The Properties and Selection of Posterior Direct Restorations

8/6/2019 The Properties and Selection of Posterior Direct Restorations

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Educational ObjectivesOverall goal: The purpose o this article is to provide dental

proessionals with expanded inormation on direct posterior

composites.

Upon completion o this course, the clinician will be able to

do the ollowing:

1. Describe the modes o ailure, advantages and disadvan-

tages o amalgam restorations.2. Describe the modes o ailure, advantages and disadvan-

tages o composite restorations.

3. Describe the properties o an ideal restorative material.

4. Describe the types o composite materials and recent new

materials and their application.

AbstractEarly tooth-colored restorative materials were weak and

only suitable or anterior teeth. Over time, composites were

developed that oered improved properties enabling theiruse in posterior teeth where subject to occlusal loading and

orces o mastication. Secondary caries is the main reason

or ailure o both amalgam and composite restorations.

Amalgam restorations oer ease-o-use but poor esthetics.

In the case o composite restorations, minimizing polym-

erization shrinkage, wear and discoloration increase the

longevity o these restorations. Posterior composite resins

oer excellent esthetics, the main driver or patients who

preer composite llings.

IntroductionHistorically, posterior direct restorations involved the use o

amalgam. The rst modern tooth-colored restorations used

acrylic, which was introduced more than six decades ago.

Subsequently, silicates and (di)methacrylate materials were

investigated. Silicate cements and early composite materials

were suitable only or anterior restorations due to their weak

physical properties, and the silicate cements needed to be

placed in one movement incremental placement was not

an option. Silicate cements had a high ailure rate. Old sili-

cate restorations were assessed or longevity in a 1986 study

and were ound to have an estimated 66% replaced due to

marginal discrepancies and lost llings.1 Early resin-based

composite restorations were an improvement over silicate

cements; however, they were sel-curing and required mix-

ing o a base and a catalyst or curing, resulting in operator

error during mixing and diculties in timely and accurate

placement. In addition, strength, bonding and retention

were poor. Light-cured dimethacrylate composite restora-

tions were introduced in the 1970s.2 By the 1980s, posterior

tooth-colored restorations had been introduced, and thesehave continued to evolve to oer improved physical proper-

ties, user-riendliness and esthetics. Bonding systems and

techniques have also evolved.

Figure 1. Introduction o tooth-colored restorations

Acrylic filling

material introduced1944

Investigation of

epoxy filling materials1955

UV-cured resins introduced1973

Introduction of

BisGMA composites1958

Dimethacrylate

based fillings investigated1964

Silicate cements and early

composites dominate1970s

Posterior composites in use1980s

Improved composites

and adhesive systems1990s

Investigation and introduction

of siloranebased material2006-2008

The trend over the last decade has been placement o an

increasing number o posterior composite restorations and

a decreasing number o amalgams. By 1999, at least 39% o

direct posterior restorations were composites, compared to

at least 11% in 1990 (in both cases, or the purposes o trend

analysis, conservatively making the assumption that all amal-

gam placements estimated in the ADA surveys were posterior

restorations) (Table 1).3

Table 1. Trends in pos terior composite placement

1999Numberplaced

% ageo total

1990Numberplaced

% ageo total

Posteriorcomposites

46,116,300 39.38% 13,130,200 11.68%

Amalgams 70,994,700 60.62% 99,256,900 88.32%


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Clinician needs and patient demand or esthetic dentistry

continue to drive these trends as well as development o

products or restorations with improved physical properties

and esthetics.

Ideal Restorative MaterialThe ideal posterior restorative material should exhibit a

number o eatures (Table 2). It should be dimensionallystable, with no expansion or shrinkage either during place-

ment or subsequent to placement, and without any wear

ollowing placement. It must also oer sucient compressive

and fexural strength in the case o posterior Class I and II

restorations, it must resist both occlusal orces and the orces

o mastication. Neither the material nor the tooth should be

subject to stress during loading o the material and/or tooth.

Biocompatibility is important the material should neither

deteriorate intraorally nor result in any toxic, teratogenic

or other iatrogenic eects. Ideally, the restorative material

should oer antibacterial properties against oral bacteria, andpreerably should be bactericidal. It should be user-riendly,

oering an appropriate operating time and ease o placement.

Finally, the material should also be esthetically pleasing to the

patient and be color-stable and stain-resistant.

Table 2. Ideal Restorative Material Properties

Dimensionally stable Cost-eective

Resi st ant to orces and st res ses Bi ocompat ible

Wear-resistant BactericidalRetentive and adhesive to the tooth Esthetically p leasing

Requires minimal tooth preparation Color-stable

Easily placed Stain-resistant

Requires minimum time to restore

The ideal restorative material does not exist, although mate-

rial developments have signicantly improved how closely

products approach these parameters.

Direct Restoration LongevityAnnual ailure rates or dierent materials have been ex-

amined in a number o studies. Some studies have ound

ranges o 0%-7% or amalgams, 0%-9% or direct compos-

ites and 1.4%-14.4% or glass ionomer cements in posterior

stress-bearing restorations.4 A separate, more recent study,

involving only two dentists, ound comparable ailure rates

or composites and amalgams assessed as a ve-year survival

rate.5 Annual ailure rates in a study conducted on restora-

tions predominantly placed since 1990 were 3% or amalgamsand 2.2% or direct composites, and it was also concluded

that more recent studies demonstrated better results.6 Failure

rates in one study covering restoration placement during the

decade up to 2001 ound an annual ailure rate o 1.1% or

amalgams, 2.1% or composites and 7.7% or glass ionomer

cements.7 Reasons or the ailure and replacement o resto-

rations include secondary caries, racture, wear, marginal

deects and postoperative sensitivity.

The primary reason or the replacement o direct restora-

tions has been ound to be secondary caries irrespective o the

restorative material.8,9,10,11

While it has been ound to be di-cult to reliably diagnose secondary caries, and the condition

is responsible or the majority o restoration replacements,

the quality o the restoration and the patients (preventive)

home care are important actors in precluding urther repeat

replacements.12 It was ound in one study that 65% o direct

and indirect (5% o total) restorations placed were replace-

ment restorations, with secondary caries the most requent

reason given, regardless o material used.13 The longevity

o restorations depends on clinical technique, materials and

patient care.

Figure 2. Marginal degradation o amalgam

Figure 3. Secondary caries

Amalgam RestorationsAmalgam has been ound to be a cost-eective restorative

material and to oer good longevity in studies o up to a more

than 20-year period.14 Amalgam restorations are less tech-

nique-sensitive than composites, less sensitive to the presenceo moisture and easier to place. They require less time to place

than direct composites; an estimated 2.5 times more time is re-

quired or composite placement.15 While improved materials



and light-curing options may have reduced the time required

or composites, more chairside time is still required than with

amalgams. Amalgam is also bactericidal, which helps to re-

duce bacterial colonization and biolm ormation.16,17

Bulk ractures and marginal degradation have been ound

to be the main material actors in the replacement o amal-

gam restorations.18 Bulk racture rates have been ound to be

similar with or without bonding o amalgams (such as withAmalgamBond Plus) in large restorations, although smaller

restorations benet rom bonding.19 Bonded amalgam res-

torations have been ound to oer support o undermined

enamel equal to that o composites, but inerior marginal

adaptation.20 Creep-atigue may be a major actor in marginal

racture o amalgam restorations.21 Amalgam restorations are

subject to expansion, which can result in cuspal stress over

time, depending upon the design o the preparation and/or

the location o the initial lesion. Expansion o amalgam results

rom internal phase changes over time, that must be relieved

to reduce stress it is believed this occurs as a result o creepo the amalgam rom the connes o the restoration and its

subsequent extrusion. On the other hand, development o a

reduced amalgam-tooth margin interace gap size over time

and improved marginal seal may occur due to such creep.22

Amalgam restorations require more tooth preparation

than composites, and careul disposal o the mercury-

containing amalgam is mandatory. The poor esthetic results

provided by amalgams are a major concern or patients, and

amalgam staining o the tooth over time urther compromises

the appearance. Corrosion is also an issue. Poor esthetics with

amalgam is the main reason why patients increasingly preerthe use o direct posterior composites as well as tooth-colored

indirect restorative materials and techniques.

Table 3. Modes o ailure, advantages and disadvantageso amalgams

Modes o Failure

Secondary cariesBulk racture

Marginal degradationExpansion and cuspal stress

Advantages

Ease o useCost-eective Can be bondedBactericidal

Disadvantages

More tooth preparationPoor esthetics

CorrosionMercury disposal

Composite RestorationsMaterial ailures accounted or more replacements o compos-

ites than amalgams in a review o surveys o dentists across the

United States, Scandinavia and the United Kingdom rom the

1980s and 1990s. These ailures included bulk racture, mar-ginal degradation, discoloration and loss o anatomic shape.23

Nonetheless, the main reason or replacement is the same

as or amalgam restorations secondary caries. In addition,

composite restorations have improved over time, and recent

studies have shown longevity to more closely reach the lon-

gevity o amalgams (albeit over a shorter tested time span).

Table 4. Modes o ailure, advantages and disadvantageso composites

Modes o Failure

Secondary cariesBulk ractureMarginal degradation

DiscolorationLoss o anatomic shape and wear

Advantages

Less tooth preparationEective bonding

Excellent estheticsNo expansion over time

Disadvantages

Technique-sensitiveIncreased chairside time

Polymerization shrinkageIncreased bacterial adhesion

While amalgams expand over time, composite restorationsare subject to polymerization shrinkage. This is regarded as

the largest problem associated with composite use.24 Polym-

erization shrinkage results in stresses that can lead to enamel

cracks, marginal degradation and microleakage, and postoper-

ative sensitivity. Other associated problems include potential

debonding o the tooth-composite interace.25 Polymerization

shrinkage occurs due to the aliation o the resin molecules

with one another and the ormation o chemical bonds that

reduce the materials bulk. Shrinkage and occlusal loading

o composites result in cuspal defection, which results in

enamel cracks and hypersensitivity. The amount o defectionhas been ound to be greater in larger restorations (MODs)

than smaller ones (MOs).26 The amount o shrinkage and re-

sulting stresses also varies with the composite lling material

used.27,28 It is infuenced by the materials fow, chemistry and

curing dynamics, and the size and shape o the preparation.

The intensity and duration o light curing have been ound to

aect polymerization shrinkage.29 Shrinkage can be reduced

by increasing the amount o ller in composite restorative

materials, as well as by having pre-polymerized clusters in the

material.30 A recent study by Bouillaguet et al. ound that cus-

pal defection (tooth deormation) was statistically similar or

conventional hybrid composites and fowable composites.31

Table 5. Potential eects o polymerization shrinkage

Enamel cracks

Marginal degradation

Microleakage

Postoperative sensitivity

Debonding o tooth-composite interace

Composite restorations generally oer poor antibacterial

properties compared to amalgam. One in vitro study ound a

minimal antibacterial eect with composites that lasted only a



ew days. It was suggested that this might explain the greater

biolm growth seen on composites compared to amalgams.32

A second study assessed the behavior o three dierent com-

posites (Charisma, Heraeus Kulzer; Dyract, Dentsply; and

Pertac, 3M ESPE) in the presence o three common oral

bacteria (S. mutans, S. oralis and A. naeslundii) or up to 35

days and ound that the bacteria colonized the composites in

a matter o hours and ormed deep biolms. The study alsoound, using scanning electron microscopy, that the poly-

acid modied composite demonstrated surace damage and

roughness.33 Fluoride-releasing composites appear to oer no

benet over nonfuoride composites.34

While polymerization shrinkage in particular and biolm

ormation on the surace o the restoration are disadvantages

o composites compared to amalgams, composites still oer

several advantages over amalgams superior esthetics, no ex-

pansion over time, as well as highly eective bonding systems

or adhesion and retention that enable minimal preparation

and improved tooth structure preservation. From the patientsperspective, the most obvious advantage o composite resto-

rations is esthetics. Improved color stability, luster and stain

resistance have urther improved esthetics as composites have

evolved. Improvements in handling and user-riendliness

continue to be developed since the introduction o a choice in

bonding agents and unit doses, and recent developments are

aimed at overcoming the physical weaknesses o composites.

Recent Composite Material DevelopmentsComposites have been modied to provide greater physical

and biological properties. Biolm-ormation reduction hasbeen tried by modiying composites as well as dentin bonders,

such as by including glutaraldehyde in the dentin bonder or

incorporating an acidic property.35

Recent investigations have included researching novel pos-

terior composite materials with the objective o nding materi-

als that oer reduced polymerization shrinkage and improved

esthetic stability. Silsesquioxane (SSQ)-based nanocomposites

have been ound in in vitro testing to oer reduced polymer-

ization shrinkage and rigidity, oering potential solutions or

stresses and clinical issues associated with shrinkage.36 Simi-

larly, oligomeric thiolene-based materials have been ound in

in vitro testing to exhibit up to 92% less polymerization stress

compared to conventional dimethacrylate-based composites.37

A recently developed composite material based on silorane has

been used and tested clinically and has been ound to result in

reduced polymerization shrinkage and stresses.38

Silorane-based Posterior RestorationsSilorane-based posterior composite material (Filtek LS

Low Shrink Posterior Restorative, 3M ESPE) has been ound

to reduce polymerization shrinkage and associated stresses,39

which would also reduce microleakage and postoperative hy-

persensitivity while demonstrating other physical properties

comparable to leading composites in in vitro testing.40 Shrink-

age is decreased due to the materials chemical composition

and polymerization dynamics. Silorane is derived rom the

combination o siloxane and oxirane and has a compact ring

structure (Figure 4a) that unlinks during polymerization.

When polymerization shrinkage begins, the silorane ring si-

multaneously opens up and compensates or material shrink-

age by expanding its molecular volume and bulking up the

material. Shrinkage has been ound to be less than 1% usingthis material (Figures 4bd).41 An initiator included in the ma-

terial starts the ring-opening process in a controlled manner

and, according to the manuacturer, increases operating time.

Figure 4a. Silorane molecule

Figure 4b. Application o primer

Figure 4c. Silorane-based material in preparation ater separateapplications and curing o both primer and adhesive

Figure 4d. Light-curing o silorane-based material opens silorane

ring structure, reduces shrinkage



In vitro testing has ound lower polymerization shrinkage

and reduced polymerization stress and tooth deormation

compared to leading methacrylate-based conventional and

fowable composite resin materials.42,43,44 At the same time,

adhesion and shear bond strength have not been compro-

mised, and reduced shrinkage helps preserve the tooth

bond-composite adhesive interaces. Other desired physi-

cal properties, such as compressive and fexural strength,have been ound to be similar to those o leading composite

materials. The silorane-based restorative is a microhybrid

composite that contains ne silane-coated quartz ller

with yttrium fuoride or radiopacity. Bacterial adhesion

o common oral bacteria has been ound to be reduced in

in vitro testing using silorane-based composite, associated

with its hydrophobic chemistry.45 One-year clinical testing

has ound good clinical perormance using this new mate-

rial compared to other posterior composite material.

Case StudyThe case shown here demonstrated the use o posterior com-

posite material (Filtek LS restorative) in the restoration o

a carious upper let rst bicuspid. On examination, a distal

lesion was identied (Figure 5a). A rubber dam was placed

prior to the DO preparation.

Figure 5a. Distal lesion in upper let irst bicuspid

Figure 5b. Rubber dam placement prior to preparation

Figure 5c. Cavity preparation and Composi -Tight matrix and

wedge placed

Ater the matrix and wedge (Composi-Tight, Garrison

Dental) were placed around the distal box, a thin layer o

sel-etching primer (LS System Adhesive Sel-Etch Primer,

3M ESPE) was placed on the dentin in the preparation using amicrobrush or 15 seconds, dispersed using air, then cured or

10 seconds. The primer has a pH o 2.7, produces mild etching

and increases the hydrophobicity o the area prior to placement

o the adhesive (LS System Adhesive Bond, 3M ESPE).

Figure 5d. Sel-etching primer placed

Figure 5e. Curing o sel-etching primer

The next step is to place a thin layer o the adhesive in thepreparation over the cured primer, and to light-cure the ad-

hesive or 10 seconds beore placing any composite material

in the preparation. Filtek LS restorative is highly hydrophobic



and the LS System Adhesive must unction as a bridging

mechanism between the primer and the composite. Only the

LS System Adhesive Sel-Etch Primer and Bond are compat-

ible with Filtek LS restorative chemistry (the use o other

primers and adhesives is contraindicated).

The composite shade is selected and injected rst as a 2 mm

increment in the distal box, where it is condensed using a #9

Garrison. The remainder o the void is lled by injecting morecomposite, taking care not to overll the area, and the #9 com-

posite instrument is used to remove fash prior to light-curing

the composite or 20 seconds (note: plasma lights, lasers and

other high-power curing lights should not be used with Filtek

LS restorative). A long working time under operatory light

aids detailed shaping and fash removal prior to curing.

Figure 5. Injecting distal box with Filtek LS restorative

Figure 5g. Condensing composite with #9 Garrison

Figure 5h. Flash being removed rom illed preparation prior to curing

Figure 5i. Cured composite ater removal o matrix and wedge

Figure 5j. High polish created using Jiy polisher

Figure 5k. Final polished restoration

Ater removal o the matrix and wedge, the restoration is

polished using a So-Lex disk (Ultradent) used to remove

any fash and a Jiy Polisher (Ultradent) is then used to cre-

ate a high shine. The nal restoration using the low shrinkage

posterior composite oers excellent esthetics and unction.

Case StudyThe second case here shows replacement o a degrading

and ractured amalgam restoration with a silorane-basedposterior composite. Ater preparation and application o

a liner, the primer and adhesive were separately applied

and separately cured. The restorative material was then



injected, condensed and light-cured prior to nishing and

polishing the restoration.

Figure 6a. Fractured, degrading amalgam

Figure 6b. Preparation with liner mesially

Figure 6c. Application o primer

Figure 6d. Application o adhesive ater primer was cured

Figure 6e. Finished restoration

SummaryIncreasingly, composites are being placed in preerence to

amalgams in large part due to patient demands or esthetics

as well as the clinical desire to do minimal preparation where

possible and provide patients with bonded, esthetic restora-

tions. Since their introduction, the properties o compositeshave improved dramatically. Amalgam and composite res-

torations both have advantages and disadvantages. While

amalgam restorations ail by secondary caries and are subject

to expansion, composite restorations ail by secondary caries

and are subject to shrinkage. Recent developments and inves-

tigations o materials are aimed at reducing polymerization

shrinkage o composites to increase the longevity o these

restorations and reduce the potential or ailure.

References1 Qvist V, Thylstrup A, Mjr IA. Restorative treatment

pattern and longevity o resin restorations in Denmark. ActaOdontol Scand. 1986;44(6):351-6.

2 Small BW. Direct resin composites or 2002 and beyond.Gen Dent. 2002;50(1):30-3.

3 ADA Survey o Services Rendered, 2002.4 Hickel R, Manhart J. Longevity o restorations in

posterior teeth and reasons or ailure. J Adhes Dent.2001;3(1):45-64.

5 Opdam NJ, Bronkhorst EM, Roeters JM, Loomans BA.A retrospective clinical study on longevity o posteriorcomposite and amalgam restorations. Dent Mater.2007;23(1):2-8. Epub 2006 Jan 18.

6 Manhart J, Chen H, Hamm G, Hickel R. BuonocoreMemorial Lecture. Review o the clinical survival o directand indirect restorations in posterior teeth o the permanentdentition. Oper Dent. 2004;29(5):481-508.

7 Hickel R, Manhart J, Garca-Godoy F. Clinical results andnew developments o direct posterior restorations. Am JDent. 2000;13(Spec No):41D-54D.

8 Hickel R, Manhart J. Longevity o restorations inposterior teeth and reasons or ailure. J Adhes Dent.2001;3(1):45-64.

9 Deligeorgi V, Mjr IA, Wilson NH. An overview o reasonsor the placement and replacement o restorations. PrimDent Care. 2001;8(1):5-11.

10 Mjr IA, Moorhead JE, Dahl JE. Reasons or replacemento restorations in permanent teeth in general dental practice.Int Dent J. 2000;50(6):361-6.

11 Allander L, Birkhed D, Bratthall D. Reasons or replacemento Class II amalgam restorations in private practice. SwedDent J. 1990;14(4):179-84.



12 Kidd EA, Toenetti F, Mjr IA. Secondary caries. Int Dent J. 1992;42(3):127-38.

13 Forss H, Widstrm E. Reasons or restorative therapy andthe longevity o restorations in adults. Acta Odontol Scand.2004;62(2):82-6.

14 Roulet JF. Benets and disadvantages o tooth-colouredalternatives to amalgam. J Dent. 1997;25(6):459-73.

15 Ibid.16 Beyth N, Domb AJ, Weiss EI. An in vitro quantitative

antibacterial analysis o amalgam and composite resins. JDent. 2007;35(3):201-6. Epub 2006 Sep 25.

17 Willershausen B, Callaway A, Ernst CP, Stender E. Theinfuence o oral bacteria on the suraces o resin-baseddental restorative materials: an in vitro study. Int Dent J.1999;49(4):231-9.

18 Qvist V, Thylstrup A, Mjr IA. Restorative treatment patternand longevity o amalgam restorations in Denmark. ActaOdontol Scand. 1986;44(6):343-9.

19 Lindemuth JS, Hagge MS, Broome JS. Eect o restorationsize on racture resistance o bonded amalgam restorations.Oper Dent. 2000;25(3):177-81.

20 Franchi M, Breschi L, Ruggeri O. Cusp racture resistancein composite-amalgam combined restorations. J Dent.

1999;27(1):47-52.21 Williams PT, Hedge GL. Creep-atigue as a possible

cause o dental amalgam margin ailure. J Dent Res.1985;64(3):470-5.

22 Osborne JW. Creep as a mechanism or sealing amalgams.Oper Dent. 2006;31(2):161-4.

23 Deligeorgi V, Mjr IA, Wilson NH. An overview o reasonsor the placement and replacement o restorations. PrimDent Care. 2001;8(1):5-11.

24 Giachetti L, Scaminaci Russo D, Bambi C, GrandiniR. A review o polymerization shrinkage stress: currenttechniques or posterior direct resin restorations. J ContempDent Pract. 2006;7(4):79-88.

25 van Dijken JW. A 6-year clinical evaluation o Class I poly-acid modied resin composite/resin composite laminaterestorations cured with a two-step curing technique. DentMater. 2003;19(5):423-8.

26 Gonzlez-Lpez S, Vilchez Daz MA, de Haro-GasquetF, Ceballos L, de Haro-Muoz C. Cuspal fexure o teethwith composite restorations subjected to occlusal loading. JAdhes Dent. 2007 Feb;9(1):11-5.

27 Rttermann S, Krger S, Raab WH, Janda R. Polymerizationshrinkage and hygroscopic expansion o contemporaryposterior resin-based lling materials: a comparative study.J Dent. 2007;35(10):806-13. Epub 2007 Sep 10.

28 Cadenaro M, Biasotto M, Scuor N, Breschi L, DavidsonCL, Di Lenarda R. Assessment o polymerization

contraction stress o three composite resins. Dent Mater.2008;24(5):681-5. Epub 2007 Aug 31.

29 Visvanathan A, Ilie N, Hickel R, Kunzelmann KH. Theinfuence o curing times and light curing methods on thepolymerization shrinkage stress o a shrinkage-optimizedcomposite with hybrid-type prepolymer llers. Dent Mater.2007;23(7):777-84. Epub 2006 Aug 17.

30 Kleverlaan CJ, Feilzer AJ. Polymerization shrinkage andcontraction stress o dental resin composites. Dent Mater.2005;21(12):1150-7. Epub 2005 Jul 22.

31 Bouillaguet S, Gamba J, Forchelet J, Krejci I, Wataha JC. Dynamics o composite polymerization mediates the development o cuspal strain. Dent Mater.2006;22(10):896-902. Epub 2005 Dec 20.

32 Beyth N, Domb AJ, Weiss EI. An in vitro quantitativeantibacterial analysis o amalgam and composite resins. JDent. 2007;35(3):201-6. Epub 2006 Sep 25.

33 Willershausen B, Callaway A, Ernst CP, Stender E. The

infuence o oral bacteria on the suraces o resin-baseddental restorative materials: an in vitro study. Int Dent J.1999;49(4):231-9.

34 Imazato S. Antibacterial properties o resin composites anddentin bonding systems. Dent Mater. 2003;19(6):449-57.

35 Ibid.36 Soh MS, Yap AU, Sellinger A. Physicomechanical

evaluation o low-shrinkage dental nanocomposites basedon silsesquioxane cores. Eur J Oral Sci. 2007;115(3):230-8.

37 Carioscia JA, Lu H, Stanbury JW, Bowman CN. Thioleneoligomers as dental restorative materials. Dent Mater.2005;21(12):1137-43. Epub 2005 Jul 25.


39 Ilie N, Jelen E, Clementino-Luedemann T, Hickel R. Low-shrinkage composite or dental application. Dent Mater J.2007;26(2):149-55.

40 Ilie N, Hickel R. Silorane-based dental composite: behaviorand abilities. Dent Mater J. 2006;25(3):445-54.

41 Weinmann W, Thalacker C, Guggenberger R. Siloranes indental composites. Dent Mater. 2005 Jan;21(1):68-74.

42 Musanje L, Sakaguchi RL, Ferracane JL et al. Light-source,material and measuring-device eects on contraction stressin composites. IADR 2005;Abstract 0294.


44 Ernst CP, Meyer GR, Klcker K, Willershausen B.Determination o polymerization shrinkage stress bymeans o a photoelastic investigation. Dent Mater.2004;20(4):313-21.

45 Lang R, Groeger G, Rosentritt M, Handel G. Adhesion oS. mutans to dental restorations. CED 2005, abstract 0426.

Author Profile

Robert C. Margeas, DDS, FAGD

Dr. Robert Margeas currently serves as Adjunct

Proessor in the Department o Operative Dentistry

at the University o Iowa College o Dentistry. He is

also the Clinical Director and Instructor at the Center

or Esthetic Excellence, Chicago, IL. Dr. Margeas

has published numerous articles on esthetic dentistry and is a highly

sought ater international lecturer on the subject. His credentials

include board certication by the American Board o Operative Den-

tistry and he is a Fellow o the Academy o General Dentistry (AGD).

Dr. Margeas is a consultant in Oral Health matters or the country o

Canada. He maintains a very successul private practice, with a ocus

on comprehensive esthetic restorative dentistry, in Des Moines, IA.

DisclaimerDr. Margeas has been a speaker on behal o 3M ESPE as well

as other composite manuacturers.

Reader FeedbackWe encourage your comments on this or any PennWell course.For your convenience, an online eedback orm is available at

www.ineedce.com.



Questions

1. Historically, posterior direct restorationsinvolved the use o _________.a. lamentsb. amalgamsc. compositesd. all o the above

2. Old silicate restorations were oundin a 1986 study to be replaced due to_________ and _________.a. expansion, microleakageb. expansion, lost llingsc. marginal discrepancies, lost llingsd. expansion, contraction

3. Posterior tooth-colored restorationshad been introduced _________.a. by the 1960sb. by the 1970sc. by the 1980sd. none o the above

4. By 1999, at least 59% o direct posteriorrestorations were composites.a. Trueb. False

5. The ideal posterior restorative materialshould oer _________.a. ease o placementb. biocompatibilityc. appropriate fexural and compressive

strengthd. all o the above

6. Posterior Class I and II restorationsmust resist _________ and _________.

a. occlusal orces, buccal orcesb. occlusal orces, orces o masticationc. buccal orces, orces o dysphagiad. none o the above

7. Annual ailure rates in a study o directposterior restorations predominantlyplaced since 1990 were _________and _________.a. 2% or amalgams, 4.5% or compositesb. 1% or composites, 3% or amalgamsc. 3% or amalgams, 2.2% or compositesd. none o the above

8. As a result o recent developments, the

ideal restorative material now exists.a. Trueb. False

9. The quality o a restoration and thepatients (preventive) home care areimportant actors in precluding repeatreplacement o restorations.a. Trueb. False

10. The main material actors in thereplacement o amalgam restorationshave been ound to be _________and _________.

a. bulk ractures, marginal degradationb. polymerization shrinkage, microsopic

racturesc. bulk ractures, polymerization shrinkaged. all o the above

11. The longevity o restorations dependsonly on clinical technique.a. Trueb. False

12. Bonded amalgam restorationshave been ound to oer support oundermined enamel equal to that o

composites, with _________.a. superior marginal adaptationb. inerior marginal adaptationc. inerior obtusiond. none o the above

13. Creep-atigue may be a actorin _________.a. marginal racture o amalgam restorationsb. bulk racture o amalgam restorationsc. reducing stress caused by expansion o

amalgam restorationsd. a and c

14. Poor esthetics with amalgam is the

main reason why patients increasinglypreer direct posterior composites overamalgams.a. Trueb. False

15. Reasons or composite restorationailure include _________.a. marginal degradationb. discoloration and loss o anatomic shapec. bulk ractured. all o the above

16. Secondary caries is the single mostcommon reason or the replacemento both amalgam and posteriorcomposite restorations.a. Trueb. False

17. Polymerization shrinkage ocomposites results in stresses that canlead to _________.a. enamel cracksb. postoperative sensitivityc. marginal degradationd. all o the above

18. Polymerization shrinkage occurs dueto the aliation o resin moleculeswith one another and the ormation

o chemical bonds that reduce thematerials bulk.a. Trueb. False

19. Polymerization shrinkage isinfuenced by the _________.a. intensity and duration o light curingb. materials shadec. materials chemistry and curing dynamicsd. a and c

20. A recent study by _________ound that cuspal defection (toothdeormation) was statistically similaror conventional hybrid compositesand fowable composites.a. Bourguignon et al.b. Bouillaguet et al.c. Black et al.d. Bellman et al.

21. Composite restorations generallyoer superior antibacterial propertiescompared to amalgam.a. Trueb. False

22. Fluoride-releasing composites appearto oer substantial benets overnonfuoride composites.a. Trueb. False

23. Currently-available composites oer_________ compared to the earliestcomposites.a. improved color stability and estheticsb. improved physical propertiesc. improved handlingd. all o the above

24. Biolm-ormation reduction oncomposites has been tried by _________.a. modiying compositesb. modiying dentin bondersc. including glutaraldehyde in the dentin

bonderd. all o the above

25. Silsesquioxane-based nanocompositesand oligomeric thiolene-basedmaterials have been investigated orreductions in shrinkage.a. Trueb. False

26. Silorane-based posterior compositematerial has been ound to reducepolymerization shrinkage to


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AUTHOR DISCLAIMERDr. Margeas has been a speaker on behalf of 3M ESPE as well as other composite manufacturers.

SPONSOR/PROVIDERThis course was made possible through an unrestricted educational grant rom 3M ESPE.No manuacturer or third party has had any input into the development o course content.All content has been derived rom reerences listed, and or the opinions o clinicians. Pleasedirect all questions pertaining to PennWell or the administration o this course to MacheleGalloway, 1421 S. Sheridan Rd., Tulsa, OK 74112 or [email protected].

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REST0807PAT

ANSWER SHEET

The Properties and Selection of Posterior Direct Restorations

Name: Title: Specialty:

Address: E-mail:

City: State: ZIP:

Telephone: Home () Ofce ()Requirements for successful completion of the course and to obtain dental continuing education credits: 1) Read the entire course. 2) Complete all

information above. 3) Complete answer sheets in either pen or pencil. 4) Mark only one answer for each question. 5) A score of 70% on this test will earn

you 4 CE credits. 6) Complete the Course Evaluation below. 7) Make check payable to PennWell Corp.

Educational Objectives

1. Describe the modes o ailure, advantages and disadvantages o amalgam restorations

2. Describe the modes o ailure, advantages and disadvantages o composite restorations

3. Describe the properties o an ideal restorative material

4 Describe the types o composite materials and recent new materials and their application

Course Evaluation

Please evaluate this course by responding to the ollowing statements, using a scale o Excellent = 5 to Poor = 0.

1. Were the individual course objectives met? Objective #1:YesNo Objective #3:YesNoObjective #2:YesNo Objective #4:YesNo

2. To what extent were the course objectives accomplished overall? 5 4 3 2 1 0

3. Please rate your personal mastery o the course objectives. 5 4 3 2 1 0

4. How would you rate the objectives and educational methods? 5 4 3 2 1 0

5. How do you rate the authors grasp o the topic? 5 4 3 2 1 0

6. Please rate the instructors efectiveness. 5 4 3 2 1 0

7. Was the overall administration o the course efective? 5 4 3 2 1 0

8. Do you eel that the reerences were adequate? Yes No

9. Would you participate in a similar program on a diferent topic? Yes No

10. I any o the continuing education questions were unclear or ambiguous, please list them.

___________________________________________________________________

11. Was there any subject matter you ound conusing? Please d escribe.

___________________________________________________________________

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12. What additional continuing dental education topics would you like to see?

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___________________________________________________________________ AGD Code 253

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The Properties and Selection of Posterior Direct Restorations

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