The aim of this experimental study was to compare the traditional cement systems with those of the latest generation, to assess if indeed these could represent of viable substitutes in the cementation of indirect restorations, and in the specific case of endodontic posts

Besharat, Laith Konstantinos

Di Carlo, Stefano

Dolci, Marco

Migliau, Guido

Piccoli, Luca

Pompa, Giorgio

Annali di Stomatologia

English

Archivio della ricerca- Università di Roma La Sapienza

Guido Migliau MD, DDS, PhD1Luca Piccoli DDS, PhD1Stefano Di Carlo MD, DDS, PhD1Giorgio Pompa MD, DDS, PhD1Laith Konstantinos Besharat DDS, MsC, PhD1Marco Dolci MD, DDS, PhD21 Department of Oral and Maxillofacial Sciences,“Sapienza” University of Rome,  Rome, Italy2 Department of Medical, Oral and BiotechnologicalSciences, “G. D’Annunzio” University of Chieti,Chieti, ItalyCorresponding author:Laith Konstantinos BesharatDepartment of Oral and Maxillofacial Sciences,“Sapienza” University of Rome,Via Caserta 600161 Rome, ItalyE-mail: besharatlk84@yahoo.itSummaryObjective. The aim of this experimental study wasto compare the traditional cement systems withthose of the latest generation, to assess if indeedthese could represent of viable substitutes in thecementation of indirect restorations, and in thespecific case of endodontic posts.Methods. The assessment of the validity of thecementing methods was performed according tothe test of the push-out, conducted on sectionsobtained from the roots of treated teeth. The sam-ples were divided into three groups. Group A (10samples): etching for 30 seconds with 37% or-thophosphoric acid (Superlux-Thixo-etch-DMG)combined with a dual-curing adhesive system(LuxaBond-Total Etch-DMG), dual-cured resin-composite cement (LuxaCore-DMG) and glassfiber posts (LuxaPost-DMG). Group B (10 sam-ples): self-adhesive resin cement (Breeze-PentronClinical) and glass fiber posts (LuxaPost-DMG).Group C (10 samples): 3 steps light-curing, self-etching, self-conditioning bonding agent (Contax-Total-etch-DMG), dual-cured resin-composite ce-ment (LuxaCore-DMG) and glass fiber posts(LuxaPost-DMG). The survey was conducted byexamining the breaking resistance of the post-ce-ment-tooth complex, subjected to a mechanicalforce. Stati stical analysis was performed usingSPSS Inc. ver. 13.0, Chicago, IL, USA. Results. Group A values of bond strenth rangedfrom a minimum of 10.14 Mpa to a maximum valueof 14.73 Mpa with a mean value of 12.58 Mpa. InGroup B the highest value of bond strength was6.54 Mpa and the minimum 5.55 Mpa. The meanvalue of the bond strength for the entire groupwas 6.58 Mpa. In Group C the highest bondstrength was 6.59 Mpa whereas the lowest bondstrength was 4.84 Mpa. Mean value of the bondstrength of Group C was calculated at 5.7 Mpa.Conclusions. Etching with orthophosphoric acidcombined with a dual-curing adhesive system anda dual-cured resin-composite cement was thetechnique that guaranteed the highest bondstrength. Lowest bond strength values were ob-tained when dual self-adhesive cement was used.Key words: glass fiber post, self-adhesive ce-ment, etching.IntroductionFor a complete understanding of the several aspectsof adhesion, it is fundamental to know and recognizethe substrates the materials work on. Enamel, dentinand cementum represent very different adhesive sur-faces due to their composition, morphology andbiomechanical characteristics. The adhesion obtainedthrough the adhesive systems is both chemical andespecially micro-mechanical, with the formation of thehybrid layer and resin tags, which are achievedthrough the etching time: it increases the availablesurface and, consequently, the contact with the resin.All the above remarks hold true in the restoration ofendodontically treated teeth, as well. In this sort ofteeth, the substrate with which the adhesion is ob-tained is basically the dentin, at both a pulp chamberand root canal. Post cementation is a delicate proce-dure where the cement must have the ability to bond(1-7) to three different surfaces; the post, the dentaltissue and the restorative material. In detail two dif-ferent types of cementation can be described. Firstly,the standard classical cementing procedure that in-cludes the use of adhesive systems (8, 9) and resincomposite cements combined with etching pretreat-ment of the tooth surface. Secondly, the last genera-tion cementing involves the use of self-etching com-posite cements. These cements are introduced di-rectly into the root canal (10-14) without having touse any adhesive system beforehand, since theycontain components that allow the enclosure of theAnnali di Stomatologia 2017;VIII (1):29-33 29Comparison between three glass fiber postcementation techniquesOriginal articleadhesion procedure in one step and therefore simpli-fying and significantly reducing the operative time.Experimental AnalysisObjective of the studyThe aim of this experimental study was to comparethe traditional cement systems with the cement sys-tems of the latest generation, to assess if indeed thelatest generation could represent viable substitutes inthe cementation of indirect restorations (15, 16), andin the specific case of endodontic posts.The non-metallic posts had several advantages com-pared to the metallic ones, such as the realization ofa homogeneous tooth-reconstruction system (17, 18),the low cost, the easy usage and a vast field of appli-cation; reasons that favored the selection of the fiber-glass posts (LuxaPost-DMG) for this study.The assessment of the validity of the cementingmethods was performed according to the push-outtest, conducted on sections obtained from the roots oftreated teeth and performed at the Department ofBiomedicine at the University of Trieste.Material and MethodsComparison of the retentive efficiency (19, 20) ofthree different types of cementation using the sametype of post (LuxaPost-DMG) was performed for allsamples. The survey was conducted by examiningthe breaking resistance of the post-cement-toothcomplex, subjected to a mechanical force.The following products were used in our samplepreparation:- a dual-curing adhesive system (LuxaBond-TotalEtch-DMG)- phosphoric acid at 37% (Superlux-Thixo-etch-DMG)- conventional  dual-cured resin-composite cement(LuxaCore-DMG)- dual self adhesive cement (Breeze-Pentron Clin-ic)- a 3 steps light-curing, self-etching, self-condition-ing bonding agent (Contax-Total-etch-DMG)- fiber posts (LuxaPost-DMG).Sample preparationWe examined 30 roots of monoradicular teeth, ex-tracted for periodontal reasons and stored in water.The applied protocol concerning the preparation ofthe root canal filling and post-space is described be-low.All samples were prepared using the simultaneoustechnique with NiTi M2 instruments (Sweden & Marti-na) with the following sequence: 10/taper 4% - 15/ta-per 5% - 20/taper 6% - 25/taper 6%. Irrigation, duringpreparation, was performed by the use of sodiumhypochlorite at 5% (Niclor5, Ogna), with a final wash(for 2 minutes) with the same product at 37 °C. Theroot canal filling was carried out with cold lateral con-densation technique with ISO standardized gutta-per-cha cones and cement containing epoxy resin TopSeal (Dentsplay, Maillefer). Preparation of the postspace was carried out with Largo 1 and 2 burs(Dentsplay, Maillefer) at the length of 10 mm for eachsample.The samples were then divided into 3 groups:- group A (10 samples): etching for 30 secondswith 37% orthophosphoric acid (Superlux-Thixo-etch-DMG) combined with a dual-curing  adhesivesystem (LuxaBond-Total Etch-DMG), dual-curedresin-composite cement (LuxaCore-DMG) andglass fiber posts (LuxaPost-DMG)- group B (10 samples): self-adhesive resin cement(Breeze-Pentron Clinical) and glass fiber posts(LuxaPost-DMG)- group C (10 samples): 3 steps light-curing, self-etching, self-conditioning bonding agent (Contax-Total-etch-DMG), dual-cured resin-composite ce-ment (LuxaCore-DMG) and glass fiber posts(LuxaPost-DMG).Preparation of the samples for the mechani-cal testThe portion of each root corresponding to the bondedfiber post was transversally sectioned into 1mm-thickserial slices, using a microtome (Micormet-Remet)posting a low speed saw (Norton-Dia Wheel), 0.2 mmthick, under water-cooling operating at 2.240 spinsper minute. The sections were realized in apical-coro-nal direction and each section was marked on theapical surface to put it exactly under the punch of themachine for the push-out test. A number was as-signed to each root and a progressive alphabeticalletter to each slice from the apical surface to thecoronal one (Fig. 1). The push-out testPush-out load was applied using a universal testingmachine Galdabini-Sun 500 at a crosshead speed of0.5 mm/min to obtain the extrusion of the post. Thepunch was positioned to touch the post only, withoutstressing the surrounding dentinal walls. The load wasapplied on the apical surface of the slice in apical-coro-nal direction, with the purpose of preventing the coni-cal shape of the canal from withstanding the dislodg-ment of the post. Push-out strength data was calculat-ed in Newtons (N), which was converted to MegaPas-cals (Mpa) by dividing the load by the bonded surfacearea. In order to obtain the bonded surface area ofeach sample, we took pictures of the apical surface us-ing an optical microscope (Zeiss laser scan). We usedfor each picture the same angle of view and enlarge-ment (50x) after the Push-out test (Fig. 2).Annali di Stomatologia 2017;VIII (1):29-3330G. Migliau et al.Similarly a picture of a marked size (1 mm) was tak-en. Image processing software provided with the opti-cal microscope was used to analyze the pictures aftercalibrating the space using the marked size. The visi-ble circumference size was found, following the lineof the fracture. Knowing the thickness of the sample(1 mm) and the taper of the apical surface of thepost, we calculated the lateral surface area of a trun-cated cone which is the bonded surface area throughthe formula:SL = π (R + r) [(h2+ (R – r)2]0.5Where R is the coronal post radius, r the apical postradius, and h the thickness of the slice.Each slice was submitted to the same procedure.Statistical analysis was performed using SPSS Inc.ver. 13.0, Chicago, IL, USA. Chi-squared test wasused for statistical evaluation of proportions. In casesof more than 2 independent means we used theANOVA test. A p-value of less than 0.05 was consid-ered significant. A 95% CI was used in all analysis. Inorder to assure data reliability, data were entered intwo different personal computers by two examiners;the two data files were compared in order to detectentry errors. The two files resulted identical.ResultsFor each analyzed section we obtained the bondstrength between the post and the dentin (MPa). Re-sults were analyzed using the ANOVA test.For the samples of the group A the values of the vari-ous samples ranged from a minimum value of 10.14Mpa for the slice A6 to a maximum value of 14.73 Mpafor the A1 sample with a mean value of  12.58 Mpa. In group B the highest value of bond strength was re-ported in the B1 slice with 6.54 Mpa and the minimumat the B8 with 5.55 Mpa. The mean value of the bondstrength for the entire group was 6.58 Mpa. Finally, in group C the highest bond strength was re-ported at the C6 slice with 6.59 Mpa whereas the low-est bond strength was reported at the C2 slice with4.84 Mpa. Mean value of the group C was calculatedat 5.7 Mpa. (Tab. 1). The results obtained are reported in the Table 1 be-low.DiscussionIn this study, we show that the adhesion force isgreater for the group A, differences are statisticallysignificant when group A is compared to group B andgroup C. Moreover, highest bond strength values ob-tained in group B compared to group C aren’t statisti-cally significant. Lowest bond strength values wereobtained where the etching step wasn’t performed.Our results can be useful for comparison with recentAnnali di Stomatologia 2017;VIII (1):29-33 31Comparison between three glass fiber post cementation techniquesFigure 1. Marked slices after sectioned.Figure 2. Pictures obtained with the optical microscope af-ter the push-out test.similar studies (21). Etching with orthophosphoricacid combined with a dual-curing adhesive systemand a dual-cured resin-composite cement is the tech-nique that guarantees a satisfying bond strength, adual self adhesive cement could be used in situationsin our daily clinical practice where the patient doesn’tfully collaborate and we have to diminish executiontime and simplify the post cementation procedure. Further studies need to be carried out on this issuetaking into account new dual self-adhesive cementsthat will be launched next year from several multina-tional dental companies such as 3M and Kerr.References1. Abu-Hanna A, Gordan VV, Mjor I. The effect of variation inetching times on dentin bonding. Gen Dent. 2004 Jan-Feb;52(1):28-33.2. Migliau G, Piccoli L, Besharat LK, Di Carlo S, Pompa G. Eval-uation of over-etching technique in the endodontically treat-ed tooth restoration. Ann Stomatol (Roma). eCollection 2015Jan-Mar. 2015 May18;6(1):10-14.3. Ahid F, Andrade MF, Campos EA, Luscino F, Vaz LG. In-fluence of different dentin etching times and concentrationsand air-abrasion technique on dentin microtensile bondstrength. Am J Dent. 2004 Dec;17(6):447-450.4. Bouillaguet S, Troesch S, Wataha JC, Krejci I, Meyer JM,Pashley DH. Microtensile bond strenght between adhesivecements and root canal dentin. Dent Mater. 2003;19(3):199-205.5. 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The effect of hybrid layer thickness on bond strength: dem-ineralized dentin zone of the hybrid layer. Dent Mater. 2000Nov;16(6):406-411.11. Hashimoto M, Ohno H, Kaga M, Sano H, Tay FR, OguchiH, Araki Y, Kubota M. Over-etching effects on micro-tensilebond strength and failure patterns for two dentin bonding sys-tems. J Dent. 2002 Feb-Mar;30(2-3):99-105.12. Hayashi M, Takahashi Y, Hirai M, Iwami Y, Imazato S, EbisuS. Effect of endodontic irrigation on bonding of resin cementto radicular dentin. Eur J Oral Sci. 2005 Feb;113(1):70-76.13. Lopes GC, Cardoso Pde C, Vieira LC, Baratieri LN. Mi-crotensile bond strength to root canal vs pulp chamber dentin:effect of bonding strategies. J Adhes Dent. 2004 Sum-mer;6(2):129-3.14. Rosella D, Rosella G, Brauner E, Papi P, Piccoli L, PompaG. A tooth preparation technique in fixed prosthodontics forstudents and neophyte dentists. Ann Stomatol (Roma). 2016Feb12;6(3-4):104-109.15. Marshall GW Jr, Marshall SJ, Kinney JH, Balooch M. 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Group A samples Mpa Group B samples Mpa Group C samples MpaA1 4 14.73 B1 5 7.54 C1 6 6.04A2 5 12.98 B2 4 6.58 C2 5 4.84A3 5 12.01 B3 4 5.95 C3 4 5.75A4 5 13.47 B4 5 6.6 C5 5 5.91A5 5 11.25 B5 5 7.07 C5 6 4.97A6 5 10.14 B6 5 6.73 C6 6 6.59A7 5 14.5 B7 6 6.8 C7 5 6.39A8 6 14.23 B8 5 5.55 C8 6 6.07A9 5 11.33 B9 5 7.41 C9 5 5.33A10 5 11.2 B10 5 5.91 C10 5 5.58Mean 12.58 Mean 6.58 Mean 5.74):113-8.eCollection 2015 Jul-Dec. Review.19. Perdigão J, Gomes G, Augusto V. The effect of dowel spaceon the bond strengths of fiber posts. J Prosthodont. 2007 May-Jun;16(3):154-164.20. Pioch T, Stotz S, Buff E, Duschner H, Staehle HJ. Influenceof different etching times on hybrid layer formation and ten-sile bond strength. Am J Dent. 1998 Oct;11(5):202-206.21. Durski MT, Metz MJ, Thompson JY, Mascarenhas AK, CrimGA, Vieira S, Mazur RF. Push-Out Bond Strength Evalua-tion of Glass Fiber Posts With Different Resin Cements andApplication Techniques. Oper Dent. 2016 Jan-Feb;41(1):103-110. doi: 10.2341/14-343-L. Epub 2015 Sep 2.Annali di Stomatologia 2017;VIII (1):29-33 33Comparison between three glass fiber post cementation techniques

Comparison between three glass fiber post cementation techniques

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Comparison between three glass fiber post cementation techniques

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