Indian Journal of Dental ResearchIndian Journal of Dental ResearchIndian Journal of Dental Research
HOME | ABOUT US | EDITORIAL BOARD | AHEAD OF PRINT | CURRENT ISSUE | ARCHIVES | INSTRUCTIONS | SUBSCRIBE | ADVERTISE | CONTACT
Indian Journal of Dental Research   Login   |  Users online:

Home Bookmark this page Print this page Email this page Small font sizeDefault font size Increase font size         

 


 
Table of Contents   
ORIGINAL ARTICLE  
Year : 2022  |  Volume : 33  |  Issue : 1  |  Page : 14-17
Root canal morphology of primary molars – A cone beam computed tomography (CBCT) study


1 Department of Pediatric Dentistry, College of Dental Medicine, Nova Southeastern University, Florida, USA
2 Department of Oral Medicine and Radiology, Maulana Azad Institute of Dental Sciences, New Delhi, India
3 Division of Pedodontics and Preventive Dentistry, Centre for Dental Education and Research (CDER), All India Institute of Medical Sciences, New Delhi, India

Click here for correspondence address and email

Date of Submission26-Jul-2020
Date of Decision08-Mar-2021
Date of Acceptance12-Apr-2022
Date of Web Publication09-Aug-2022
 

   Abstract 


Objectives: To evaluate the root and canal morphology of primary maxillary and mandibular molars in an Indian population using cone-beam computed tomography (CBCT). Methods: A retrospective cross-sectional study was performed, where CBCT scans of children less than 10 years of age taken for valid diagnostic purposes previously were considered and images were analyzed. The number of roots, root canals, and variations in morphology were recorded. Left–right symmetry was also noted. Results: A total of 433 deciduous maxillary and mandibular primary molars were studied. It was observed that two separate roots with three separate canals were common in primary mandibular first molars, whereas two separate roots with two canals in each root were common in mandibular second primary molars. In primary maxillary molars, three separate roots with one canal each were the most common. Maxillary first molars (17.21%) and 17.35% second molars had fused distobuccal and palatal roots. It was observed that primary maxillary molars showed more left–right symmetry (86.7% in first molars and 82.7% in second molars) compared to primary mandibular molars (54.05% in first molars and 68% in second molars). Conclusions: It was concluded that in both primary maxillary first and second molars, three separate roots, a mesiobuccal root, a distobuccal root, and a palatal root with one canal in each root, were the most common. Two separate roots with three separate canals were the most common in primary mandibular first molars, whereas two separate roots with two canals each in both roots were more common in mandibular second primary molars.

Keywords: CBCT, primary molars, primary teeth, root canal morphology

How to cite this article:
Dhillon JK, Ghosh S, Mathur VP. Root canal morphology of primary molars – A cone beam computed tomography (CBCT) study. Indian J Dent Res 2022;33:14-7

How to cite this URL:
Dhillon JK, Ghosh S, Mathur VP. Root canal morphology of primary molars – A cone beam computed tomography (CBCT) study. Indian J Dent Res [serial online] 2022 [cited 2022 Sep 29];33:14-7. Available from: https://www.ijdr.in/text.asp?2022/33/1/14/353543



   Introduction Top


Primary teeth often show bizarre root canal anatomy,[1] and exception is often the norm. This necessitates that the clinician acquires a thorough knowledge of the root canal anatomy and morphology. The various methods of studying the root canal morphology include radiographic methods,[2],[3] clearing techniques,[4],[5] direct observation with a microscope,[6] 3D re-construction,[7] macroscopic sections,[8] and computed tomography.[9]

Recently, cone-beam computed tomography (CBCT) has gained traction as a diagnostic tool in endodontic procedures because of its accuracy in determining the root and canal morphology in permanent teeth. The scanning times are shorter with CBCT, and the radiation dosage is 15–100 times less than that in conventional CT. CBCT has isotropic voxels which are equal in all three dimensions, which helps in achieving a sub-millimetre resolution.[10] Moreover, the image could be analysed, altered, and re-constructed by the computer, and it is non-invasive. However, few studies have been performed using CBCT to study the primary teeth morphology. Thus, this study was undertaken to evaluate the root and canal morphology of primary maxillary and mandibular molars in an Indian population using CBCT.


   Methodology Top


The study was a retrospective cross-sectional study, where CBCT scans of children less than 10 years of age taken for valid diagnostic purposes previously were considered and images were analysed. The collection of data was approved by the institutional ethics committee via a letter dated 25/02/2011; Ref. No.IEC/NP-23/2011. CBCT images taken using a single machine [iCAT machine (Imaging Sciences International, Hatfield, PA)] were used to ensure uniformity. The scans were viewed and analysed using i-CAT Vision software (version 1.9.3.14) with a scan time of 22 seconds and a re-construction time of 2–3 minutes (FOV- 13/16, resolution 0.250 Voxels in three axes, horizontal and vertical sections - 0.25 mm). Teeth with root resorption, peri-apical lesions, and/or root canal treatment were excluded to ensure the integrity of the original morphology. The number of roots, the number of canals, and variations in morphology were recorded by two examiners. Left–right symmetry was also noted when both the left and right counterparts of a tooth were present in the respective arch. The experimental data are represented as categorical variables.


   Results Top


A total of 433 deciduous molars were studied, which included both 220 maxillary primary molars (99 first and 121 second molars) and 213 mandibular primary molars (95 first and 118 second molars). The root canal morphology of primary mandibular molars was categorized into seven main variants [Table 1], [Figure 1]a as given by Yang R et al. (2013).[11] Another variant (variant eight) was seen, in which deciduous molars had two roots with one mesial canal and two separate distal canals. However, a taurodont was observed in a primary mandibular first molar and C- shaped canal and was observed in two primary mandibular second molars. The morphology of mandibular primary molars as observed in the present study is depicted in [Figure 1]a. The root canal morphology of primary maxillary molars was also categorised into nine main variants [Table 1], [Figure 1]b. The distribution of variants in primary maxillary molars is shown in [Table 2], and the distribution of variants in mandibular primary first and second molars is shown in [Table 3]. It was observed that two separate roots with three separate canals (variant 2) were the most common in primary mandibular first molars, whereas two separate roots with two canals in the mesial root and two canals in the distal root (variant 3) were more common in mandibular second primary molars. In both primary maxillary first and second molars, three separate roots with one canal in each root (variant 1) were the most common. Maxillary first molars (17.21%) and 17.35% second molars had fused distobuccal and palatal roots. Primary maxillary molars showed more left–right symmetry (86.7% in first molars and 82.7% in second molars) as compared to mandibular molars (54.05% in first molars and 68% in second molars) [Table 4]. The inter-examiner reliability (Kappa) was found to be 0.87, which indicates a high level of agreement between the different examiners.
Table 1: The categorisation of the variants in primary mandibular molars (Yang R et al. 2013)[11] and primary maxillary molars

Click here to view
Figure 1: (a). Variants found in primary mandibular molars in the study. (b). Variants found in primary maxillary molars in the study

Click here to view
Table 2: Distribution and percentages of the different categories of variants in root canal anatomy of primary maxillary molars

Click here to view
Table 3: Distribution and percentages of the seven categories of variants in root canal anatomy of primary mandibular molars

Click here to view
Table 4: Distribution of left–right symmetrical pairs in primary mandibular molars

Click here to view



   Discussion Top


In the present study, we used CBCT to evaluate the numbers of roots and canals in 433 primary molars. Canal staining and tooth clearing are generally considered the gold standard for studying the root canal morphology. The drawbacks of this method include disturbance of the pulp space and its surrounding structures during preparation of the teeth, difficulty in collecting a large number of extracted teeth, infection control, storage of teeth, extensive laboratory set-up, time spent, and inability to use in vivo.[12] The most commonly used method in vivo is conventional radiography. However, this technique has the drawbacks of super-imposition of roots and root canals. Moreover, it is a 2D representation of a 3D object. Studies involving contrast radiography have shown that it results in the entrapment of air bubbles, hampering proper visualisation.

Several studies using CBCT have been performed for studying the root and canal morphology of permanent teeth. It is non-invasive and can provide an accurate 3D image in vivo of the dentomaxillofacial region. CBCT scanning is as accurate as canal staining and clearing techniques in identifying root canal anatomy. Studies have also shown that CBCT is more accurate and reliable than peri-apical radiographs for tooth-length and root-length determination because there is no distortion.[13] The volumetric data can also be re-constructed to produce a view that is perceived as true 3D. All teeth can be visualised in a single scan, thus obviating the need for several exposures for multiple 2D images.[14] Thus, CBCT was used in the present study to study the morphology of primary molars.

Zoremchhingi et al. (2005) observed that 53.3% maxillary first molars had fused distobuccal and palatal roots and 46.7% had three roots using CT. All the primary maxillary second molars had three roots. It was observed that 93.33% maxillary first molars had three canals and 6.67% had four canals. It was observed that 53.3% maxillary second molars had two mesial canals, 26.6% had two distal canals, and 40% had two palatal canals.[9],[10]

In the present study, however, 17.31% primary maxillary first molars had fused distobuccal and palatal roots and 78.81% had three roots. It was observed that 83.9% primary maxillary first molars had three canals and 12.11% had four canals. This is similar to the study conducted by Ozcan G et al. (2016),[15] who observed that maxillary molars often had a single canal in each root. In another study by Katge F and Wakpanjar M (2018),[16] all maxillary molars had three roots with one canal each and mesial roots of mandibular first (80%) and mandibular second (100%) molars showed two canals, which is similar to our study.

Aminabadi et al. (2008)[17] observed that 29.1% (n = 10) primary second molars had four canals, namely, a mesiobuccal canal, a distobuccal canal, a palatal canal, and a separate distal canal. In the present study, 21.48% primary maxillary second molars had four canals.

Bagherian et al. (2010)[18] observed that 7.4% primary first molars had an MB2 canal and 3.7% had two canals in the DB root, whereas all the second primary molars had three canals. Gaurav V et al. (2013)[19] used CBCT to study the root canal morphology in primary molars and reported that all molars (n = 15) in their study had three canals. In the present study, 12.11% primary maxillary first molars and 22.31% second molars had an MB2 canal.

In the study by Yang R et al. (2013),[11],[12] the majority of primary mandibular second molars had two (72.28%) roots. The symmetrical incidence of three-root primary mandibular second molars was 50.65%. Three canals were seen in 25.26% of primary mandibular second molars, and four canals were seen in 73.31%.

In the present study, it was observed that 90.67% primary mandibular second molars had two roots and 40.68% had three canals and 55.08% had four canals. Sim D and Mah Y (2019)[20] observed that the canal morphology was more symmetric in primary mandibular molars than in maxillary molars, whereas in our study, symmetry was observed more in maxillary molars, and this could be because of different populations studied. This can help clinicians predict the root canal morphology on the opposite side if endodontic treatment is needed in molars on both sides.


   Conclusion Top


It was concluded that in both primary maxillary first and second molars, three separate roots with one canal in each root were the most common type of morphology seen. Two separate roots with three separate canals were the most common morphologic type seen in primary mandibular first molars, whereas two separate roots with two canals in each root were more common in mandibular second primary molars.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
   References Top

1.
Kurthukoti AJ, Sharma P, Swamy DF, Shashidara R, Swamy EB. Computed tomographic morphometry of the internal anatomy of mandibular second primary molars. Int J Clin Pediatr Dent 2015;8:202-7.  Back to cited text no. 1
    
2.
Pineda F, Kuttler Y. Mesiodistal and buccolingual roentgenographic investigation of 7,275 root canals. Oral Surg Oral Med Oral Pathol 1972;33:101-10.  Back to cited text no. 2
    
3.
Weine FS, Hayami S, Hata G, Toda T. Canal configuration of the mesiobuccal root of the maxillary first molar of a Japanese sub-population. Int Endod J 1999;32:79-87.  Back to cited text no. 3
    
4.
Singh S, Pawar M. Root canal morphology of South asian Indian mandibular premolar teeth. J Endod 2014;40:1338-41.  Back to cited text no. 4
    
5.
Vertucci FJ. Root canal morphology of mandibular premolars. J Am Dent Assoc 1978;97:47-50.  Back to cited text no. 5
    
6.
Sempira HN, Hartwell GR. Frequency of second mesiobuccal canals in maxillary molars as determined by use of an operating microscope: A clinical study. J Endod 2000;26:673-4.  Back to cited text no. 6
    
7.
Mikrogeorgis G, Lyroudia KL, Nikopoulos N, Pitas I, Molyvdas I, Lambrianidis TH. 3D computer-aided reconstruction of six teeth with morphological abnormalities. Int Endod J 1999;32:88-93.  Back to cited text no. 7
    
8.
Baisden MK, Kulild JC, Weller RN. Root canal configuration of the mandibular first premolar. J Endod 1992;18:505-8.  Back to cited text no. 8
    
9.
Zoremchhingi, Joseph T, 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.
John GP, Joy TE, Mathew J, Kumar VR. Fundamentals of cone beam computed tomography for a prosthodontist. J Indian Prosthodont Soc 2015;15:8-13.  Back to cited text no. 10
[PUBMED]  [Full text]  
11.
Yang R, Yang C, Liu Y, Hu Y, Zou J. Evaluate root and canal morphology of primary mandibular second molars in Chinese individuals by using cone-beam computed tomography. J Formosan Med Assoc 2013;112:390-5.  Back to cited text no. 11
    
12.
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. 12
    
13.
Sherrard JF, Rossouw EP, Benson BW, Carrillo R, Buschang PH. Accuracy and reliability of tooth and root lengths measured on cone-beam computed tomographs. Am J Orthod Dentofacial Orthop 2010;137:S100-8.  Back to cited text no. 13
    
14.
Scarfe WC, Levin MD, Gane D, Farman AG. Use of cone beam computed tomography in endodontics. Int J Dent 2009;1-20.  Back to cited text no. 14
    
15.
Ozcan G, Sekerci AE, Cantekin K, Aydinbelge M, Dogan S. Evaluation of root canal morphology of human primary molars by using CBCT and comprehensive review of the literature. Acta Odontol Scand 2016;74:250-8.  Back to cited text no. 15
    
16.
Katge F, Wakpanjar MM. Root canal morphology of primary molars by clearing technique: An in vitro study. J Indian Soc Pedod Prev Dent 2018;36:151-7.  Back to cited text no. 16
[PUBMED]  [Full text]  
17.
Aminabadi NA, Farahani RMZ, Gajan EB. Study of root canal accessibility in human primary molars. J Oral Sci 2008;50:69-74.  Back to cited text no. 17
    
18.
Bagherian A, Kalhori KAM, 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. 18
    
19.
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 Ind Soc Pedod Prev Dent 2013;31:254-9.  Back to cited text no. 19
    
20.
Sim D, Mah Y. A study of root canals morphology in primary molars using computerized tomography. J Korean Acad Pediatr Dent 2019;46:400-8.  Back to cited text no. 20
    

Top
Correspondence Address:
Dr. Jatinder K Dhillon
Department of Pediatric Dentistry, College of Dental Medicine, Nova Southeastern University, Florida
USA
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ijdr.IJDR_748_20

Rights and Permissions


    Figures

  [Figure 1]
 
 
    Tables

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



 

Top
 
 
 
  Search
 
    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
    Email Alert *
    Add to My List *
* Registration required (free)  
 


    Abstract
   Introduction
   Methodology
   Results
   Discussion
   Conclusion
    References
    Article Figures
    Article Tables

 Article Access Statistics
    Viewed1498    
    Printed78    
    Emailed0    
    PDF Downloaded52    
    Comments [Add]    

Recommend this journal