Material Selection for Direct Posterior Restoratives - IneedCE.com

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This course was 

written for dentists, 

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and assistants. 

Material Selection 

for Direct Posterior 

Restoratives 

A Peer-Reviewed Publication 

Written by John O. Burgess, DDS, MS and Deniz Cakir, DDS, MS 

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Educational Objectives 

The overall goal of this article is to provide dental professionals 

with information on the options available for posterior 

esthetic restorations. Upon completion of this course, the 

participant will be able to do the following: 

1. Know the considerations involved in the selection of 

posterior restorative materials 

2. Know the history and safety profile of amalgam, its 

advantages and disadvantages 

3. Know how polymerization stress occurs and its relevance 

to restoration failure 

4. Understand the technologies that can now be incorporated 

into posterior composite restoratives to combat polymerization 

shrinkage and/or polymerization stress 

Abstract 

The posterior restorative material of choice depends on the 

individual clinical situation and patient. Amalgam has a long 

history of use and clinical success. Esthetic restorations are 

increasingly in demand, and include glass ionomers, compomers 

and composite resins. Fluoride release is a desirable 

attribute in a restorative material, as are wear resistance, low 

polymerization shrinkage and low polymerization stress. 

Recently, technologies have been incorporated into composite 

resins that lower polymerization shrinkage and stress. 

Introduction 

Material selection for restoring posterior teeth depends 

upon the patient’s age, caries risk, esthetic requirements, 

ability to isolate the tooth and functional demands placed 

on the restoration. Although amalgam has been an effective 

restorative material for Class I and II cavity preparations, 

patient expectations are varied and range from high functional 

requirements to high esthetic demands. Each material 

used to restore posterior teeth has specific advantages 

and disadvantages and these should be carefully weighed 

before selecting a restorative material. Compomers, glass 

ionomers and composite resins bond to tooth structure and 

may reinforce weakened tooth structure. They have proven 

longevity in minimally invasive preparations, are excellent 

thermal insulators, esthetic, and produce varying levels of 

fluoride release, which may inhibit recurrent caries. However, 

esthetic restorative materials have disadvantages. 

Composite resin, while the most durable of the esthetic 

direct restorative materials, has clinical limitations that 

restrict its use as a posterior restorative material, especially 

in areas where isolation is poor and wear is high. Resin restorations 

require greater attention to detail during adhesive 

placement, increased placement time and are technically 

more difficult than a similar-sized amalgam restoration. 

Postoperatively, sensitivity to cold is a frequent complaint 

with Class II restorations, due primarily to polymerization 

shrinkage or poor adhesive placement – both of which create 

leakage at the resin/tooth interface. 

Posterior Amalgam Restorations 

Amalgam has a long-term clinical history of success for several 

reasons: the margins corrode and seal, it has good moisture 

tolerance and excellent wear resistance. Although amalgam 

does not bond to tooth structure and has other limitations, 

such as galvanism, high thermal conductivity, and poor esthetics, 

it may be placed in areas when some contamination, 

especially blood and saliva, are likely and still provide good 

clinical results. Amalgam can be used to successfully restore 

decimated teeth (Figures 1, 2). 

Figure 1. Placement of amalgam restorations 

Figure 2. Polished amalgam restorations 

Amalgam restorations may be bonded to tooth structure 

with adhesives using the bonded amalgam technique. 

One of the most clinically successful systems is the 

4-META-based Amalgambond Plus (Parkell). In amalgam 

bonding, the bonding agent bonds to dentin by creating 

a hybrid layer. The attachment of the bonding resin 

to amalgam, however, is largely mechanical rather than 

chemical. Unset amalgam is condensed into the bonding 

resin before it polymerizes, incorporating fingers of resin 

into the amalgam at the interface. 1 Several clinical studies 

of bonded amalgam restorations have demonstrated their 

success. 2,3,4 Belcher and Stewart compared the clinical 

success of amalgams that were pin-retained, retained 

with Amalgambond Plus with no filler powder or retained 

with Amalgambond Plus with filler. At two years, 

all restorations were intact with minimal sensitivity, good 

marginal adaptation and no recurrent caries. Summitt et 

al. recorded a six-year recall of Amalgambond-retained 

cuspal coverage Tytin restorations with no failures in the 

bonded amalgam group. 

2 www.ineedce.com

Amalgam has been strongly criticized, especially when 

used as a restorative material in children, since it contains 

mercury. Two recent well-conducted randomized controlled 

clinical studies sponsored by the NIH have provided additional 

evidence for the safety of amalgam in children. More 

than 500 children were studied in two clinical trials. In the 

first clinical trial the children were followed for seven years, 5 

and in the second for five years. 6 In each study, children 

with carious lesions were randomized to one of two groups 

to receive either amalgam or composite resin restorations. 

After conducting numerous tests (IQ, blood, urine, social 

interaction tests, etc.), no significant differences in the health 

of the children were reported. Nonetheless, amalgam use has 

declined as greater numbers of clinicians and patients have selected 

esthetic, adhesive, mercury-free restorative materials. 

Fluoride-releasing Materials 

Fluoride-releasing materials may be classified into several 

categories based on similarities in properties (Table 1). 7,8,9 

Fluoride-releasing composites release low levels of fluoride 

and have limited ability to recharge; therefore they may not 

be effective for high caries risk patients. Fluoride-releasing 

composite resins have better wear resistance and toughness 

than any other fluoride-releasing material. Glass ionomer 

and resin modified glass ionomer restorative materials have 

the highest levels of fluoride release and good recharge, which 

increases long-term fluoride release. These are useful for the 

high caries risk patient, but their poor wear resistance and 

low fracture toughness limits their usefulness as a posterior 

restorative. However, glass ionomers are useful as a liner or 

extended base and should be used in deep cavity preparations, 

especially when the proximal margin is subgingival 

(sandwich technique) (Figure 3). 10 

A conditioner or primer is provided with glass ionomer 

restorative materials. These conditioners are weak inorganic 

acids and clean rather than etch the tooth surface prior to 

bonding. They effectively improve the bond of the glass ionomer 

to the tooth structure. Fuji Fill LC (GC, Tokyo, Japan) 

was the first resin modified glass ionomer available in a paste/ 

paste delivery rather than a powder/liquid system. While 

paste/paste resin modified glass ionomers are easier to mix 

and place than powder/liquid resin modified glass ionomers, 

paste systems have slightly lower mechanical properties and 

lower bonds than the original powder/liquid systems. Recently, 

nanofillers have been added to a resin modified glass 

ionomer (RMGI) (Ketac Nano, 3M ESPE, St. Paul, Minnesota) 

to reduce the filler particle size, producing a smoother, 

more esthetic restoration. All glass ionomers should be 

bonded to moist tooth structure, after the conditioner is applied 

and rinsed off or light-cured, depending upon the brand 

used, and the mixed resin modified glass ionomer applied to 

the moist tooth and light-cured. After curing, the resin modified 

glass ionomer is wet-finished. 

Although wear with resin modified and high-viscosity 

glass ionomers has improved, they have significantly more 

wear than composite resin and should not be used to restore 

occlusal surfaces in the permanent dentition. 11,12 Compomers 

are blends of resin composite and glass ionomer, containing 

more resin than resin modified glass ionomers but with good 

fluoride release and recharge. Compomers have mechanical 

properties closely related to fluoride-releasing resin composites 

and have been used successfully in the primary dentition. 

Since single paste compomers require a bonding system to 

achieve a clinically usable bond and fluoride uptake into cut 

dentin is blocked by the adhesive, the fluoride release from 

these materials influences the outer tooth surface only. Compomers 

are useful, since their fluoride release and wear resistance 

is midway between that of resin composites and glass 

ionomers, and they may be a successful esthetic restorative 

material for children. 

Composite Resin 

Composite resin use has increased as composite and bonding 

agents have improved. The first clinical trials measuring 

the effectiveness of composite resin as posterior restorations 

reported that composites had poor wear resistance and recommended 

that their use be restricted to bicuspids, where 

esthetics was critical. 13 As composite resins evolved, wear 

resistance improved dramatically, and currently more than 

50% of all direct posterior restorations are composite. 14,15 

While physical and mechanical properties have improved, 

composite resin placement is difficult compared to amalgam 

Table 1: Fluoride-releasing materials – property comparisons 

Fluoride 

release 

Bond 

strength 

Strength 

Wear 

resistance 

Fluoride 

recharge 

Glass ionomers Ketac-Fil, Fuji II High Low Low Low Medium 

High-viscosity glass ionomers Ketac Molar, Fuji IX High Medium Medium Medium Medium 

Resin-modified glass ionomers 

Photac-Fil, Vitremer, Ketac 

Nano, Fuji II LC, Fuji Fill LC 

Highest Medium Low Low– 

Medium 

Highest 

Compomers Dyract, F-2000, Compoglass Medium High Medium Medium Medium 

Fluoride-releasing composites Heliomolar, SureFil Lowest High High Highest Lowest 

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Figure 3. Sandwich technique 

Enamel 

Enamel 

Enamel 

Enamel 

Resin modified glass ionomer 

Sandwich technique 

Dentin-enamel 

junction 

Wear resistant 

composite 

SureFil SDR flow adaptable up to 

4 mm in one increment 

SureFil SDR is applied in a larger 

increment compared with the traditional 

GI technique, leaving a single 2 mm 

increment for the final composite layer 

Sandwich technique 

Wear resistant 

composite 

SureFil SDR flow adaptable 

up to 4 mm in one increment 

Dentin-enamel 

junction 

Composite 

resin 

Dentin 

Composite 

resin 

Resin modified 

glass ionomer 

Dentinenamel 

junction 

placement. 16 Ideal proximal contacts are difficult to obtain 

with composite resins because composite condensation does 

not deform the matrix band against the adjacent tooth. 17,18 To 

remove some of the difficulties associated with developing a 

contact area, sectional matrices have been developed (Trio- 

Dent V3 ring, Katikati 3166, New Zealand; Garrison 3D matrices, 

Garrison Dental Solutions, Spring Lake, Michigan). 

Composite resin shrinkage during polymerization contributes 

to marginal breakdown and postoperative thermal 

sensitivity. 19,20,21 Visible light-cured composite resin is placed 

in 2 mm increments into a cavity preparation, contoured to 

the desired shape and light-cured. This time-consuming 

incremental placement procedure is necessary, as light attenuates 

as it passes through composite resin. Photoinitiators 

in the composite resin, typically camphoroquinone, are activated 

by visible light in the presence of an amine accelerator/ 

catalyst. 22 The photoactivated diketone/amine complex initiates 

polymerization of the dimethacrylate resin monomers. 

Composite resins may contain a combination of photoinitiators, 

each requiring its own specific wavelength for maximum 

reactivity. While many composite resins contain camphoroquinone, 

it imparts a yellow color to composites and alternate 

photoinitiators are used to reduce yellowing. These alternate 

photoinitiators absorb light in the 390–410 nm range, which 

is lower than the wavelength emitted by most LED curing 

lights. Curing composite resin containing these alternative 

photoinitiators requires the use of curing lights with a wider 

spectral distribution (such as quartz-tungsten-halogen or 

plasma arc curing lights that will polymerize all photoinitiators). 

Poorly cured composite resin has poor mechanical 

properties and low wear resistance; therefore, most composite 

resins should be cured in 2 mm increments with a curing light 

that emits the proper wavelength of light. 

Soft-start curing lights and other curing modes have been 

advocated as a means for decreasing polymerization stress 

in composite resin restorations. In the last 15 years, various 

light-curing units have been developed to decrease contraction 

stress by slowing the rate of composite resin polymerization. 

These units cure at an initial low intensity and/or a short 

pulse cure. 23,24 It is thought that this slower set permits movement 

of the polymer chains, thereby allowing stress relief and 

enabling improved marginal integrity. 25 The objective with 

curing lights with variable output (soft-start polymerization 

curing units) is to reduce or delay polymerization stress 

without reducing the conversion rates of the polymer. These 

methods of “soft curing” include step-curing, ramp-curing 

and pulse-delayed curing. In vitro studies have shown mixed 

results. In our laboratory, we could find no significant difference 

in leakage when using these techniques. 26,27 The pulse 

delay or the pulse cure technique places increments of composite 

resin and cures each increment using 20- to 30-second 

cure times. 28 The final enamel replacement increment is cured 

with a brief burst of energy for two to three seconds. After 

a three-to-five-minute delay to allow the composite time to 


flow and shrink, the restoration is finished and polished. 

After finishing, the restoration is cured at high intensity to 

complete polymerization of the composite. While this technique 

has in vitro support, its clinical support is weak, with 

several studies reporting no significant difference in marginal 

integrity or marginal discoloration when composite resins 

are polymerized with or without a soft-start polymerization 

or with a chemical-cured composite resin. 29,30,31,32,33,34 The literature 

shows that attempts to reduce polymerization stress 

with a curing light remain unproven. 

Flowable Composites 

Flowable composite resins are often used today to reduce polymerization 

stress. Flowable composites are conventional or 

microfilled composite resins with a reduced filler load, which 

lowers their viscosity, resulting in better adaptation to the 

cavity walls. 35 Low filler content has caused some concern, 

since highly filled composites have greater wear resistance 

for contact-supporting posterior restorations and less polymerization 

shrinkage than flowable composites. 36 However, 

flowable composite resins are now available with filler loads 

ranging from 34% to 68%, which provides a wide range of 

properties. In small noncontact restorations where longevity 

may be dictated by abrasion, flowable microfilled resins 

may be adequate. One clinical study related the wear of three 

flowable composite resins and evaluated the performance of 

flowables in three different-sized occlusal preparations. 37 In 

small occlusal cavity preparations (defined as those with an 

isthmus width that did not exceed one-fourth of the intercuspal 

distance), one-year clinical performance was good. In 

larger preparations, wear was high and it was determined that 

flowable composites were contraindicated for load-bearing 

posterior restorations in permanent teeth with wide isthmus 

widths. 

Flowable composite resin was originally used as a resin 

liner to improve the adaptation of condensable composites 

to the prepared tooth, especially in a cavity preparation with 

sharp line angles and uneven pulpal floors. Later it was speculated 

that even though flowables had higher polymerization 

shrinkage than highly filled composite resins, flowable composite 

resins with their lower elastic modulus would deform 

and create less stress at the tooth composite interface. Flowable 

composites would then act as a stress-absorbing layer 

between the hybrid layer created by the bonding agent and 

the highly filled resin composite. Cadenaro et al. reported 

significant differences in the contraction stress development 

of different flowable composite resins. 38 In this study, Filtek 

Supreme XT Flowable had the highest stress values and the 

lowest values were recorded with Tetric Flow (which was the 

only flowable composite with lower stress values than the 

conventional composite Filtek Z250). The authors concluded 

that most flowable composites had shrinkage stress comparable 

to conventional resin restorative materials, supporting 

the hypothesis that “flowable materials do not automatically 

lead to stress reduction” and that the risk of debonding at 

the adhesive interface due to polymerization contraction is 

similar for some flowables and highly filled composite resins. 

In another study supporting this premise, Stavridakis et al. 

measured the linear polymerization displacement and polymerization 

forces induced by polymerization shrinkage of 

22 flowable resin-based restorative materials. 39 Polymerization 

forces (3.23 to 7.48 kilograms) were recorded showing 

that flowable resins produced considerable shrinkage stress. 

Flowable composites vary substantially in contraction force 

generated as well as wear and other properties. The in vitro 

and in vivo data demonstrate that using flowable composites 

to reduce polymerization shrinkage stress is controversial and 

may be dependent upon the specific flowable material used. 

This debate is further complicated by the clinical studies 

demonstrating no difference in marginal integrity between 

flowable lined composite resin restorations and composite 

restorations where no flowable was used. 40 The consensus 

seems to be that the major benefit in using a flowable composite 

is cavity adaptation. 

Composite Resin Shrinkage and Stress 

Another method to reduce polymerization shrinkage of composite 

resin uses new chemistry. Polymerization shrinkage 

of composite resins ranges from 3.7% to 0.9%. 41,42 While increasing 

filler content of composite reduces shrinkage, it also 

increases composite stiffness, which also increases the forces 

of contraction. 43 Recently, new resin monomers have been 

developed with different chemistries to reduce polymerization 

shrinkage stress. The first low-shrinkage commercially 

available composite resin was Filtek LS (3M ESPE, St. Paul, 

Minnesota), based on a silorane ring-opening chemistry. In 

our laboratory, shrinkage measurements for this composite 

ranged from 0.7% to 0.9% vol. Another newly developed 

composite, N’Durance (Septodont, New Castle, Delaware), 

uses dimer chemistry and has shrinkage measurements of 

1.2% vol. Thiolene polymers also offer potential for reducing 

polymerization stress. Carioscia and Lu reported that thiolene/thiol-epoxy 

hybrid networks produced significantly 

reduced shrinkage stress of 0.2 MPa, which is 90% lower than 

the stress developed in a control dimethacrylate resin. 44,45 

This chemistry is not available commercially. 

While clinical verification for these low-shrinkage 

composite resins is still being gathered, it seems likely that 

these commercially available low shrinkage composites have 

significant advantages when compared to conventional composite 

resins. 

The shape of the preparation or the C-factor (the ratio 

of the bonded surfaces of the restoration to the unbonded 

surfaces) affects the stress created at the margins. 46,47 In this 

classification system, a Class I or Class V preparation would 

create the greatest stress at the marginal interfaces. During 

polymerization of the composite resin, stress buildup can be 

reduced by flow of the resin. Incremental placement of com- 


posite resin can partially compensate for shrinkage by flow of 

the composite material; however, this is time consuming and 

voids can be created during placement of incremental layers. 48 

Composite with higher shrinkage produces postoperative 

sensitivity by creating marginal defects into which percolation 

can occur, 49,50 and it is indicated for use as a bulk-fill base 

to be overlaid with a methacrylate-based composite resin. 

Low-stress Composite 

A low-stress “adaptable” material has been developed that 

can be polymerized in one 4 mm increment rather than in the 

typical 1–2 mm (Figure 3). This material (Stress Decreasing 

Resin (SDR ) Technology) was engineered to create a new 

resin system that would allow internal reduction of the stress 

resulting from polymerization shrinkage. To control stress 

development within a radically polymerizable material, it 

was necessary to regulate the overall modulus development 

while maintaining its polymerization rate and conversion. 

With SDR Technology, a polymerization modulator was 

chemically embedded in the polymerizable resin backbone 

(Figure 4). Based on scientific evidence gathered to date, the 

polymerization modulator synergistically interacts with the 

camphorquinone photoinitiator to slow modulus development, 

allowing stress reduction without a reduction in the 

polymerization rate or conversion. The SDR Technology 

resin provides significantly lower curing stress than other 

conventional resin systems, while maintaining a high degree 

of conversion of the SureFil ® SDR flow material. 

This ensures the development of the required physical and 

mechanical properties for the use of the material as a posterior 

bulk fill flowable base. Essentially, the entire radical 

photopolymerization process is mediated by the polymerization 

modulator specially built into the resin; this allows 

more linear/branching chain propagation without much 

cross-linking and hence slower modulus development. This 

modulating effect allows extended polymerization without 

a sudden increase in cross-link density. Thus, the extended 

“curing phase” maximizes the overall degree of conversion 

and minimizes the resulting polymerization stress. 

This adaptable material (SureFil SDR, LD Caulk, Milford, 

Delaware) is placed in the box and bulk light-cured up 

to the enamel margin. Its rheology makes it highly adaptable 

to the preparation form to avoid the incorporation of voids 

(Figure 5). 

Figure 5. Photomicrograph of bulk-cured stress-reducing resin 

Note: excellent adaptation and virtual absence of voids 

Figure 4. Curing of stress-decreasing resin 

Polymerization modulator 

Conventional: 

SDR 

X O 

Y 

O R 

O 

X 

O 

+ 

R 1 

O 

X 

O 

Curing 

O 

Y 

R O 

X 

High translucency allows significant light transmission to 

bulk polymerize the material. This adaptable composite 

should not be placed onto the enamel occlusal margin of the 

cavity preparation due to its low wear resistance. Although 

not a low-shrinkage material (polymerization shrinkage is 

3.6% vol.), it is a low-stress-producing material. It is important 

to understand that shrinkage stress, not shrinkage, 

is the cause of many stress related restorative complications. 

Note in Figure 6 that the shrinkage of the adaptable 

material is not dissimilar to other commonly used flowable 

composites, while shrinkage stress is considerably lower 

(Figure 7). Because the adaptable material is a flowable 

composite and not indicated for larger occlusal surfaces, a 

highly filled material such as EsthetX or SureFil should be 

placed in the final occlusal increment. The material selflevels, 

ensuring that the occlusal surface of the material is 

even for placement of the final increment of highly filled 

material. This two-increment technique reduces placement 

time and is effective and efficient for Class I and II 

restorations. In an ongoing clinical trial with the material, 

we have placed more than 100 restorations with excellent 

success. The case example below shows the use of SureFil 

SDR for posterior restorations. 


Figure 6. Percent shrinkage of bulk-fill base material compared 

with other flowable composites 

5 

4 

3 

2 

1 

0 

3.6 

4.5 4.5 4.3 4.4 

3.8 3.9 3.5 

4.9 

SureFil SDR flow 

Esthet-X flow 

TPH3 flow 

Brand A 

Brand B 

Brand C 

Brand D 

Brand E 

Brand F 

Figure 7. Shrinkage stress of bulk-fill base material compared with 

other flowable composites 

5.0 

4.5 

4.0 

3.5 

3.0 

2.5 

2.0 

1.5 

1.0 

0.5 

0.0 

1.4 

3.2 3.1 2.9 

4.1 

3.2 

4.2 

3 

SureFil SDR flow 

Esthet-X flow 

TPH3 flow 

Brand A 

Brand B 

Brand C 

Brand D 

Brand E 

Brand F 

Case Study 

In this case, a carious lesion was detected distally by radiograph 

in tooth number 13. A rubber dam was placed over 

the tooth, followed by cavity preparation and placement of a 

sectional matrix and band. 

Figure 8. Tooth #13 pre-operatively 

3.2 

Etchant was first applied, the tooth rinsed and dried, and 

Prime and Bond NT ® was then applied to the dried preparation. 

SureFil SDR flow adaptable was then placed in the 

preparation using the disposable unit dose. 

Figure 10. Application of etchant 

Figure 11. Application of Prime and Bond NT® 

Figure 12. Placement of bulk layer flow adaptable composite 

Figure 9. Preparation and placement of sectional matrix and band 

Figure 13. Preparation filled to enamel margin with SureFil SDR 

Flow Adaptable 


Following placement of the bulk layer, this was light cured. 

Subsequently, EsthetX HD was placed occlusally and light 

cured to provide the final layer of composite, and the restoration 

finished . 

Figure 14. Placement of EsthetX HD occlusally 

Figure 15. Light-curing of final composite layer 

Figure 16. Tooth #13 DO after finishing 

Summary 

While amalgam has a long history of safe use, patients and 

clinicians increasingly select esthetic tooth-colored posterior 

restorative materials. Each material has advantages 

and limitations. New developments in esthetic composite 

resins have resulted in low polymerization shrinkage and 

most recently a low-stress-producing esthetic restorative 

material. Each restorative material has advantages and 

should be used with the understanding that the material(s) 

selected depend upon the needs of the individual patient 

and clinical situation. 

References 

1 Summitt, JB, Burgess JO, Berry TG, Robbins JW, Osborne JW, 

Haveman CW. The performance of bonded vs. pin-retained 

complex amalgam restorations: a five-year clinical evaluation. J 

Am Dent Assoc. 2001;132(7):923–31. 

2 Ibid. 

3 Browning WD, Johnson WW, Gregory PN. Clinical performance 

of bonded amalgam restorations at 42 months. J Am Dent Assoc. 

2000;131(5):607–11. 

4 Belcher MA, Stewart GP. Two-year clinical evaluation of an 

amalgam adhesive. J Am Dent Assoc. 1997;128(3):309–14. 

5 DeRouen TA, Martin MD, Leroux BG, Townes BD, Woods JS, 

Leitão J, Castro-Caldas A, Luis H, Bernardo M, Rosenbaum G, 

Martins IP. Neurobehavioral effects of dental amalgam in children: 

a randomized clinical trial. J Am Med Assoc. 2006;295(15):1784– 

92. 

6 Bellinger DC, Trachtenberg F, Daniel D, Zhang A, Tavares MA, 

McKinlay S. A dose-effect analysis of children’s exposure to dental 

amalgam and neuropsychological function: the New England 

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6. 

7 Burgess J, Norling B, Summitt JB. Advances in glass ionomer 

material. Esthet Dent Update. 1993;4:54–8. 

8 Burgess J, Norling B, Summitt JB. Resin ionomer restorative 

materials: the new generation. J Esthet Dent. 1994;6(5):207–15. 

9 Burgess JO, Norling BK, Rawls HR, Ong JL. Directly placed 

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10 Burgess JO, Summitt JB, Robbins JW et al. Clinical evaluation of 

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esthetic restorative materials—the continuum. Compend Contin 

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14 Barkmeier W et al. In vitro wear assessment of high density 

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41. 

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Dent. 1994;71(1):7–12. 

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composite contraction stresses at the enamel cavosurface margins. 

Am J Dent. 1999;12(3):107–12. 

24 Goracci G, Mori G, Casa de’Martinis L. Curing light intensity and 

marginal leakage of resin composite restorations. Quintessence 

Int. 1996;27:355–62. 

25 Ibid. 

26 Walker RS, Burgess JO. Microleakage of class V composite 

restorations with different visible-light-curing methods. J Dent 

Res. (Abstract 397), 1999;78:155. 

27 Walker RS, Burgess JO. Microleakage of class V composite 

restorations with different curing methods. J Dent Res. 

2000;79:45. 

28 Kanca J 3rd, Suh BI. Pulse activation: reducing resin-based 

composite contraction stresses at the enamel cavosurface margins. 

Am J Dent. 1999;12(3):107–12. 

29 Lopes GC, Baratieri LN, Monteiro S, Vieira LC. Effect of posterior 

placement technique on the resin-dentin interface formed in vivo. 

Quintessence Int. 2004;35(2):156–61. 

30 van Dijken JW, Hörstedt P, Waern R. Directed polymerization 

shrinkage versus a horizontal incremental filling technique: 

interfacial adaptation in vivo in Class II cavities. Am J Dent. 

1998;11(4):165–72. 

31 Oberländer H, Friedl KH, Schmalz G, Hiller KA, Kopp A. Clinical 

performance of polyacid-modified resin restorations using 

“softstart-polymerization.” Clin Oral Investig. 1999;3(2):55–61. 

32 Brackett WW, Covey DA, St Germain HA Jr. One-year clinical 

performance of a self-etching adhesive in class V resin composites 

cured by two methods. Oper Dent. 2002;27(3):218–22. 

33 Bernardo, Martin, Johnson. J Dent Res. (Abstract 442), 2002. 

34 Chan DC, Browning WD, Frazier KB, Brackett MG. Clinical 

evaluation of the soft-start (pulse-delay) polymerization 

technique in Class I and II composite restorations. Oper Dent. 

2008;33(3):265–71. 

35 Clelland NL, Pagnotto MP, Kerby RE, Seghi RR. Relative 

wear of flowable and highly filled composite. J Prosthet Dent. 

2005;93(2):153–7. 

36 Ibid. 

37 Gallo JR, Burgess JO, Ripps AH, Walker RS, Bell MJ, Turpin- 

Mair JS, Mercante DE, Davidson JM. Clinical Evaluation of Two 

Flowable Composites. Quintessence Int. 2006;37(3):225–31. 

38 Cadenaro M, Marchesi G, Antoniolli F, Davidson C, De Stefano 

Dorigo E, Breschi L. Flowability of composites is no guarantee 

for contraction stress reduction. Dent Mater. 2009;25(5):649–54. 

Epub 2009 Jan 10. 

39 Stavridakis MM, Dietschi D, Krejci I. Polymerization shrinkage 

of flowable resin-based restorative materials. Oper Dent. 

2005;30(1):118–28. 

40 Efes BG, Dörter C, Gömeç Y, Koray F. Two-year clinical 

evaluation of ormocer and nanofill composite with and without 

a flowable liner. J Adhes Dent. 2006;8(2):119–26. 

41 Rees JS, Jacobsen PH. The polymerization shrinkage of composite 

resins. Dent Mater. 1989;5(1):41–4. 

42 Puckett AD, Smith R. Method to measure the polymerization 

shrinkage of light-cured composites. J Prosthet Dent. 

1992;68(1):56–8. 

43 Ferracane JL, Greener EH. The effect of resin formulation on 

the degree of conversion and mechanical properties of dental 

restorative resins. J Biomed Mater Res. 1986;20(1):121–31. 

44 Carioscia JA, Lu H, Stansbury JW, Bowman CN. Thiolene 

oligomers as dental restorative materials. Dent Mater. 

2005;21(12):1137–43. 

45 Carioscia JA, Stansbury JW, Bowman CN. Evaluation and control 

of thiol-ene/thiol-epoxy hybrid networks. Polymer (Guildf). 

2007;48(6):1526–32. 

46 Feilzer AJ, De Gee AJ, Davidson CL. Quantitative determination 

of stress reduction by flow in composite restorations. Dent Mater. 

1990;6(3):167–71. 

47 Feilzer AJ, De Gee AJ, Davidson CL. Setting stress in composite 

resin in relation to configuration of the restoration. J Dent Res. 

1987;66(11):1636–9. 

48 Ibid. 

49 Eick JD, Welch FH. Polymerization shrinkage of posterior 

composite resins and its possible influence on postoperative 

sensitivity. Quintessence Int. 1986;17(2):103–11. 

50 Borgmeijer PJ, Kreulen CM, van Amerongen WE, Akerboom 

HB, Gruythuysen RJ. The prevalence of postoperative sensitivity 

in teeth restored with Class II composite resin restorations. 

ASDC J Dent Child. 1991;58(5):378–83. 

Author Profile 

John O. Burgess, DDS, MS 

Dr. Burgess is the Assistant Dean for Clinical Research and the 

Director of The Biomaterials Graduate Program at the University 

of Alabama in Birmingham. He graduated from Emory 

University School of Dentistry and completed graduate training 

at the University of Texas Health Science Center in Houston. 

He served as military consultant to the Surgeon General in 

General Dentistry and was Chairman of Dental Research and 

Dental Materials at Wilford Hall Medical Center. Dr. Burgess 

is a diplomat of the Federal Services Board in General Dentistry 

and the American Board of General Dentistry. He is a Fellow of 

the Academy of Dental Materials and the American College of 

Dentists, and an elected member of The American Academy of 

Esthetic Dentistry and The American Restorative Academy. He is 

a member of the Academy of Operative Dentistry, The American 

and International Associations for Dental Research, the Alabama 

Dental Association and the ADA. Dr. Burgess is the author of 

over 300 journal articles, textbook chapters and abstracts and has 

presented more than 800 continuing education programs nationally 

and internationally. Dr. Burgess is an active investigator on 

clinical trials evaluating posterior composites, adhesives, fluoride 

releasing materials, impression materials and class 5 restorations. 

He maintains a part-time practice in general dentistry. 

Deniz Cakir, DDS, MS 

Dr. Deniz Cakir is an instructor the University of Alabama at 

Birmingham, School of Dentistry teaching graduates and dental 

students. She graduated from Ankara University School of Dentistry 

in 2002, and completed graduate training at the University 

of Alabama in Birmingham, School of Dentistry in 2005. Dr. 

Cakir is a member of the American Dental Association and the 

International Association for Dental Research. She is an active 

researcher in the area of dental materials and has authored numerous 

articles and abstracts on dental materials. 

Disclaimer 

The author(s) of this course has/have no commercial ties with 

the sponsors or the providers of the unrestricted educational 

grant for this course. 

Reader Feedback 

We encourage your comments on this or any PennWell course. 

For your convenience, an online feedback form is available at www. 

ineedce.com. 


Online Completion 

Use this page to review the questions and answers. Return to 

www.ineedce.com and sign in. If you have not previously purchased 

the program select it from the “Online Courses” listing and complete the 

online purchase. Once purchased the exam will be added to your Archives 

page where a Take Exam link will be provided. Click on the “Take Exam” link, 

complete all the program questions and submit your answers. An immediate 

grade report will be provided and upon receiving a passing grade your 

“Verification Form” will be provided immediately for viewing and/or printing. 

Verification Forms can be viewed and/or printed anytime in the future by 

returning to the site, sign in and return to your Archives Page. 

1. Material selection for restoring posterior 

teeth depends upon _______________. 

a. the patient’s age and caries risk 

b. esthetic and functional requirements 

c. the ability to isolate the tooth 

d. all of the above 

2. Compomers, glass ionomers and composite 

resins bond to tooth structure and may 

reinforce weakened tooth structure. 

a. True 

b. False 

3. Amalgam restorations may be bonded to 

tooth structure with adhesives using the 

_______________. 

a. self-adhesive technique 

b. chelating amalgam technique 

c. bonded amalgam technique 

d. none of the above 

4. Recent studies on amalgam by the NIH 

have provided additional evidence for the 

safety of amalgam in children. 

a. True 

b. False 

5. Fluoride-releasing composites 

_______________. 

a. release low levels of fluoride 

b. have better wear resistance and toughness than 

other fluoride-releasing restorative materials 

c. may not be effective for high-caries-risk patients 


6. Glass ionomer and resin-modified 

glass ionomer restorative materials 

_______________. 

a. have the highest levels of fluoride release 

b. have good recharge of fluoride which increases 

long-term fluoride release 

c. are useful for high-caries-risk patients 


7. The conditioners used with glass ionomer 

cements clean rather than etch the tooth 

surface prior to bonding and effectively 

improve the bond of the glass ionomer to 

the tooth. 

a. True 

b. False 

8. Nanofillers added to resin-modified glass 

ionomer cement _______________. 

a. improve its esthetics 

b. improve its handling 

c. result in a smoother restoration 


9. Compomers are blends of resin composite 

and glass ionomer. 

a. True 

b. False 

10. Compomers _______________. 

a. contain more resin than resin-modified glass 

ionomers 

b. offer good fluoride release and recharge 

c. have been used successfully in the primary dentition 


Questions 

11. Currently more than _______________of 

all direct posterior restorations are 

composite. 

a. 20% 

b. 30% 

c. 40% 

d. 50% 

12. The use of sectional matrices removes 

some of the difficulties associated with 

composite resin placement. 

a. True 

b. False 

13. Composite resin polymerization shrinkage 

contributes to _______________. 

a. marginal breakdown 

b. high release of fluoride 

c. postoperative thermal sensitivity 

d. a and c 

14. The placement of visible light-cured 

composite resin in 2 mm increments is 

time-consuming. 

a. True 

b. False 

15. Photoinitiators in composite resin are 

activated by visible light in the presence 

of an amine accelerator/catalyst; the light 

is however attenuated as it passes through 

composite resin. 

a. True 

b. False 

16. Poorly cured composite resin 

_______________. 

a. has low wear resistance 

b. has poor mechanical properties 

c. can result from the use of curing lights that do 

not have the correct spectral distribution for the 

composite being used 


17. Light-curing units have been developed 

to decrease contraction stress by slowing 

the rate of composite resin polymerization. 

a. True 

b. False 

18. Some studies have reported no 

significant difference in marginal integrity 

or marginal discoloration when composite 

resins are polymerized with or without a 

soft-start polymerization. 

a. True 

b. False 

19. Flowable composites _______________. 

a. are conventional or microfilled composite resins 

b. have lower viscosity than other composites 

c. result in better adaptation to cavity walls 


20. Flowable composites with higher 

percentage filler loads reduce the concern 

for greater wear resistance and polymerization 

shrinkage compared to lower 

percentage filler loads. 

a. True 

b. False 

21. Polymerization shrinkage of composite 

resins ranges from 3.7% to 0%. 

a. True 

b. False 

22. Flowable composite resin was originally 

used as a resin liner to improve the adaptation 

of condensable composites to the 

prepared tooth. 

a. True 

b. False 

23. Cadanero et al. found that most flowable 

composites _______________. 

a. had shrinkage stress much higher than conventional 

resin restorative materials 

b. had shrinkage stress much lower than conventional 


c. had shrinkage stress comparable to conventional 


d. none of the above 

24. Stavridakis et al. found that flowable resins 

produced considerable shrinkage stress. 

a. True 

b. False 

25. With respect to flowable composites 

and the results from clinical studies 

conducted by various investigators on 

these, _______________. 

a. their use to reduce polymerization shrinkage stress 

is controversial 

b. shrinkage stress may be product dependent 

c. the consensus appears to be that their major benefit 

is cavity adaptation 


26. Increasing the filler content of composite 

_______________. 

a. increases composite stiffness 

b. increases the forces of contraction 

c. reduces shrinkage 


27. The use of new chemistries for 

composites has resulted in reduced 

polymerization shrinkage stress. 

a. True 

b. False 

28. The use of silorane ring-opening chemistry 

or dimer chemistry in composite resins 

results in lower polymerization shrinkage. 

a. True 

b. False 

29. The use of a new polymerization modulator 

embedded in the polymerizable resin 

has resulted in _______________. 

a. reduced curing stress 

b. an extended curing phase, maintaining a high 

conversion rate 

c. no reduction in the polymerization rate 


30. High translucency of material containing 

polymerization modulator enables the 

curing of 4 mm increments versus 2 mm 

increments for conventional composite 

resins, saving time. 

a. True 

b. False 


ANSWER SHEET 

Material Selection for Direct Posterior Restoratives 

Name: Title: Specialty: 

Address: 

E-mail: 

City: State: ZIP: Country: 

Telephone: Home ( ) Office ( ) 

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. Know the considerations involved in the selection of posterior restorative materials 

2. Know the history and safety profile of amalgam, its advantages and disadvantages 

3. Know how polymerization stress occurs and its relevance to restoration failure 

4. Understand the technologies that can now be incorporated into posterior composite restoratives to combat polymerization 

shrinkage and/or polymerization stress 

Course Evaluation 

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

1. Were the individual course objectives met? Objective #1: Yes No Objective #3: Yes No 

Objective #2: Yes No Objective #4: Yes No 

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

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

If not taking online, mail completed answer sheet to 

Academy of Dental Therapeutics and Stomatology, 

A Division of PennWell Corp. 

P.O. Box 116, Chesterland, OH 44026 

or fax to: (440) 845-3447 

For immediate results, 

go to www.ineedce.com to take tests online. 

answer sheets can be faxed with credit card payment to 

(440) 845-3447, (216) 398-7922, or (216) 255-6619. 

Payment of $59.00 is enclosed. 

(Checks and credit cards are accepted.) 

If paying by credit card, please complete the 

following: MC Visa AmEx Discover 

Acct. Number: _______________________________ 

Exp. Date: _____________________ 

Charges on your statement will show up as PennWell 

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

5. How do you rate the author’s grasp of the topic? 5 4 3 2 1 0 

6. Please rate the instructor’s effectiveness. 5 4 3 2 1 0 

7. Was the overall administration of the course effective? 5 4 3 2 1 0 

8. Do you feel that the references were adequate? Yes No 

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

10. If any of the continuing education questions were unclear or ambiguous, please list them. 

___________________________________________________________________ 

11. Was there any subject matter you found confusing? Please describe. 

___________________________________________________________________ 

___________________________________________________________________ 

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

___________________________________________________________________ 

___________________________________________________________________ 

AGD Code 253 

PLEASE PHOTOCOPY ANSWER SHEET FOR ADDITIONAL PARTICIPANTS. 

AUTHOR DISCLAIMER 

The author(s) of this course has/have no commercial ties with the sponsors or the providers of 

the unrestricted educational grant for this course. 

SPONSOR/PROVIDER 

This course was made possible through an unrestricted educational grant from 

DENTSPLY Caulk. No manufacturer or third party has had any input into the 

development of course content. All content has been derived from references listed, 

and or the opinions of clinicians. Please direct all questions pertaining to PennWell or 

the administration of this course to Machele Galloway, 1421 S. Sheridan Rd., Tulsa, OK 

74112 or macheleg@pennwell.com. 

COURSE EVALUATION and PARTICIPANT FEEDBACK 

We encourage participant feedback pertaining to all courses. Please be sure to complete the 

survey included with the course. Please e-mail all questions to: macheleg@pennwell.com. 

INSTRUCTIONS 

All questions should have only one answer. Grading of this examination is done 

manually. Participants will receive confirmation of passing by receipt of a verification 

form. Verification forms will be mailed within two weeks after taking an examination. 

EDUCATIONAL DISCLAIMER 

The opinions of efficacy or perceived value of any products or companies mentioned 

in this course and expressed herein are those of the author(s) of the course and do not 

necessarily reflect those of PennWell. 

Completing a single continuing education course does not provide enough information 

to give the participant the feeling that s/he is an expert in the field related to the course 

topic. It is a combination of many educational courses and clinical experience that 

allows the participant to develop skills and expertise. 

COURSE CREDITS/COST 

All participants scoring at least 70% (answering 21 or more questions correctly) on the 

examination will receive a verification form verifying 4 CE credits. The formal continuing 

education program of this sponsor is accepted by the AGD for Fellowship/Mastership 

credit. Please contact PennWell for current term of acceptance. Participants are urged to 

contact their state dental boards for continuing education requirements. PennWell is a 

California Provider. The California Provider number is 4527. The cost for courses ranges 

from $49.00 to $110.00. 

Many PennWell self-study courses have been approved by the Dental Assisting National 

Board, Inc. (DANB) and can be used by dental assistants who are DANB Certified to meet 

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PennWell course has been approved by DANB, please contact DANB’s Recertification 

Department at 1-800-FOR-DANB, ext. 445. 

RECORD KEEPING 

PennWell maintains records of your successful completion of any exam. Please contact our 

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all credits earned to date, will be generated and mailed to you within five business days 

of receipt. 

CANCELLATION/REFUND POLICY 

Any participant who is not 100% satisfied with this course can request a full refund by 

contacting PennWell in writing. 

© 2009 by the Academy of Dental Therapeutics and Stomatology, a division 

of PennWell 

MATS1109DE 

DENT0910DE

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