Ketac Cem Glass Ionomer Cement

Technical Product Profile

Glass Ionomer Luting Cement

Ketac Cem

Ketac Cem Easymix

Ketac Cem radiopaque

Ketac Cem Aplicap / Maxicap

™

™™™

Table of Contents

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

Rationale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

Overview of Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Setting reaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Details of the setting reaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Factors influencing the setting reaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

Product composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

Technical Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

Biocompatibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

Solubility and marginal seal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12

Dimensional stability and adhesion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

Particle size distribution and film thickness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17

Release of fluoride ions and cariostatic effect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18

Special Features of Ketac

Cem Easymix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

Technological Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

Clinical Studies on Ketac

Cem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23

Comparative clinical study of Ketac Cem and a zinc phosphate cement

(University of Freiburg, Germany) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23

Comparative clinical study of Ketac Cem and a zinc phosphate cement

(University of Washington) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24

Clinical short-term study comparing Ketac Cem and a zinc phosphate cement

(University of Texas) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24

Clinical study of the long-term success of In-Ceram

bridges

(University of Portland) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25

Instructions for Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26

Questions and Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29

Literature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30

Literature on Ketac Cem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30

General literature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37

Technical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38

ESPE

in-house, ISO standard-compliant measurements . . . . . . . . . . . . . . . . . . . . . .38

Particle size distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38

Introduction

The clinical success of permanent restorations is primarily a function of the cementation pro-

cess. The loss of crown retention has been described as one of the most frequent causes for

clinical failure of traditional crown and partial tooth restorations. Though adequate tooth prepa-

ration for retention purposes remains the most important single factor for the clinical success of

restorations, other criteria such as the barrier function against bacterial colonization and the

sealing function at the interface of tooth and restoration and as a „mediator“ of different surfa-

ces must also be met by the luting material.

An ideal luting material meets the following requirements:

• Formation of a stable bond between different materials

• Adequate compressive and flexural strength

• Sufficient fracture resistance that prevents restoration detachment due to fractures at

interfaces or cohesive fractures

• Favorable flow properties during the approximation to both the tooth structure and the

restoration

• Formation of sufficiently thin films of adequate viscosity, permitting complete

attachment of the restoration to the tooth stump

• Stability under the ambient conditions inside the mouth

• Biocompatibility

• Favorable processing and setting times

History

Modern dental cements are based on inventions made in the middle of the 19th century. As

early as in 1856, Sorel presented a formulation for a magnesium chloride cement. The ensuing

search for improved materials initiated numerous developments, such that by the 1920s three

main categories of cements had become established: zinc phosphate cements, zinc oxide-

eugenol cements, and silicate cements.

In 1966, D.C. Smith introduced yet another class of cement, in which the liquid of the zinc

phosphate cement was replaced by aqueous polyacrylic acid. This so-called carboxylate cement

opened up new prospects for self-adhesive dental materials.

On the basis of these developments, Wilson et al. introduced glass ionomer cementing materi-

als in 1969, a material class which remains very successful today. The first glass ionomer

cement product, ASPA (Alumino-Silicate-Poly-Acrylate), introduced in the 1970s, was formu-

lated by adding polyacrylic acid as the liquid component to finely ground silicate powder.

This breakthrough spawned a series of rapid product developments of glass ionomer cements

(also termed „GICs“ hereinafter), leading to modifications and improvements to meet the

requirements of the broad range of indications of these products. Not even the development of

resin materials put a major dent in the continued popularity of these tried and tested biocompa-

tible dental materials.

Rationale

In spite of the increasing popularity of metal-free restorations requiring adhesive fixation, indi-

rect restorations fixed by conventional cementation, such as inlays, cast full crowns, and porce-

lain fused to metal crowns (pfm), still account for the majority of this kind of indirect restora-

tions. In fact, there is even a marked trend towards fixing single crowns with no metal parts,

such as Lava

™

, Procera

™

and In-Ceram

™

, by conventional techniques, since the materials used

in these techniques have proven to be clearly more stable than those used for classical “jacket

crowns”. Jacket crowns attached by conventional cementation would have been a failure.

A further factor in the continuing popularity of conventional cementation materials is their

easy processing, especially in subgingival areas.

Similarly to zinc phosphate cements, which have been occasionally termed obsolete in recent

literature, glass ionomer cements are easily processed, stable cementation materials that pro-

vide options for numerous applications and effectively resist the ambient conditions inside the

mouth.

™

ESPE

™

has been marketing glass ionomer cements since 1980 (Ketac

™

Cem) and assu-

med a pioneering position in the development of glass ionomer technology. Continued efforts

of product development have allowed 3M ESPE to launch new products with improved

material properties and simpler or more reliable handling features (see Figure 1) including

Ketac

™

Cem Aplicap

™

and Maxicap

™

capsules and a number of filling and core build-up

mate-rials. Introduced in 2001, Ketac

™

Cem Easymix is the most recent technological addition

to 3M ESPE’s range of products in this area. Based on the tried and tested luting material,

Ketac

™

Cem radiopaque, the processing properties in particular have been optimized in this

new product.

Fig. 1: Development of glass ionomer cements

Glass Ionomer Development

1969 First patent

1975 First generation (ASPA)

1980 Second generation (Ketac

Cem, Ketac

Fil, Fuji II

)

1985 Cermet cements (Ketac

Silver)

1990 Resin-modified GICs (Vitrebond

, Photac

Bond, Fuji LC

)

1994 RMGI luting cements (RelyX

Luting, formerly Vitremer

Luting)

1995 High viscosity GICs (Ketac

Molar, Fuji IX

)

2000 Fast-setting GICs (Ketac

Molar Quick, Fuji IX

Fast)

2001 Easily mixable GICs (Ketac

Cem Easymix)

Overview of Technology

From a chemical viewpoint, cements are substances produced by an acid-base reaction. In

practical terms, this means that a powder is mixed with a liquid to generate a mixture which

then sets and hardens through a setting reaction.

Cements can be classified on the basis of their main components as shown in Figure 2.

The figure shows that glass ionomer cements, such as Ketac

™

Cem, are composed of glass

powder and polyacrylic acid. Radiopaque glass is used in this application to meet the require-

ments of the dentist and render the cement radiopaque to X-rays.

Setting Reaction

Since the setting characteristics of the glass ionomer cement are of crucial significance, a short

description of these characteristics is provided in the following to provide the basis for a better

understanding of the development of this class of materials and their correct application in

dentistry. This discussion also highlights the Achilles heel of the earlier glass ionomers.

Once the cement powder is exposed to the aqueous solution of the polycarboxylic acid, a reac-

tion between the alkaline glass powder and the unsaturated acid ensues and a salt gel is for-

med. Obviously, it is irrelevant in this reaction whether the product is provided in the form of

capsules or if powder and solution are manually mixed. The acid-base reaction proceeding in

the salt gel leads to the formation of the bonding matrix. Water serves not only as the reaction

medium, but also as an essential component of the salt gel as it is required for hydration of the

metal-carboxylate complexes formed in the reaction (see Figure 3).

Classification of Cements

Acid + Base

➞

Cement

Liquid

Phosphoric acid Polyacrylic acid

Phosphate cement Carboxylate cement

(1966, D.C. Smith)

Silicate cement Glass ionomer cement

(1969, Willson)

ZnO

Glass

Powder

Fig. 2: Classification of cements

Details of the Setting Reaction

The setting mechanism can be subdivided into four separate reaction phases.

In the initial phase, the carboxylic acid groups of the polycarboxylic acid dissociate to form

negatively charged carboxylate anions, RCOO

, and positively charged protons, H

. The positi-

vely charged protons, H

, then attack the surface of the glass filling body, causing disintegra-

tion of the glass structure and release of the cement-forming metal ions, Al3

and Ca2

(see

Figure 4).

The influence of fluoride ions at this stage and their ability to form complexes with the released

metal ions are discussed in detail later.

The metal ions then enter into the aqueous phase of the cement. Subsequently, the primary

setting phase commences with the formation of a salt gel (see Figure 5). The released metal

ions, M

, become complex by the carboxylate residues of the polycarboxylic acid component.

Calcium ions, Ca

, are the main active ion species at this stage. The ions are present in aqueous

solution, which means that they are quite susceptible to the attack of aqueous solutions (i.e.,

being washed out).

Setting Reaction of Glass Ionomers

Fig. 3: Schematic depiction of the setting reaction of glass ionomer cements

Fig. 4: Structure of an aluminum silicate (Source: A.D. Wilson, J.W. McLean “Glasionomere”,

Quintessenz Verlag 1988, p. 37)

This is the reason why glass ionomer cements have to be protected from moisture in the first

setting phase. However, the opposite effect, i.e. drying out, is no less detrimental, which can be

easily explained as the reaction requires an aqueous medium to proceed. The process of hydra-

tion is severely impaired or prevented in the absence of water, which limits the supply of ions

needed for the setting reaction.

In the course of the reaction, the protons continually attack the silicate glass and cause the

release of aluminum ions, Al

. This initiates the secondary setting phase. The incorporation

of the trivalent aluminum cations into the preformed matrix leads to the formation of a three-

dimensional, water-insoluble calcium-aluminum-carboxylate gel that is no longer susceptible to

moisture or dehydration.

Factors Influencing the Setting Reaction

Numerous chemical and physical factors can influence the setting properties of glass ionomer

cements. Essentially being a simple acid-base reaction, the setting of glass ionomer cements is

rendered very complex by the number of different reaction mechanisms involved. This comple-

xity derives not only from the release and precipitation of calcium and aluminum ions, but also

from the fluoride- and tartrate ion-mediated process of gel formation. While some factors, such

as temperature, powder particle size and powder/liquid ratio simply accelerate or delay the

reactions, certain chemical factors have more crucial effects in that they actually modify the

reaction processes themselves. The most important factors of this type are fluoride and tartaric

acid.

Functions of Fluoride Ions

In the course of their developmental work on glass ionomer materials, Wilson and Kent obser-

ved that fluoride-free glasses yield unsuitable pastes that are difficult to process. Crisp and

Wilson, and subsequently Barry et al., showed unequivocally that the processing properties are

correlated to the amount of fluoride released by the glass. This effect of fluoride ions has been

attributed to the ability of fluoride to form metal complexes, which in turn delays the binding

of cations (Ca2+, Al3+) to negatively charged sites of the polyelectrolyte chain (see Figures 3-5)

and thereby retards gel formation.

This mechanism provides the clinical dentist with sufficient processing time.

Fig. 5: Formation of the silica gel at the surface of the glass

(Source: A.D. Wilson, J.W. McLean “Glasionomere”, Quintessenz Verlag 1988, p. 37)

Effects of Tartaric Acid

(+)-tartaric acid exerts a unique effect on the glass ionomer reaction. Added in small amounts,

tartaric acid simplifies the handling of the cement paste and increases the stability of the

material. This influence can be explained by tartaric acid’s propensity to form stable comple-

xes with aluminum ions, effectively increasing the amount of aluminum released from the

glass. Moreover, tartaric acid accelerates the final setting reaction, allowing the setting

reaction to show snap-set properties.

Indications

The Ketac

™

Cem family of products has been in clinical use for some 20 years.

Currently, this line comprises the following products:

• Ketac

™

Cem Easymix

• Ketac

™

Cem radiopaque

• Ketac

™

Cem Aplicap

™

• Ketac

™

Cem Maxicap

™

Ketac Cem is a permanent luting cement based on glass ionomer technology for use in the

following applications:

• Cementation of inlays, onlays, crowns, and bridges made from metal or metal-ceramics

or covered with composite veneer material

• Cementation of inlays, onlays, crowns, and bridges made from composite or ceramics

provided these are suitable for conventional cementing

• Cementation of posts and screws provided these are suitable for conventional cementing

• Luting cement for use on orthodontic bands

• Relinings

(For details of the indications, please refer to the Instructions for Use of the respective product).

Composition

Ketac Cem glass ionomer luting cement comprises powder / liquid components.

Ketac Cem is commercially available both for manual mixing (Ketac Cem radiopaque and

Ketac Cem Easymix) and in capsules (Ketac Cem Aplicap and Ketac Cem Maxicap).

The ingredients of Ketac Cem are listed in Table 1.

Material Powder Liquid

Ketac

Cem radiopaque / Easymix Glass powder Water

Polycarboxylic acid Tartaric acid

Pigments Conservation agents

Ketac

Cem Aplicap

/ Maxicap

Glass powder Polycarboxylic acid

Pigments Tartaric acid

Water

Conservation agents

Table 1: Ketac Cem composition

Properties

The selection of a suitable luting cement for a particular application is based on numerous cli-

nical parameters and material requirements. These latter factors principally relate either to

handling aspects or to technical material properties.

As mentioned above, Ketac

™

Cem has been successfully marketed since 1980. In addition to

the experience derived from millions of uses in clinical practice, numerous studies of the

material properties as well as controlled clinical studies are available. The following sections

provide a detailed discussion of selected results. In addition, numerous publications related to

Ketac Cem and some general references on glass ionomers have been assembled in the

Literature section of this product profile. The references are supplied with short abstracts to

allow the interested reader easy access to primary literature that is of a particular interest to him

or her.

Biocompatibility

R.C.S. Chen et al., China Medical College, Taichung, Taiwan

M. Augthun, Klinik für Zahnärztliche Prothetik, Aachen, Germany

W.H.M. Raab et al., Poliklinik für Zahnerhaltung und Parodontologie, Erlangen, Germany

C.H. Pameijer et al., University of Connecticut, USA

The biocompatibility of glass ionomer cements has been the subject of many studies and is

extensively documented in the literature.

R.C.S. Chen et al. investigated the cytotoxicity of several materials including Ketac Cem. The

Ketac Cem results corresponded to the negative control, i.e. the substance showed no cytotoxi-

city.

A Research Report of Zahnärztliche Prothetik, Aachen, Germany, also investigated the effect

of Ketac Cem on cell growth. Conducted in accordance with EN 30993-5, this investigation

applied cell culture methods and led to Ketac Cem being classified as a biocompatible material.

The cell culture tests showed little or no effect of the substance on cell growth. The tested

sample was well tolerated by (i.e. acceptable to) the cells. Taking the in vivo conditions into

consideration (flow of saliva), the low inhibitory effect after a short setting time was classified

as negligible. The number of samples investigated and the testing methods went beyond the

requirements of the standards and thus provided a valid result.

The study conducted by P. Grund and W.H.-M. Raab (Clinic for Conservative and Periodontic

Dentistry, Erlangen, Germany) investigated the potential toxic effect of the acid component of

Ketac Cem on the pulp using Laser-Doppler flow measurements to detect changes dental pulp

microcirculation. The substances investigated included 33% phosphoric acid, Ketac Cem liquid,

and a 35% solution of the acrylic acid-maleic acid copolymer derived from Ketac Cem powder.

The results allow to conclude that the free acid components of Ketac Cem are less toxic to the

pulp than Tenet (H

But ultimately, any dental material must prove its value in clinical applications. For this reason,

the clinical results have been compiled separately.

Solubility and Marginal Sealing

K.-P. Stefan, 3M ESPE, Seefeld, Germany

B.K. Norling et al., Dental School San Antonio, USA

S.R. Curtis, Naval Dental School, Maryland, USA

S.N. White, J.A. Sorensen et al., University of Southern California, LA, USA

M. Ferrari, University of Sienna, Italy

Aside from adhesion, the stability of the restoration depends mainly on its erosion and abrasion

resistance. Two sub-aspects are of importance in the process of erosion: firstly, the diffusion of

soluble components out of the cement, and secondly, the actual erosion due to chemical reac-

tions or mechanical stress. The marginal seal and quality thereof are other important factors in

this area.

Usually, the solubility of glass ionomer cements is measured quite some time after setting.

The international standard, ISO 7489, proposes determination of the solubility one hour after

setting, while the currently applicable standard for cements has the measurements performed

after 24 hours. Since neither of these procedures reflects the early exposure to saliva experien-

ced under in vivo conditions, the study of K.-P. Stefan set out to determine the solubilities after

10 min and 60 min. In these studies, the solubility of Ketac

™

Cem was shown to be significant-

ly lower than that of a resin-modified glass ionomer cement (ISO 7489).

The study of B.K. Norling et al. compared the two basic study designs for the determina-

tion of the water solubility and acid erosion. Whether or not a given study protocol truly

allows a valid comparison of different classes of materials must be evaluated with great

care. The literature contains several studies reporting favorable immersion values for

Ketac Cem. One of the underlying reasons may be the formulation of this product.

Cements with polyacrylic acid in the form of a powder show a trend to have lower solubi-

lities (see Figure 6).

Fig. 6: Solubility in water, B.K. Norling et al. (see Chapter 11 and Literature, p. 34)

Solubility (Immersion)

Solubility

Durelon

Ketac

Cem Fuji I

Fuji I

Duet Advance

Zinc

Phosphate

Another important factor in the evaluation of water-based systems is their response to the expo-

sure to moisture during the setting reaction. S.R. Curtis et al. investigated the susceptibility of

cements to moisture both before and after removing any excess material and found zinc phos-

phate cements to respond more sensitively than glass ionomers. Ketac

™

Cem does not require

application of a protective glaze.

The investigation of Ketac Cem’s properties at the margin also yielded some encouraging

results. The group of J.A. Sorenson investigated the marginal seal after cementation of cast

crowns with polycarboxylate, zinc phosphate, glass ionomer, and composite cements, and

found Ketac Cem to be second best only to the composite materials.

A similar study protocol was used in a study recently published by M. Ferrari, in which the

new, manually mixed variant, Ketac

Cem Easymix, was one of the materials examined. The

marginal sealing properties were tested by cementation of cast crowns followed by dye pene-

tration tests. The results showed that there was significantly less leakage with Ketac

Cem

radiopaque and Ketac

Cem Easymix as compared to the reference groups, Fuji I

(glass iono-

mer) and Harvard

(zinc phosphate).

Figures 8 and 9 show the rating scale and the sample analysis for the “worst case scenario”,

i.e. dye penetration down to the occlusal cervical wall. None of the samples from the Ketac

Cem groups received the worst rating.

Fig. 7: Dye penetration into cemented cast crowns, Dentin; J.A. Sorensen et al.

(see Literature, p. 31)

Fig. 8: Dye penetration rating scale; 0 = no dye penetration; 4 = penetration extending to the

occlusal cervical wall (see Literature)

Dye penetration

Dye Penetration

Panavia

Ex Ketac

Cem

DentMat Thin

film cement

Flecks

Zinc

phosphate

Dimensional Stability and Adhesion

Th.A. Zumstein et al., University of Zurich, Switzerland

C.-P. Ernst, B. Willershausen et al., Universität Mainz, Germany

R. Frankenberger et al., Universität Erlangen, Germany

D.B. Mendoza, University of California, San Francisco, USA

J.M. Casanellas, J.L. Navarro et al., University of Barcelona, Spain

G. Morando, Naval Dental School, Bethesda, USA

The majority of luting materials expand or shrink more strongly than the tooth structure or are

subject to dimensional changes during the setting process or when exposed to moisture and

saliva. A characteristic feature of glass ionomer cements is the high dimensional stability and

the resulting direct beneficial effect on the marginal gap properties and pressure on the pulp.

In addition, glass ionomer cements show direct chemical bonding to the tooth structure such

that there is no need to prepare the cavity for bonding by acid etching or application of a dentin

adhesive. The combination of low contraction during the setting process and an expansion

coefficient similar to that of teeth explains the favorable marginal gap properties of glass

ionomers.

The bonding of glass ionomers to the tooth structure and to metal alloys has been the subject of

a large number of in-vitro investigations. The effects of various steps of conditioning also have

been well described: Th. Zumstein and J.R. Strub demonstrated that glass ionomers, in general,

show stronger bonding to dentin than zinc phosphate materials.

Another interesting result was that Ketac

™

Cem attained the highest bonding strength on gold

after simple sand-blasting of the substrate, whereas tin-plating and subsequent oxidation redu-

ced the bonding strength.

The literature contains a variety of different methods for determining the bonding strength of

luting materials. One suitable method for determination of the retentive and adhesive forces of

luting materials involves stripping gold crowns from standardized tooth stumps. A bond

strength study conducted at the University of Mainz (Germany) in accordance with this proto-

col found Ketac Cem to be superior even to the compomer material, F21 (see Figure 10).

In this study, pretreatment of the dentin had a detrimental influence on the bonding strength of Ketac Cem. This observation was

accounted for in the clinical recommendation in that Ketac Cem is to be applied to the dentin without pretreatment

(and with no conditioner).

Fig. 9: No. of samples (total n = 10) with dye penetration score 4. M. Ferrari et al.

(see Literature, p. 36)

Number of samples

with a score of 4

Number of Samples With a Score of 4

(n = 10)

Ketac

Cem

Easymix

Fuji I

Harvard

Ketac

Cem rp

The push-out test of gold inlays, as established by R. Frankenberger of the University of

Erlangen, is another elegant and clinically relevant method. In this technique, non-carious

human molars are sectioned into discs and furnished with conical cavities (4°). Subsequently,

gold inlays are cemented into these inlay cavities, any excess material is removed, and then

the force required to push out the inlay with a stamp is measured (see Figure 11).

The two variants for manual mixing, Ketac

™

Cem radiopaque and Ketac

™

Cem Easymix,

attained significantly higher retention values in this test as compared to the Harvard

™

zinc

phosphate cement. A number of other publications investigated the cementation of posts,

screws, and transfixations (root canal post implants).

In a study determining the retentive forces of cemented prefabricated metal posts after

endodontic treatment of human teeth, Ketac Cem showed even higher strength than the compo-

site materials, Panavia

™

and All-Bond

™

2 (see Figure 12). The fact that the glass ionomer

cement is easier to process further emphasizes the advantages of Ketac Cem in this indication.

Fig. 11: Gold inlay push-out test, R. Frankenberger (see Literature, p. 36)

Fig. 10: Gold crown tensile test, C.-P. Ernst (see Literature, p. 33)

Retention Forces

Retention forces

Retention Forces

Retention forces

Ketac

Cem

Easymix

Dyract

Cem

Dyract

Cem

+ P&B 2.0

(non cured)

Dyract

Cem

+ P&B 2.0

(cured)

F21

Ketac

Cem Easymix

Ketac

Cem rp

Fuji I

Harvard

A study with an analogous aim was conducted by the Spanish group of J.M. Casanellas and the

results confirmed the findings of the earlier scientific study. In the study, Ketac

™

Cem was

compared to various composite luting materials and zinc phosphate cement with regard to the

cementation of prefabricated titanium posts (cylindroconical intraradicular) and showed

superior retention forces as compared to all other groups included in the investigation (see

Figure 13).

Aside from retention, a low degree of traumatization is an essential factor for the clinical

success of post insertions both with respect to the fracture risk and sensitivity of the tooth.

Researchers at the Naval Dental School (Bethesda, USA) developed a specialized in-vitro

regimen for investigation of the hydrostatic pressure experienced during post cementation. On

the assumption that the experimental design adequately reflects the clinical situation, luting

cements building up little hydrostatic pressure are to be preferred in the clinical practice.

Figure 14 below shows Fleck’s

™

zinc phosphate cement to generate the highest hydrostatic

pressure which corresponds to the least favorable result.

Retention Forces

Mean kilograms

Retention forces

Retention Forces

Retention forces

Fig. 12: Retentive forces in the removal of prefabricated posts, D.B. Mendoza et al.

(see Literature, p. 32)

Fig. 13: Retention forces in the removal of cemented titanium posts, J.M. Casanellas et al.

(see Literature, p. 36)

Ketac

Cem Panavia

All-Bond

Ketac

Cem

Panavia

All-Bond

C&B

Metabond

Panavia

Fleck’s

Zinc

phosphate

cement

Particle Size Distribution and Film Thickness

A. Patyk, M. H. lsmann et al., Universität Göttingen, Germany

J.M. Strutz et al., Loma Linda University and University of Southern California, USA

The generation of thin films is an essential criterion for permanent management with an indi-

rect restoration. Film thickness is determined by a number of different parameters, including

particle size, viscosity, flow, and setting properties. The film thickness of aqueous materials for

conventional luting particularly varies with processing temperature and humidity (atmospheric

moisture content).

The literature data regarding particle size and film thickness show Ketac

™

Cem to be an excel-

lent luting cement with favorable particle size distribution which allows the material to form

thin films.

According to a comparative study of six luting materials conducted at the University of

Göttingen in Germany, Ketac Cem showed the most favorable results in terms of its particle

size and particle size distribution. The sums of the relative frequencies (in %) are shown in

the following table:

Particle size, in µm Ketac

Cem rp Fleck’s

Zinc phosphate cement Fuji

Ionomer

0.0 - 5.0 81.84 65.88 58.33

0.0 - 10.0 98.36 87.46 91.22

0.0 - 20.0 100 99.58 98.78

0.0 - 30.0 99.76 99.46

0.0 - 40.0 100 99.46

0.0 - 50.0 99.73

0.0 - 60.0 100

Fig. 14: Hydrostatic pressure, in pounds per square inch, G. Morando et al.

(see Literature, p. 32)

Table 2: Particle size distribution, A. Patyk et al. (see Literature, p. 31)

Hydrostatic Pressure

Hydrostatic pressure

Ketac

Cem

Panavia

Fleck’s

Zinc phosphate cement

The correlation between the maximal particle size or particle size distribution and the thickness

of films of the material was demonstrated in an impressive fashion in studies conducted by

researchers at the Loma Linda University and the University of Southern California, Los

Angeles. The studies investigated the thickness of films formed by various luting materials in

combination with different metal alloys and consistently found Ketac

™

Cem to produce the

thinnest films. Figure 15 shows the most beneficial combination with a precious nobel metal-

ceramic alloy.

Release of Fluoride Ions and Cariostatic Effect

The release of fluoride ions by glass ionomer cements is a known and well-investigated effect.

In the proximity of glass ionomer cements, secondary carious lesions develop less frequently

than with other dental materials. Due to this effect, this class of material is used in dentures

with active caries and in the treatment of secondary caries and in orthodontic applications, in

which the undesirable demineralization of banded teeth plays a great role.

However, the literature fails to explain the exact mechanism of remineralization and the thres-

hold value of the cariostatic effect of fluoride ions. It is a known scientific fact, though, that the

demineralization of the tooth structure occurs at pH<5.5, while remineralization prevails at

pH>5.5 (see Figures 16 and 17).

Fig. 15: Film thickness of combinations with a precious nobel metal-ceramic alloy, J.M. Strutz

et al. (see Literature, p. 32)

Fig. 16: Schematic depiction of the demineralization process at pH<5.5

Film Thickness

Film thickness

Demineralization

pH < 5.5

Ketac

Cem

Durelon

DenMat

Hybrid

Panavia

Fleck’s

Zinc

phosphate

cement

Investigations of the pH-dependent fluoride ion release from glass ionomer cements

(see Figure 18) showed that fluoride ion release from the material is highest in acidic medium,

i.e. when the tooth structure is most severely affected by demineralization. For clinical practice,

this may mean that the cement or GIC filling material promotes remineralization best under

conditions at which the tooth structure is at risk. This is the underlying rationale for glass iono-

mer cements being called “smart material”, “intelligent dental material” or “living system”.

Fig. 17: Schematic depiction of the remineralization process at pH>5.5

Remineralization

Incorporation

pH > 5.5

Fluoride Ion Release

Fig. 18: pH-dependent fluoride ion release by Ketac

™

Cem (in-house measurements of

3M ESPE)

Special Features of

Ketac

Cem Easymix

Introduced in September 2001, Ketac Cem Easymix is the most recent addition to the

™

ESPE

™

Ketac

™

Cem product family. The features of Ketac Cem Easymix shall be

described in some detail in the following.

The rationale of this product development was to offer our customers who prefer the Ketac Cem

variant for manual mixing a product with improved handling features and high reproducibility

of dosing, since some users considered the comparatively tedious, yet sensitive mixing of pow-

der and liquid a feature that could be improved upon. A certain degree of familiarity with the

mixing technique certainly was of advantage in the past. For this reason, soon after first intro-

ducing Ketac Cem in the early 1980s, 3M ESPE followed up by introducing this product in

capsules (Aplicap

™

and Maxicap

™

) which make dosing and mixing a simple procedure that

reliably yields consistent qualities of material. However, a number of our customers still prefer

the variant for manual mixing, e.g. to be able to freely dose the material.

It is for this group of dentists that 3M ESPE developed the new material which combines the

features of Ketac Cem and the following added benefits:

• Improved wetting of the powder by the liquid rendering the mixing process much easier

and faster

• Reduced dust generation, e.g. during opening of the bottle and dosing and mixing on a

mixing pad

• Powder with improved free flowing properties affords better and more reproducible

dosing

Technological Background

The advantages described above could only be attained by 3M ESPE by developing and

establishing a novel and innovative powder technology. By application of a specialized pro-

cessing procedure, the primary filling body of the glass ionomer cement is modified such that

it can be processed into specialized granulates. Two micrographs of granulate particles are

shown in the Figures below. The granulates consist of an agglomerate of individual filling

bodies.

Fig. 19: Ketac

™

Cem Easymix granulate; 3M ESPE in-house photographs

The following figure shows the improved liquid adsorption properties of the new

Ketac

™

Cem Easymix powder as compared to its predecessor, Ketac

™

Cem radiopaque, and

other glass ionomer materials.

The user is sure to note another advantage of the material. The modified powder is clearly less

“dusty”. There is no longer any contamination of adjacent areas when the powder bottle is

opened or during dosing and mixing. This renders the application of the material in the dental

office even more hygienic. Rather than being a subjective observation alone, this effect can be

quantified with a dust measuring device like the DustView (Palas), in which the sample powder

falls through a vertical gravity tube to reach a dust reservoir. The dust formed upon impact

reduces the intensity of laser light transmitted over time. The device allows derivation of initial

dust values and also provides some information about the settling of the dust over time.

Figure 21 clearly shows Ketac Cem Easymix to possess superior properties as compared to

Ketac Cem radiopaque.

Fig. 20: Time course of liquid adsorption; S. Frank et al. (see Literature, p. 36)

Fig. 21: Analysis of dust measurements with the DustView (Palas); S. Frank et al.

(see Literature, p. 36)

Ketac

Cem

Easymix

Fuji

Ketac

Cem rp

Fuji

PLUS

RelyX

Luting

Measurements of the film thickness according to ISO 9917 show that the film thickness

yielded by Ketac Cem Easymix is at least as good or even lower than that of other conventional

cements.

In the ISO 9917 test the mixed cement is sandwiched between two glass plates and a pressure

of 150 N is applied after a certain amount of time – here after 20-30 sec.

Fig. 22: J. Powers, Industrial Report, “Film Thickness of Cements”, 2000

Film thickness according to ISO 9917*

Film thickness [µm]

*The bond was subjected to pressure stress 20-30 seconds after end of mixing time.

Harvard

Zement

Ketac

Cem rad

Ketac

Cem

Easymix

Fuji

Clinical Studies on Ketac

Cem

Even extensive testing in the laboratory never suffices to completely characterize a product for

in vivo application. The ultimate milestone must always be the test of the substance in clinical

use or clinical studies. Especially in the first years after glass ionomers were introduced and

became established, the materials had the reputation of increasing postoperative sensitivity. This

prompted several research groups to conduct controlled clinical studies of this aspect, many of

which involved the approach of direct, “split mouth” comparison with zinc phosphate cements.

Study director, Type of restoration Duration of the study

center location

Prof. Kern, Cementation of: Mean of 17.3 months of

Dr. Kleimeier, • crowns wear

Dr. Schaller, • partial crowns

Prof. Strub • bridges

Universität Freiburg

Prof. Johnson, Cementation of: 3 months

Dr. Powell, • crowns

Dr. DeRouen,

University of Washington

Prof. Bebermeyer, Short-term study Recall after 1 week

Dr. Berg, Cementation of:

University of Texas • crowns

• partial crowns

• onlays

Prof. Sorensen, Cementation of: 3 years

Dr. Kang, • 3-unit In-Ceram

Dr. Torres, • bridges

Dr. Knode,

University of Portland

Comparative Clinical Study of Ketac Cem and a Zinc

Phosphate Cement (University of Freiburg, Germany)

Patients with a need for two independent, comparable fixed metal or metal-ceramic restorations

were included in this randomized blind study conducted at the University of Freiburg,

Germany. One restoration each was cemented with Ketac

™

Cem Maxicap

™

or Phosphacap

™

The study aimed to compare the glass ionomer cement for automatic mixing, Ketac Cem

Maxicap, with a zinc phosphate cement under clinical conditions. Particular attention was

directed to the issue of postoperative sensitivity.

Study Design

A total of 60 patients between 20 and 70 years of age (mean age: 38.7 years) needing fitting

with at least two fixed restorations (crowns, partial crowns or dentures with crown abutment)

were included in the study. Overall, 60 restorations were randomly assigned to Ketac Cem

Maxicap or Phosphacap each and cemented using a split-mouth design. Follow-up was conduc-

ted after one month and in 6-month intervals thereafter. The clinical parameters evaluated inclu-

ded viability of the tooth, secondary caries, retention of the restoration, and development of

hypersensitivity.

Table 3: Overview of prospective clinical studies on Ketac

™

Cem (see Literature)

Results of the Study

The observation period varied between 1 and 33 months (mean: 17.3 months). More than

three-quarters of the patients were evaluated between 12 and 17 months after receiving the res-

torations, whereas only one-third was available for follow-up after 24 to 33 months. None of

the follow-ups showed any clinically significant differences between the two cement groups.

There was not a single case of loss of viability or need for endodontic treatment and none of

the restorations was lost. One case of secondary caries was detected in the zinc phosphate

group after 24 months.

Postoperative thermal hypersensitivity was observed in 9 of 60 patients during the first

5 months (7 teeth with glass ionomer, 6 teeth with zinc phosphate cement). All teeth had been

fitted with full crowns. Hypersensitivity subsided spontaneously in all cases. In the final

follow-up after 33 months, not a single case of thermal hypersensitivity was detected.

Summary

Cementation with glass ionomer versus zinc phosphate cement did not show any difference in

the incidence of postoperative sensitivity. This prompted the authors to recommend Ketac

™

Cem Maxicap

™

as a very good alternative to zinc phosphate cements, especially as the dosage

form of capsules provides for easy, reliable and convenient clinical handling of the substance.

Comparative Clinical Study of Ketac

Cem and a Zinc

Phosphate Cement (University of Washington)

Patients in need of management with a full crown who were treated by dental service providers

of the US Air Force and Navy were included in a randomized blind study monitored by resear-

chers from the University of Washington. The restoration was fixed with Ketac Cem or

Fleck’s

™

zinc phosphate cement. The aim of the study was to determine if there are differences

in the incidence of postoperative sensitivity after the use of Ketac Cem versus zinc phosphate

cement. Any differences were to be evaluated in relation to various clinical and technical

parameters.

Study Design

Of a total of 214 cemented crowns, 204 were followed up after 2 weeks and 185 crowns after

3 months. The crowns had been fixed with Ketac Cem (n=113) or Fleck’s zinc phosphate

cement (n=101) by a total of 10 dental service providers of the US Air Force or Navy.

Results of the Study

There were significantly more reports of postoperative sensitivity during the first two weeks in

the patients managed with zinc phosphate-fixed restorations as compared to the group with

Ketac Cem-cemented crowns. However, in the 3-month follow-up these differences in postope-

rative sensitivity were no longer detected. Both groups showed less sensitivity in the 3-month

follow-up than at baseline.

Summary

The authors concluded that there was no evidence of elevated postoperative sensitivity after

cementation with the glass ionomer, Ketac Cem, as compared to zinc phosphate cementing. In

addition, the authors found that the sensitivity may be reduced after cementing due to specific

properties of the material.

Clinical Short-Term Study Comparing Ketac Cem and a

Zinc Phosphate Cement (University of Texas)

Patients needing two independent, comparable crowns or partial crowns were included in a

short-term study conducted at the University of Texas (Houston). It was the aim of the study to

determine the patient-reported differences in postoperative sensitivity during the initial phase

after crowns had been fixed with zinc phosphate or Ketac Cem cement.

Study Design

A total of 51 patients needing at least two comparable crowns or partial crowns were included

in this prospective, randomized blind study with split-mouth design. The study was conducted

on the population treated in the clinical student teaching course at the University of Texas.

Forty-five patients were available for follow-up after 1 week. All patients completed a compre-

hensive questionnaire that included both open answers and rating scales. The patients were

asked to rate the degree of sensitivity of the two restorations using an numeric scale with scores

ranging from 1 to 5. The open questions served to provide a more detailed description of the

sensitivities (e.g. chronic vs. transient pain, temperature sensitivity, etc).

Results of the Study

No differences in the postoperative sensitivity between the glass ionomer and the zinc phospha-

te groups were detected. Four patients reported strong pain in a tooth managed with glass iono-

mer, while three patients of the zinc phosphate group reported strong sensitivity. None of the

restorations needed to be replaced or reworked later on.

Summary

This study detected no differences in the incidence or severity of postoperative sensitivity after

cementation with glass ionomer versus zinc phosphate cement.

Clinical Study of the Long-Term Success of In-Ceram

Bridges (University of Portland)

Patients with at least 20 residual teeth and needing at least a 3-unit bridge were included in

this prospective long-term study conducted at the University of Portland. The study aimed to

evaluate the extension of indications of In-Ceram bridges to premolar and molar restorations.

Cementing was performed by a conventional technique using Ketac

™

Cem Aplicap

™

Study Design

A total of 61 three-unit bridges were fixed in 47 patients between the ages of 19 and 66 years.

One third each of the bridges had the bridge connector at the front teeth, premolars, and

molars, respectively. As one requirement, the opposite teeth of bridge units had to be natural

teeth or fixed restorations. The manufacturer-recommended indication of In-Ceram bridges was

deliberately extended under close control. The restorations were not fixed by adhesive forces,

but rather attached conventionally using Ketac Cem glass ionomer cement.

Results of the Study

None of the restorations fixed according to the study protocol gave rise to postoperative sensiti-

vity. None of the stumps had to be subjected to endodontic follow-up treatment prior to the

3-year follow up. Seven of the fixed restorations showed total fracture with none of the fractu-

res manifesting at the frontal teeth, which are included in the indications recommended by the

manufacturer. Eleven percent of the fractures occurred in premolar connectors and 24% in res-

torations of molar teeth.

Summary

From the results of this study, it can be concluded that Ketac Cem is suitable for use in the

cementation of In-Ceram restorations.

Instructions For Use

ESPE

Ketac

Cem Easymix

Product Description

Ketac Cem Easymix is a fixing cement for mixing by hand.

For details on 3M

™

ESPE

™

Alkaliner

™

please refer to corresponding information for use. The

information for use on the product concerned must be kept available for the length of time it is

employed.

Indication

• Cementation of inlays, onlays, crowns, and bridges made from metal or metal-ceramics

or covered with composite veneer material

• Cementation of inlays, onlays, crowns, and bridges made from composite or ceramics

provided these are suitable for conventional cementing

• Cementation of posts and screws provided these are suitable for conventional cementing

• Luting cement for use on orthodontic bands

• Relinings

Preparation

For maximum possible adhesion, enamel, dentine and metal surfaces must be given a careful

cleaning and dried. Avoid excessive drying!

Pulp Protection

The glass ionomer cement must not be applied directly to dentin – e.g. on inlays – situated

close to the pulp or to the exposed pulp. Prior to taking the impression, cover areas close to the

pulp using a hard-setting calcium hydroxide preparation, e.g. 3M ESPE Alkaliner.

Dosage

Shake bottle to loosen powder. Screw off cap and replace by dispensing dropper. For cementing

work, the standard powder-to-liquid mixing ratio is 3.8 : 1 w/w, this corresponding to 1 level

spoonful of powder to two drops of liquid. Skim off spoon on plastic segment. Do not com-

press the powder.

Dose powder and liquid next to each other on a mixing pad or glass slab. Keep bottle upright

while dispensing. Crystallized liquid must not be allowed to form on the dispensing dropper.

For relinings more powder may be added according to the desired consistency. Carefully seal

bottles after use.

If the mix is too thin (due to insufficient dosing of powder) this may produce symptoms of

pulpitis.

Mixing

Working of Ketac

™

Cem Easymix should proceed at a room temperature of 20-25°C.

Mix using a metal or plastic cement spatula. Add the powder to the liquid in one portion. On

principle a sufficient quantity of powder should be added to the liquid to produce viscid consis-

tency. The quantity of cement required for a crown should just about drip from the spatula.

Continue to smooth out the paste until a homogeneous mixture is obtained.

Application

During application, water and saliva must be prevented from entering the working area. Apply

a thin coat of cement to the inside of the crown and stump. Afterwards proceed with restora-

tion. Avoid overfilling the crown.

Applying hydrostatic pressure buildup in closely adjoining crowns may cause pulp discomfort.

Times

The following time scale applies at a room temperature of 23°C and 50% relative atmospheric

humidity:

min:sec

Mixing 0:30

Application incl. mixing 3:10

Setting from begin of mix 7:00

Higher temperatures shorten the working time, whereas lower temperatures will extend this

period (e.g. mixing on a cooled glass slab). A higher amount of powder also brings about a

shorter working time. Exceeding the working time causes loss of adhesion to enamel and

dentine.

Removal of Excess

Remove excess using a Heidemann spatula and/or probe 6-8 min. after beginning of mix.

Incompatibilities

The product may cause allergic reactions to sensitive persons. If such reactions are experienced,

discontinue the use of the product. Pulp complaints may be experienced in rare cases, in parti-

cular where working instructions are not properly observed.

Storage and Shelf Life

Keep the powder in a dry place away from damp.

Carefully reseal the powder bottle after each use.

Do not store the product above 25°C.

Do not use after the expiry date.

Questions & Answers

Question:

Ketac

™

Cem was inadvertently mixed with water. Do I have to remove a restoration that was

fixed despite this mishap?

Answer:

The liquid of Ketac Cem contains water and tartaric acid, and benzoic acid as a conservation

agent. The role of tartaric acid is to provide for optimal setting properties and increase the stabi-

lity by 10%. However, if the restoration has been fixed in the proper place, the setting proper-

ties are no longer of concern. A 10% decrease in stability can be tolerated provided there are no

other complications.

However, as a matter of principle Ketac Cem should not be prepared by mixing with water.

Question:

Is it possible or advisable to fix full-ceramic crowns with Ketac Cem?

Answer:

This answer depends on the ceramic material used.

Available materials:

• Glass ceramic

• Zirconium oxide or aluminum oxide ceramic

Due to the low inherent stability of glass ceramics, the teeth and restorations made from these

materials need to be stabilized by formation of an adhesive bond. This bond cannot be gene-

rated with Ketac Cem or other glass ionomer cements, but requires the use of a composite

luting material and application of the total-etch technique. Moreover, it is advisable to coat the

inside of the ceramic crown according to the Rocatec procedure and follow this step up by

silanizing with 3M

™

ESPE

™

Sil

™

. Fluoric acid etching and subsequent silanization is a

suitable alternative. Both procedures provide for optimal bonding between the tooth structure,

the luting material, and the indirect restoration.

The inherent strength of the so-called high-strength ceramic materials, such as aluminum

oxide and zirconium oxide, is sufficient for conventional cementation, i.e. Ketac Cem can be

used with this type of material. Please check the manufacturer recommendation to find out

whether the ceramic material in question is approved for this type of cementation by the manu-

facturer.

Initial etching with fluoric acid is not possible in this application. For optimal conditioning of

the indirect restoration, use the Rocatec silicatization procedure with ensuing silanization.

Question:

How much material do Ketac Cem capsules contain?

Answer:

Product Net mass Dispensable quantity

Ketac

™

Cem Aplicap

™

260 mg 0.07 ml

Ketac

™

Cem Maxicap

™

1060 mg 0.36 ml

Question:

How can I distinguish the accessories of Aplicap

™

and Maxicap

™

products?

Answer:

The accessories for processing of Aplicap products are color-coded in orange.

To be distinguishable, the accessories for processing of Maxicap products are color-coded in

blue.

Summary

Cementation is an essential step in the management of patients with indirect restorations. The

requirements on both the handling and material properties of the substances used for cementa-

tion are high.

Ketac

™

Cem has been on the market since the 1980s and has demonstrated its utility in mil-

lions of uses in clinical practice. Moreover, Ketac Cem has been the subject of extensive scien-

tific studies and often has been described in the literature as the “Gold Standard” for conven-

tional cementation.

Ketac Cem is both easy and convenient to use. The capsule version of the product provides a

pre-dosed dosage form for automatic mixing which effectively prevents dosing and mixing

errors. However, manual dosing and mixing has also become much more convenient since the

introduction of Ketac

™

Cem Easymix. Additional beneficial features of the material simplify-

ing the clinical handling include the consistency of the material, which provides for both

stabi-lity and free-flowing properties, and the ease with which any excess material can be

removed.

As was outlined above, Ketac Cem has been extensively investigated in scientific studies cove-

ring all essential requirements.

The high level of biocompatibility accompanied by good marginal sealing properties, low

solubility, and high resistance to mechanical stress are features assuring long-term clinical

success. Due to its high dimensional stability, Ketac Cem protects the pulp from hydrostatic

pressure as the result of which Ketac Cem is a simple and user-friendly cementation material

that can also be used with high-strength ceramic materials. Especially in comparison to the zinc

phosphate cements, the inherent adhesive properties of this glass ionomer cement, which

afford bonding to the tooth structure and metal parts, is a great advantage. It goes without

saying that the thin films of the material allow for ideal fitting of indirect restorations.

The extraordinary clinical utility of Ketac Cem has been demonstrated not only in material

science studies, but also in clinical investigations. A selection of these studies has been dis-

cussed before.

Literature

Literature on Ketac

Cem

Th.A. Zumstein, J.R. Strub,

Zementhaftung (Cement bonding), Schweiz. Mschr. Zahnheilk. 1981, 91 (4), 196-205.

The dependence of the adhesion properties of three cements on the dentin and metal pre-treat-

ment method was investigated. GICs showed higher bonding strength as compared to zinc

phosphate cements. The highest bonding strength for Ketac Cem was observed with untreated

dentin and sand-blasted gold.

Th. Zumstein, J.R. Strub,

Adhesion of Cement, Quintessence Int 1983, 14, 1-8.

H.W. Seeholzer, W. Dasch,

Befestigung von Bändern mit einem Glasionomerzement (Adaptation of bands with glass iono-

mer cement),

Informationen aus Orthodontie und Kieferorthopädie 1986, 18 (1); 89-96.

The use of bands always carries the risk of marginal gap formation and de-mineralization of

the enamel. Due to their good adhesion to metals and direct chemical bonding to dentin and

enamel, glass ionomer cements are suitable for use in banding. The restrictions imposed by the

relatively short processing time and moisture-sensitivity of the first setting phase of Ketac Cem

are well accounted for in the “two-step band adaptation” method.

H.W. Seeholzer, W. Dasch,

Banding with Glass Ionomer Cement, J. Clinical Orthodontics 1988, 12 (12).

1. Comparison of the material properties of Ketac Cem and phosphate cement.

2. Clinical study on orthodontic bands. Even in the absence of mechanical abrasion of the

bands, the use of Ketac Cem was associated with 19.7% fewer losses as compared to the

control group using zinc phosphate cement.

P. Grund,W.H.-M. Raab,

Zur Pulpatoxizität der Säurekomponente von Befestigungszementen (On the pulpal toxicity of

acid components of luting cements),

Dtsch. Zahnärztl. Z. 1990, 45 (9).

Laser-Doppler flow measurements were used to determine changes of the microcircula-

tion of the pulp effected by 33% phosphoric acid, Ketac Cem liquid, and a 35% solution

of the acrylic-maleic acid copolymer of Ketac Cem powder. The results of the study allow

to conclude that the free acid components of Ketac Cem show lower pulpal toxicity as

compared to Tenet (H

B. Kleimeier, H.G. Schaller, M. Kern, J.R. Strub,

Is the Glass-Ionomer Luting Cement an Alternative to Zincoxyphosphate Cement?,

IADR meeting 1991, Acapulco.

No clinical difference between zinc phosphate and Ketac Cem was detected in the 1-year-

recall. There was no evidence for the commonly held view that GICs generate higher postope-

rative sensitivity than zinc phosphate cement.

F. Rezk-Lega, B. Øgaard, J.Arends,

An in vivo study on the merits of two glass ionomers for the cementation of orthodontic bands,

Am J Orthod Dentofac Orthop 1991, 99, 162-167.

It was shown in this in-vivo study on orthodontic bands that GICs may reduce the enamel

demineralization. Ketac Cem showed significantly better results than Aqua Cem

™

G.H. Johnson, L.V. Powell, T.A. DeRouen,

Pulpal Sensitivity from Zinc Phosphate and Glass Ionomer Cements Following Crown

Cementation,

IADR Meeting, Glasgow, 1992.

S.N. White, J.A. Sorensen, S.K.Kang, A.A. Caputo,

Microleakage of new crown and fixed partial denture luting agents,

J. Prosth. Dent. 1992, 67 (2), 156-161.

Determination of the degree of microleakage in cast crowns following cementation with poly-

carboxylate, zinc phosphate, glass ionomer, and composite cements. Ketac Cem was second

best only to the composite cements.

M. Kern, H.-G. Schaller, J.R. Strub,

Microleakage of new crown and fixed partial denture luting agents,

J. Prosth. Dent. 1992, 67 (2), 156-161.

G.H. Johnson, L.V. Powell, T.A. DeRouen,

Evaluation and Control of Postcementation Pulpal Sensitivity: Zinc Phosphate and Glass

Ionomer Luting Cements,

JADA 1993, 124, 39-46.

After being in situ for two weeks, the zinc phosphate cement group showed significantly more

frequent postoperative complaints than the Ketac Cem group.

A. Patyk, M. Hülsmann, S. Rinke,

Untersuchung zur Partikelgröße zahnärztlicher Befestigungszemente (Determination of the par-

ticle size of dental luting materials),

Dtsch Zahnärztl Z 1993, 48, 372-375.

The particle size distribution of 6 different dental luting materials was compared. In this study,

the glass polyalkenoate cements showed a more favorable particle size distribution as compa-

red to carboxylate cements. However, the most favorable maximal particle size (20 µm) and

particle size distribution was detected in the glass polyalkenoate cement, Ketac Cem.

S.R. Curtis, M.W. Richards, J.C. Meiers,

Early Erosion of Glass-Ionomer Cement at Crown Margins,

Int J. Prostodontics 1993, 6 (6), 553-557.

Ketac Cem must be protected from moisture for approx. 10 min. Once the excess material is

removed, the material needs no further protection, e.g. by application of Ketac

™

Glaze. Zinc

phosphate cements are more sensitive to moisture than GICs.

R.D. Berbermeyer, J.H. Berg,

Comparison of patient-perceived post cementation sensitivity with glass-ionomer and zinc

phosphate cements,

Quintessence Int 1994, 25 (3), 209-214.

Randomized, split-mouth design study on partial and full gold crowns. Both phosphate cement

and Ketac

™

Cem were evaluated. One week postoperatively, the patients were interviewed with

a questionnaire regarding their experience with postoperative complications. No differences

between the study groups were detected.

J.M. Strutz, S.N. White, Z. Yu, C.L. Kane,

Luting cement-metal surface physicochemical interactions on film thickness,

J. Prosth. Dent. 1994, 72 (2), 128-132.

The results regarding the film thickness determined in this study showed the glass ionomer

cement, Ketac Cem, to generate the thinnest films with all types of metal. The observed differen-

ces were significant.

D.B. Mendoza,W.S. Eakle,

Retention of posts cemented with various dentinal bonding cements,

J. Prosth. Dent. 1994, 72 (6), 591-594.

Second only to C&B Metabond

™

, Ketac Cem attained the highest bonding strength of all

cements in the cementation of endodontic posts. The results were superior even to those of the

composite materials, Panavia

™

and All-Bond

™

2. The fact that the glass ionomer cement is also

easier to process further emphasizes the advantages of Ketac Cem in this indication.

G. Morando, R.J. Leupold, J.C. Meiers,

Measurement of hydrostatic pressures during simulated post cementation,

J. Prosth. Dent. 1995, 74 (6), 586-590.

Strong pressure during the cementation of intracoronal posts may induce root fractures.

However, reduced pressure often causes the post to be improperly seated. In a simulated in-

vitro study, the use of Ketac Cem generated the lowest pressure during the cementation of gold

posts.

D.T. Millett, J.F. McCabe, T.G. Bennett, N.E. Carter, P.H. Gordon,

The Effect of Sandblasting on the Retention of First Molar Orthodontic Bands cemented with

Glass Ionomer Cement, Br. J. Orthodontics 1995, 22, 161-169.

In-vivo (split-mouth) and in-vitro application of Ketac Cem.

T. Morneburg, A. Schulz,

Zum Einfluss der Sealer auf die Retention unterschiedlicher Stiftimplantate im Wurzelkanal

(On the influence of sealers on the retention of different post implants in the root canal),

Zahnärztl Implantol 1995, 11, 105-110.

Fixation of post implants in the root canal (transfixation). Ketac

™

Cem and Harvard

™

cement

are recommended as suitable materials for practical use.

M. Kern, B. Kleimeier, H.-G. Schaller, J.R. Strub,

Clinical comparison of postoperative sensitivity for a glass ionomer and a zinc phosphate luting

cement, J. Prosth. Dent. 1996, 75 (2), 159-162.

The recall after 17.3 months revealed no clinical difference between zinc phosphate and

Ketac Cem. There was no evidence whatsoever supporting the commonly held view that GICs

gene-rate higher postoperative sensitivity. The study investigated single crowns, partial crowns,

and crowns being components of fixed restorations.

Y. Gömeç, I. Duman,

Bond Strengths of Different Casting Inlay Alloy-Luting Cement Systems,

IADR / CED meeting, 1996, Berlin.

Ketac Cem showed higher bonding strength with various metal alloys as compared to polycar-

boxylate or zinc phosphate cement.

C.-P. Ernst, N. Wenzl, B. Willershausen,

Adhesive strength of a new compomer cement, IADR/CED meeting, Berlin, 1996.

Bonding is the essential feature determining the clinical success of cemented gold crowns and

depends both on the preparation and the type of cement used. Ketac Cem and Dyract

™

Cem

yielded significantly better results than F21.

M. Augthun,

Erfassung der zellwachstumsbeeinflussenden Wirkung von Ketac Cem,

Unveröffentlichte Ergebnisse: Forschungsbericht Klinik für Zahnärztliche Prothetik Aachen

(Determination of the effects of Ketac Cem on cellular growth; unpublished results:

A Research Report), 1996.

Conducted in accordance with EN 30993-5, this investigation applied cell culture methods and

led to Ketac Cem being classified as a biocompatible material. The cell culture tests showed

little or no effect of the substance on cell growth. The tested sample was well tolerated by (i.e.

acceptable to) the cells. Taking the in vivo conditions into consideration (flow of saliva), the

low inhibitory effect after a short setting time was classified as negligible. The number of sam-

ples investigated and the testing methods went beyond the requirements of the standards and

thus provide a valid result.

Permanent Cements,

The Dental Advisor 1997, 14 (2), 1-8.

Clinical Rating of Ketac

™

Cem Maxicap

™

and Ketac

™

Cem radiopaque.

B.K. Norling, J.O. Burgess, J.M. Powers, H.L. Cardenas,

Immersion and Jet Erosion Solubilities of Fluoride Releasing Cements,

J. Dent. Res. 1997, 76 (IADR Abstracts) 210.

Ketac

™

Cem showed low solubility in both tests of this study.

Teilkrone Zahn 16, MOD-Inlay Zahn 17,Anwenderbericht,

Partial crown 16, MOD inlay 17, User Report) Dental Magazin 1998, 3.

Case report describing fixation of two cast fillings with Ketac

™

Cem Aplicap

™

Ketac Cem Maxicap,

The Dental Advisor 1998, 15 (2), 6.

4 1/2 star rating after clinical application of more than 500 cementations.

T.J. Gillgrass, D.T. Millett, S.L. Creanor,

In Vitro Assessment of Microleakage for Two Orthodontic Band Cements,

IADR meeting, Nice, 1998, Abstract # 1416.

The microleakage properties of orthodontic bands after cementation were investigated.

T.A. Örtendahl, B. Thilander,

Use of glass-ionomers for bracket bonding - an ex in vivo study evaluating a testing device for

in vivo purposes,

European Journal of Orthodontics 1998, 20, 201-208.

GICs for condensation polymerization (including Ketac Cem) are suitable materials for ortho-

dontic applications. It is sufficient to pretreat to the degree recommended by the manufacturer:

additional measures afford no improvement in the bonding to the tooth structure.

J.A. Sorensen, S.-K. Kang, T.J. Torres, H. Knode,

In-Ceram Fixed Partial Dentures: Three-Year Clinical Trial Results,

CDA Journal 1998, 26 (3), 207-214.

3-year recall of 3-unit In-Ceram

™

bridges. All restorations had been fixed with Ketac Cem: no

postoperative sensitivity was observed and no endodontic follow-up treatment was required.

Ketac Cem can be recommended for the cementation of In-Ceram-fixed partial dentures.

R.C.S. Chen, L.R. Chiou, K.H. Chen,

Cytotoxicity of Resin-modified Glass Ionomer Cements,

IADR meeting, Nice, 1998, Abstract #1441.

Ketac Cem showed no cytotoxity and was identical to the negative control.

C.-P. Ernst, N. Wenzl, E. Stender, B. Willershausen,

Retentive strengths of cast gold crowns using glass ionomer, compomer, resin cement, J.

Prosth. Dent. 1998, 79 (4), 472-476.

Dyract

™

Cem and Ketac Cem showed better retention than F21.

K.-P. Stefan,

Early solubility of glass ionomer cements,

IADR meeting, Nice, 1998, Abstract # 454.

It is customary to measure the solubility of GICs at a time long after setting is complete

(1 h pursuant to ISO 7489; 24 h pursuant to ISO 9917). However, this fails to adequately

reflect the in vivo situation characterized by early exposure to saliva. This study reports the

solubility values of GICs after 10 and 60 min.

K. Thedens,

Prothetik-Zyklus ‘98 - ‘99; Ein Fallbeispiel aus dem zahnärztlichen Praxisalltag; Teil 3: Die

provisorische und definitive Eingliederung (A case report from common dental practice; part 3:

temporary and permanent fixation),

Zahnarzt Magazin 1999, 1.

Fixation of temporary restorations and permanent management with cast inlays.

H. Lammers,

Von der Vorabformung bis zur definitiven Befestigung,

Quadranten-Sanierung mit System (From impression taking to permanent management: syste-

matic quadrant regeneration), Dental Spiegel 1999, 4.

Quadrant regeneration (tooth 14 and 15) with In-Ceram

™

ceramics and management of tooth

16 and 17 with high gold content, palladium-free partial crowns.

Z.C. Li, S.N.White,

Mechanical properties of dental luting cements,

J. Prosth. Dent. 1999, 81, 597-609.

Current overview of classes of materials and investigations of materials science. GICs were

convincing mainly because of the low tendency to form marginal gaps and good crown reten-

tion.

G. Eickemeyer, P. Rammelsberg, P. Pospiech, W. Gernet,

In-vitro study of fracture resistance of metal-free Artglass crowns,

J. Dent. Res. 1999, 78, 158. (IADR meeting 1999, Vancouver, Abstract # 421)

The fracture resistance of Artglass crowns after thermocycling was significantly better with the

adhesive technique or Ketac

™

Cem as compared to Zinc phosphate cement.

M. Rosin, M. Wilkens,A. Welk, C. Splieth, G. Meyer,

Effect of cement type on retention of a prefabricated tapered post,

CED Meeting, Montpellier, 1999.

Cementation of Perma-tex with four different cements and determination of the retention after

storage in water, plus thermocycling, plus exposure to mechanical stress. Stored in water and

exposed to stress, Ketac Cem showed a clear increase of the retention values which may be

explained by the often described ageing of glass ionomer cements.

J.M. Casanellas, J.L. Navarro, A. Espias, X. Gil,

Retention of a cylindroconical post comparing various cements,

IADR/CED meeting, Madrid, 1999, Abstract # 421.

Ketac

™

Cem yielded the most favorable results in the cementation of metal posts.

M. Martin, C.-P. Ernst, B. Willershausen,

Ketac Cem: Eine Literaturübersicht (A literature overview),

ZWR 2000, 109 (7/8), 388-391. ZWR 2000, 109 (9), 475-481.

Short overview of/about cement classes. Literatur overview of in-vitro and in-vivo results

on Ketac

™

Cem.

S. Frank, J. Glaser, H. Nirschl, G. Rackelmann, K.-P. Stefan,

Dust formation and wettability of glass ionomer powders,

AADR meeting, Chicago, 2001, Abstract # 1303.

Due to its exellent wettability and reduced tendency to generate dust, Ketac

™

Cem Easymix

represents a clear improvement in terms of the handling of glass ionomer cements for manual

mixing.

B. Windmüller, M. Ferrari,

Influence of Conventional Luting Materials on Leakage of Gold Crowns,

IADR meeting, Chiba, 2001, Abstract # 1862.

Ketac

™

Cem radiopaque and Ketac Cem Easymix showed less dye penetration than the other

materials tested, Fuji I

™

and Harvard

™

Zinc phosphate cement.

R. Frankenberger, H. Oberschachtsiek,A. Teubner, N. Krämer,

Retentive Strengths of Cast Gold Inlays Luted with Different Cements,

IADR / CED meeting, Rom, 2001, Abstract # 344.

Ketac Cem radiopaque, Ketac Cem Easymix, and RelyX

™

Luting showed significantly higher

retention values than Harvard

™

cement.

General Literature

A.D.Wilson, J.W. McLean,

Glasionomerzement (Glass Ionomer Cement), Quintessenz, Berlin, 1988.

Textbook.

Ed. W. F. Wathen,

The glass ionomer cement, JADA 1990, 120, 19-68. Theme issue

Including:

D. C. Smith,

Composition and characteristics of glass ionomer cements,

JADA 1990, 120, 20-22.

GICs are suitable for use in filling, lining, fixation, and prophylactic applications. The proper-

ties of the material are dominated by factors like composition, processing, and application. In

general, being stable and strong materials that bond to the tooth structure, GICs may show a

low degree of toxicity and potentially have an anti-cariogenic effect.

G.J. Christensen,

Glass ionomer as a luting material, JADA 1990, 120, 59-62.

Cariostatic activity, dimensional stability (expansion and shrinking), material properties, such

as strength and E-modulus, bonding to the tooth structure, flow properties, lowest solubility of

all cements.

H. Schuh,

Glasionomerzemente - Entwicklung und Tendenzen (Teil 1) (Glass Ionomer Cements -

Development and Trends (Part 1)), Zahnarzt Magazin 1993, 1.

Chemical function of a glass ionomer and resin-modified glass ionomer cement.

S.F. Rosenstiel, M.F. Land, B.J. Crispin,

Dental luting agents: A review of current literature,

J. Prosth. Dent. 1998, 80 (3), 280-301.

Overview of the current literature on dental luting cements.

A.M. Diaz-Arnold, M.A.Vargas, D.R. Haselton,

Current status of luting agents for fixed prosthodontics,

J. Prosth. Dent. 1999, 81 (2), 135-141.

Review of 5 classes of luting materials with an emphasis on the advantages and disadvantages

and indications.

C.L. Davidson, I.A. Mjör,

Advances in Glass-Ionomer Cements, Quintessence, Chicago, 1999.

Textbook.

K. Stefan in,

Ullmann’s Encyclopedia of Industrial Chemistry, Dental Materials

(Chapter: cements), Electronic Release, Wiley, 2000.

Overview of the classes of materials including history, chemistry, and benefits.

Technical Data

3M ESPE in-house measurements according to ISO standards

Film Setting Compressive Surface Flexural Radio-

Test: thickness time strength hardness strength opacity

Test methods. ISO 9917 ISO 9917 ISO 9917 DIN 53456 ISO 4049 ISO 4049

Limit: <25 µm 2:00 - 6:00 >70 MPa

Measure unit: µm min:sec MPa MPa MPa %

Ketac

Cem radiopaque

3M ESPE 18 ± 1 03:45 140 ± 14 207 ± 15 12 ± 5 152

# 0064075 (1:30)

Ketac

Cem Easymix

3M ESPE 17 ± 2 03:00 141 ± 14 235 ± 25 15 ± 5 n.d.

# USA-G301

Ketac

Cem Aplicap

3M ESPE 16 ± 1 03:10 157 ± 8 206 ± 24 20 ± 10 230

# 0024

Ketac

Cem Maxicap

3M ESPE 16 ± 1 03:00 109 ± 17 252 ± 16 21 ± 7 230

# 0033

Harvard

Cement

Richter & Hoffmann

Shade: yellow 22 ± 1 07:00 115 ± 10 218 ± 14 15 ± 1 563

# 2112400007 / 2111000009

Fuji I

GC 22 ± 1 03:15 164 ± 18 209 ± 17 8 ± 1 180

# 9905251

Fuji

Luting

Shade: yellow 10 ± 1 03:15 101 ± 9 124 ± 4 11 ± 1 n.d.

# 0003261

Particle size distribution

Mean particle size Maximum

(d50) [µm] (>98%) [µm]

Ketac

Fil Plus 6 - 7 42

Ketac

Cem radiopaque ca. 2,5 12

Ketac Cem Aplicap ca. 2,5 12

Ketac Cem Maxicap ca. 2,5 12

Ketac Cem Easymix ca. 2,5 12

70200947649/03(10.2004)

The charts in this Technical Product Profile

were reproduced by 3M ESPE from data

listed in the cited sources.

3M, ESPE, Alkaliner, Aplicap, Ketac, Maxicap,

Photac, Rocatec and Vitrebond are trademarks

of 3M or 3M ESPE AG.

Advance is a trademark of Caulk/Dentsply.

All-Bond is a trademark of Bisco, Inc.

Empress, Phosphacap and Targis-Vectris are

trademarks of Ivoclar-Vivadent, Inc.

Fuji II and Fuji LC are trademarks of GC Corp.

Harvard is a trademark of Harvard Dental

GmbH.

In-Ceram is a trademark of VITA Zahnfabrik.

Metabond is a trademark of Parkell, Inc.

Panavia is a trademark of Kuraray Co., Ltd.

Procera is a trademark of Nobel Biocare

Holding AG.

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