriteria for restorativematerials, which is 95 per-cent acceptable restora-tions rates at the two-year recall period.17

Two adjacent restorations fell out, and theoperator replaced them with amalgam after onemonth. Owing to the patient’s occlusion, theamalgam restorations fell out one week later. Thedepth and the design of the cavity had to be modi-fied, and we considered the two restorations tohave failed.

Within the same period, 10 percent of the restorations showed a slight color change at therestoration margins. Despite the early identifica-tion and overall high levels for this criterion, discoloration was not found to be associated with

or to necessarily lead to recurrent caries beingdiagnosed clinically.

At the end of the study, 6 percent of the resto-rations had a slight crevice along the marginalinterface. The crevices probably were the result ofa fracture of overlapping fine-type marginalexcess, which formed a ledge that caught theexplorer during the follow-up examination. Wefound that 2 percent of the restorations evaluatedwere undercountoured approximal contours.

The color match of 31 restorations was scoredas Bravo at the baseline examination; thisremained the same throughout the two-year


R E S E A R C H

TABLE 3

THE CLINICAL ASSESSMENT FINDINGS AND NUMBEROF RESTORATIONS.

PARAMETERS* BASELINE SIXMONTHS

ONE YEAR TWO YEARS

Color MatchABC

Cavosurface Margin DiscolorationABC

Secondary CariesAB

Surface TextureABC

Anatomical Form(Occlusal)ABC

Anatomical Form (Proximal)ABC

Marginal Adaptation(Occlusal)ABC

Marginal Adaptation(Proximal)ABC

19310

5500

550

5500

1600

3900

1600

3900

19310

5300

530

5300

1600

3702

1600

3702

19310

5210

530

5300

1600

3412

1600

3412

19310

455†

0

500

5000

1500

3212

1500

303†

2

* A: Highest degree of clinical acceptability; B and C: progressively lessening degrees of acceptability.† P < .05.


period. This was due to the limited choice of colorshades (only three) for SureFil. The restorationswere predominantly lighter than the adjacenttooth structure. According to the manufacturer,the shades were deliberately selected to be lighterthan the corresponding Vita (Vita Zahnfabrik H.Rauter GmbH KG, Bad Säckingen, Germany)

shades so that marginal areas could be visualizedduring placement. We, however, think thatpatients’ demand for posterior resin-based com-posites is due mostly to their esthetic properties.Therefore, a posterior resin-based compositeshould have enough shades available to matchthe color of the adjacent teeth.


R E S E A R C H

Figure 1. A Class II mesio-occlusal restoration using theresin-based composite in the maxillary left first molar(arrow) at the two-year recall period clinically rated asAlfa.

Figure 2. An excellent mesio-occlusal restoration in themaxillary right first molar (arrow) after two years.

Figure 3. A crevice (arrows) along the margin of thedisto-occlusal Class II restoration in the maxillary rightfirst molar after two years.

Figure 4. Two Class I restorations in the mandibular rightmolars (arrows). The restoration on the first molar wasexcellent, while the restoration of the second molar hadcolor-mismatch and marginal discolorations after two-year period.


In an attempt to overcome some of the diffi-culties associated with the placement of posteriorresin-based composite restorations, manufac-turers developed “condensable” or “packable”resin-based composites. These resin-based com-posites are filled with glass to increase viscosityand condensability. These materials do not feellike amalgam when they are condensed, but theycan deform a matrix band when they are insertedwith an instrument, and they allow a tight proxi-mal contact.1,10,18-20 These materials have 60 to 70percent filler volume. The range of particle sizesin many of these materials is greater than thatfor “conventional” hybrid resin-based composites,whose filler sizes are 0.04 to 10 micrometers.8

SureFil achieves its packability by using awide range of irregularly shaped and different-sized filler particles that the manufacturers sayproduce an “interlocking” effect between thelarger and smaller particles.9 According to Combeand Burke,21 this may be achieved because of thelarge variation in particle sizes (0.04-10 µm),with the larger particles preventing the flow ofsmaller particles past or around the larger 10-µmparticles. This coupling of filler and resin tech-nologies gives SureFil the posterior resin-basedcomposite attributes of packability, carvability,nonslumping and polishability.

In a two-year clinical trial, Perry and Kugel12

evaluated the performance of SureFil. At the one-year recall period, three restorations were scoredBravo for surface staining, and three more werescored Bravo at the two-year recall period. Therewas no evidence of secondary caries. The investi-gators concluded that this high-density resin-based composite material demonstrated clinicalacceptability.

Loguerico and colleagues13 evaluated the one-year clinical performance of four packable resin-based composite restorative materials comparedwith one hybrid resin-based composite. Theyfound that Solitaire (Heraeus Kulzer GmbH,Wehrheim, Germany) and TPH (Dentsply DeTreyGmbH) showed some fractures at the marginalridges. Moreover, Solitaire, Alert (Jeneric Pen-tron, Wallingford, Conn.) and TPH had some con-cerns related to color match and surface texture,while SureFil and Filtek P60 (3M ESPE, St. Paul,Minn.) had excellent clinical performance. Ourfindings are in agreement with those of Perry andKugel12 and Loguerico and colleagues.13

Ernst and colleagues14 evaluated the clinicalperformance of the packable resin-based com-

posite Solitaire over three years.At the end of the study, 18.2percent of the restorations werescored Bravo for marginal adap-

tation, 15.2 percent for anatomical form, 26.1 per-cent for marginal discoloration and 3.5 percent forsecondary caries. After three years, 79 percent ofthe restorations still were performing at clinicallyacceptable levels. Therefore, Solitaire failed tomeet the ADA’s criteria for resin restoratives.17

Oberlander and colleagues15 investigated theclinical performance of the packable resin-basedcomposites Definite (Degussa Dental GmbH,Hanau, Germany) and Solitaire at one year. Atthe end of the study, Definite showed signifi-cantly worse marginal adaptation compared withSolitaire. Furthermore, both materials displayedsignificant discoloration and deterioration ofapproximal contact and restoration fracture. Witha failure rate of 9.6 percent after one year, Defi-nite did not fulfill the ADA’s criteria for restora-tive materials.17

The longevity of restorations is dependent onmany factors, including operator skill, thematerials and techniques used, the replacementcriteria, patients’ compliance with oral hygieneadvice, the oral environment and its contributionto the patients’ susceptibility to caries, and pos-sibly the means by which the treatment isfunded.22 There are no shortcuts to use whenplacing posterior resin-based composites, and anycompromise in the placement technique will haveserious consequences for the clinical performance.Dentists should realize that placing a posteriorresin-based composite could take approximatelytwo and one-half times as long as placing a similar amalgam restoration.23,24

Choosing limited-sized cavities and payingmeticulous attention to the restorative techniqueare essential for achieving longer-term clinicalsuccess with posterior resin-based composite res-


R E S E A R C H

Dr. L. Sebnem Türkünis an assistant pro-fessor, Department ofRestorative Dentistryand Endodontics, EgeUniversity, School ofDentistry, 35100 Izmir,Turkey, e-mail “[email protected]”. Addressreprint requests to Dr.Türkün.

Dr. Özata is a professorand the head, Depart-ment of RestorativeDentistry and Endodon-tics, Ege University,School of Dentistry,Izmir, Turkey.

Dr. Murat Türkün is anassociate professor,Department of Restora-tive Dentistry andEndodontics, Ege Uni-versity, School of Den-tistry, Izmir, Turkey.

¸


torations. Evaluations, however, still need to beconducted to reveal the longer-term clinical per-formance of packable resin-based composites.

CONCLUSION

After two years of clinical service, SureFil pack-able resin-based composite had a success rate of96 percent, and we considered it to be successfulin restoring Class I and II restorations. ■

The authors would like to thank Timur Köse, Ph.D., for the statisticalanalysis and Atlan Destici for his help on the photographs.

1. Cobb DS, MacGregor KM, Vargas MA, Denehy GE. The physicalproperties of packable and conventional posterior resin-based compos-ites: a comparison. JADA 2000;131:1610-5.

2. Gerbo L, Leinfelder KF, Mueninghoff L, Russell C. Use of opticalstandards for determining wear of posterior composite resins. J EsthetDent 1990;2(5):148-52.

3. Leinfelder KF. Posterior composite resins: the materials and theirclinical performance. JADA 1995;126:663-72.

4. Nash RW, Lowe RA, Leinfelder KF. Using packable composites fordirect posterior placement. JADA 2001;132:1099-4.

5. Miller MB, Castellanos IR, Vargas MA, Denehy GE. Effect ofrestorative materials on microleakage of Class II composites. J EsthetDent 1996;8(3)107-13.

6. Opdam N, Roeters J, Peter TC, Burgersdijk R, Kuijs R. Consis-tency of resin composites for posterior use. Dent Mater 1996;12:350-4.

7. Wilder AD Jr., Bayne SC, Heymann HO. Long-term clinical per-formance of direct posterior composites. Trans Acad Dent Mater1996;9:151-9.

8. Condensable restorative resins. CRA Newsletter 1998;22(7):1.9. SureFil (product profile). Weybridge, England: Dentsply UK; 1998.

10. Choi KK, Ferracane JL, Hilton TJ, Charlton D. Properties ofpackable composites. J Esthet Dent 2000;12:216-26.

11. Brackett WW, Covey DA. Resistance to condensation of ‘condens-able’ resin composites as evaluated by a mechanical test. Oper Dent2000;25:424-6.

12. Perry RD, Kugel G. Two-year clinical evaluation of a high-densityposterior restorative material. Compend Contin Educ Dent 2000;21(12):1067-76.

13. Loguercio AD, Reis A, Rodrigues FL, Busato AL. One-year clinicalevaluation of posterior packable resin composite restorations. OperDent 2001;26(5):427-34.

14. Ernst CP, Martin M, Stuff S, Willershausen B. Clinical perform-ance of a packable resin composite for posterior teeth after three years.Clin Oral Investig 2001;5(3):148-55.

15. Oberlander H, Hiller KA, Thonemann B, Schmalz G. Clinicalevaluation of packable composite resins in Class II restorations. ClinOral Investig 2001;5(2):102-7.

16. Ryge G, Snyder M. Evaluating the clinical quality of restorations.JADA 1973;87:369-77.

17. ADA Council on Scientific Affairs; ADA Council on Dental BenefitPrograms. Statement on posterior composites. JADA 1998;129:1627-8.

18. Sakaguchi RL, Douglas WH, Peters MC. Curing light perform-ance and polymerization of composite restorative materials. J Dent1992;20(3):183-8.

19. Nash RW, Radz GM. Condensable composites. J Am Acad CosmetDent 1998;46-0.

20. Freedman G. Condensable composites: the new paradigm inamalgam alternatives. Dent Today 1998;17(10):72-4.

21. Combe EC, Burke FJ. Contemporary resin-based compositematerials for direct placement restorations: packables, flowables andothers. Dent Update 2000;27:326-36.

22. Burke FJT, Wilson NHF, Cheung SW, Mjör IA. Influence ofpatient factors on age of restorations at failure and reasons for theirplacement and replacement. J Dent 2001;29:317-24.

23. Leidal TI. Accomplishments and expectation with posterior com-posite resins. In: Vanherle G, Smith DS, eds. Posterior composite resindental restorative materials. St. Paul, Minn.: 3M Espe; 1985:541-7.

24. Mjör IA. Long term cost of restorative therapy using differentmaterials. Scand J Dent Res 1992;100:60-5.


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two-year clinical evaluation of a packable resin-based composite

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