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 Table of Contents  
Year : 2017  |  Volume : 9  |  Issue : 5  |  Page : 197-200  

Evaluation of push out bond strength of fiber post after treating the intra radicular post space with different post space treatment techniques: A randomized controlled In vitro trial

Department of Conservative and Endodontics, KSR Institute of Dental Science and Research, Thokkavadi, Tiruchengode, Namakkal, Tamil Nadu, India

Date of Web Publication27-Nov-2017

Correspondence Address:
Sebeena Mathew
Department of Conservative and Endodontics, KSR Institute of Dental Science and Research, Thokkavadi - 637 215, Tiruchengode, Namakkal, Tamil Nadu
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jpbs.JPBS_156_17

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Objective: The aim of this study was to evaluate the push out bond strength after treating the post space with different irrigation procedures. Study Design: The study sample comprised of 60 recently extracted premolars. These teeth were placed in 5.25% sodium hypochlorite solution for 5 min and then washed under tap water. De-coronated samples were biomechanically prepared until F3 ProTaper and obturated using AH-Plus and 30# (6%) gutta-percha. The specimens were allowed to set for 24 h and then post space was prepared. The teeth were randomly assigned into three experimental groups based on the treatment technique: Group A – control, Group B – sodium hypochlorite and ethylene diamine tetra acetic acid (EDTA) and Group C – diode laser and EDTA. The samples were sectioned horizontally and push out bond strength was evaluated. The stereomicroscopic examination was done for evaluating the failure mode. One-way ANOVA variance followed by Tukey's post-hoc test was used for statistical analysis using SPSS software. Results: Use of diode laser does not enhance the bond strength of fiber post. Conclusion: Diode laser at a very low pulse can be used as an irrigant adjuvant to vaporize the cement residues. Using diode laser does not enhance the bond strength. EDTA as final irrigant increases the bond strength of fiber post.

Keywords: Diode laser, ethylene diamine tetra acetic acid, fiber post, push out bond strength, sodium hypochlorite

How to cite this article:
Mathew S, Raju IR, Sreedev C P, Karthick K, Boopathi T, Deepa N T. Evaluation of push out bond strength of fiber post after treating the intra radicular post space with different post space treatment techniques: A randomized controlled In vitro trial. J Pharm Bioall Sci 2017;9, Suppl S1:197-200

How to cite this URL:
Mathew S, Raju IR, Sreedev C P, Karthick K, Boopathi T, Deepa N T. Evaluation of push out bond strength of fiber post after treating the intra radicular post space with different post space treatment techniques: A randomized controlled In vitro trial. J Pharm Bioall Sci [serial online] 2017 [cited 2022 Jul 6];9, Suppl S1:197-200. Available from:

   Introduction Top

Posts play a significant role in restoring debilitated, endodontically treated teeth. Fiber posts are esthetically appealing, have a modulus of elasticity similar to that of dentin and have the advantage of adhesive bonding.[1] Effective adhesive bonding between post and root canal dentin improves the distribution of forces at dentin post interface.[2] Luting relies on hybrid layer formation into dentin, which depends on the dentinal surface treatment. It improves resin tag formation between adhesive materials and intertubular dentin.[3]

Preparation of post space results in heavy smear layer deposits on dentine walls. Post space irrigation (PSI) may influence the strength of the cement bond within the root canal system.[1]

The purpose of this study was to evaluate the effectiveness of PSI procedures on the pushout bond strength of fiber posts.

   Materials and Methods Top

A total of 60 uniradicular teeth extracted for periodontal and orthodontic reasons were used in this study. Inclusion criteria for this study were teeth with single-rooted canals, the absence of resorption, root caries, cracks, and root length >15 mm. The teeth were stored in distilled water. These samples were placed in 5.25% sodium hypochlorite for 5 min and washed under tap water. The samples were decoronated, and working length was standardized to 15 mm. The canals were prepared apically using 15 and 20 size K files. Root canal preparation was completed using ProTaper rotary files (S1, S2, F1, F2 and F3). Samples were irrigated with 5 ml of 5% sodium hypochlorite (Prime DentPro) and 5 ml of 17% ethylene diamine tetra acetic acid (EDTA) (Provest DentPro) after each change of file. Saline was used to stop the reaction of each irrigant. Obturation was done using sealer (AH-Plus; Dentsply DeTrey GmbH) and gutta-percha (Dentsply Mallifer) by single cone technique. An interim filling material (Cavit 3M ESPE) was used to seal the endodontic access cavities.

After the root canal treatment was completed, the roots were stored in gauze dampened with sterile saline for 24 h for the sealer to set. The root canal filling was removed at 10 mm depth with number 1 (0.70 mm) peeso reamer (Mani INC), and preparation was completed using drill number 1 (Hi Rem Endod Drill 201). After post space preparation, the specimens were divided into three groups according to the PSI procedure.

Group A – Control group specimens were irrigated with 5 ml saline (0.9% sodium chloride W/V Nirlife) for 1 min.

Group B – Specimens were irrigated with 5 ml of 5% sodium hypochlorite for 1 min followed by 5 ml of 17% EDTA for 1 min.

Group C – Specimens were treated with a diode laser (Zolar Photon Plus) of 3 watts power. The laser was used in a continuous mode in the presence of 5% sodium hypochlorite for 20 s irradiation time of three cycles. After each cycle, sodium hypochlorite was replenished to compensate the vaporization of the solution.

All the specimens were irrigated with distilled water, After post space treatment, absorbent paper points were used to dry the root canals and self-adhesive resin cement (G Cem LinkAce, GC Pro) was used to lute the fiber posts of size 1 (Hi Rem Over Fiber Post 201) which were seated with light finger pressure. Self-adhesive resin polymerization was initiated using light emitting diode curing unit (Woodpecker LED. D) for 20 s and left for another 4 min for the material to set. After 24 h, the specimens were sectioned horizontally with a water cooled, low speed diamond disc (Premiere dental: Shofu INC). Three slices were obtained from apical, middle, and coronal region. Each slice of sample was standardized to 1 mm thickness. A push out test was applied to slices at 0.5 mm/min using 1 mm diameter metallic plunger in coronal third, 0.7 mm in middle third portions, and 0.5 mm in apical third portion from apical to coronal direction in all samples until the post dislodges from the tooth. A Jig was used to hold the slices in position. [Figure 1] shows the specimen preparation and jig apparatus. A computerized universal testing machine (Kalpak) was used to measure the maximum push out bond failure load in newtons (N). Maximum failure load was converted to megapascals for each post to its bonding area of each slice. The total bonding area was calculated using formula A= π(r + R) *h2 + (R − r) where R = coronal post radius, r = apical post radius, and h = slice thickness.[4] The post diameter at coronal and apical portion of each slice and thickness of dentin sections were measured using caliper. Statistical analysis one-way ANOVA of variance and Tukey's multiple comparison test was performed to evaluate the statistical difference between experimental groups (α = 0.05) at different root thirds. Adhesive, cohesive, and mixed failure modes were evaluated with respect to each post space treatment protocol using stereomicroscope.
Figure 1: (a) Post luted specimen cut in coronal, middle and apical third region with 1 mm thickness (b) Push out test apparatus and customized jig for holding the slices

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   Results Top

Push out results are shown in [Table 1]. Statistical analysis showed that both the PSI procedures and section level (root thirds) significantly affected the bond strength values. The interaction between these two factors was not significant. The samples treated with sodium hypochlorite and EDTA showed highest bond strength. The diode group showed lowest bond strength. For the root section level factor, there was a reduction in values from coronal to middle and apical thirds of all samples. The middle and apical third of all groups showed similar bond strength values with no statistically significant difference among them (P = 0.05). The failure mode analyzed using stereomicroscope displayed cohesive failure at dentin in the saline group. A prevalence of mixed failure at post-cement-dentin interface was found. Failure pattern was similar among all the groups [Chart 1].
Table 1: Push out bond strength based on post space treatment techniques at different root sections (Mean±standard deviation)*

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   Discussion Top

The objective of this study was to evaluate the bond strength after different post space treatments at different levels of root sections (apical, middle, and coronal third). Push out bond strength is evaluated as it depicts the polymerization stress at the dentin cement interface. The test was performed to mimic dentin cement interface failure. Push out test is more reliable for testing the bond strength of post cement interface due to premature failure in specimen preparation and large data distribution spread linked with micro tensile testing.[5]

EDTA and sodium hypochlorite group had better efficacy than diode laser and the Sodium hypochlorite group. This is due to the use of EDTA as a final irrigant. This finding coincides with studies done previously. It improves penetration into the dentinal tubules by removing smear layer. EDTA reacts with calcium ions in dentin and forms water soluble calcium chelates. It also causes dentin demineralization and allows penetration of resin monomers.[6] Diode laser of 980 nm is absorbed more by water, whereas 810 nm is absorbed by melanin so it dehydrates the dentin water.[7] Diode laser helps in disinfection of root canal and produces acid etch like appearance.[8] The diode laser does not enhance bond strength. This finding is similar to that of several studies.[9],[10] This is against the finding of the study done by Maenosono et al.[11] in which he used diode laser with low power watts. In the present study, temperature is one of the factors, which affect the bond strength of fiber post. The use of diode laser at 3 weeks for 20 s of three cycles increases the temperature of the dentin.[10] Laser melts the dentinal tubules and vaporizes the irrigating solution. Use of NaOCl as a final irrigant produces free oxygen radicals which inhibit the vinyl free radicals produced in the light activation of adhesives which consequently affects the initiation and propagation of addition polymerization.[12] Sodium Hypochlorite when used as final irrigant, shows no difference in bond strength when compared with non-oxidizing agents according to Morris et al.[13]

Bond strength values were varied at different section levels. This can be due to different tubule density of dentin at different regions of roots, as well as technical sensitivity and difficulty in applying adhesives to post space, limited light transmission to narrow post space.[14] Diode laser at the apical third showed less bond strength. This can be due to the positioning of the optic fiber, which concentrates continuous power delivery at the apical portion. The most likely explanation for low resistance to post dislodgement at apical portion of all samples relies on the decreasing effect of curing light at a greater distance and difficulty in moisture control causing incomplete infiltration of adhesive agent. Moreover, coronal part is easily accessible, easier to etch, and apply adhesive agents. Different types of defects such as bubbles, bonding defects, polymerization defects, and cement residues were observed in the post space in other studies[1] on using different irrigating solutions. The traces of gutta-percha and cement residues remain at apical thirds after post space preparation.

Self-etch adhesives are claimed to require smear layer for proper bonding to dentine. In contrast, Cecchin et al.[15] concluded smear layer removal is necessary for better penetration of self-etch adhesive cements into dentinal tubules.

   Conclusion Top

The present study displayed that bond strength of fiber post is affected by post space treatment techniques at various section levels. Use of diode laser does not improve bond strength. Low-level pulsed diode laser can be used only as an adjuvant to other techniques for vaporizing the traces of gutta-percha and cement traces at inaccessible apical third regions.

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Conflicts of interest

There are no conflicts of interest.

   References Top

Mariasevera Di Comite, Crincoli V, Fatone L, Ballini A, Mori G, Rapone B, et al. Quantitative analysis of defects at the dentin post space in Endodontically treated teeth. Materials 2015;3:268-83.  Back to cited text no. 1
Belwalkar VR, Gade J, Mankar NP. Comparison of the effect of shear bond strength with silane and other three chemical presurface treatments of a glass fiber-reinforced post on adhesion with a resin based luting agent. An in vitro study. Contemp Clin Dent 2016;7:193-7.  Back to cited text no. 2
[PUBMED]  [Full text]  
Haragushiku GA, Back ED, Tomazinho PH, Baratto Filho F, Furuse AY. Influence of antimicrobial solutions in the decontamination and adhesion of glass-fiber posts to root canals. J Appl Oral Sci 2015;23:436-41.  Back to cited text no. 3
Zicari F, De Munck J, Scotti R, Naert I, Van Meerbeek B. Factors affecting the cement-post interface. Dent Mater 2012;28:287-97.  Back to cited text no. 4
Goracci C, Tavares AU, Fabianelli A, Monticelli F, Raffaelli O, Cardoso PC, et al. The adhesion between fiber posts and root canal walls: Comparison between microtensile and push-out bond strength measurements. Eur J Oral Sci 2004;112:353-61.  Back to cited text no. 5
Faria-e-Silva AL, Menezes Mde S, Silva FP, Reis GR, Moraes RR. Intra-radicular dentin treatments and retention of fiber posts with self-adhesive resin cements. Braz Oral Res 2013;27:14-9.  Back to cited text no. 6
Tsai CL, Chen JC, Wang WJ. Nearinfrared absorption property of biological soft tissue constituents. J Med Biol Eng 2001;2:714.  Back to cited text no. 7
Israel M, Cobb CM, Rossmann JA, Spencer P. The effects of CO2, nd: YAG and er: YAG lasers with and without surface coolant on tooth root surfaces. An in vitro study. J Clin Periodontol 1997;24:595-602.  Back to cited text no. 8
Gomes KGF, Faria NS, Neto WR, Colucci V, Gomes EA. Influence of laser irradiation on the push-out bond strength between a glass fiber post and root dentin. J Prosthet Dent 2017. pii: S0022-3913(17) 30078-1.  Back to cited text no. 9
Malekipour M, Alizadeh F, Shirani F, Amini S. The effect of 808 nm diode laser irradiation on shear bond strength of composite bonded to dentin before and after bonding. J Dent Lasers 2015;9:69-74.  Back to cited text no. 10
  [Full text]  
Maenosono RM, Bim Júnior O, Duarte MA, Palma-Dibb RG, Wang L, Ishikiriama SK, et al. Diode laser irradiation increases microtensile bond strength of dentin. Braz Oral Res 2015;29:1-5.  Back to cited text no. 11
Pelegrine RA, De Martin AS, Cunha RS, Pelegrine AA, da Silveira Bueno CE. Influence of chemical irrigants on the tensile bond strength of an adhesive system used to cement glass fiber posts to root dentin. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010;110:e73-6.  Back to cited text no. 12
Morris MD, Lee KW, Agee KA, Bouillaguet S, Pashley DH. Effects of sodium hypochlorite and RC-prep on bond strengths of resin cement to endodontic surfaces. J Endod 2001;27:753-7.  Back to cited text no. 13
Kul E, Yesildal K, Ihsan L, Benan L. Effect of different post space irrigation procedures on the bond strength of a fiber post attached with self adhesive resin cement. J Prosthet Dent. 2016;115:601-5.  Back to cited text no. 14
Cecchin D, Farina AP, Galafassi D, Barbizam JV, Corona SA, Carlini-Júnior B, et al. Influence of sodium hypochlorite and EDTA on the microtensile bond strength of a self-etching adhesive system. J Appl Oral Sci 2010;18:385-9.  Back to cited text no. 15


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  [Table 1]

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