The Evaluation of Bond Strength of a Composite and aCompomer to White Mineral Trioxide Aggregate with TwoDifferent Bonding SystemsEmine Sen Tunç, DDS, PhD,* Isıl Saroglu Sönmez, DDS, PhD,† Sule Bayrak, DDS, PhD,* andTürkan Egilmez, DDS*

Abstract

The purpose of this study was to evaluate the bondstrength of a resin composite and a polyacid modifiedcomposite or “compomer” to white mineral trioxideaggregate (WMTA) with two different bonding systems(total-etch one bottle and self-etch one step). Fortyspecimens of WMTA were prepared and divided intofour groups. In group one, Single Bond (3M/ESPE, StPaul, MN) and Z250 (3M/ESPE) were placed overWMTA. In group two, Prompt L-Pop (3M Dental Prod-ucts, St Paul, MN) and Z250 were applied. In groupthree, Single Bond was applied with Dyract AP(Dentsply DeTrey, Konstanz, Germany), and, in groupfour, Prompt L-Pop was applied with Dyract AP. Theshear bond strength was measured, and the fracturedsurfaces were examined. The results of the shear bondstrength tests were analyzed by one-way analysis ofvariance test. The results of this study have suggestedthat the total-etch one-bottle adhesive system medi-ated a stronger bond to WMTA for both the resincomposite and the compomer investigated. The place-ment of composite (Z250) and compomer materials(Dyract AP), used with total-etch one-bottle adhesive(Single Bond), over WMTA as final restoration may beappropriate. (J Endod 2008;34:603–605)

Key Words

Compomer, composite resin, shear bond strength,white mineral trioxide aggregate

Mineral trioxide aggregate (MTA) is a biocompatible material with numerous ex-citing clinical applications in endodontics (1-3). MTA is a powder consisting of

fine hydrophilic particles of tricalcium aluminate, tricalcium silicate, and tricalciumoxide. It also contains small amounts of othermineral oxides, whichmodify its chemicaland physical properties (4, 5). In the presence of moisture, MTA sets into a hard massby forming calcium hydroxide and silicate hydrate gel (6). It is available commerciallyas ProRoot MTA (Dentsply; Tulsa Dental, Tulsa, OK) and has been proposed as apotential material for furcation repair, internal resorption treatment, pulpotomy pro-cedures, and capping of pulps with reversible pulpitis (2, 4, 7–12).

As the use of MTA in vital pulp therapy has gained popularity, the material thatwould be placed over MTA as final restoration is an important matter. The potential ofrestorative materials to attach to MTA is not well known. Until the initiation of this study,there were no published reports documenting the bond strength between MTA andrestorative materials. The aim of this study was to measure the bond strength of afrequently used resin composite (Z250; 3M/ESPE, St Paul, MN) and a polyacidmodifiedcomposite resin or “compomer” (Dyract AP; Dentsply DeTrey, Konstanz, Germany)when bonded to white MTA (WMTA) with two different bonding systems (one bottletotal etch and one step self-etch).

Materials and MethodsForty specimens of WMTA (Dentsply, Tulsa Dental) were prepared by using cylin-

drical acryl blocks. The blocks had central hole measuring 4mm in diameter and 2mmin depth. WMTA was mixed according to the manufacturer’s instructions. The acrylicblocks were filled with WMTA and covered with a wet cotton pellet and temporary fillingmaterial (Cavit; ESPE America, Inc, Norristown, PA). Then, the specimens were storedat 37°C with 100% humidity for 48 hours to encourage setting. After the removal of thetemporary material, the WMTA surface was not rinsed or polished. Specimens weredivided into 4 groups of 10 specimens.

Group One

TheWMTA surface was etched for 15 seconds with 37.5% phosphoric acid etchinggel (Kerr, Karlsruhe, Germany), rinsed with water for 10 seconds, and excess water wasremoved by blotting with absorbent paper, leaving the surface visibly moist dried. SingleBond (3M/ESPE) was then applied in 2 consecutive coats, gently air dried with oil-freecompressed air from an air syringe for 5 seconds to evaporate the solvent (keepingthe air syringe 2 cm from the surface), and light cured for 10 seconds. Resin com-posite Z250 was applied into a cylindrical shaped plastic matrix with an internal diam-eter of 2 mm and height of 2 mm and then light cured with a light-emitting diodelight-curing unit (Elipar Freelight II, 3M ESPE)with the intensity at 1,200mV/cm2 for 20seconds.

Group Two

The WMTA surface was dried for 10 seconds (keeping the air syringe 2 cm fromthe surface) to ensure a dry surface. Prompt L-Pop (3M Dental Products, St Paul, MN)was applied with scrubbing for 15 seconds. Then, the surface was gently air dried with

From the *Department of Pediatric Dentistry, University ofOndokuz Mayıs, Samsun, Turkey; and †Department of PediatricDentistry, Faculty of Dentistry, University of Kırıkkale,Kırıkkale, Turkey.

Address requests for reprints to Dr Isıl Saroglu Sönmez,Kırıkkale Universitesi, Dis Hekimligi Fakültesi, Pedodonti ABD,Kırıkkale, Turkey. E-mail address: isilsaroglu@yahoo.com.0099-2399/$0 - see front matter

Copyright © 2008 by the American Association ofEndodontists.doi:10.1016/j.joen.2008.02.026

Basic Research—Technology

JOE — Volume 34, Number 5, May 2008 Evaluating Bond Strength of a Composite and a Compomer to MTA 603

an air syringe for 5 seconds and light cured for 10 seconds. Z250 wasapplied as in group one.

Group Three

The same procedures were performed as in group one, but com-pomer material Dyract AP was placed over Single Bond instead of Z250.

Group Four

The same procedures were performed as in group two, and DyractAP was placed over Prompt L-Pop.

The polymerized specimens were stored in 100% relative humidityat 37°C for 24 hours. For shear bond strength testing, the samples weresecured in a holder placed on the platen of the testing machine and thensheared with a knife-edge blade on a universal testing machine (LloydLRX; Lloyd Instruments, Fareham, Hants, UK) at a cross-head speed of1.0 mm/min. Shear bond strength in MPa was calculated from the peakload at failure divided by the specimen surface area.

The mean bond strengths of each group were compared by usingone-way analysis of variance. Significance was set at the 5% level. Posthoc comparisons were made by using the Scheffé test.

ResultsThe mean values and standard deviations of shear bond strengths

are given in Table 1. When the adhesive systems were compared, SingleBond presented significantly higher bond strength values than PromptL-Pop in both Z250 and Dyract AP groups (p 0.05).

When comparing the restorative materials, the difference betweenSingle Bond applied with Dyract AP (15.09 MPa) was not statisticallysignificant (p ! 0.05) from Single Bond applied with Z250 (13.22MPa). The lowest bond strength means was observed with Prompt L-Pop when applied with Dyract AP, and the difference between this groupand the other three groups was statistically significant (p 0.05).

DiscussionA clinical trial is the most valid way to evaluate the quality and

efficacy of adhesion of materials. However, long-term clinical trials aredifficult to perform (13). The most common method to evaluate adhe-sive properties of restorative materials is bond strength assessment.This has become a well-recognizedmethod to analyze an important partof the in vitro performance of materials (14, 15). So the shear bondstrength test has been used in this study to evaluate the adhesive prop-erties of WMTA to composite and compomer restorative materials.

The bond strength between two materials is of importance for thequality of the fillings. It has been estimated that bond strengths of 17 to20 MPa may be required to resist contraction forces sufficiently toproduce gap-free restoration margins (16, 17). Despite the improve-ments of compomer materials, the dentin bond strength of these mate-rials remains inferior to resin composites (18–20). In the presentstudy, the difference between the resin composite and compomer ma-terials was not significant (p! 0.05) when applied with the total-etchone bottle adhesive system (Single Bond). When used with the one stepself-etch adhesive system (Prompt L-Pop), compomer material showedsignificantly (p 0.05) lower bond strength values than the compositematerial.

Self-etch systems contain a simultaneously acidic and hydrophilicmonomer and do not need to be rinsed away after etching. By decreas-ing the time and steps required for placement, they have a simplifiedapplicationmethod and they are less technique sensitive (20, 21). How-ever there is controversy concerning the efficacy of self-etch systems.Some investigations show that they provide dentin bond strengths com-parable with those obtained with the total-etch technique (14, 22–24),whereas others have observed significantly lower bond strengths (25–28). In the present study, the total-etch one-bottle bonding system(Singlebond) showed significantly (p 0.05) higher bond strengths inboth composite and compomer materials compared with the one-stepself-etch bonding system (Prompt L-Pop) when bonded to WMTA. Thefollowing reasons have been advocated to account for the suboptimalperformance of self-etching primers: (1) the combination of acidichydrophilic and hydrophobic monomers into a single step may com-promise polymerization of the adhesive, (2) the inherent low strength ofthe adhesive polymer, and (3) the lower degree of polymerization of theresin monomer because of a major solvent/oxygen inhibition effectduring light activation of these materials (14). Also, one of the expla-nations of this low bond strength might be the incompatibility betweenthe adhesive and the restorative material.

The present results have shown that the total-etch one-bottle ad-hesive system (Single Bond) bonded to WMTA significantly morestrongly than the self-etch one-step adhesive system (Prompt L-Pop) inboth composite (Z250) and compomer (Dyract) materials. However,there are a number of different bonding materials, resin composites,and compomers available on the market. Because of the variations inthe composition of different dentin adhesives, resin composites, andcompomers, different results could be achieved. Further investigationswith different materials are required.

References1. Schwartz RS, Mauger M, Clement DJ, Walker WA. Mineral trioxide aggregate: a new

material for endodontics. J Am Dent Assoc 1999;130:967–75.2. Naik S, Hedge AH. Mineral trioxide aggregate as a pulpotomy agent in primary

molars: an in vivo study. J Indian Soc Pedod Prev Dent 2005;23:13–6.3. Oliveira MG, Xavier CB, Demarco FF, Pinheiro ALB, Costa AT, Pozza DH. Comparative

chemical study of MTA and portland cements. Braz Dent J 2007;18:3–7.4. Torabinejad M, Chivian N. Clinical applications of mineral trioxide aggregate. J

Endod 1999;25:197–205.5. Ferris DM, Baumgartner JC. Perforation repair comparing two types of mineral

trioxide aggregate. J Endod 2004;30:422–4.6. Camilleri J, Montesin FE, Brady K, Sweeney R, Curtis RV, Ford TR. The constitution of

mineral trioxide aggregate. Dent Mater 2005;21:297–303.7. Karabucak B, Li D, Lim J, Iqbal M. Vital pulp therapy with mineral trioxide aggregate.

Dent Traumatol 2005;21:240–3.8. Ford TR, Torabinejad M, Abedi HR, Bakland LK, Kariyawasam SP. Using mineral

trioxide aggregate as a pulp capping material. J Am Dent Assoc 1996;127:1491– 4.

9. Andelin WE, Shabahang S, Wrigth K, TorabinejadM. Identification of hard tissue afterexperimental pulp capping using dentin sialoprotein (DSP) as a marker. J Endod2003;29:646–50.

10. Sarı S, Sönmez D. Internal resorption treated with mineral trioxide aggregate in aprimary molar tooth: 18 month follow-up. J Endod 2006;32:69–71.

11. Witherspoon DE, Small JC, Harris GZ. Mineral trioxide aggregate pulpotomies. A caseof series outcomes assessment. J Am Dent Assoc 2006;137:610–8.

12. Tuna D, Olmez A. Clinical long-term evaluation of MTA as a direct pulp cappingmaterial in primary teeth. Int Endod J 2008;41:273–8.

13. Perdiago J, Lopes M. Dentin bonding questions for the newmillennium. J Adhes Dent1999;1:191–209.

14. Borges MAP, Matos IC, Dias KRHC. Influence of two self-etching primer systems onenamel adhesion. Braz Dent J 2007;18:113–8.

15. Souza-Zaroni WS, Seixas LC, Ciccone-Nogueira JC, Chimello DT, Palma-Dibb RG.Tensile bond strength of different adhesive systems to enamel and dentin. Braz DentJ 2007;18:124–8.

16. Davidson CL, Gee AJ, Feilzer A. The competition between the composite dentin bondstrength and the polymerization contraction stress. J Dent Res 1984;63:1396–9.

TABLE 1. Mean Shear Bond Strength Values

n 10 Single bond Prompt L-Pop

Z250 13.22a " 1.22 10.73b " 1.67Dyract 15.09a " 2.74 5.44c " 0.86

Groups identified by different superscript letters were significantly different at p 0.05.

Basic Research—Technology

604 Sen Tunç et al. JOE — Volume 34, Number 5, May 2008

17. Al-Sarheed MA. Evaluation of shear bond strength and SEM observation of all-in-oneself-etching primer used for bonding of fissure sealants. J Contemp Dent Pract2006;7:9–16.

18. Meyer JM, Cattani-Lorente MA, Dupuis V. Compomers: between glass-ionomer ce-ments and composites. Biomaterials 1998;19:529–39.

19. Schneider BT, Bauman MA, Watanabe LG, Marshall GW Jr. Dentin shear bondstrength of compomers and composites. Dent Mater 2000;16:15–9.

20. Al-Nahedh H, Ateyah N. Effect of different bonding conditions on the shear bondstrength of two compomers to bovine dentin. J Contemp Dent Pract 2006;7:9–16.

21. Kanca J. Improving bond strength through acid etching of dentin and bonding to wetdentin surfaces. J Am Dent Assoc 1992;123:35–43.

22. Arnold RW, Combe EC, Warford JH Jr. Bonding of stainless steel brackets toenamel with a new self-etching primer. Am J Orthod Dentofac Orthop 2002;122:274 – 6.

23. Cacciafesta V, Sfondrini MF, De Angelis M, Scribante A, Klersy C. Effect of water andsaliva contamination on shear bond strength of brackets bonded with conventional

hydrophilic and self-etching primers. Am J Orthod Dentofac Orthop 2003;123:633–40.

24. Dorminey JC, Dunn WJ, Taloumis LJ. Shear bond strength of orthodontic bracketsbonded with a modified 1-step etchant and primer technique. Am J Orthod DentofacOrthop 2003;124:410–3.

25. Bishara SE, VonWald L, Laffoon JF, Warren JJ. Effect of a self-etch primer/adhesive onthe shear bond strength of orthodontic brackets. Am J Orthod Dentofac Orthop2001;119:621–4.

26. Bishara SE, Ajlouni R, Laffoon JF, Warren JJ. Effect of a fluoride-releasing self-etchacidic primer on the shear bond strength of orthodontic brackets. Angle Orthod2002;72:199–202.

27. Yamada R, Hayakawa T, Kasai K. Effect of using self-etching primer for bondingorthodontic brackets. Angle Orthod 2002;72:558–64.

28. Zeppieri IL, Chung CH, Mante FK. Effect of saliva on shear bond strength of anorthodontic adhesive used with moisture-insensitive and self-etching primers. Am JOrthod Dentofac Orthop 2003;124:414–9.

Basic Research—Technology

JOE — Volume 34, Number 5, May 2008 Evaluating Bond Strength of a Composite and a Compomer to MTA 605