effect of differ bonding

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32 Journal of Restorative Dentistry / Vol - 2 / Issue - 1 / Jan-Apr 2014

Effect of different bonding techniques

on the bond strength of two differentfiber postsKanad Pala, Sezer Demirbua, Hasan nder Gm1, Soley Arslan, Yahya Orun Zorba

Departments of Restorative Dentistry and 1Prostodontics, Faculty of Dentistry, Erciyes University, Kayseri, Turkey

Address for correspondence: Dr. Yahya Orcun Zorba, Department of Restorative Dentistry, Faculty of Dentistry, Erciyes University, Kayseri, Turkey.E-mail: [email protected]

INTRODUCTION

It is suggested that, failure in root canal treatment is closerelated to nal restoration. Final restoration; must sealthe access cavity eectively that microorganisms cannot

enter the coronally, preserve radicular and coronal toothtissues and nal restoration must seem to be esthetic.[1]

In general, the remaining coronal tooth tissue atendodontically treated teeth is poor for a core restorationwithout using a post. Due to increasing demand for theesthetic restorations, clinicians may use ber posts in asingle visit, for the advantages of corrosion resistance,

esthetic appearance.[2]Previous studies concluded that,both ber posts had similar elasticity modulus of soundroot dentin and might distribute occlusal stresses moreevenly in the root dentin.[1,3,4]

Adhesive resin cements, which have an more closelymatch the elastic modulus with both the post anddentin, are commonly preferred to lute the post intoroot canal.[5] Selecting a correct luting procedure andadhesive technique for bonding posts to root dentine is ademanding issue. Previous studies have showed that the

Aim:The aim of this study was to investigate the effect of three different bonding techniques on the bond

strength of two different ber posts to root dentin with push out test. Materials and Methods:A totalof 30 extracted teeth were sectioned at the cementenamel junction using a diamond disc underwatercoolant to obtain 18 mm root length. All roots were treated endodontically and lled with sealer

and Guttapercha points. The roots were randomly divided into two groups according to chosen

post systems (Rebilda DC [VOCO, Cuxhaven, Germany] or UniCore [Ultradent, South Jordan, UT]).

Following preparation specimens were randomly divided into three subgroups of 3 teeth each. Luting of

the posts were completed with Rebilda DC (selfetch); BisCem (selfadhesive, Bisco, Schaumburg, IL)

DuoLink (etch and rinse Bisco). Specimens were transversally sectioned into 2 0.05 mm thick discs

and pushout test was performed. The data was analyzed statistically by using threeway ANOVA and

Tukey tests. Results:The bond strengths between ber posts and root dentin were affected by type ofresin cement and post (P< 0.05). Push out bond strengths of Rebilda groups was lower than UniCore

groups (P< 0.05). Push out bond strength of DuoLink and Rebilda DC cement groups were higher

than BisCem groups. There were no statistically differences between root region. Conclusion:It can

be concluded that, bond strength between ber post and root dentin affected by the using of differentpost and cement types. Selfadhesion techniques were showed lower bond strength than both selfetch

and etch and rinse techniques

Keywords:Adhesive cements, bonding techniques, ber post, pushout bond strength

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DOI:10.4103/23214619.129019

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ABSTRACT

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Pala, et al.: Effects of different bonding techniques on ber post bond strength

Journal of Restorative Dentistry / Vol - 2 / Issue - 1 / Jan-Apr 2014 33

1.25% NaOCl solution was used for irrigation afterevery change of instrument and lubricant (Glyde FilePrep; Dentsply, MontignyleBretonneux, France) wasused throughout the shaping and cleaning of the rootcanal. Shaping was completed with a size F3 le at theworking length. Finally, the canals were rinsed with 17%ethylenediaminetetraacetic acid and distilled water for

removing the smear layer and dried with paper points.The roots were lled with sealer (MMSeal, Micro Mega,Besancon, France) and Guapercha points (DiadentGuttaPercha Points, DiaDent Group International,Chongju, Korea) by using the cold lateral condensationtechnique with a nger spreader (MANI, Tochigi, Japan).After root canal treatment was completed, roots werestored at 100% humidity at 37C (EN 032, Nve, stanbul,Turkey) for 7 days to allow the sealer to set.

The roots randomly divided into two groups regarding topost systems (Rebilda DC [VOCO, Cuxhaven, Germany]or UniCore [Ultradent, South Jordan, UT]). The post

holes were prepared with their own drills Rebilda DCor UniCore, up to a xed depth of 12 mm [Figure 1].1.25% NaOCl solution was used after preparationof the root canals and distilled water was used forfinal flushing. The canals were dried with paperpoints. The samples were randomly divided into threesubgroups of 3 teeth each. Luting of the posts werecompleted with Rebilda DC (selfetch) in group 1 and 4;BisCem (selfadhesive, Bisco, Schaumburg, IL) in group 2and 5 and DuoLink (etch and rinse Bisco) in group 3 and 6,according to the manufacturers instructions.

Lowspeed diamond saw (Micracut, Metkon, Bursa,

Turkey) was used for sectioning of root from the coronal tothe apical direction, which was perpendicularly to the axisof the root. Six slices, each 2.0 mm thick, were obtainedfrom each root, as described previously [Figure 2].[13,14]Thecoronal two slices were deemed to represent the coronalregion of the root and the apical two slices were deemedto represent the apical region of the root [Figure 1].

most common failure reason of the ber post adhesionwas caused by debonding between ber post and resincement or between resin cement and root canal walls.[6,7]Luting with resin cements can be divided into threesubgroups regarding to adhesion techniques used, whichetch and rinse, selfetch and selfadhesive systems.[8]

There were a lot of studies about the bonding eectivenessof dierent luting agent.[1,9]A previous study reportedthat, pushout bond strength of ber post was aectednumerous factors, such as; light transmiing into the postspace, high polymerization shrinkage stress, anatomicaldierences between coronal and root dentin, the weakbond strength between ber post and composites.[10]

Some studies showed no dierences between the usedluting techniques systems whilst others suggest etch andrinse techniques have a superiority than selfetch andselfadhesive techniques.[9] Furthermore in a dierentstudy, etch and rinse adhesives was showed signicantly

lower microleakage at the cement root dentin interface,than selfetching primer when used for fiber postcementation.[11]

A further improvement of reduction of working steps isintroduction of selfadhesive cements. Selfadhesivecements are do not require pretreatment of tooth substratesand posts. Selfadhesive cements can both inltrate toothsubstrate, which results micromechanical retention andoer chemical adhesion like glassionomers.[12]

Both selfetching and selfadhesive approaches providesimplicity and reduction in chair sidetime. Although,there is no clarication about which ber post lutingmethod might be most useful. Therefore, the aim ofthis study was to investigate the eect of three dierentbonding techniques (etchandrinse, selfetch andselfadhesive) on the bond strength of two dierentber posts to root dentin with push out test.[8]The testedhypothesis was; both type of adhesive cements and postsdo not aect bonding strength to dentin.

MATERIALS AND METHODS

A total of 30 freshly extracted teeth with a single and round

root segment were selected for this study. Each tooth wasplaced in 5.25% of sodium hypochlorite (NaOCl) for2 h for surface disinfection and then stored in distilledwater. The crown of each tooth was sectioned at thecementenamel junction using a diamond disc underwatercoolant to achieve 18mm root length. The workinglength was determined visually by subtracting 1 mm fromthe length of a size 10 le (KFiles Limas K; MANI, Tochigi,Japan) at the apical foramen. Root canals were preparedusing the ProTaper (Dentsply, Konstanz, Germany)system to manufacturer recommendation. Nearly Figure 1:Root canal preparation



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The slice was then xed on the metal support of a universaltesting machine (Instron Canton, MA, USA) with theapical aspect facing a cylindrical plunger of 0.65mmdiameter [Figure 2]. Loading was performed at a crossheadspeed of 0.1 mm/min until bond failure occurred. Thepushout strength was finally calculated in MPa bydividing the load at debonding (N) by the area (mm2).[15]

The failure types were determined using a stereomicroscope(Olympus SZ 6045 TR Zoom stereomicroscope, OlympusOptical Co., Tokyo, Japan) at original magnication 40,after testing the pushout bond strengths. The type offailure was classied into the following 4 categories: (1)Adhesive failure between dentin and luting material, (2)adhesive failure between post and luting material, (3)cohesive failure of the post system (4) and mixed type, acombination of 2 of the aforementioned types.

KolmogorovSmirnov test was used for determinationof the values distribution. The data were analyzed

using threeway analysis of variance (ANOVA). Post hocmultiple comparisons were performed using the Tukeytest. The failure mode data were analyzed using theChisquare test. In all the tests, the level of signicancewas set at (P< 0.05) and calculations were completedusing SPSS, version 11.0 (SPSS, Chicago, IL, USA).

Scanning electron microscopy analysisTwo specimens were randomly selected from eachsubgroup for SEM examination of the post space.Following dislocation of post, in order to qualitativelyassess the cleanliness of the post space the roots weresplit along the axis in the linguobuccal direction usinga chisel and a hammer to expose the entire extent ofthe root canal. The exposed root canals were immersedin 90% alcohol, airdried, mounted on a metallic stub,goldsputtered (Polaron Range SC7620, QuorumTechnology, Newhaven, UK) and observed under aSEM (SEM, JSM5600, JEOL Ltd., Tokyo, Japan) atdierent magnications.

RESULTS

None of the prepared specimens failed prematurely. Themean (standard deviation) pushout bond strength foreach luting strategy (and statistically signicant dierences),curing techniques, the root region are indicated in Table 1.

The results showed that bond strengths of ber posts wereaected by the type of post and the resin cement (P< 0.05).

Push out bond strengths of UniCore groups were higherthan Rebilda groups (P< 0.05). Push out bond strengthof BisCem cement groups was lower than DuoLinkand Rebilda DC groups. There were no statisticallysignicant dierences between DuoLink cement andRebilda DC cement groups (P< 0.05) [Table 1]. There areno statistically dierences between apical and coronalgroups [Table 1]. In this study, Unicore (post) and RebildaDC (cement) groups show best results.

The distribution of failure modes is reported in Figure 3.There were no statistical signicant dierences found infailure modes except coronal and apical region of Unicorepost with luted BisCem resin cement [Figure 3].

SEM analyses revealed that there were more openeddentinal tubules at etch and rinse adhesives. Furthermore,

Figure 2:Root cut into discs and push-out test

Table 1: Push out bond strengths of UniCore and Rebilda

groups

Posttype

Rootregion

Luting agent

Rebilda DCB(self-etch)

BisCemA(self adhesive)

Duo-linkA(ethc and rinse)

Unicore#

Apical 28.09(20.52)a,b

2.33(1.69)d

34.09(27.15)a

Coronal 26.26(18.39)a,b,c 8.10 (3.19)c,d 32.27 (18.16)a

Rebillda Apical 9.11 (6.91)b,c,d 4.48 (3.33)d 4.13 (2.71)d

Coronal 6.55 (4.58)d 3.60 (2.52)d 5.72 (4.43)d

Values are meanSD in MPa. Superscript letters represent signicant differences with regard

factor root region (P


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Journal of Restorative Dentistry / Vol - 2 / Issue - 1 / Jan-Apr 2014 35

the type of ber post can aect pushout bond strengthto a greater extent than the luting agent. In addition,Farina et al.[14] concluded that bond strength of berpost signicantly aected by the post and cement used.In the present study, Unicore showed higher bondstrength than Rebilda groups, which was in agreementwith previous studies. However, review of clinical

followups Cagidiaco et al.[6]

showed that, althoughber posts have beer performance than metal posts,there were no statistical dierences of survival rate ofber posts.

Previous studies showed that bond strength of ber postcan inuence from root regions.[1921]These studies werefounded that bond strength at apical third was lowerthan coronal third of root canal and they claimed thismight occurred both lack of micromechanical bondingand diculty of cementing agent ow in apical regionof post. In our study, although there were dierences inbond strength between coronal and apical region, this

dierences was not statistically signicant.

Adhesion to dentin may inuenced by many factors.However, bonding into root canals might be dicultdue to the handling characteristics of adhesive systems,root anatomy, etc. [22,23] A new resin cement wasintroduced in 2002, which has selfadhesion mechanism(RelyX Unicem, 3MESPE; St. Paul MN, USA). Thesematerials were designed with intent to bring favorablecharacteristics of different cement classes in orderto single products.[8] Today, clinicians can use eithercombinations of dualcure bonding agents and resincement or self adhesive resin cement, dependingon their chooses. This study was aimed to comparedierent adhesion techniques (selfadhesive, selfetchand etch and rinse) on push out bond strength of berpost in root canal. The results of this study showed thatselfetch and etch and rinse luting cements had higherbond strength than selfadhesive cement. This resultscan explain by resin dentin inter diusion zone andresin tags, which can occurred strength at selfetch andetch and rinse adhesion techniques, might lead beerbond strength. However, further studies needed toexplain this issue.

Fracture analysis showed a large number of mixed failure,which was contain both cohesive failure in resin cement andadhesive failure both within resin cement post and betweenresin cement root canal walls. This was explained by theboth absence of polymerization of cements close to dentinand due to lack of adhesion to root canals. Furthermore,because of high conguration factor (Cfactor) occurredpolymerization shrinkage during the curing of cements.Cfactor may have a detrimental eect on the integrity ofthe bond to the root canal walls.[24]

both of tested adhesive had higher resin tags at coronalregion than apical region. Figure 4 shows the SEM images.

DISCUSSION

The null hypothesis, that there are both type of adhesivecements and posts do not aect bonding strength to

dentin was rejected. Two main groups and three subgroups (totally six groups) tested showed noticeableadhesive properties. In this study, Unicore post andRebilda DC cement combination showed best pushoutbond strength result and Unicore posts showed beerresults than Rebilda posts. The push out bond strengthof selfadhesive cements was lower than other twoadhesion techniques results. On the other hand, therewere no statistically signicant dierences between etchand rinse and selfetch cement groups.

The push-out test is based on the shear bond stressat the interface between cement and dentin as well

as between cement and post, which is comparable tothe stresses under clinical conditions.[16,17] Obtainingfor beer estimation of the dislocation resistance thanthe conventional shear bond test pushout test wasrecommended, due to parallel occurrence of the fractureto the dentinebonding interface.[15]

There is a lot of post brand in dental marketing. In aprevious laboratory study, Kur et al.[18]claimed that,

Figure 4:Morphological aspects of interradicular dentin at differentmagnications (a: Duolink coronal, b: Duolink apical, c: Rebildacoronal, d: Rebilda apical, e: Bis-Cem coronal, f: Bis-Cem apical)

dc

b

f

a

e



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9. Onay EO, Korkmaz Y, Kiremitci A. Effect of adhesive system typeand root region on the pushout bond strength of glassbre poststo radicular dentine. Int Endod J 2010;43:259-68.

10. Rathke A, Haj-Omer D, Muche R, Haller B. Effectiveness ofbonding ber posts to root canals and composite core buildups.Eur J Oral Sci 2009;117:604-10.

11. Mannocci F, Ferrari M, Watson TF. Microleakage of endodonticallytreated teeth restored with ber posts and composite cores aftercyclic loading: A confocal microscopic study. J Prosthet Dent

2001;85:284-91.12. Jongsma LA, Bolhuis PB, Pallav P, Feilzer AJ, Kleverlaan CJ.Benets of a twostep cementation procedure for prefabricatedber posts. J Adhes Dent 2010;12:5562.

13. Nagas E, Cehreli ZC, Durmaz V, Vallittu PK, Lassila LV. Regionalpush-out bond strength and coronal microleakage of Resilon afterdifferent light-curing methods. J Endod 2007;33:1464-8.

14. Farina AP, Cecchin D, Garcia Lda F, Naves LZ, Sobrinho LC,PiresdeSouza Fde C. Bond strength of ber posts in differentroot thirds using resin cement. J Adhes Dent 2011;13:179-86.

15. Goracci C, Tavares AU, Fabianelli A, Monticelli F, Raffaelli O,Cardoso PC, et al. The adhesion between ber posts and rootcanal walls: Comparison between microtensile and push-out bondstrength measurements. Eur J Oral Sci 2004;112:353-61.

16. Van Meerbeek B, De Munck J, Yoshida Y, Inoue S, Vargas M,Vijay P, et al. Buonocore memorial lecture. Adhesion to enamel

and dentin: Current status and future challenges. Oper Dent2003;28:215-35.17. Frankenberger R, Krmer N, Petschelt A. Fatigue behaviour of

different dentin adhesives. Clin Oral Investig 1999;3:11-7.18. Kurtz JS, Perdigo J, Geraldeli S, Hodges JS, Bowles WR. Bond

strengths of tooth-colored posts, effect of sealer, dentin adhesive,and root region. Am J Dent 2003;16 Spec No: 31A-6A.

19. Bouillaguet S, Troesch S, Wataha JC, Krejci I, Meyer JM,Pashley DH. Microtensile bond strength between adhesivecements and root canal dentin. Dent Mater 2003;19:199-205.

20. Zorba YO, Erdemir A, Turkyilmaz A, Eldeniz AU. Effects ofdifferent curing units and luting agents on push-out bond strengthof translucent posts. J Endod 2010;36:1521-5.

21. Perdigo J, Geraldeli S, Lee IK. Push-out bond strengths oftooth-colored posts bonded with different adhesive systems. AmJ Dent 2004;17:422-6.

22. Ferrari M, Mannocci F, Vichi A, Cagidiaco MC, Mjr IA. Bondingto root canal: Structural characteristics of the substrate. Am JDent 2000;13:255-60.

23. Drummond JL, Toepke TR, King TJ. Thermal and cyclic loadingof endodontic posts. Eur J Oral Sci 1999;107:220-4.

24. Jongsma LA, Kleverlaan CJ, Pallav P, Feilzer AJ. Inuenceof polymerization mode and C-factor on cohesive strength ofdual-cured resin cements. Dent Mater 2012;28:722-8.

CONCLUSION

Within the limitation of results this study, bond strengthsignicantly aected by the post type and resin cementsused for luting. The highest bond strength was obtainedfor Unicore post luted with Duolink cement. Thepushout bond strength in selfadhesive cement was

signicantly lower than selfetch and etches and rinseadhesives cement.

Fracture analysis showed there was predominanceof mixed failure in all groups. Furthermore, nosignicant dierences found in failure modes exceptcoronal and apical region of Unicore post with lutedBisCem resin cement.

ACKNOWLEDGMENTS

This study was presented as a poster presentation at 5thbiennialmeeting of the European Federation of Conservative Dentistry

1315 October 2011, Istanbul, Turkey.

REFERENCES

1. Schwartz RS, Robbins JW. Post placement and restorationof endodontically treated teeth: A literature review. J Endod2004;30:289-301.

2. Cheung W. A review of the management of endodontically treatedteeth. Post, core and the nal restoration. J Am Dent Assoc2005;136:611-9.

3. Bateman G, Ricketts DN, Saunders WP. Fibre-based postsystems: A review. Br Dent J 2003;195:43-8.

4. Fokkinga WA, Kreulen CM, Vallittu PK, Creugers NH. A structuredanalysis of in vitro failure loads and failure modes of ber,metal, and ceramic post-and-core systems. Int J Prosthodont2004;17:476-82.

5. Mirmohammadi H, Gerges E, Salameh Z, Wesselink PR. Effectof post diameter and cement thickness on bond strength of berposts. Quintessence Int 2013;44:801-10.

6. Cagidiaco MC, Goracci C, Garcia-Godoy F, Ferrari M. Clinicalstudies of ber posts: A literature review. Int J Prosthodont2008;21:328-36.

7. Aksornmuang J, Foxton RM, Nakajima M, Tagami J. Microtensilebond strength of a dual-cure resin core material to glass andquartz bre posts. J Dent 2004;32:44350.

8. Radovic I, Mazzitelli C, Chief N, Ferrari M. Evaluation of theadhesion of fiber posts cemented using different adhesiveapproaches. Eur J Oral Sci 2008;116:557-63.

How to cite this article:Pala K, Demirbuga S, Gms H, Arslan S,Zorba YO. Effect of different bonding techniques on the bond strength of

two different ber posts. J Res Dent 2014;2:326.

Source of Support:Nil, Conict of Intrest:Nil.


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