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Year : 2014  |  Volume : 25  |  Issue : 3  |  Page : 336-339
An ex vivo evaluation of the sealing ability of polydimethylsiloxane-based root canal sealers

1 Departments of Conservative Dentistry and Endodontics, New Delhi, India
2 Maulana Azad Institute of Dental Sciences, New Delhi, New Delhi, India
3 Government Dental College, Amritsar, Punjab, India

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Date of Submission11-Nov-2013
Date of Decision06-Dec-2013
Date of Acceptance21-May-2014
Date of Web Publication7-Aug-2014


Aim: The aim was to study the sealing efficacy of polydimethylsiloxane-based root canal sealers.
Materials and Methods: Polydimethylsiloxane-based root canal sealers were reviewed and subjected to an ex vivo study. A total of 60 extracted maxillary incisors were included in this study, which was conducted under two groups, Groups A and B, of 30 teeth each. In Group A, GuttaFlow and in Group B, RoekoSeal as sealers were used for obturation with Gutta-percha cones after preparing canal with a step back technique. The criterion for evaluating sealing efficacy of the sealers was light absorption by spectrophotometer. The collected data were analyzed statistically using one-way ANOVA test.
Results: The findings of the study revealed that the mean leakage in Group B (0.1027) was significantly less than Group A (0.1649) (P < 0.001). RoekoSeal showed superior sealing ability.
Conclusion: RoekoSeal had the better sealing ability than GuttaFlow and may be recommended for clinical use.

Keywords: GuttaFlow, polydimethylsiloxane, RoekoSeal, sealing efficacy

How to cite this article:
Jain P, Pruthi V, Sikri VK. An ex vivo evaluation of the sealing ability of polydimethylsiloxane-based root canal sealers. Indian J Dent Res 2014;25:336-9

How to cite this URL:
Jain P, Pruthi V, Sikri VK. An ex vivo evaluation of the sealing ability of polydimethylsiloxane-based root canal sealers. Indian J Dent Res [serial online] 2014 [cited 2023 Oct 1];25:336-9. Available from:
The primary objective of root canal therapy is a complete obturation of the root canal space with the aim of sealing as much of the cleaned and shaped root canal system as possible. [1] The sealing off of the root canal system from the periodontal ligament and the surrounding bone ensures success and consequently the health of the attachment apparatus.

The most commonly used core filling material is gutta-percha. [2] Although gutta-percha can be reasonably adapted to the root canal walls, because of the canal irregularities and the size of the dentinal tubules a root canal sealer is essential to not only assist in filling irregular spaces, but also to enhance the seal during compaction and to penetrate into small, normally inaccessible areas, that is, the dentinal tubules. [3] Various authors have shown that teeth obturated with gutta-percha along with sealer displayed significantly less leakage than those without sealer. [4],[5],[6] Over the years, root canal sealers based upon zinc-oxide and eugenol combination have served the profession; however, their irritation potential led to the development of noneugenol sealers. The sealers should have both good sealing ability and biocompatibility for clinical use as endodontic filling materials are placed directly into vital tissues. [2]

An array of filling materials and techniques has been developed with the purpose of achieving a physiological hermetic seal. Recently, polydimethylsiloxane-based materials have been investigated as a potential material to seal off the pathways of communications between the root canal system and the external environment.

Polydimethylsiloxane belongs to a group of polymeric organo-silicon compounds that are commonly referred to as silicones. It is optically clear, and in general, inert, nontoxic, nonflammable and is particularly known for its unusual rheological (or flow) properties. It is viscoelastic, that is, at high temperatures; it acts like a viscous liquid, similar to honey. However, at low temperatures, it acts like an elastic solid, similar to rubber. In other words, at elevated temperature, it flows to cover the surface and mold to any surface imperfections. [7]

RoekoSeal and GuttaFlow are two polydimethylsiloxane-based root canal filling materials. RoekoSeal consists of polydimethylsiloxane, silicon oil, paraffin-base oil, hexachloroplatinic acid (catalyst) and zirconium dioxide (radiopaque material). It expands by 0.2% during the first 4 weeks and remains stable thereafter which improves its sealing ability without creating excessive forces within the root canal. [8] RoekoSeal is considerably less cytotoxic than epoxy resin-based root canal sealers. [9]

GuttaFlow has been introduced as the first nonheated, flowable gutta-percha that, unlike heated gutta-percha, does not shrink. It has the same composition as RoekoSeal, except for the added finely ground gutta-percha of size <30 μm 3 and nano silver particles to prevent further spread of bacteria. Nano silver is highly biocompatible and doesn't cause corrosion or color changes in the material. [10] GuttaFlow has very promising properties because of its insolubility, biocompatibility, postsetting expansion, great fluidity, and for providing a thin film of sealer. The moderate expansion of the GuttaFlow sealer may be beneficial. [10],[11]

This study was carried out to evaluate and compare the sealing ability of polydimethylsiloxane-based root canal sealers, GuttaFlow and RoekoSeal, when used along with conventional gutta-percha technique ex vivo.

   Materials and methods Top

The study was conducted ex vivo on freshly extracted 60 permanent maxillary incisors which were cleaned off of soft tissues and calculus deposits and stored in 10% formalin at room temperature. Carious teeth and fractured roots were not included in the study.

All the teeth were sectioned from cemento-enamel junction. The working length was determined by passing a #15 K file into the root canal until the tip was visible at the apical foramen and then subtracting 0.5 mm from the total length. The selected teeth were randomly divided into two groups: Groups A and B, comprising of thirty teeth each.

After access cavity preparation, root canals were prepared using step back technique and irrigated with 2.5% sodium hypochlorite solution followed by normal saline copiously. The canals were dried with paper points and obturated. For obturation, in Group A, conventional gutta-percha cones were used with sealer GuttaFlow [Figure 1] whereas in Group B, with gutta-percha, RoekoSeal [Figure 2] was used as a sealer. The treated roots were covered with two coats of nail polish, except 2.0 mm apically [Figure 3]. The specimens were immersed in 0.5% methylene blue dye.
Figure 1: GuttaFlow

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Figure 2: RoekoSeal

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After 1 week, all the teeth were washed with tap water to remove excess dye and were dried. Nail polish was scraped off from all the surfaces [Figure 4].

After dye penetration procedure, each tooth was kept in 10 ml of 65% nitric acid for complete dissolution of the tooth [Figure 5]. Following this, a spectrophotometer [Figure 6] was used to determine the dye concentration in each sample. The higher the spectrophotometric reading, the greater was the amount of leakage. The amount of light (at the wavelength of maximum absorption) absorbed by the sample solution was recorded. The collected data was statistically analyzed using one-way ANOVA test.
Figure 3: Samples coated with nail polish

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Figure 4: Samples after dye immersion and nail polish removal

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Figure 5: Samples immersed in nitric acid

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Figure 6: Spectrophotometer

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   Results Top

The results are summarized in [Table 1] and Graph 1. The mean light absorption for Group A was 0.17 and for Group B was 0.10. The mean leakage in Group B was less when compared to Group A.
Table 1: Statistical evaluation

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On statistical evaluation, mean leakage in Group B (0.1027) was statistically highly significantly less than Group A (0.1649) (P < 0.001).

   Discussion Top

Total obliteration of the root canal system and achieving hermetic seal at the cemento-dentinal junction with an inert material is the ultimate goal of successful endodontic treatment.

Polydimethylsiloxane has been used in dentistry for a long time owing to its properties. It has an extremely low surface tension, which provides a high flow rate, limited dimensional change on setting (0.6-0.2%) and low water sorption. [12] A high flow rate and low film thickness would allow this material to flow into tiny crevices and tubules. It is insoluble and has an excellent radiopacity. While it does not form a chemical bond with dentin, it does expand 0.2% on setting, which results in its close adherence to the canal walls.

Genηoglu et al. investigated microleakage and found the best results in teeth in which silicone-based sealers were used. [13] According to a scanning electron microscopic study by Leski and Pawlicka, RoekoSeal and GuttaFlow have shown good adaptation to the root canal walls and better penetration into the dentinal tubules. [14]

De-Deus et al. compared the sealing ability of four endodontic materials namely  AH Plus (Dentsply DeTrey, Konstanz), Pulp Canal Sealer EWT (SybronEndo, Kerr Dental, USA), RoekoSeal and GuttaFlow. [12] It was observed that silicone-based sealers resulted in significantly fewer samples being contaminated at the end of the experimental period when compared with the other sealers tested.

The sealing efficacy of GuttaFlow and RoekoSeal, along with some other sealers, has also been studied by Eldeniz AU and Orstavik D who found that GuttaFlow prevented leakage significantly better than RoekoSeal. [15] On the contrary, Barbizam et al. observed that RoekoSeal was not as effective as the Grossman's sealer for filling simulated canals. [16]

As far as the cytotoxicity is concerned, Al-Awadhi et al. have demonstrated that RoekoSeal induced significantly less apoptotic activity in cultured osteoblasts than a conventional zinc-oxide eugenol-based sealer. [17] Furthermore, according to a recent study, silver nano-particles, present in GuttaFlow, are cytotoxic to  Escherichia More Details coli at very low concentrations. [18]

Whitworth and Baco compared the effectiveness of AH Plus and RoekoSeal sealers alone and Gutta-percha compacted with sealer, in preventing coronal microleakage. They observed that sealer-only backfills with AH Plus and RoekoSeal prevented coronal microleakage better than warm gutta-percha alone or with sealer. [19]

The findings of the present study are in concurrence with the study of Ozok et al., who evaluated the sealing ability of GuttaFlow, RoekoSeal and AH26 in root canals and observed that GuttaFlow had the highest amount of leakage, whereas AH26 showed the least. Further, there was no significant difference between RoekoSeal and AH26 filled root canals. [20] In our study, RoekoSeal showed superior sealing ability as compared to GuttaFlow. This might be due to the ability of RoekoSeal to seal the lateral canals and also the dentinal tubules, exhibiting a gap-free interface between filling and dentin. In contrast, GuttaFlow, a thixotropic sealer might flow under the pressure, leaving only the Gutta-percha particles between the cones and the dentin wall, thereby providing an inferior seal.

   Conclusion Top

Under the conditions of this ex vivo evaluation, we may conclude that RoekoSeal has the better sealing ability and may be recommended for clinical use. However, before any definite conclusion can be drawn, a large number of samples and longitudinal studies should be encouraged to evaluate the efficacy of these sealers and their potential for achieving the hermetic seal.

   References Top

1.Schilder H. Filling root canals in three dimensions. 1967. J Endod 2006;32:281-90.  Back to cited text no. 1
2.Ørstavik D. Materials used for root canal obturation: Technical, biological and clinical testing. Endod Topics 2005;12:25.  Back to cited text no. 2
3.Wu MK, Ozok AR, Wesselink PR. Sealer distribution in root canals obturated by three techniques. Int Endod J 2000;33:340-5.  Back to cited text no. 3
4.Sen BH, Piºkin B, Baran N. The effect of tubular penetration of root canal sealers on dye microleakage. Int Endod J 1996;29:23-8.  Back to cited text no. 4
5.Okºan T, Aktener BO, Sen BH, Tezel H. The penetration of root canal sealers into dentinal tubules. A scanning electron microscopic study. Int Endod J 1993;26:301-5.  Back to cited text no. 5
6.Tagger M, Greenberg B, Sela G. Interaction between sealers and gutta-percha cones. J Endod 2003;29:835-7.  Back to cited text no. 6
7.European Centre for Eco-Toxicology and Toxicology of Chemicals, Joint Assessment of Commodity Chemicals, No. 26, Linear Polydimethylsiloxanes (1994).  Back to cited text no. 7
8.Ørstavik D, Nordahl I, Tibballs JE. Dimensional change following setting of root canal sealer materials. Dent Mater 2001;17:512-9.  Back to cited text no. 8
9.Miletiæ I, Devciæ N, Aniæ I, Borciæ J, Karloviæ Z, Osmak M. The cytotoxicity of RoekoSeal and AH plus compared during different setting periods. J Endod 2005;31:307-9.  Back to cited text no. 9
10.Monticelli F, Sword J, Martin RL, Schuster GS, Weller RN, Ferrari M, et al. Sealing properties of two contemporary single-cone obturation systems. Int Endod J 2007;40:374-85.  Back to cited text no. 10
11.Elayouti A, Achleithner C, Löst C, Weiger R. Homogeneity and adaptation of a new gutta-percha paste to root canal walls. J Endod 2005;31:687-90.  Back to cited text no. 11
12.De-Deus G, Brandão MC, Fidel RA, Fidel SR. The sealing ability of GuttaFlow in oval-shaped canals: An ex vivo study using a polymicrobial leakage model. Int Endod J 2007;40:794-9.  Back to cited text no. 12
13.Gençoglu N, Türkmen C, Ahiskali R. A new silicon-based root canal sealer (Roekoseal-Automix). J Oral Rehabil 2003;30:753-7.  Back to cited text no. 13
14.Leski M, Pawlicka H. A comparison of the penetration of three sealers into dentinal tubules; A SEM study. Int Endod J 2005;38:932.  Back to cited text no. 14
15.Eldeniz AU, Ørstavik D. A laboratory assessment of coronal bacterial leakage in root canals filled with new and conventional sealers. Int Endod J 2009;42:303-12.  Back to cited text no. 15
16.Barbizam JV, Souza M, Cecchin D, Dabbel J. Effectiveness of a silicon-based root canal sealer for filling of simulated lateral canals. Braz Dent J 2007;18:20-3.  Back to cited text no. 16
17.Al-Awadhi S, Spears R, Gutmann JL, Opperman LA. Cultured primary osteoblast viability and apoptosis in the presence of root canal sealers. J Endod 2004;30:527-33.  Back to cited text no. 17
18.Baker C, Pradhan A, Pakstis L, Pochan DJ, Shah SI. Synthesis and antibacterial properties of silver nanoparticles. J Nanosci Nanotechnol 2005;5:244-9.  Back to cited text no. 18
19.Whitworth JM, Baco L. Coronal leakage of sealer-only backfill: An in vitro evaluation. J Endod 2005;31:280-2.  Back to cited text no. 19
20.Ozok AR, van der Sluis LW, Wu MK, Wesselink PR. Sealing ability of a new polydimethylsiloxane-based root canal filling material. J Endod 2008;34:204-7.  Back to cited text no. 20

Correspondence Address:
Preeti Jain
Departments of Conservative Dentistry and Endodontics, New Delhi
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0970-9290.138332

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  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]

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