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 Table of Contents  
ORIGINAL ARTICLE
Year : 2016  |  Volume : 28  |  Issue : 2  |  Page : 102-108

Evaluating the quality of seal of root canals in the presence of separated rotary instrument when obturated with different obturation techniques using liquid photospectrometry


1 Department of Conservative Dentistry and Endodontics, Sharad Pawar Dental College, Sawangi (Meghe), Wardha, Maharashtra, India
2 Department of Prosthodontics, Sharad Pawar Dental College, Sawangi (Meghe), Wardha, Maharashtra, India
3 Department of Oral Medicine and Radiology, Swargiya Dadasaheb Kalmegh Smruti Dental College and Hospital, Nagpur, Maharashtra, India

Date of Web Publication9-Dec-2016

Correspondence Address:
Fresca Bhagwandas Adwani
Department of Conservative Dentistry and Endodontics, Sharad Pawar Dental College, Sawangi (Meghe), Wardha - 442 001, Maharashtra
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0970-7212.195423

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  Abstract 


Introduction: Complete sealing of the root canal system is essential for the successful outcome of the endodontic treatment. unfortunately instrument may separate during biomechanical preparation and achieving a fluid tight seal may be difficult. Three dimensional obturation thus plays an important role in achievement of fluid tight in presence of separated rotary instruments. To evaluate the quality of seal of root canals in the presence of separated rotary instrument when obturated with different obturation techniques using liquid photospectrometry.
Materials and Methods: One hundred and twenty freshly extracted mandibular human premolars with straight and single root canal were selected. The preparations of canal were completed by single file system with primary file size 25/08 (WaveOne system, Dentsply Maillefer, Switzerland). The roots were randomly assigned into two groups: Group I (n = 60) and Group II (n = 60). Group I (n = 60) was subdivided into three subgroups A, B, and C. Group A (n = 20): Roots were obturated with lateral condensation technique without sealer placement and without instrument being separated at apical third. Group B (n = 20): Roots were obturated with lateral compaction technique using epoxy resin based sealer (AH Plus) placed in canals without instrument being separated at apical third. Group C (n = 20): Roots were obturated with lateral compaction technique using epoxy resin-based sealer (AH Plus) placed along the root canals with instrument being separated at apical third. Group II (n = 60) was also subdivided into three subgroups A, B, and C with twenty roots in each subgroup. In subgroups A, B, and C of Group II, the same methodology was used, except obturation was done using thermoplasticized Gutta-percha (Calamus, Dentsply Maillefer, Switzerland). The modified glucose penetration setup was used and samples were then analyzed with a spectrophotometer (ELICO SL 244-double beam ultraviolet-visible) at 340 nm wavelength. Statistical analysis was done using descriptive and inferential statistics using Student's paired and unpaired t-test and softwares used in the analysis were SPSS 17.0 version and GraphPad Prism 5.0 version and P< 0.05 is considered as level of significance (P < 0.05).
Results: Significant variation was found in mean glucose leakage in groups obturated with lateral condensation and thermoplasticized Gutta-percha (t = 2.10, P = 0.042).
Conclusions: Leakage observed with thermoplasticized obturation was less when compared to lateral condensation. Three-dimensional obturation plays a crucial role than the separated instrument during endodontic therapy.

Keywords: Apical seal; glucose penetration; spectrophotometer; thermoplasticized Gutta-percha.


How to cite this article:
Chandak MG, Adwani FB, Mankar NP, Kela SM, Dawani MN, Chandak RM. Evaluating the quality of seal of root canals in the presence of separated rotary instrument when obturated with different obturation techniques using liquid photospectrometry. Endodontology 2016;28:102-8

How to cite this URL:
Chandak MG, Adwani FB, Mankar NP, Kela SM, Dawani MN, Chandak RM. Evaluating the quality of seal of root canals in the presence of separated rotary instrument when obturated with different obturation techniques using liquid photospectrometry. Endodontology [serial online] 2016 [cited 2019 May 25];28:102-8. Available from: http://www.endodontologyonweb.org/text.asp?2016/28/2/102/195423




  Introduction Top


The ultimate and utmost important goal of endodontic treatment is the complete sealing of root canals after complete cleaning and shaping. Nevertheless, this objective can be compromised by the presence of a fractured instrument if separation occurs before completion of biomechanical preparation of the canal. Fracture of endodontic instruments within the root canal is a frequent problem, representing a major obstacle. In spite of using various separated instrument retrieval techniques, sometimes, it becomes difficult to remove separated instrument and it has to be left in the root canal.[1]

An ideal root canal filling should fill the entire root canal system in three dimensions and form a homogenous mass.[2] There are a variety of techniques used to obturate the root canal system, which can be divided into two basic groups: Cold lateral compaction or warm vertical (WV) compaction. WV compaction of Gutta-percha was proposed in the 1960s,[2] and this technique has been shown to lead to satisfactory results in terms of homogeneity and to fill a high percentage of the root canal area with Gutta-percha material.[3] Cold lateral compaction stands as a practical and reliable method; using this technique, the pulp space can be obturated effectively. Most of the studies of new obturation system use lateral condensation for comparison purpose.[3] Gutta-percha is considered as a “gold standard” filling material.[4] Although it has many desirable properties, it solely fails to provide an effective three-dimensional seal. To overcome this insufficiency, endodontic sealers are used in conjunction with Gutta-percha.

Endodontic sealers are important in root canal obturation because they complete the spaces that are not filled by Gutta-percha, thus avoiding periapical exudates, making it difficult for resistant microorganisms to survive, and preventing them or their products from reaching the apical region. The use of endodontic sealers associated with Gutta-percha became indispensable for proper sealing of the root canal system, improving the final quality of the treatment.[4],[5],[6],[7]

Liquid spectrophotometry at wavelength 340 nm was used in the present study to determine the amount of leakage by measuring the amount of glucose in each model. Glucose as a marker in leakage studies has clinical relevance because it is important nutrient for microorganisms, and even at very low concentrations, a biofilm is able to survive.[8] The objective of the present study was to evaluate the quality of seal of root canals in the presence of separated rotary instrument when obturated with different obturation techniques (cold lateral condensation and thermoplasticized) using liquid photospectrometry.


  Subjects and Methods Top


One hundred and twenty recently extracted mandibular human premolars for orthodontic reasons, similar in size and with straight and single root canals, were selected and stored according to the Occupational Safety and Health Administration guidelines. The selected samples were free of any resorption, root caries, hypercementosis, curved root, crack, and open apex. All teeth were decoronated with a diamond disc (Brasseler Dental Products, Savannah, GA, USA) to leave a uniform length of 14 mm apical sections of roots to avoid anatomical variations and to obtain standardization for the leakage measurements. The patency of canal was verified with the use of size 10 K-file. The working length was determined by introducing a size 10 K-file into the canal up to the apical foramen and then withdrawn to the extent of 1 mm, which has been confirmed from the radiovisiography. The apical width of the canal was standardized by selecting samples, in which 15-file snugly fitted at working length. The biomechanical preparations of roots were completed by single file system with primary file of size 25/08 (WaveOne, Dentsply). During chemomechanical preparation, 15% ethylenediaminetetraacetic acid (EDTA) gel (Glyde File Prep-Maillefer Dentsply, Switzerland) was used as a lubricant with instrument. After instrumentation, the canal was irrigated with 3 ml of 3% sodium hypochlorite (Vishal Dentocare Pvt. Ltd., India) using a syringe and a 27-gauge needle.

Then, file was nicked with a diamond bur 3 mm from the tip to facilitate separation. The diameter of the tip of the separated file at broken end was measured with a Gutta-percha gauge, and Gutta-percha corresponding to the master apical file was trimmed to the same tip diameter using Gutta-percha cutter.

Prior to obturation, each canal was irrigated with 5 ml of 17% aqueous EDTA solution (Dent Wash - Prime Dental, India) for 60 s, followed by 5 ml of 3% sodium hypochlorite to remove smear layer. Ten milliliters of normal saline was used for the final rinse. The canals were dried with paper points. The roots were randomly assigned into two groups: Group I (n = 60) and Group II (n = 60). [Table 1] Group I (n = 60) was subdivided into three subgroups A, B, and C. Group A (n = 20): Roots were obturated with lateral condensation technique without sealer placement and without instrument being separated at apical third. Group B (n = 20): Roots were obturated with lateral compaction technique using epoxy resin based sealer (AH Plus) placed in canals without instrument being separated at apical third. Group C (n = 20): Roots were obturated with lateral compaction technique using epoxy resin-based sealer (AH Plus) placed along the root canals with instrument being separated at apical third. Group II (n = 60) was also subdivided into three subgroups A, B, and C with twenty roots in each subgroup. In subgroups A, B, and C of Group II, the same methodology was used, except obturation was done using thermoplasticized Gutta-percha (Calamus, Dentsply Maillefer, Switzerland). After obturation, the specimens were stored separately for 1 week at 37°C and100% humidity to allow for the complete set of the sealer.
Table 1: Distribution of samples

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Preparation of model

Coronal 4 mm of the root specimens was embedded in acrylic. Resin block around the coronal part of each root was connected to a rubber tube. To improve adaptation of the specimen to rubber tube, nylon thread was used. Cyanoacrylate glue was used for achieving leak-free interface between the rubber tube and acrylic. The other end of the tube was similarly connected to a 16 cm long pipette (erythrocyte sedimentation rate [ESR] tube). Again, cyanoacrylate glue was applied to interface between rubber tube and ESR tube to achieve better seal. A uniform hole with dimension corresponding to ESR tube end was drilled in the screw cap of the bulb using a bur with low-speed micromotor for placement of prepared assembly. The assembly was then placed in a sterile bulb with a screw cap, sealed with sticky wax. Two milliliters of 0.2% NaN3 solution was inserted into the glass bottle such that the root samples were completely immersed. NaN3 was used to inhibit the growth of microorganisms that might influence the glucose readings. The tracer used here was 1 mol/L glucose solution (pH 7.0) that has a low molecular weight and is hydrophilic and chemically stable. About 4.5 mL of the glucose solution, containing 0.2% NaN3, was injected into the pipette until the top of the solution was 14 cm higher than the top of the tooth that created a hydrostatic pressure of 1.5 kPa or 15 cm H2O (Xu et al. 2005).[5],[8] All specimens were then returned to the incubator at 37°C for the duration of 4 weeks. A total of 100 µL of the solution was drawn from the glass bottle using a micropipette at 1st and 4th weeks. The same amount of fresh NaN3 was added to the glass bottle reservoir to maintain a constant volume of 2 ml.

For evaluation of leakage, a modified glucose penetration setup was used.[8] The sample were then analyzed with a spectrophotometer (ELICO SL 244-double beam ultraviolet-visible) at 340 nm wavelength. Concentrations of glucose in the lower chamber were evaluated in g/L at that particular time after obturation at 1st and 4th week.


  Results Top


Comparison of mean glucose leakage in g/L along the root canal fillings at 1st and 4th week was assesed when obturated using lateral compaction technique [Table 2] and [Graph 1] and Thermoplasticized technique [Table 3] and [Graph 2].
Table 2: Comparison of mean glucose leakage in g/L along the root canal filling at 1st and 4th week in three groups when lateral condensation was used for obturation

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Table 3: Comparison of mean glucose leakage in g/L along the root canal filling at 1st and 4th week in three groups when thermoplasticized condensation was used for obturation

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No significant variation was found in mean glucose leakage in Group B and Group C of Groups I and II [Table 4] and [Table 5], [Graph 3] and [Graph 4].

Table 4: Comparison of Mean glucose leakage in g/L along the root canal filling in three groups at 4th week when lateral condensation was used for obturation

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Table 5: Comparison of mean glucose leakage in g/L along the root canal filling in three groups at 4th week

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Statistical difference was found when Group A was compared to Group B and Group C of Groups I and II at 4th week [Table 4] and [Table 5], [Graph 3] and [Graph 4].

Mean glucose leakage level in Group A with lateral obturation was 0.25 ± 0.21 and with thermoplasticized was 0.13 ± 003. Using Student's unpaired t-test, statistically, significant difference was found among lateral and thermoplasticized obturation (t = 2.44, P = 0.019) [Table 6] and [Graph 5].
Table 6: Comparison of mean glucose leakage in g/L along the root canal filling in three groups at 4th week

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Mean glucose leakage level in Group B with lateral obturation was 0.10 ± 0.13 and with thermoplasticized was 0.04 ± 0.02. Using Student's unpaired t-test, statistically, significant difference was found among lateral and thermoplasticized obturation (t = 2.11, P = 0.041) [Table 6] and [Graph 5].

Mean glucose leakage level in Group C with lateral obturation was 0.10 ± 0.14 and with thermoplasticized was 0.02 ± 0.02. Using Student's unpaired t-test, statistically, significant difference was found among lateral and thermoplasticized obturation (t = 2.10, P = 0.042) [Table 6] and [Graph 5].

The mean glucose leakage in all groups increased with time. Significant variation was found in mean glucose leakage in groups obturated with lateral condensation and thermoplasticized Gutta-percha [Table 6] and [Graph 5]. Statistical difference was found when Group I was compared to Group II at 1st and 4th week.


  Discussion Top


In this study, we accessed the quality of seal of root canals in the presence of separated rotary instrument when obturated with different obturation techniques using liquid photospectrometry and glucose penetration model. Microleakage was assessed by a recently introduced method: Glucose penetration model.[8] Instrument separation is an unfortunate sequel of endodontic instrumentation. When separation occurs, the clinician has the choice of leaving the instrument in the canal or attempting to remove it either surgically or nonsurgically. An instrument fragment is rarely the direct cause of the problem and when the obstacle can be bypassed, and disinfection obtained, the prognosis is hardly affected.

Saunders et al. in 2004 reported the fact that the presence of a fractured instrument within the apical third of a given root canal bears no influence on the time required for bacterial invasion when dealing with canals filled with lateral, cold compaction technique.[1] Mohammadi and Khademi in 2006 obtained similar results from a later study, where they concluded that a fractured instrument, by itself bears no influence on sealing capacity of the filling material.[9] Nevertheless, these results contradict those reported by Altundasar et al., who reported finding greater amounts of filtration in canals filled in the presence of fractured rotary instruments in the apical third, when compared to that found in canals filled without the presence of fractured instruments fragments.[10]

In the present study, the amount of leakage was less in roots with thermoplasticized obturation [Table 6] and [Graph 5], when both the groups [Table 6] and [Graph 5] with lateral and thermoplasticized obturation were compared [Table 6] and [Graph 5], which is in agreement with a study by Moreno et al., were the apical sealing of two filling techniques, thermafil and lateral cold compaction technique were assessed, in the presence of an instrument fractured at apical level and showed that when filling with thermafil, more satisfactory results were obtained than those achieved by the lateral technique. With the first technique, lesser amounts of microfiltration were found.[11]

Thermoplasticized techniques are able to mediate a closer adaptation of Gutta-percha to the root canal wall than canal length compaction could be obtained. However, though none of the obturation techniques does, Gutta-percha get penetrated into any lateral canal, or to fill the isthmus entirely. Thus, the use of a root canal sealer is required during root canal obturation. Root canal sealer is therefore essential for any obturation technique involving Gutta-percha, including thermoplasticized techniques.[2],[3]

According to Ostroski,[7] sealers play an important role in sealing the root canal system with entombment of remaining microorganisms and filling of inaccessible areas of the prepared canal. In addition, root canal sealers often have the ability to penetrate into the accessory canals, lateral canals, and dentinal tubules.

Epoxy resin-based sealers were introduced in endodontics by Schroeder and had since been used because of their reduced solubility, apical seal, and microretention to root dentin. AH Plus (Dentsply Maillefer, Ballaigues, Switzerland) is a widely used epoxy resin-based sealer and possesses positive handling characteristics and superior physical properties.

Previously, microleakage of root canal filling materials has been tested using different methods that included dyes, radioisotopes, and bacteria penetration methods.[12],[13],[14],[15],[16],[17] However, the results of published sealability studies in endodontics are controversial and had unclear clinical implications.[18],[19] Due to the variation in these results, it is difficult to draw firm conclusions as to which canal filling material is the best for sealing the root canal system.[20] Fortunately, leakage tests are improving, and Xu et al. reported a new model measuring the leakage of glucose molecules. The advantage of this method is the ability to perform continuous quantitative microleakage analysis as such methods are rare in root canal filling materials.[21],[22]

Shemesh et al.[23] and Kececi et al.[24] reported that the glucose penetration model seemed to have a superior sensitivity to measure the sealing ability of root canal filling material than the fluid penetration model. The choice of tracer material should be carefully chosen because its size and physicochemical properties may influence the result. A smaller molecular size (MW ¼ 180 Da) and stricter testability may be seen as more relevant to clinical outcomes. Therefore, in the current study, glucose penetration method was selected to evaluate the possible microleakage of root canal filling materials.

The difference between the current version of the glucose penetration model and the original model introduced by Xu et al. lies mainly in the environment, in which the equipment was stored: To overcome evaporation of fluids, specimens were placed in a closed jar with 100% humidity.

It is a common misconception that a separated file is the specific cause of conventional endodontic treatment failure. However, the basis of endodontic treatment failure after a file breaks is the inability to remove the remaining vital or nonvital pulp tissue due to the impediment that the separated file poses, which can lead to inflammation or infection.[24] Single file system was thus used in the present study as finishing files are usually ones to fracture during instrumentation, and while using single file system, file could break before the complete debridement of the root canal. The prognosis for a tooth with a separated instrument depends on the extent of undebrided and unobturated canal that remains below the broken instrument when the instrument cannot be removed or bypassed.[25]

The study helped to identify the sealing ability of sealer obturated with lateral compaction technique and thermoplasticized technique placed over apically separated rotary instruments, using liquid photospectrometry and glucose penetration model.

Thus, achieving effective apical seal will help in successful outcome of treatment.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
  References Top

1.
Saunders JL, Eleazer PD, Zhang P, Michalek S. Effect of a separated instrument on bacterial penetration of obturated root canals. J Endod 2004;30:177-9.  Back to cited text no. 1
    
2.
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Lea CS, Apicella MJ, Mines P, Yancich PP, Parker MH. Comparison of the obturation density of cold lateral compaction versus warm vertical compaction using the continuous wave of condensation technique. J Endod 2005;31:37-9.  Back to cited text no. 3
    
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Patil SA, Dodwad PK, Patil AA. An in vitro comparison of bond strengths of gutta-percha/AH plus, resilon/epiphany self-etch and EndoREZ obturation system to intraradicular dentin using a push-out test design. J Conserv Dent 2013;16:238-42.  Back to cited text no. 4
[PUBMED]  Medknow Journal  
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Dultra F, Barroso JM, Carrasco LD, Capelli A, Guerisoli DM, Pécora JD. Evaluation of apical microleakage of teeth sealed with four different root canal sealers. J Appl Oral Sci 2006;14:341-5.  Back to cited text no. 6
    
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Xu Q, Fan MW, Fan B, Cheung GS, Hu HL. A new quantitative method using glucose for analysis of endodontic leakage. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2005;99:107-11.  Back to cited text no. 8
    
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10.
Altundasar E, Sahin C, Ozcelik B, Cehreli ZC. Sealing properties of different obturation systems applied over apically fractured rotary nickel-titanium files. J Endod 2008;34:194-7.  Back to cited text no. 10
    
11.
Moreno González VA, Argüello Regalado G, Pérez Tejada HE 2nd. Assessment of apical sealing of three warm obturation techniques in the presence of fractured NiTi rotary instruments. Rev Odontol Mex 2013;17:20-5.  Back to cited text no. 11
    
12.
Starkey DL, Anderson RW, Pashley DH. An evaluation of the effect of methylene blue dye pH on apical leakage. J Endod 1993;19:435-9.  Back to cited text no. 12
    
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Wu MK, De Gee AJ, Wesselink PR, Moorer WR. Fluid transport and bacterial penetration along root canal fillings. Int Endod J 1993;26:203-8.  Back to cited text no. 13
    
14.
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. 14
    
15.
Shipper G, Trope M.In vitro microbial leakage of endodontically treated teeth using new and standard obturation techniques. J Endod 2004;30:154-8.  Back to cited text no. 15
    
16.
Yücel AC, Ciftçi A. Effects of different root canal obturation techniques on bacterial penetration. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2006;102:e88-92.  Back to cited text no. 16
    
17.
Kqiku L, Städtler P, Gruber HJ, Baraba A, Anic I, Miletic I. Active versus passive microleakage of resilon/epiphany and gutta-percha/AH Plus. Aust Endod J 2011;37:141-6.  Back to cited text no. 17
    
18.
Oliver CM, Abbott PV. Correlation between clinical success and apical dye penetration. Int Endod J 2001;34:637-44.  Back to cited text no. 18
    
19.
Susini G, Pommel L, About I, Camps J. Lack of correlation between ex vivo apical dye penetration and presence of apical radiolucencies. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2006;102:e19-23.  Back to cited text no. 19
    
20.
Editorial Board of the Journal of Endodontics. Wanted: A base of evidence. J Endod 2007;33:1401-2.  Back to cited text no. 20
    
21.
Kim SY, Ahn JS, Yi YA, Lee Y, Hwang JY, Seo DG. Quantitative microleakage analysis of endodontic temporary filling materials using a glucose penetration model. Acta Odontol Scand 2015;73:137-43.  Back to cited text no. 21
    
22.
Jang JA, Kim HL, Her MJ, Lee KW, Yu MK. Effect of moisture on sealing ability of root canal filling with different types of sealer through the glucose penetration model. J Korean Acad Conserv Dent 2010;35:335-43.  Back to cited text no. 22
    
23.
Shemesh H, van den Bos M, Wu MK, Wesselink PR. Glucose penetration and fluid transport through coronal root structure and filled root canals. Int Endod J 2007;40:866-72.  Back to cited text no. 23
    
24.
Kececi AD, Kaya BU, Belli S. Corono-apical leakage of various root filling materials using two different penetration models – A 3-month study. J Biomed Mater Res B Appl Biomater 2010;92:261-7.  Back to cited text no. 24
    
25.
Lin LM, Rosenberg PA, Lin J. Do procedural errors cause endodontic treatment failure? J Am Dent Assoc 2005;136:187-93.  Back to cited text no. 25
    



 
 
    Tables

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



 

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