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 Table of Contents  
ORIGINAL ARTICLE
Year : 2019  |  Volume : 31  |  Issue : 1  |  Page : 40-44

Comparative evaluation of apical dye penetration of hydrophilic and hydrophobic obturation system: A stereomicroscopic study


Department of Conservative Dentistry and Endodontics, Sardar Patel Post Graduate Institute of Dental and Medical Sciences, Lucknow, Uttar Pradesh, India

Date of Web Publication19-Jun-2019

Correspondence Address:
Dr. Asit Vats
Sardar Patel Post Graduate Institute of Dental and Medical Sciences, Lucknow, Uttar Pradesh
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/endo.endo_67_18

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  Abstract 

Aim: The aim of this study is to evaluate the apical leakage of hydrophilic and hydrophobic obturation systems using a dye penetration method under stereomicroscope.
Materials and Methods: Sixty freshly extracted human single-rooted mandibular incisors were decoronated and standardized to a working length of 16 mm. Root canal preparation was done with rotary ProTaper file system in all samples. The teeth were randomly divided into three groups (20 each) and obturation was done. Group A was obturated using gutta-percha (GP)/AH Plus (hydrophobic), Group B using Resilon/Epiphany system (hydrophilic), and Group C using SmartSeal system (hydrophilic). The linear apical dye leakage was measured using methylene blue dye under stereomicroscope.
Statistical Analysis: Statistical analysis was performed using SPSS version 21.0. Kruskal–Wallis test (nonparametric ANOVA) was used for intergroup comparisons. Between-group comparisons were made using Mann–Whitney U-test was done.
Results: All three groups showed dye leakage. Intergroup comparison exhibited statistically significant difference among the groups. GP with AH Plus showed a highest dye leakage value.
Conclusion: The sealing to apical leakage shown by hydrophilic obturation systems was significantly better as compared to hydrophobic obturation systems, though none of the obturation systems were found out to be completely devoid of leakage.

Keywords: AH Plus, bioceramic, RealSeal system, SmartSeal system


How to cite this article:
Vats A, Farva U, Paliwal A, Bharadawaj K, Chhabbra HS, Singh A. Comparative evaluation of apical dye penetration of hydrophilic and hydrophobic obturation system: A stereomicroscopic study. Endodontology 2019;31:40-4

How to cite this URL:
Vats A, Farva U, Paliwal A, Bharadawaj K, Chhabbra HS, Singh A. Comparative evaluation of apical dye penetration of hydrophilic and hydrophobic obturation system: A stereomicroscopic study. Endodontology [serial online] 2019 [cited 2019 Jul 21];31:40-4. Available from: http://www.endodontologyonweb.org/text.asp?2019/31/1/40/260533


  Introduction Top


Root canal treatment is attributed to various essential factors such as instrumentation, biomechanical preparation, debridement, obturation, and postendodontic restoration. Successful endodontic treatment depends on a thorough debridement of the root canal system, the elimination of pathogenic organisms, and finally, the complete sealing of the canal space to prevent egress and ingress of bacteria from the oral and periapical environment.

The presence of great anatomic complexity of the root canal system has advocated the evolution of different materials and techniques to achieve the desired fluid-tight hermetic seal.[1] Gutta-percha (GP), in combination with sealer, is the most widely used material for endodontic root canal obturation. A root canal sealer is essential not only assisting in filling irregular spaces but also enhances the sealing during compaction enabling to penetrate small and normally inaccessible areas, i.e., in the dentinal tubules. Sealer along with solid obturating material acts synergistically to create hermetic seal.[2],[3]

GP is having higher bond strength and decreases leakage and good dimensional stability in root canal.[4] Despite multiple properties, GP in combination with resin-based sealer has still its own shortcomings, such as inability to strengthen root, not adhering to dentin, and inability to control microleakage.[5]

In advanced endodontics, hydrophilic root canal obturating system has been introduced with an aim to improve the marginal seal. The RealSeal SE system (Epiphany™, Pentron Clinical Technologies, Wallingford, CT, USA; SybronEndo, Orange, CA, USA) consists of a self-etching methacrylate epiphany sealer and Resilon core material which is a polycaprolactone polymer containing bioactive glass and radiopaque fillers.

Epiphany sealer bonds to both the Resilon core and radicular dentin through hybrid layers leading to a monoblock unit. It is the first obturation system to claim the ability to compose a monoblock unit.[6]

The most recent advancement in endodontic obturating materials utilizes a hydrophilic polymer in the root canal called as SmartSeal system (known as Shrewsbury, MA, USA). This system consists of premade obturation points containing a polyamide core, with an outer bonded hydrophilic polymer coating and an accompanying sealer (EndoSequence bioceramic sealer).

A polymeric endodontic point takes advantage of dentinal fluid and induces nonisotropic radial expansion to adapt to canal irregularities.[7],[8] The lateral expansion of propoints is claimed to occur nonuniformly.

EndoSequence BC sealer (Brasseler USA, Savannah, GA, USA) is a new hydrophilic resin-based sealer uses moisture in dentinal tubules to initiate and complete its setting reaction.[9] In addition, no shrinkage occurs on setting, resulting in a gap-free interface between the propoint, sealer, and dentin. BC sealer has the ability to form hydroxyapatite forming chemical bond with the dentin wall.[10]

Hence, this study have been undertaken to compare the apical sealing ability of hydrophobic GP/AH Plus obturation system, hydrophilic Resilon/Epiphany obturation system, and SmartSeal obturation system by utilizing a dye penetration method under stereomicroscope (Olympus BX-50) with the help of calibrated scale.


  Materials and Methods Top


Sixty freshly extracted human single-rooted mandibular central incisors were taken. Teeth were carefully cleaned with curettes to remove the soft-tissue remnants and were stored in saline solution before instrumentation.

The crowns of all the teeth were decoronated diamond disc to adjust the length of the roots to a standardized length of 16 mm from radiographic apex to cementoenamel junction. They were subsequently immersed in 6% NaOCl for 6 h and stored in distilled water.

Working length was determined using #10 K-file. Root canal preparation was subjected to crown-down technique with rotary ProTaper files. After each file, 1 ml of 3% sodium hypochlorite was used as an irrigating solution delivered with 27G side-vented needles inserted 3 mm from the apex, followed by EDTA and normal saline. On completion of instrumentation, the canals were dried using sterile absorbent paper points. The samples were divided into three groups of twenty teeth in each group [Table 1].
Table 1: Sample-wise microleakage seen in experimental groups under stereomicroscope

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  • Group A: Teeth were obturated with GP/AH Plus
  • In Group B: Teeth were obturated with RealSeal system
  • Group C: Teeth were obturated with SmartSeal system.


After 20 min of obturation, 2 mm of coronal obturation was removed. The access opening sealed with composite resin. On completion of the filling process, all samples were stored in saline solution at 37°C for 48 h. After 2 days, root surfaces of samples were covered with two layers of nail varnish, except apical 2 mm. Then, the sample was left to dry.

The samples were placed into 2% methylene blue dye solution for 3 days at 37°C. After being removed from the dye solution, the samples were washed with water and dried. The teeth were sectioned in a buccolingual direction through the center of the root. Linear apical leakage was measured from the apex to the coronal extent of the methylene blue dye penetration.

The depth of dye penetration was measured with the calibrated metallurgical scale in stereomicroscope (Olympus 50 × magnification) [Table 1].


  Results Top


Statistical analysis was performed using SPSS version 21.0. SmartSeal system, Resilon/Epiphany system, and GP system showed microleakage after obturation. Significant difference is seen among all the groups; hence, a nonparametric evaluation plan was followed. Kruskal–Wallis test (nonparametric ANOVA) was used for intergroup comparisons. Between-group comparisons were made using Mann–Whitney U-test was done. The mean value for microleakage was maximum seen in AH Plus 7.66 mm and minimum for SmartSeal 1.27. All the between-group differences were statistically significant (P < 0.001). On the basis of above evaluation, the order of microleakage in different groups was as follows [Figure 1]:
Figure 1: SmartSeal < Resilon < AH Plus

Click here to view


Smart Seal < Resilon < AH Plus.

[Figure 2] shows Group A, B, C apical dye penetration in obtuarted tooth seen under stereomicroscope.
Figure 2: Group A, Group B, Group C apical dye penetration in obturated tooth seen under stereomicroscope. (a) Group A – Gutta percha with AH Plus. (b) Group B – Real seal system. (c) Group C – Smart seal system

Click here to view


  • Group A – GP with AH Plus
  • Group B – RealSeal system
  • Group C – SmartSeal system.



  Discussion Top


Three-dimensional sealing of the root canal is one of the main goals of endodontic treatment and is essential for preventing apical and coronal leakage in the root canal system.

Ingle and Backland (1996) stated that 60% of failures in endodontics can be attributed to incomplete seal of the root canal. This underlines the importance of three-dimensional obturation, to decrease the microleakage that may occur through the root canal filling. Variations in root canal anatomy create difficulty in three-dimensional obturation of canal space which may contribute to endodontic failure. One classical study on cross-section of mandibular incisors reported that root canals have different cross-sectional shape with some being oval and are thus difficult to obturate.[11]

Methylene blue dye is used as it allows quantitative measurement of the extent of dye penetration by linear measurement techniques.

In the present study, mean microleakage was maximum in Group A (AH Plus) (7.66 ± 2.52 mm). The major demerit evaluated with GP is that it does not bond chemically to the dentinal wall. Moreover, due to the hydrophobic nature of the GP cones, the sealer tends to pull away from the GP on setting.[12]

AH Plus is having good tissue compatibility, low polymerization shrinkage, low solubility, and dimensional stability in comparison to other resin-based sealers, but still, hydrophobic nature of GP and its inability to sufficiently reinforce the root canal remain its drawbacks.[13] It does not compose the monoblock. This might be explained by the fast setting and subsequent polymerization shrinkage of AH Plus sealer; the lack of bonding between sealer and GP prevents good adaptation to the incompletely dried canal.

GP with AH Plus promotes a poor barrier to dye leakage and is considered to be the one of the most fragile phases in root canal therapy. These inferior properties of GP with AH Plus (Group A) displayed a poor sealing ability as compared to Group B and Group C.

RealSeal system and SmartSeal system provide a more predictable seal of the root canal. Thus, superior seal of the root canal by these systems is due to monoblock effect. Within the parameters of this study, it did not appear that a consummate seal occurred for any of the systems tested, but the seal achieved with the hydrophilic obturations (Group B and Group C) was far more superior to the hydrophobic system (Group A).

A new material, RealSeal system Group B showed mean microleakage value 4.83 ± 2.71 mm of dye that was significantly higher than Group C (SmartSeal) (1.27 ± 1.18 mm) and significantly lesser than Group A (7.66 ± 2.52 mm). Resilon is a polymer-based thermoplastic resin with low solubility in an oral environment and it is hydrophilic in nature. Epiphany is a dual-cured resin with matrix bonding to root-canal filling material and to dentin, which leads to the formation of monoblock.

Epiphany increases the formation of free oxygen radicals in cells, thus contributing to the generation of oxidative stress and impairment of their function. Epiphany sealer is having higher film thickness and increase in shrinkage stress.

Moreover, Resilon core exhibits extensive surface thinning and weight loss after incubation with bacterial and salivary enzymes. Any endodontic sealer that undergoes polymerization would be subjected to greater volume of stresses during the setting process. Adhesion of the sealer to both Resilon cone and dentin improves the sealing properties of (Group B) RealSeal system in comparison to (Group A) GP with AH Plus.

Therefore, even with the incorporation of hydrophilic components, leakage with RealSeal system (Group B) was significantly more as compared to Group C.

In the present study, least leakage is seen in Group C (1.27 ± 1.18 mm). The leakage value of Group of C was statistically significant to Group B (4.83 ± 2.71 mm). Such result can be attributed to many reasons. The C-point and smart-paste bioceramic sealer expands after obturation when it comes in contact with dentinal fluid. Expansion occurs only laterally without expanding axially because the polyimide coating is present only laterally. The lateral expansion of C-points depends on the degree to which it is prestressed.

The inner core of C-points is a mix of two proprietary nylon polymers:

  • Trogamid T
  • Trogamid CX.


The polymer coating is a cross-linked copolymer of acrylonitrile and vinyl pyrrolidone which has been polymerized and cross-linked using allyl methacrylate and a thermal initiator.

EndoSequence BC sealer uses the moisture within the dentinal tubules. Camilleri reported that dentin is composed of approximately 20% (by volume) of water and “iRoot SP” uses this water to initiate and complete its setting reaction.[14]

All three groups exhibit substantial leakage. Statistically, intergroup difference was seen significant (P < 0.001). It goes on to show that none of the sealers despite of all the technological advances is ideal. The hydrophilic obturating system (Groups B and C) might have performed better than hydrophobic obturation system (Group A), but their performance also leaves a lot to be desired. Hence, more clinical trials and studies are required to come up with an obturating system that displays impeccable sealing properties.


  Conclusion Top


Within the limitation of this study, it was concluded that hydrophilic obturating system is significantly superior to the hydrophobic obturating system, as far as the sealing ability is concerned. Hence, hydrophilicity should be of paramount importance when selecting an obturating system.

This study concludes that SmartSeal system Group C has significantly improved sealing properties as compared to Groups A and B. Such improved sealing ability can be attributed to its self-expansion property. The hydrophobicity of the GP is the major drawback of GP which inhibits chemically bond to the dentin wall.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
  References Top

1.
Arora S, Hegde V. Comparative evaluation of a novel smart-seal obturating system and its homogeneity of using cone beam computed tomography:In vitro simulated lateral canal study. J Conserv Dent 2014;17:364-8.  Back to cited text no. 1
[PUBMED]  [Full text]  
2.
Timpawat S, Amornchat C, Trisuwan WR. Bacterial coronal leakage after obturation with three root canal sealers. J Endod 2001;27:36-9.  Back to cited text no. 2
    
3.
Torabinejad M, Walton RE. Endodontics: Principles and Practice. Philadelphia: W.B. Saunders Co.; 2009. p. 3.  Back to cited text no. 3
    
4.
Forough Reyhani M, Ghasemi N, Rahimi S, Salem Milani A, Mokhtari H, Shakouie S, et al. Push-out bond strength of dorifill, epiphany and MTA-Fillapex sealers to root canal dentin with and without smear layer. Iran Endod J 2014;9:246-50.  Back to cited text no. 4
    
5.
Hegde V, Arora S. Fracture resistance of roots obturated with novel hydrophilic obturation systems. J Conserv Dent 2015;18:261-4.  Back to cited text no. 5
[PUBMED]  [Full text]  
6.
Shipper G, Ørstavik D, Teixeira FB, Trope M. An evaluation of microbial leakage in roots filled with a thermoplastic synthetic polymer-based root canal filling material (Resilon). J Endod 2004;30:342-7.  Back to cited text no. 6
    
7.
Highgate DJ, Lloyd JA. Expandable/Contractable Composition of Bioceramic for Surgical or Dental Use. United States Patent Number 7,210,935; May 2007.  Back to cited text no. 7
    
8.
Levin MD, Sin, Tay FR, Rueggeberg FA. Lateral hygroscopic expansion and biocompatibility of a water-expandable endodontic obturation point. J Dent 2014;43:796-800.  Back to cited text no. 8
    
9.
Chen CC, Ho CC, David Chen CH, Ding SJ. Physicochemical properties of calcium silicate cements for endodontic treatment. J Endod 2009;35:1288-91.  Back to cited text no. 9
    
10.
Ghoneim AG, Lutfy RA, Sabet NE, Fayyad DM. Resistance to fracture of roots obturated with novel canal-filling systems. J Endod 2011;37:1590-2.  Back to cited text no. 10
    
11.
Mauger MJ, Schindler WG, Walker WA 3rd. An evaluation of canal morphology at different levels of root resection in mandibular incisors. J Endod 1998;24:607-9.  Back to cited text no. 11
    
12.
Leyhausen G, Heil J, Reifferscheid G, Waldmann P, Geurtsen W. Genotoxicity and cytotoxicity of the epoxy resin-based root canal sealer AH plus. J Endod 1999;25:109-13.  Back to cited text no. 12
    
13.
Roggendorf MJ, Ebert J, Petschelt A, Frankenberger R. Influence of moisture on the apical seal of root canal fillings with five different types of sealer. J Endod 2007;33:31-3.  Back to cited text no. 13
    
14.
Camilleri J. Hydration characteristics of calcium silicate cements with alternative radiopacifiers used as root-end filling materials. J Endod 2010;36:502-8.  Back to cited text no. 14
    


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