In vitro evaluation of the shear bond strength between fiber posts and methacrylate or silorane based composite resins

Abstract

Abstract

Fiber posts (FP) are commonly used for extensive coronal reconstructions, often being associated with composite resins (CR) in order to minimize the space between the post and the intraradicular dentin. This study evaluated the shear bond strength of three different CR to a FP surface, with and without FP pretreatment with adhesive. Sixty #3 FP (Exacto Translúcido) were divided into six experimental groups (n = 10), according to the surface treatment used: G1--Filtek(TM) Z250; G2--Filtek(TM) P90; G3--Filtek(TM) bulk fill restorative; G4--Scotchbond(TM) Universal adhesive + Filtek(TM) Z250; G5--Silorane adhesive + Filtek(TM) P90 and G6--Scotchbond(TM) Universal adhesive + Filtek(TM) Bulkfill restorative. Two 2.0 mm thick specimens were obtained from each fiber post unit and submitted to a push-out test in a universal testing machine with a 5 mm/min crosshead speed and 5 Kilo-newton load cell. Mean and standard deviation values for bond strength (MPa) were: G1: 5.54 ± 1.78; G2: 1.69 ± 1.02; G3: 5.31 ± 1.58; G4: 7.39 ± 2.05; G5: 6.07 ± 1.88e G6: 5.50 ± 3.03. The results were analyzed through two-way analysis of variance (ANOVA) and statistical significant differences were determined by Tukey test (p = 0.05). When no adhesive was used, the bond strength was statistically significantly higher for G1 and G3, which were not statistically significantly different between them. Adhesive application showed statistically significantly higher bond strength only for G5. Without the FP pretreatment with adhesive, the bond strength was statistically significantly higher for the methacrylate-based resins and the FP pretreatment with adhesive increased the bond strength only for the silorane-based resin and changed the prevalence of failure mode type to cohesive in all composite resin study groups. The use of silorane-based composite resins to customize posts require the use of adhesive as FP surface pretreatment. The use of adhesive as pretreatment of simulated customized FP, regardless of the CR used, appear to improve the mechanical behavior of the FP-CR unit.

da Silva et al. Appl Adhes Sci (2016) 4:14 DOI 10.1186/s40563-016-0071-7

In vitro evaluation ofthe shear bondstrength betweenber posts andmethacrylate or silorane based composite resins

Pedro Jos Andrade da Silva1*, Roberta Tarkany Basting Hoffing1, Flvia L. B. do Amaral1, Ceclia P. Turssi1, Carlos Eduardo Sabrosa Borges da Silva2 and Fabiana Mantovani Gomes Frana1

*Correspondence: [email protected]

1 So Leopoldo Mandic Institute and Dental Research Center, Rua Jos Rocha Junqueira, 13, Ponte Preta, Campinas, SP 13045-755, BrazilFull list of author information is available at the end of the article

2016 The Author(s). This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/

Web End =http://creativecommons.org/licenses/by/4.0/ ), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

da Silva et al. Appl Adhes Sci (2016) 4:14

Background

FP are used to aid the retention of restorative materials in endodontically treated teeth with severe destruction [1, 2]. In some clinical situations, the space between the FP and the walls of the root canal may be too wide due to the root canal anatomy and/or treatment [1, 3, 4]. As the thickness of the composite resin cement directly inuences the FP adaptation and consequently the bond strength [3, 4], thinner cement layers are desirable for better mechanical properties [5, 6]. In addition, the greater the space between FP and the root canal wall, the greater chance for catastrophic root fractures [7] due to eventual post loosening. There are two techniques proposed in the literature to minimize this space, the use of accessory ber posts [8, 9] and customization of the ber post with CR [1012]. The purpose of both techniques is to reduce the eect of shrinkage stress associated with CR cements, obtaining a more stable adhesive interface [1013].

CR can be used to ll in this space as well as the core build up material [1, 1416]. The vast majority of methacrylate-based CR has polymerization shrinkage between 2 and 5% [17], whereas silorane-based CR exhibits polymerization shrinkage below 1% [18, 19], which would make the adaptation of the post to the root canal better.

New CR materials have been developed to be used in thicker increments either as an intermediate layer in composite resin restorations or as the nal restorative material. A photoactive group was added to these to control the kinetic of the polymerization and also a polymerization modulator in the center of the dimethacrylate urethane monomer, increasing the monomer size compared to regular restorative CR. This modication reduces the polymerization shrinkage compared to the owable and packable methacrylate-based CR [20, 21]. This CR is used to simplify the incremental technique and reduce clinical hours, with up to 4mm increment thickness [22, 23]. The depth polymerization capability and lower polymerization shrinkage of this group of composite resins could aid in obtaining the most root-wall-t personalization of the ber post within the customization post technique, guarantying the thinner cement layer possible (Table1).

Several studies have evaluated the shear bond strength between customized FP and dentin [2427]. However the fracture patterns are usually about failures in adhesion between post and resin material, either composite or resin cement [3, 28]. In that matter, dierent surface treatments have been described, such as silanization and application of an adhesive system [3, 4, 2832], to ensure the bond between the resin-based materials and FP. However, for the customized-post technique there are not enough studies to determine if the adhesive use in the preparation of FP surface is actually required [33, 34].

Therefore, the current study evaluated the bond strength of silorane-based, a bulkll methacrylate-based and a conventional methacrylate-based CR to a ber post, with and without the use of adhesive systems.

The null hypothesis was that there was no dierence on the shear bond strength between FP and tested CR, regardless of adhesive application.

Methods

Specimen preparation

FP were divided into 06 (six) groups, cardinally numbered, from 1 to 6, with 10 (ten) posts each, according to the surface treatment and CR selected, as shown in Table2. The sample size was based on literature [35, 36].

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Table 1 Materials, manufacturer, composition andapplication

Material/manufacturer Composition Application

Filtek Z250, A2 Shade, 3 M/ESPE

7585 % silanized ceramic; 1-10 % BISEMA6; 110 % UDMA; 110 % BIS-GMA; <5 % TEGDMA; <5 % aluminum oxide; <0.5 % benzotriazole; <0.2 % EDMAB

2.5 mm maximum increment, photo-activated for 80 s

Filtek P90, A2 Shade, 3 M/ESPE

515 % 3,4-epoxi-ciclohexil-ethyl-cyclopolimethylsiloxane; 515 % bis-3,4-epoxi-ciclohexil-ethylfenil-methyl-silane; 5070 % silanized quartz; 1020 % Yttrium uoride; camphorquinone

2.5 mm maximum increment, photo-activated for 80 s

Filtek Bulk Fill Restorative, A2 Shade, 3 M/ ESPE

6070 % silanized ceramic; 1020 % aromatic di methacrylate urethane; 110 % Ytterbium uo-ride; 1-10 % UDMA; 110 % silanized silica; <5 % DDDMA; <5 % water; <5 % silanized zirconium; <1 % modied methacrylate monomer; <0.5 % EDMAB; <0.5 % benzotriazole

2.5 mm maximum increment, photo-activated for 80 s

Scotchbond Universal, 3 M/ESPE

1525 % BIS-GMA; 15-25 % HEMA; 5-15 % deca methylene di methacrylate; 1015 % ethanol; 1015 % water; 515 % silanized silica; 110 % propenoic acid, 2-methyl, decanediole and phosphoric anidryde byproducts; 1-5 % itaconic and acrylic co-polymer acids; <2 % dimethyl amine benzoate; <2 % camphorquinone; <2 % dimethyl amine ethyl methacrylate; <2 % methyl ethyl ketone

Application of a thin layer for 15 s, Air drying for 5 s, Light-curing for 20 s

Filtek P90 SA, 3 M/ESPE Primer: 1525 % HEMA; 1525 % BIS-GMA; 1015 % water; 1015 % ethanol; 515 % phosphoric acid methacryl-oxi-hexil-esters; 812 % silanized silica; 510 % 1,6-hexanediol di methacrylate; <5 % ita-conic and acrylic acid co-polymer; <5 % (dimethyl amine) ethyl methacrylate; <3 % DL- camphorqui-none; <3 % phosphine oxide; Bond: 7080 % replaced di methacrylate; 510 % silanized silica; 510 % TEGDMA; <5 % phosphoric acid methacryl-oxi-hexil-esters; <3 % DL-camphorquinone; 1,6 hexanediol di methacrylate

Homogenous bond application, Light-curing for 20 s

Exacto Translcido #03,

Angelus

80 % glass ber, 20 % epoxy resin Cleansing with ethanol 70 % for 15 s

Silano Angelus X-RSi (OR) 3n, X: organic-functional group bonds to composite resin, R: methylene group, OR: hydrolysable group bonds with porcelains, composite resins and glass ber posts, Si: Silicium. n: 03

Thin layer application 60 s waiting time Smooth air drying for 5 s

BISEMA6 bisphenol a polyethylene glycol diether dimethacrylate; UDMA diurethane dimethacrylate; BISGMA bisphenol a diglycidyl ether dimethacrylate; TEGDMA triethylene glycol dimethacrylate: EDMAB ethyl 4-dimethyl aminobenzoate; HEMA 2-hydroxyethyl methacrylate

Following manufacturers instructions all FP were cleansed with a gauge embedded in ethanol 70% (Ciclofarma) for 10s and treated with silane (Angelus). Following manufacturer recommendations, all FP were previously treated with silane (Angelus). In groups G4, G5and G6, the FP was treated with the correspondent adhesive (Table2), with a thin layer application, as recommended by the manufacturer, followed by air drying for 05s in order to evaporate the solvent and homogenize the adhesive thickness and light curing with a light emitting diode (LED) (Elipar Paradigm; 3M/ESPE, Seefeld, Germany) for 20s.

Once treated, the FP was individually placed into a transparent plastic matrix (Fig.1) specially designed to keep the posts in an up-right position, keeping them centralized and to standardize the CR lling procedure. The matrix was then, incrementally lled,

da Silva et al. Appl Adhes Sci (2016) 4:14

Table 2 Experimental groups

Group N Surface treatment

1 10 Filtek Z250 lling

2 10 Filtek P90 lling

3 10 Filtek Bulk Fill Restorative lling

4 10 Scotchbond Universal adhesive application; Filtek Z250 lling

5 10 Filtek P90 silorane adhesive application; Filtek P90 lling

6 10 Scotchbond Universal adhesive application; Filtek bulk ll restorative lling

leaving approximately 6.0 mm of the posts extremity free at the top and 1.0 mm at the bottom end and 2.0mm of composite resin around the post. Each increment was inserted around the FP (Fig.2) and condensed with a Teon instrument (Fig.3) and light cured 04 (four) times for 20s each, with an 1200mW/cm2 irradiance LED (Elipar Paradigm; 3M/ESPE).All CR used were of A2 shade.

The posts involved with CR were removed from the plastic matrix and stored in distilled water for 24h in an oven (ECB 3; Odontobrs, Ribeiro Preto, SP, Brazil) at 37C. The FP-CR samples were then perpendicularly glued to an acrylic plate with wax (Asfer,

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So Caetano do Sul, SP, Brazil) and positioned in a precision cutter machine (IsoMet

1000; Buehler, Blu, IL, USA). With a wafering diamond blade (11-4244 15HC; Buehler), three parallel cuts were made perpendicularly to the posts long axis (Fig.4), obtaining two 2.0mm-thick testing specimens from each post (Fig.5), resulting in 20 test samples for each experimental group. For each FP-CR sample, an average value for the bond strength was calculated from both test samples derived from it.

Pushout test

A stainless steel base was positioned on a universal testing machine (EZ test EZ-LX; Shimadzu Corporation, Suzhou, S, China) to perform the push-out test. This base had a 12.8mm diameter-wide table designed to receive a second stainless steel base that was prepared to receive the test samples. This second base had a 2.5mm diameter-wide orice in the center and was fabricated to allow the post to drop into it during testing. All samples were loaded with the bottom part of the post facing up.

A metallic arm, with an 1mm diameter active tip attached to the load cell (5Kilo-newton), was aligned to the rst metal base so its active tip would only touch the post

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during testing. The push-out test was performed with a crosshead speed of 0.5mm/min until automatic detection of failure (Fig.6).

The shear bond strength values in Mega Pascal (MPa) were obtained by dividing the maximum force needed to dislodge the post, in Newton (N), by the adhesive interface area. The area was calculated through the diameters of the post and the thickness of the

specimen. Therefore, the area =

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0.5

~[~(R + r)]

h2(R r)2

, where is constant and

equals 3.1416; R represents the radius of the top part of the post, r is the radius of the bottom part of the post and h represents the height of the post section, in mm.

The values were recorded and submitted to statistical analysis.

Failure mode

After the push-out test, all specimens were observed under a stereoscopic loupe (Eikonal, So Paulo, SP, Brazil) with 40 magnication, to determine the failure mode, divided as: (1) adhesive failure between post and resin; (2) mixed failure and (3) cohesive failure within post and resin.

da Silva et al. Appl Adhes Sci (2016) 4:14

Statistical analysis

The results gathered for the shear bond strength are expressed by average and standard deviation and were submitted to two-way ANOVA testing and for average multiple comparisons Tukey post hoc test was employed. Signicance level was set at 5%.

Results

Two-way ANOVA, with test power of 57%, showed there was interaction between the study factors (composite resin and adhesive application).

Tukey test revealed that in the absence of adhesive (groups G1, G2 and G3), the bond strength of the methacrylate-based CR (Filtek Z250 and Filtek Bulkll restorative) to the FP was statistically signicantly higher, but it did not dier among each other (Table3).

The bond strength of the silorane-based CR (Filtek P90) specimens was not statistically signicantly dierent from the others when the adhesive was applied. With such treatment, the shear bond strength for Filtek P90 increased signicantly while for the other CR the adhesive application did not allow for better performance (Table3).

For the failure mode, it was noticed that in G2 (Filtek P90) there was predominantly adhesive failures (55 %). When the adhesive for the same CR (G5silorane adhesive+Filtek P90) was applied, the failures were cohesive in 90% of the specimens.

The same failure mode was most prevalent in all methacrylate-based CR groups when the adhesive was used (G4, 85% and G6, 70%). In G1 (Filtek Z250), mixed failures were predominant (60%), while in G3 (Filtek Bulkll restorative), there were adhesive (45%) and mixed failures (40%) in similar proportions, as noticeable in Graphic 1 (Fig.7).

Table 3 Average andstandard deviation values forshear bond strength ofFP, according totechnique

Composite Resin Adhesive

Absent Present

Methacrylate-based resin (Filtek Z250) 5.54 (1.78) Aa 7.39 (2.05) Aa

Silorane-based resin (Filtek P90) 1.69 (1.02) Bb 6.07 (1.88) Aa

Methacrylate bulk ll resin (Filtek Bulk Fill) 5.31 (1.58) Aa 5.50 (3.03) Aa

Statistical dierence is indicated through dierent capital letters in the row and dierent small letters in the columns

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Discussion

The results of this study rejected the null hypothesis, since the type of CR used and the FP pretreatment with adhesive aected the bond strength between the FP and the CR.

In this study the shear bond strength was tested through a push-out test, seeking similarity to the clinical situation, as the push-out test evaluate a failure that occurs parallel to the adhesive interface [30, 37, 38]. The 2.0mm test sample thickness was selected in order to minimize the inuence of the CR fracture resistance in the bond strength of the FP-CR sample tested [3941].

The use of silane as surface pre-treatment for every group was based on the manufacturers recommendation and in some literature reports that showed increase in the bond strength of silanized FP [1, 42, 43]. To simplify the methodology of this study, the studies of Rosatto etal. [44] and Novais [45] were considered regarding the use of prehydrolyzed silane and the absence of heat drying, respectively.

Based on recent studies that showed that acid etching does not increase the bond strength [46], but could damage the FP epoxy-matrix [47], this study did not use any etching as FP surface pre-treatment.

A previous study mapped the formation of multiple gaps through the FP-CR interface when no surface treatment was used [2]. On the other hand, Lastumaki [48] showed the positive inuence of adhesive usage as surface treatment on the bond strength of FP. In accordance, each CR correspondent adhesive was used.

The present study showed that the type of CR inuences the bond strength only when the adhesives were not used as surface treatment, having methacrylate-based resins (FZ250 and FBFR) achieved higher bond strength values (p<0.05) when compared to the silorane-based resin (FP90). This could be related to the dierence in polymerization shrinkage between silorane-based resins (lower than 1%) and the other CR (2 and 5%) [15]. The volumetric reduction that occurs because of cross bonding between the molecules in the CR organic matrix would be reduced in silorane-based CR due to the opening of a cationic ring previously to the formations of such chemical bonds, during the material polymerization [18, 19, 49, 50]. It is known that silorane-based CR has signicantly lower polymerization shrinkage, although showcasing similar mechanical properties to the methacrylate-based composites [51]. The volumetric decrease (shrinkage) of methacrylate-based composite materials could be responsible for the increase in the push-out bond strength of those materials to the FP through the tightening of the contact between post and CR.

The increase of bond strength when adhesives were applied in this study, only showed statistic signicant dierence (p<0.05) between the silorane-based CR groups, which could be explained by the fact that these CR seem to have lower adhesion power to substrate than methacrylate-based CR [52]. In addition, the silorane adhesive system has two phases: one self-etching hydrophilic primer and one hydrophobic resinous adhesive [53].

Despite the shear bond strength showing no statistic dierence among the methacrylate-based CR groups, the change in failure mode was noticeable. For all CR groups, when adhesive was not applied, adhesive and mixed failures were predominant for the low-shrinkage CR G2 (Filtek P90)+G3 (Filtek Bulkll Restorative) and G1 (Filtek

Z250) group, respectively, supporting once more the theory that the polymerization

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shrinkage could inuence the bond strength due to the increase in the contact between

the FP and CR surfaces, which was suggested by Goracci etal. [54].

Furthermore, in all groups that the specic adhesive was applied (G4, G5 and G6), cohesive failure was predominant, which could be supported by the reduction of gaps through the adhesive interface, responsible for initiating mechanical failures and increasing the number of stress points inside the FP-CR sample [32].

The clinical relevance of these ndings resides on the fact that adhesive application as surface treatment for personalizing FP could allow for a more safely indication of the customized-post technique, since the failure patterns in this study showed that the FP-CR sample showcased a one-body mechanical behavior when the specic adhesive was used.

Further studies are necessary in order to evaluate the invitro inuence of aging in the adhesive interface resistance and whether the positive performance of the adhesive-treated ber post, especially regarding the failure mode and mechanical behavior, is similar to the performance seeing in this invitro study.

Conclusions

Within the limitations of this study, it can be concluded that:

The use of silorane-based composite resins to customize posts require the use of adhesive as FP surface pretreatment;

The use of adhesive as pretreatment of simulated customized FP, regardless of the CR used, appear to improve the mechanical behavior of the FP-CR unit;

The null-hypothesis was discarded, as:

the bond strength was statistically higher for the methacrylate-based resins without the FP pretreatment with adhesive;

the FP pretreatment with adhesive increased the bond strength only for the silorane-based resin and changed the prevalence of failure mode type to cohesive in all composite resin study groups.

Abbreviations

FP: glass ber post(s); CR: composite resin(s); LED: light emitting diode; MPa: mega pascal; N: Newton; ANOVA: analysis of variance.

Authors contributions

PAS carried out all in vitro assays and drafted the manuscript. RTB helped to draft and in revising the manuscript. FA participated in the design of the study. CT performed the statistical analysis. CES conceived of the study and participated in its design. FMF participated in the coordination and helped to draft the manuscript. All authors read and approved the nal manuscript.

Author details

1 So Leopoldo Mandic Institute and Dental Research Center, Rua Jos Rocha Junqueira, 13, Ponte Preta, Campinas, SP 13045-755, Brazil. 2 University of the State of Rio de Janeiro, Boulevard 28 de Setembro, 157, Vila Isabel, Rio de Janeiro, RJ 20550-030, Brazil.

Acknowledgements

The authors would like to thank 3M Deutschland GmbH (Seefeld, Germany) for supplying part of the materials used in this study.

Competing interests

The authors declare that they have no competing interests.

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Received: 10 April 2016 Accepted: 1 July 2016

References

1. Aksornmuang J, Foxton RM, Nakajima M, Tagami J. Microtensile bond strength of a dual-cure resin core material to glass and quartz ber posts. J Dent. 2004;32(6):44350.

2. Sadek FT, Monticelli F, Goracci C, et al. Bond strength performance of dierent resin composites used as core materials around ber posts. Dent Mater J. 2007;23(1):959.

3. Perdigo J, Gomes G, Augusto V. The eect of dowel space on the bond strengths of ber posts. J Prosthodont. 2007;16(3):15464.

4. Schmage P, Pfeier P, Pinto E, et al. Inuence of oversized dowel space preparation on the bond strengths of frc posts. Oper Dent. 2009;34(1):91101.

5. Gomes GM, Rezende EC, Gomes OMM, et al. Inuence of the resin cement thickness on bond strength and gap formation of ber posts bonded to root dentin. J Adhes Dent. 2014;16:718.

6. DArcangelo C, Cinelli M, De Angelis F, DAmario M. The eect of resin cement lm thickness on the pullout strength of a ber-reinforced post system. J Prost Dent. 2007;98(3):1938.

7. Tey KC, Lui JL. The eect of glass ber-reinforced epoxy resin dowel diameter on the fracture resistance of endodontically treated teeth. J Prosthodontic. 2014;23:57281.

8. Sivieri-Araujo G, et al. Fracture resistance of simulated immature teeth after dierent intra-radicular treatments. Braz Dent J. 2015;26(3):2115.

9. Sharafeddin F, Alavi AA, Zare S. Fracture resistance of structurally compromised premolar roots restored with single and accessory glass or quartz ber posts. Dent Res J (Isfahan). 2014;11(2):26471.

10. Boksman L, Hepburn AB, Kogan E, et al. Fiber post techniques for anatomical root variations. Dent Today.

2011;30(5):10611.

11. Costa RG, Morais ECC, Leo MP, Bindo MJF, Campos EA, Correr GM. Three-year follow up of customized glass ber esthetic posts. Europ J Dent. 2011;5:10712.

12. Savi A, Manfredi M, Tamani M, Fazzi M, Pizzi S. Use of customized ber posts for the aesthetic treatment of severely compromised teeth: a case report. Dent Traumatol. 2008;24:6715.

13. Zogheib LV, Saavedra GSFA, Cardoso PE, Valera MC, Araujo MAM. Resistance to compression of weakened roots subjected to dierent root reconstruction protocols. J Appl Oral Sci. 2011;19(6):64854.

14. Saygili G, Sahmali SM. Comparative study of the physical properties of core materials. Int J Periodontics Restor Dent.

2002;22(4):35563.

15. Mendoza DB, Eakle WS, Kahl EA, et al. Root reinforcement with a resin-bonded preformed post. J Prosthet Dent. 1997;78(1):105.

16. Combe EC, Shaglouf A, Watts DC, et al. Mechanical properties of direct core build-up materials. Dent Mater. 1999;15:15865.

17. Labella R, Lambrechts P, Van Meerbeek B, Vanherle G. Polymerization shrinkage and elasticity of owable composites and lled adhesives. Dent Mater. 1999;15:12837.

18. Weinmann W, Thalacker C, Guggenberger R. Siloranes in dental composites. Dent Mater J. 2005;21(1):6874.19. Duarte JS, Botta AC, Phark JH, Sadan A. Selected mechanical and physical properties and clinical application of a new low-shrinkage composite restoration. Quintessence Int. 2009;40(8):6318.

20. Ilie N, Hickel R. Investigations on a methacrylate-based owable composite based on the SDR technology. Dent Mater. 2011;27:34855.

21. Hernandes NMAP, Catelan A, Soares GP, et al. Inuence of owable composite and restorative technique on microleakage of class II restorations. J Invest Clin Dent. 2013;4:16.

22. Fleming GJ, Awan M, Cooper PR, Sloan AJ. The potential of a resin-composite to be cured to a 4 mm depth. Dent Mater J. 2008;24:5229.

23. Roggendorf MJ, Krmer N, Appelt A, et al. Marginal quality of owable 4-mm base vs. conventionally layered resin composite. J Dent. 2011;39:6437.

24. Akkayan B, Glmez T. Resistance to fracture of endodontically treated teeth restored with dierent post systems. J Prosth Dent. 2002;87(4):4317.

25. Rathke A, Haj-Omer D, Muche R, et al. Eectiveness of bonding ber posts to root canals and composite core buildups. Eur J Oral Sci. 2009;117:60410.

26. Koch AT, Binus SM, Holzschuh B, Petschelt A, Powers JM, Berthold C. Restoration of endodontically treated teeth with major hard tissue loss-inuence of post surface design on pull-out bond strength of ber-reinforced composite posts. Dent Traumatol. 2014;30(4):2709.

27. Carvalho CA, Breschi L, Navarro MF, et al. Push-out bond strength and SEM evaluation of a new bonding approach into the root canal. J Appl Oral Sci. 2012;20(6):6139.

28. Salameh Z, Papacchini F, Ounsi HF, Goracci C, Tashkandi E, Ferrari M. Adhesion between prefabricated ber-reinforced posts and dierent composite resin cores: a microtensile bond strength evaluation. J Adhes Dent. 2006;8(2):1137.

29. Debnath S, Wunder SL, McCool JI, Baran GR. Silane treatment eects on glass/resin interfacial shear strengths. Dent Mater. 2003;19:4418.

30. Elsaka SE. Inuence of chemical surface treatments on adhesion of ber posts to composite resin core materials. Dent Mater J. 2013;29:5508.

31. Leme AA, et al. Eects of silane application on luting ber posts using self-adhesive resin cement. J Adhes Dent. 2013;15(1):26974.

Page 10 of 11

da Silva et al. Appl Adhes Sci (2016) 4:14

32. Vano M, Goracci C, Monticelli F, et al. The adhesion between ber posts and composite resin cores: the evaluation of microtensile bond strength following various surface chemical treatments to posts. Inter Endo Journal. 2006;39:319.

33. Costa RG, De Morais EC, Campos EA, Michel MD, Gonzaga CC, Correr GM. Customized ber glass posts. Fatigue and fracture resistance. Am J Dent. 2012;25(1):358.

34. Bosso K, Jnior AG, Guiraldo RD, Berger SB, Lopes MB. Stress generated by customized glass ber posts and other types by photoelastic analysis. Braz Dent J. 2015;26(3):2227.

35. Anche S, Kakarla P, Kadiyala KK, Sreedevi B, Chiramana S, Dev JRR, Manne SD, Deepthi G. The comparison of shear bond strength between ber reinforced composite posts with three dierent composite core materialsan in vitro study. J Clin Diagnost Res. 2014;8(1):2368.

36. Shori D, Pandey S, Kubde R, Rathod Y, Atara R, Rathi S. To evaluate and compare the eect of dierent post surface treatments on the tensile bond strength between ber posts and composite resin. J Int Oral Health. 2013;5(5):2732.

37. Cekic-Nagas I, Sukuroglu E, Canay S. Does the surface treatment aect the bond strength of various ber-post systems to resin-core materials? J Dent. 2011;39(2):1719.

38. Cekic-Nagas I, Ergun G, Nagas E, Tezvergil A, Vallittu PK, Lassila LV. Comparison between regional micropush-out and microtensile bond strength of resin composite to dentin. Acta Odontol Scand. 2008;66(2):7381.

39. Arslan H, Barutcigil C, Ylmaz CB, Ceyhanl KT, Topcuoglu HS. Push-out bond strength between composite core buildup and ber-reinforced posts after dierent surface treatments. Photomed Laser Surg. 2013;31(7):32833.

40. Das AK, Muddugangadhar BC, Amarnath GS, Garg A, Kumar U, Rao TR. Comparative evaluation of push out bond strength of a ber post system using four dierent resin cements: an in vitro study. J Int Oral Health. 2015;7(Suppl 1):627.41. Kadam A, Pujar M, Patil C. Evaluation of push-out bond strength of two ber-reinforced composite posts systems using two luting cements in vitro. J Conserv Dent. 2013;16:4448.

42. Goracci C, Rafaelli O, Monticelli F, Balleri B, Bertelli E, Ferrari M. The adhesion between prefabricated FRC posts and composite resin cores: microtensile bond strength with and without post-silanization. Dent Mater. 2005;21(5):43744.

43. Perdigo J, Gomes G, Lee IK. The eect of silane on the bond strengths of ber posts. Dent Mater. 2006;22:7528.44. Rosatto CMP, Roscoe MG, Novais VR, Menezes MS, Soares CJ. Eect of silane type and air-drying temperature on bonding ber post to composite core and resin cement. Braz Dental J. 2014;25(3):21724.

45. Novais VR, Simamoto Junior PC, Rontani RMP, Correr-sobrinho L, Soares CJ. Bond strength between ber posts and composite resin coreinuence of temperature on silane coupling agents. Braz Dent J. 2011;23(1):814.46. Bergoli CD, Amaral M, Boaro LC, Braga RR, Valandro LF. Fiber post cementation strategies: eect of mechanical cycling on push-out bond strength and cement polymerization stress. J Adhes Dent. 2012;14(5):4718.

47. Gller AU, Kurt M, Duran I, Uludamar A, Inan O. Eects of dierent acids and etching times on the bond strength of glass ber-reinforced composite root canal posts to composite core material. Quint Int. 2012;43(1):18.

48. Lastumki TM, Kallio TT, Vallittu PK. The bond strength of light-curing composite resin to nally polymerized and aged glass ber-reinforced composite substrate. Biomaterials. 2012;23:45339.

49. Palin WM, Fleming GJP, Burke FJT, et al. The inuence of short and medium-term water immersion on the hydrolytic stability of novel low-shrink dental composites. Dent Mater J. 2005;21(9):85263.

50. Ilie N, Hickel R. Silorane-based dental composite: behavior and abilities. Dent Mater J. 2006;25(3):44554.51. Arrais CAG, Oliveira MTD, Mettenburg D, et al. Silorane and high lled-based low-shrinkage resin composites: shrinkage, exural strength and modulus. Braz Oral Res. 2013;27(2):91102.

52. Ozer S, Tunc ES, Gonulol N. Bond strengths of silorane- and methacrylate-based composites to various underlying materials. BioMed Res Inter. 2004;16:10.

53. Mine A, et al. TEM characterization of a silorane composite bonded to enamel/dentin. Dent Mater J. 2010;26(6):52432.

54. Goracci C, Fabianelli A, Sadek FT, Papacchini F, Tay FR, Ferrari M. The contribution of friction to the dislocation resistance of bonded ber posts. J Endod. 2005;31(8):60812.

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