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 Table of Contents  
ORIGINAL ARTICLE
Year : 2018  |  Volume : 3  |  Issue : 1  |  Page : 36-41

Three-dimensional assessment of root canal morphology of human deciduous molars using cone beam computed tomography: An In vitro Study


Department of Pedodontics and Preventive Dentistry, Mamata Dental College, Khammam, Telangana, India

Date of Web Publication20-Mar-2018

Correspondence Address:
Dr. N Venugopal Reddy
Department of Pedodontics and Preventive Dentistry, Mamata Dental College, Khammam, Telangana
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ijpr.ijpr_21_17

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  Abstract 


Background: Endodontic treatment involves cleaning, shaping, and obturation of the root canal system which requires knowledge of root canal morphology and its commonly occurring variation. Aim: The aim of the present study was to assess the variations in number and morphology of deciduous molar teeth using cone beam computed tomography (CBCT) an auxiliary imaging modality. Materials and Methods: A total of ninety recently extracted deciduous molar teeth were collected which are divided into four groups: Group I: mandibular first molars (n = 22), Group II: maxillary first molars (n = 18), Group III: mandibular second molars (n = 21), Group IV: maxillary second molars (n = 29). The length of the roots, angulation of the roots, number of the root canals, curvature of the root canals, and the type of root canals were determined using CBCT. Statistical Analysis: Descriptive statistics were used to find out the frequency, mean, standard deviation, and range of all the five parameters. Results: CBCT showed that the distobuccal root of primary maxillary molars had the greatest angulation, whereas, in deciduous mandibular molars, distal root has the greatest angulation. S-shaped canals were more common in the palatal root of maxillary molars, and curved canals were more common in the mesial root in mandibular molars. Conclusions: CBCT was found to be an effective and accurate diagnostic tool which provides an auxiliary imaging technology to assess the root canal morphology of primary teeth.

Keywords: Cone beam computed tomography, primary teeth, root canal morphology


How to cite this article:
Reddy N V, Daneswari V, Patil R, Meghana B, Reddy A, Niharika P. Three-dimensional assessment of root canal morphology of human deciduous molars using cone beam computed tomography: An In vitro Study. Int J Pedod Rehabil 2018;3:36-41

How to cite this URL:
Reddy N V, Daneswari V, Patil R, Meghana B, Reddy A, Niharika P. Three-dimensional assessment of root canal morphology of human deciduous molars using cone beam computed tomography: An In vitro Study. Int J Pedod Rehabil [serial online] 2018 [cited 2019 Nov 22];3:36-41. Available from: http://www.ijpedor.org/text.asp?2018/3/1/36/227950




  Introduction Top


Dental caries and dental trauma are the two main etiologic factors responsible for pulp involvement necessitating treatment to maintain the integrity of oral tissues. Endodontic procedures for the treatment of deciduous teeth are indicated if the canals are accessible and there is evidence of essential normal supporting bone.[1]

This knowledge of the anatomy of root canal systems is an essential prerequisite for endodontic treatment. Many of the problems encountered during and after root canal treatment occur because of inadequate understanding of the pulp space anatomy. Studies on the internal and external anatomy of teeth have shown that anatomic variations can occur in all groups of teeth and can be extremely complex.[2]

Pulpectomy of primary teeth is indicated when the dental pulp is nonvital or irreversibly inflamed. However, as the primary teeth may show bizarre internal geometry of the pulp cavity, with features not commonly observed in permanent teeth, such as connections involving furcations and horizontal anastomosis, endodontic treatment of primary teeth is considered highly complicated.[3]

There are numerous reports on the root canal morphologies of different populations, which is extremely important for a pedodontist as well as general dental practitioners. The methods most commonly used in analyzing the root canal morphology are canal staining and tooth clearing, conventional radiographs, digital and contrast medium-enhanced radiographic techniques, radiographic assessment enhanced with contrast media, and more recently computed tomographic techniques.[4]

However, as root resorption of primary teeth begins, dentin is deposited within the root canal system and may change the number, size, and/or shape of the root canals significantly. The presence of necrotic pulp or the unsuccessful outcome of pulpotomy procedures may make endodontic therapy of the root canal systems desirable if extraction of the tooth is to be avoided.[5]

The purpose of this study was to assess the variations in the length, angulation of the roots, type of canals, number of root canals, and root canal curvature using a cone beam computed tomography (CBCT) which provides a three-dimensional (3D) visualization of the internal and external root canal anatomy.


  Materials and Methods Top


A total of 1000 primary molars were collected from the Department of Pedodontics and Preventive Dentistry, Khammam, and from different private practices in and around Khammam district. Out of the sample procured, only ninety primary molars with at least two-third root length and without any evidence of root fracture were used in the study.

These samples were then divided into four groups:

  • Group I: Mandibular first molars (n = 22)
  • Group II: Maxillary first molars (n = 18)
  • Group III: Mandibular second molars (n = 21)
  • Group IV: Maxillary second molars (n = 29).


To remove any debris or attached tissue remnants, all teeth were cleaned with soap and washed using vigorous amount of ultrapure water. Hand scalers were used to remove calculus if present on the root surface and stored in individual glass container containing 10% formalin solution while waiting for further experimentation. The teeth were mounted in a straight line on the modeling wax after determining the various aspects of the tooth, i.e., buccal, lingual, mesial and distal, so as to maintain uniformity in the samples [Figure 1].
Figure 1: Teeth mounted on wax for cone beam computed tomography.

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The mounted teeth were then scanned using CBCT scanner (KODAK-9000 3D, Carestream Dental, USA) and ported to the vision preview screen for 2D and 3D reconstruction images in three planes, i.e., sagittal, axial, and coronal [Figure 2]. An experienced radiologist acquired the images according to the manufacturer's instructions. The whole CBCT imaging protocol was carried by a registered dental radiologist following the as low as reasonably practicable protocol. Two examiners evaluated the CBCT images: a senior postgraduate (PG) pedodontist student (Examiner 1) and a certified oral and maxillofacial radiologist (Examiner 2). Before evaluation of the CBCT images, adequate training of the PG student in image processing and reconstruction was conducted. Then, case definitions and criteria for reading and recording data were set.
Figure 2: Cone beam computed tomography imaging technology.

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Once the sample data were acquired or data for a sample were loaded, the software immediately reconstructs the tooth images in sagittal, axial, and coronal planes. The length and the angulation of each root were measured by taking the maximum length from the apex of the tooth to the greatest area of constriction at the cementoenamel junction. The length of the roots, angulation of the roots, number of the root canals, curvature of the root canals, and the type of root canals were determined [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7].
Figure 3: Length of roots.

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Figure 4: Angulation of roots.

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Figure 5: Number of root canals.

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Figure 6: Shape of canals.

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Figure 7: Type of the canals.

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Statistical analysis

The readings obtained during the scanning procedure were put to statistical analysis. Descriptive statistics were used to find out the frequency, mean, standard deviation, and range for all the five parameters: (1) Length of roots; (2) angulation of the roots; (3) number of the root canals; (4) type of the root canal (Vertucci's classification); and (5) curvature of root canals


  Results Top


The mean root length of the maxillary molar teeth was considered; it was found that palatal root was found to be longest while distobuccal root was shortest. In mandibular molars, the mesial root is longer than distal root [Table 1]. On comparing the mean root angulation of the teeth, it was found that the distobuccal root of primary maxillary molars had the greatest angulation, whereas in deciduous mandibular molars, distal root had the greatest angulation [Table 2]. When the number of root canals in the teeth was considered, in maxillary molars, single root canals are found in most of the teeth specimens whereas mesial root of all mandibular molars had two canals (100%) whereas distal root showed single canal (77.3%) [Table 3]. Vertucci's classification Type I or Type IV type canals were found in all the primary molar teeth specimens [Table 4]. S-shaped canals were more commonly seen in the palatal root of maxillary molars, and curved canals were seen in the mesial root in mandibular molars [Table 5].
Table 1: Length of the roots

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Table 2: Angulation of roots

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Table 3: Number of roots and canals

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Table 4: Type of canals (Vertucci's classification)

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Table 5: Shape of canals

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  Discussion Top


Knowledge of the size, morphology, and disparity of the root canals of primary teeth are helpful in visualizing the pulp cavity during treatment. Since primary teeth exhibit morphologic differences from the permanent teeth both in size, external and internal morphology, successful endodontic treatment lies in understanding the complex root canal system. Many of the errors occur during the access cavity preparation or when locating the canal orifices, which is dependent on the dentists' tactile perception and knowledge of the dental anatomy.[6]

In the present study, CBCT was found to be an effective and accurate diagnostic tool which provides an auxiliary imaging modality to supplement conventional radiography in difficult situations demanding localization and description of root canal systems because of its ability to render 3D information.[7],[8]

In Group I and III, the mean length of the mesial root was longer than the distal root. In Group II, the mesiobuccal root showed longest measurement (7.85 mm) followed by palatal root and distobuccal root, which was in accordance with Bagherian et al., but in contrast to the findings of Zoremchhingi et al.[1],[9] This difference might be attributed to the different populations examined. In Group IV, the palatal root showed the longest measurement (8.95 mm) followed by mesiobuccal root and the distobuccal root; these results were in accordance with the study conducted by Gaurav et al. on primary molars.[7] Better knowledge of root length may be useful for determining the working length which prevents over or under instrumentation wherein debris removal might be hampered.

In the present study, mean root angulation of the deciduous molars, it was found that the distobuccal root of primary maxillary molars had the greatest angulation (84.24°), whereas in deciduous mandibular molars, distal root had the greatest angulation (90.64°), the present results were slightly varied when compared to the results obtained by Gaurav et al. on primary molars.[7] These angulations help in determining the amount of file precurving for easier access to the root canal during pulpectomy procedures so that endodontic mishaps such zipping, transportation can be avoided.

The results of this study indicated that all the deciduous mandibular first molars had two roots (100%) and 2–4 root canals. These results were in agreement with the studies conducted by Gupta and Grewal and Hibbard and Ireland [10],[11] Most of the in vivo and in vitro studies have shown that deciduous mandibular first molars have two or three roots with three or four root canals. A radiographic study of extracted mandibular first molar with three distal canals was noticed which occurs only in 1.7% of cases. Further review of endodontic literature also reveals that the mandibular first molar presenting with three distal canals was a rare phenomenon.[12] A deciduous mandibular first molar with three distal canals was first reported by Berthiaume; however, the three distal canals ended in two apical foramina. Reuben et al. using spiral computerized tomography examined 125 mandibular first molars in an Indian population, and none of the teeth had three distal canals.[13],[14] Gupta et al. reported three case reports where he observed primary bifurcated maxillary left canine, primary three-rooted mandibular right first molar, and a third case having bilaterally primary three-rooted mandibular first and second molars.[15]

All the teeth specimens in this study were of Vertucci classification Type I and Type IV; therefore, if there were two root canals in one root, these two canals were completely separated, which is in agreement with the study conducted by Bagherian et al.[1]

In the present study, curved and straight profiles of the root canals were dominant in all classes. S-shaped curvature was observed only in primary maxillary molars, especially in the palatal root of second maxillary molars. Since curvature of the root canal may pose problems such as perforation during the cleaning procedure, more detailed knowledge of the frequency of these curvature types may be beneficial for avoiding this kind of complication.

As there is sparse availability of literature on the study of root and canal morphology of primary molars, it is necessary to conduct further studies with a larger sample size in different groups of population with more advanced techniques such as high-resolution CBCT, microcomputed tomography, and peripheral quantitative computed tomography. These studies will further aid the pedodontist as well as the general dentist in gaining thorough knowledge regarding primary root canal morphology which will lead to success of pulp therapy in primary teeth.


  Conclusions Top


CBCT was found to be an effective and accurate diagnostic tool to study the root length, angulation, and root canal morphology of primary teeth. The distobuccal root of primary maxillary molars had the greatest angulation, whereas, in deciduous mandibular molars, distal root showed the greatest angulation. One or two root canals are found in mesial and distal roots of primary mandibular molars. In maxillary molars, single root canals are found in most of the teeth specimens. Only Type I or Type IV type of canals is found in all the primary molar teeth specimens. Curved canals were more common in the mesial roots in mandibular molars with S-shaped canals more predominantly seen in the palatal roots of maxillary molars.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Bagherian A, Kalhori KA, Sadeghi M, Mirhosseini F, Parisay I. An in vitro study of root and canal morphology of human deciduous molars in an Iranian population. J Oral Sci 2010;52:397-403.  Back to cited text no. 1
    
2.
Boruah LC, Bhuyan AC. Morphologic characteristics of root canal of mandibular incisors in North-East Indian population: An in vitro study. J Conserv Dent 2011;14:346-50.  Back to cited text no. 2
[PUBMED]  [Full text]  
3.
Aminabadi NA, Farahani RM, Gajan EB. Study of root canal accessibility in human primary molars. J Oral Sci 2008;50:69-74.  Back to cited text no. 3
    
4.
Neelakantan P, Subbarao C, Subbarao CV. Comparative evaluation of modified canal staining and clearing technique, cone-beam computed tomography, peripheral quantitative computed tomography, spiral computed tomography, and plain and contrast medium-enhanced digital radiography in studying root canal morphology. J Endod 2010;36:1547-51.  Back to cited text no. 4
    
5.
Salama FS, Anderson RW, McKnight-Hanes C, Barenie JT, Myers DR. Anatomy of primary incisor and molar root canals. Pediatr Dent 1992;14:117-8.  Back to cited text no. 5
    
6.
Velmurugan N, Venkateshbabu N, Abarajithan M, Kandaswamy D. Evaluation of the pulp chamber size of human maxillary first molars: An institution based in vitro study. Indian J Dent Res 2008;19:92-4.  Back to cited text no. 6
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7.
Gaurav V, Srivastava N, Rana V, Adlakha VK. A study of root canal morphology of human primary incisors and molars using cone beam computerized tomography: An in vitro study. J Indian Soc Pedod Prev Dent 2013;31:254-9.  Back to cited text no. 7
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Patel S, Horner K. The use of cone beam computed tomography in endodontics. Int Endod J 2009;42:755-6.  Back to cited text no. 8
    
9.
Zoremchhingi JT, Varma B, Mungara J. A study of root canal morphology of human primary molars using computerised tomography: An in vitro study. J Indian Soc Pedod Prev Dent 2005;23:7-12.  Back to cited text no. 9
    
10.
Gupta D, Grewal N. Root canal configuration of deciduous mandibular first molars – An in vitro study. J Indian Soc Pedod Prev Dent 2005;23:134-7.  Back to cited text no. 10
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11.
Hibbard ED, Ireland RL. Morphology of the root canals of the primary molar teeth. J Dent Child 1957;24:250-7.  Back to cited text no. 11
    
12.
Neha, Kansal R, Kharbanda A, Mehta SD, Kriti. 3-D visualization of a mandibular first molar with three distal root canals using spiral CT and volume rendering technique: A case report. Int J Clin Dent 2008;6:86-96.  Back to cited text no. 12
    
13.
Agarwal M, Trivedi HP, Gupta M, Mittal S. Endodontic management of mandibular first molar with three distal root canals. J Endod 2008;34:116-9.  Back to cited text no. 13
    
14.
Kaushik A, Talwar S, Yadav S, Chaudhary S, Nawal RR. The role of cone beam computed tomography in the endodontic management of a mandibular first molar with three distal canals. Dent Res J (Isfahan) 2014;11:700-4.  Back to cited text no. 14
    
15.
Gupta S, Nagaveni NB, Chandranee NJ. Three-rooted mandibular first primary molar: Report of three cases. Contemp Clin Dent 2012;3:S134-6.  Back to cited text no. 15
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7]
 
 
    Tables

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


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