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 Table of Contents  
ORIGINAL ARTICLE
Year : 2019  |  Volume : 31  |  Issue : 1  |  Page : 45-50

Volumetric analysis of hand and rotary root canal instrumentation using different obturation techniques: An in vitro spiral computed tomography study


Department of Conservative Dentistry and Endodontics, National Dental College and Hospital, Dera Bassi, Punjab, India

Date of Web Publication19-Jun-2019

Correspondence Address:
Dr. Jatinderpal Singh
Department of Conservative Dentistry and Endodontics, National Dental College and Hospital, Dera Bassi, Punjab
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/endo.endo_15_18

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  Abstract 

Aim: The aim of this study is to volumetrically analyze the root canal volume after instrumentation with hand and rotary files and to evaluate and compare the volume percentage of root canals obturated (POV) with gutta-percha (GP), with various techniques using spiral computed tomography (SCT).
Materials and Methods: Sixty sound, noncarious, single-rooted extracted human teeth were sectioned at the cementoenamel junction. The specimens were divided into five groups based on the type of canal instrumentation and obturation technique used. Specimens were prepared with Hand Files and ProTaper Next and HyFlex CM rotary Files. The volume of root canal space was measured using SCT, and root canals were obturated (cold lateral condensation, cold flowable “GuttaFlow 2,” and single cone). A second SCT scan was performed to determine the POV of GP at coronal, middle, and apical third. The data were subjected to statistical analysis using one-way ANOVA and Tukey's post hoc multiple comparison tests.
Results: There was a highly significant difference in percentage of obturated volume between the groups at coronal, middle, and apical third, and also, there was a highly significant difference in the total percentage of obturated volume of canal between the groups.
Conclusion: No obturation technique produced void-free root canal fillings and the greatest POV was obtained with lateral condensation followed by single cone and least with cold flowable obturation technique. Lateral condensation and single-cone technique showed 100% POV in the apical third region and GuttaFlow 2 had the maximum voids.

Keywords: Cold lateral condensation, GuttaFlow 2, Single cone, Spiral computed tomography


How to cite this article:
Singh J, Aggarwal A, Mann NS, Jhamb A. Volumetric analysis of hand and rotary root canal instrumentation using different obturation techniques: An in vitro spiral computed tomography study. Endodontology 2019;31:45-50

How to cite this URL:
Singh J, Aggarwal A, Mann NS, Jhamb A. Volumetric analysis of hand and rotary root canal instrumentation using different obturation techniques: An in vitro spiral computed tomography study. Endodontology [serial online] 2019 [cited 2019 Jul 23];31:45-50. Available from: http://www.endodontologyonweb.org/text.asp?2019/31/1/45/260522


  Introduction Top


As microorganisms are the main etiological factor in pulpitis and apical periodontitis, their elimination during root canal treatment by instrumentation, irrigation, and intracanal medication is essential.[1] The most important factors for successful root canal treatment are biomechanical instrumentation, disinfection of the “corridor of sepsis,” and three-dimensional (3D) obturation of this root canal space that is challenging.[2] To have 3D obturation, the obturating material must adapt to all the portions of the root canal.[3]

Voids created by inadequate fusion of the gutta-percha (GP) cones, penetration of bacterial toxins, and their flow into periapical tissue from oral cavity jeopardize the endodontic treatment success.[4] The Washington study of endodontic success and failures indicates that nearly 60% of the failures are apparently caused by incomplete obturation and it is indispensable that the obturation should have a fluid-tight seal.[5]

Several materials and techniques have been developed for achieving a successful obturation. GP is the most commonly used root canal obturation material and its physical properties have made it possible to use it in several different techniques.[3]

Cold lateral condensation is the technique of choice by many dental practitioners for years and serves as the gold standard against the new techniques for comparison and having advantage of excellent controlled placement of GP. One of the most recent techniques which use cold flowable filling system for obturation of the root canal system is “GuttaFlow 2” which is a combination of sealer and GP powder.[3] With the introduction of Ni–Ti rotary instruments for canal preparation, a simple and time efficient obturation technique, i.e., matched tapered single-cone obturation has become popular which closely matches the geometry of rotary instrumentation systems.

The quality of root fillings has been assessed through different experimental approaches such as acid dissolution of roots, electrochemical method, fluid filtration, dye penetration, radiographs, sections of the sample, and scanning electron microscopy analysis of interface between the filling material and the canal wall. They provide semi-quantitative results showing a high level of variation.[6] Hence, the rationale of this study was to check the 3D obturation of the root canal using spiral computed tomography (SCT) without sectioning the specimens and loss of material.

Among the previous studies which have compared the POV of various obturating techniques using different methods, very limited studies involve the single-cone technique which is the most common method of obturation in recent years.[7],[8],[9]


  Materials and Methods Top


This in vitro study was conducted for the thesis project in the Department of Conservative Dentistry and Endodontics, National Dental College, Dera Bassi. A sample size of sixty sound, noncarious intact single-rooted human teeth was collected from the Department of Oral and Maxillofacial Surgery, National Dental College, Dera Bassi. The collected teeth were stored in 3% sodium hypochlorite solution for 1 week and later transferred to normal saline.

Inclusion criteria

  • Single-rooted, sound, noncarious teeth
  • Teeth with round canals
  • Teeth with mature apex
  • Teeth without defects such as cracks and calcifications were included in the study.


Exclusion criteria

  • Multirooted teeth
  • Teeth with oval canals
  • Teeth with open apex
  • Teeth with defects (cracks and calcifications)
  • Teeth with fracture or lacking Vertucci Type I canal
  • Teeth with resorbed roots were excluded from the study.


Preparation of specimens

The selected teeth were sectioned at the cementoenamel junction (CEJ) with a diamond disc to standardize root length to 13 mm. Working length was determined by placing a 15 size K file in the canal till the file tip was seen at the apex and then retrieving 0.5 mm short of the apex. The teeth were then divided into five groups based on the type of canal instrumentation and obturation technique used.

The specimens were randomly divided into the following groups:

Group A: Specimens prepared using Hand files (crown-down technique) and obturated with cold lateral condensation.

Group B: Specimens prepared using ProTaper Next rotary files and obturated with single-cone technique.

Group C: Specimens prepared using ProTaper Next rotary files and obturated with GuttaFlow 2.

Group D: Specimens prepared using HyFlex CM rotary files and obturated with single-cone technique.

Group E: Specimens prepared using HyFlex CM rotary files and obturated with GuttaFlow 2.

Preparation of a root canal

Group A: Specimens were prepared using Hand files (crown-down technique). Apical enlargement was done to size 30 K File.

Groups B and C: Specimens were prepared using ProTaper Next rotary files (Dentsply/Maillefer). Apical enlargement was done to size 30 and 7% taper with the crown-down technique.

Groups D and E: Specimens were prepared using HyFlex CM rotary files (Coltene). Apical enlargement was done to size 30 and 6% taper with the crown-down technique.

Glyde File Prep (Dentsply) was used as a lubricant in each group. One milliliter of 3% sodium hypochlorite was used as an irrigant after each instrumentation for a 1 min period. Finally, 1 ml of 17% ethylenediaminetetraacetic acid (AvuePrep+) was used for canal irrigation to enable the removal of the smear layer.

Scanning the specimens using spiral computed tomography

The specimens were mounted on cold cure acrylic plate and scanned using a SOMATOM Scope (Siemens AG, Wittelsbacherplatz 2, Muenchen, Germany). They were then viewed under high resolution both in cross section and longitudinal section with a constant thickness of 1 mm/slice and a constant spiral or table speed of 0.5 and 140 kvp. The scanner was then transferred to DICOM viewer (OsiriX) for image analysis. Each tooth was viewed for section of 12 slices where coronal, middle, and apical third was calculated for 4 sections each. Apical and coronal 0.5 mm were excluded from the calculations. The inner area of each slice was measured, and the volume was calculated by multiplying the area by the slice thickness (1 mm). Finally, the total volume of each canal was calculated by summing up. The volume was also calculated separately for apical, middle, and coronal third of root canals.

Obturation of a root canal

GuttaFlow 2 (Coltene) was used as a root canal sealer in all the groups. All the canals were dried with paper points. The canals were coated with the sealer using a lentulospiral (Mani, Japan) placed in low-speed handpiece. Lentulospiral was introduced into the root canal to a location 3-4 mm short of the working length and then slowly withdrawn from the canal, with continuous rotation.

Obturation was done as follows

Group A: Cold lateral condensation: A size 30 GP (Dentsply/Maillefer) with 2% taper was coated with the sealer and placed in the canal to the working length with tug back. Lateral condensation was achieved, with additional accessory cones which were also coated with the sealer, using a standardized finger spreader starting 1 mm short of working length. When the points prevented the spreader penetration beyond the coronal third of the canal, the canal was considered to be adequately filled and excess GP was removed at CEJ using a heated condenser. GP at CEJ was compacted using a cold plugger.

Group B: Single-cone obturation: A size 30 GP point of 7% taper (Dentsply/Maillefer) coated with the sealer was used as a master cone and was placed in the canal up to the working length. The excess cone was removed at CEJ using a heated condenser. GP at CEJ was compacted using a cold plugger.

Group C: Cold flowable obturation: The needle of GuttaFlow 2 (Coltene) was inserted into the root canal up to the level 2–3 mm short of working length. The trigger was pulled slowly and backfill was completed up to the root canal orifice. During obturation, the needle was pushed back simultaneously by GuttaFlow 2 paste being filled.

Group D: Single-cone obturation: A size 30 GP point of 6% taper (Dentsply/Maillefer) coated with the sealer was used as a master cone and was placed in the canal up to the working length. The excess cone was removed at CEJ using a heated condenser. GP at CEJ was compacted using a cold plugger.

Group E: Cold flowable obturation: The needle of GuttaFlow 2 (Coltene) was inserted into the root canal up to the level 2–3 mm short of working length. The trigger was pulled slowly and backfill was completed up to the root canal orifice. During obturation, the needle was pushed back simultaneously by GuttaFlow 2 paste being filled.

Scanning the specimens using spiral computed tomography

A second SCT scan was performed to determine POV of GP. POV in the coronal, middle, and apical third was also calculated individually.

Each tooth was viewed for a section of 12 slices for the presence of void space. In the specimens where the void space was seen, the inner area of the void was measured and multiplied by a slice thickness to get the volume of the void [Figure 1].
Figure 1: DICOM viewer showing voids in obturation

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The volume percentage (POV) was calculated by the formula: (a–b × 100/a).

Where, a is volume of a root canal space and b is volume of void space.

Statistical analysis

The data were subjected to statistical analysis using IBM SPSS version 16. The level of significance was set at P < 0.05 and with a confidence interval level of 95%.

Inter- and intra-group comparisons were done with one-way ANOVA followed by a pairwise comparison with Tukey's post hoc test. The statistical data obtained were analyzed for discussion and conclusion.


  Results Top


Within the limitations of this study, the results showed that there was a highly significant difference in the percentage of obturated volume between the groups at coronal, middle, and apical third, [Figure 2], and also, there was a highly significant difference in the total percentage of obturated volume of canal between the groups [Table 1] and [Table 2].
Figure 2: Bar chart for comparison of mean obturated volume in five groups (%)

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Table 1: One-way ANOVA

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Table 2: ANOVA for subgroups

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  Discussion Top


The most important factors for a successful root canal treatment are biomechanical instrumentation of the root canal, disinfection, and dissolution of organic matter to eliminate bacterial pathogens and 3D obturation of this space.[2] Voids created by an inadequate fusion of the GP cones, penetration of bacterial toxins, and their flow into periapical tissue from oral cavity jeopardize the endodontic treatment success.[4]

In the present study, sound, noncarious intact single-rooted human teeth were used. Mandibular premolars and maxillary central incisor with round canals were selected through standard periapical images taken from both mesiodistal and buccolingual directions using a radiovisiography. Teeth with oval canals, open apex, and defects (cracks and calcifications) were discarded. Single-rooted teeth with single patent round root canal were selected for the study to minimize anatomic variation and to achieve standardization.[10]

The results of this study revealed that none of the scanned root canal fillings (lateral condensation, single cone, and cold flowable) were void free. These outcomes corroborate studies by other authors.[8],[11],[12]

The results of this study have depicted that the lateral condensation group showed overall (99.2%) percentage of obturated volume of canal (POV). Crasta et al.[6] did volumetric analysis of root canals obturated with cold lateral condensation, single-cone, and thermoplasticized GP techniques using SCT and reported that lateral condensation group had overall 100% POV. These results were in accordance with our study.

In the present study, no voids were seen in apical third in both lateral condensation and single-cone technique, both groups had 100% POV at apical third, and the same results were seen in study done by Kocak and Yaman, 2012.[13]

Crasta et al.[6] did volumetric analysis of root canals obturated with GP with various techniques using SCT and reported that single-cone group had overall 98.3% POV, and also, single-cone obturation showed the least POV in the middle third. These results were similar to the results of our study in which the single-cone groups (Group B and Group D) showed overall (98.2%) percentage of obturated volume of canal (POV).

The results of this study depicted that GuttaFlow 2 groups (Group C and Group E) in which cold flowable obturation was done had shown overall (80.5%) percentage of obturated volume of canal (POV).

The results of this study also depicted that, in GuttaFlow 2 group, the maximum voids were present in the apical region which had reduced the overall percentage of obturated volume and these results matched with the results of a study done by Bhatt et al., 2015.[14] The maximum voids present in the apical region may be due to the failure of the tip to reach the apical third, poor compaction, and entrapment of air. The minute voids, which were present within the core of the GuttaFlow 2, may be a result of the manufacturing process.

Bacterial leakage studies do not simulate exact clinical conditions, need long periods of observation, and do not allow quantification of the number of penetrating bacteria (Siqueira et al. 2000).[15] Recent studies have proved that SCT provides volumetric analysis of root fillings and remaining remnants of root fillings.[16],[17] Hence, the rationale of this study was to check the 3D obturation of the root canal using SCT without sectioning the specimens and loss of material. It is a noninvasive technique and the specimens can be used for further research. It is possible to reconstruct overlapping structures at arbitrary intervals and thus the ability to resolve small objects.[18] For the above reasons, we have used SCT to volumetrically analyze and compare the different obturation techniques.


  Conclusion Top


Within the limitations and parameters considered in the present study, it can be concluded that:

  1. No obturation technique produced void-free root canal fillings
  2. The greatest POV was obtained with lateral condensation followed by single-cone and least POV with cold flowable obturation technique (GuttaFlow 2)
  3. Lateral condensation and single-cone technique showed 100% POV in the apical third region
  4. GuttaFlow 2 had the maximum voids in the apical third region
  5. SCT appears to be a valuable tool to locate voids and to assess the efficacy of obturation at various levels.


Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
  References Top

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Resende LM, Rached-Junior FJ, Versiani MA, Souza-Gabriel AE, Miranda CE, Silva-Sousa YT, et al. Acomparative study of physicochemical properties of AH plus, epiphany, and epiphany SE root canal sealers. Int Endod J 2009;42:785-93.  Back to cited text no. 1
    
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von Fraunhofer JA, Fagundes DK, McDonald NJ, Dumsha TC. The effect of root canal preparation on microleakage within endodontically treated teeth: An in vitro study. Int Endod J 2000;33:355-60.  Back to cited text no. 2
    
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Senthil KP, Vivekananda PA, Kundabala M. A three-dimensional evaluation of density and homogeneity of root canal obturation with Guttaflow using backfilling technique in comparison with conventional lateral compaction technique using spiral computed tomography-an in vitro study. Endodontology 2008;20:43-50.  Back to cited text no. 3
    
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Benenati FW. Obturation of the radicular space. In: Ingle JI, Bakland LK, Baumgartner JC, editors. Endodontics. 6th ed. Hamilton: B.C. Decker; 2008. p. 1053-87.  Back to cited text no. 5
    
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Crasta SA, Nanjundasetty JK, Panuganti V, Marigowda JC, Kumar S, Kumar A. Volumetric analysis of root canals obturated with cold lateral condensation, single-cone and thermoplasticized gutta-percha techniques using spiral computed tomography: An in vitro study. Saudi Endod J 2014;4:64-9.  Back to cited text no. 6
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Kandaswamy D, Venkateshbabu N, Krishna RG, Hannah R, Arathi G, Roohi R, et al. Comparison of laterally condensed, vertically compacted thermoplasticized, cold free-flow GP obturations – A volumetric analysis using spiral CT. J Conserv Dent 2009;12:145-9.  Back to cited text no. 7
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Upadhyay V, Upadhyay M, Panday RK, Chturvedi TP, Bajpai U. A SEM evaluation of dentinal adaptation of root canal obturation with Guttaflow and conventional obturating material. Indian J Dent Res 2011;22:881.  Back to cited text no. 10
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Jung M, Lommel D, Klimek J. The imaging of root canal obturation using micro-CT. Int Endod J 2005;38:617-26.  Back to cited text no. 11
    
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Somma F, Cretella G, Carotenuto M, Pecci R, Bedini R, De Biasi M, et al. Quality of thermoplasticized and single point root fillings assessed by micro-computed tomography. Int Endod J 2011;44:362-9.  Back to cited text no. 12
    
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Koçak MM, Darendeliler-Yaman S. Sealing ability of lateral compaction and tapered single cone Gutta-Percha techniques in root canals prepared with stainless steel and rotary nickel titanium instruments. J Clin Exp Dent 2012;4:e156-9.  Back to cited text no. 13
    
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Bhatt A, Rajkumar B, Gupta V, Srivastava V. A comparative evaluation of volumetric analysis during Lateral condensation technique, GuttaFlow technique and thermoplasticized technique (System B and Thermafil) using spiral computed tomography:In vitro study. Int J Sci Res 2015;4:299-301.  Back to cited text no. 14
    
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Siqueira JF Jr., Rôças IN, Favieri A, Abad EC, Castro AJ, Gahyva SM, et al. Bacterial leakage in coronally unsealed root canals obturated with 3 different techniques. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2000;90:647-50.  Back to cited text no. 15
    
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Barletta FB, de Sousa Reis M, Wagner M, Borges JC, Dall'Agnol C. Computed tomography assessment of three techniques for removal of filling material. Aust Endod J 2008;34:101-5.  Back to cited text no. 16
    
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Hammad M, Qualtrough A, Silikas N. Three-dimensional evaluation of effectiveness of hand and rotary instrumentation for retreatment of canals filled with different materials. J Endod 2008;34:1370-3.  Back to cited text no. 17
    
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    Figures

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    Tables

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