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: 1653

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

 


 
Table of Contents   
ORIGINAL RESEARCH  
Year : 2013  |  Volume : 24  |  Issue : 2  |  Page : 234-236
Prevalence of two root canals in human mandibular anterior teeth in an Iranian population


1 Dental and Periodontal Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
2 Private Dental Practitioner, Urmia, Iran
3 Department of Oral and Maxillofacial Surgery, Tabriz Faculty of Dentistry, Tabriz University of Medical Sciences, Tabriz, Iran

Click here for correspondence address and email

Date of Submission24-Mar-2011
Date of Decision28-Jun-2011
Date of Acceptance01-Jul-2011
Date of Web Publication20-Aug-2013
 

   Abstract 

Background: Complete debridement and obturation of the root canal system is a key factor in successful endodontic treatment and the operator should therefore have thorough knowledge of the root canal morphology of the teeth. Numerous studies have been carried out to investigate the canal configuration of different tooth types in various populations.
Aims: The aim of the present study was to investigate the internal anatomy of mandibular incisors and canines in an Iranian population.
Materials and Methods: A total of 463 mandibular anterior teeth, including 186 centrals, 128 laterals, and 149 canines, were examined. A standard clearing technique was used to make the teeth transparent. India ink was injected into the canals of the teeth and the samples were examined with a magnifying glass. The root canal configurations were categorized according to the Vertucci classification.
Results: All the incisors in this study had one root, and 12.08% of the canines had two roots. We found a slightly higher prevalence of the second canal in incisors than in canines (36.62% vs. 20.48%). However, the probability of canines having two separate apical foramina was higher than that for incisors (12.08% vs. 0.64%).
Conclusions: In view of the high prevalence of two-canaled mandibular anterior teeth found in this study, it would be prudent to assume that any mandibular anterior tooth being treated is two-canaled until a thorough search proves otherwise.

Keywords: Canal configuration, clearing technique, mandibular canine, mandibular incisors

How to cite this article:
Rahimi S, Milani AS, Shahi S, Sergiz Y, Nezafati S, Lotfi M. Prevalence of two root canals in human mandibular anterior teeth in an Iranian population. Indian J Dent Res 2013;24:234-6

How to cite this URL:
Rahimi S, Milani AS, Shahi S, Sergiz Y, Nezafati S, Lotfi M. Prevalence of two root canals in human mandibular anterior teeth in an Iranian population. Indian J Dent Res [serial online] 2013 [cited 2019 Sep 15];24:234-6. Available from: http://www.ijdr.in/text.asp?2013/24/2/234/116694
Complete debridement and obturation of the root canal system is a key factor for successful endodontic treatment. The operator should therefore have thorough knowledge of the root canal morphology of the teeth. The mandibular anterior teeth are not frequently cariously involved, but there are many situations where these teeth require endodontic treatment. It was first believed that mandibular incisors generally have only one root canal. [1] However, studies have revealed high variation of root canal morphology among mandibular anterior teeth. [2],[3],[4],[5],[6] The study carried out by Rankine et al. in 1965 showed high prevalence of two canals in the mandibular incisors, [5] which stimulated further researches on the canal configuration of other teeth, particularly ones with relatively low endodontic success rate. These studies, carried out on different populations with different methods, [2],[7],[8],[9],[10],[11],[12] showed that the root canal morphology varies with race, sex, and age. [3],[6] The prevalence of two-canaled mandibular incisors has been reported to be 11% in UK and 70% in Turkey. [6],[13],[14] The presence of the second canal in mandibular canines has been reported to be 7.8% in a Brazilian population and 38% in a Turkish population. [6],[15] The present study was conducted to investigate the internal anatomy of mandibular incisors and canines in an Iranian population.


   Materials and Methods Top


A total of 463 mandibular anterior teeth, including 186 centrals, 128 laterals, and 149 canines, were examined in this study. The teeth belonged to Iranian patients who underwent tooth extraction at the Tabriz Faculty of Dentistry, Tabriz University of Medical Sciences, or at private clinics in Tabriz. Following extraction, the teeth were stored in 5.25% sodium hypochlorite for 30 minutes. Any remaining tissues were then cleaned off the surface under running water. The teeth were categorized as mandibular central or lateral incisor or mandibular canine by two independent observers using the criteria of Woelfel. [16] The teeth were then stored in 10% formaldehyde until use.

Access cavities were prepared using a fissure diamond bur (D + Z, Diamant, Germany). After locating the orifices, the teeth were stored in 5.25% sodium hypochlorite for 48 hours. They were then cleaned under running water for 4 hours. A standard clearing technique was applied, with some modifications. [4],[17],[18] First, the teeth were immersed in 5% nitric acid for 5 days, with daily solution replenishment. Demineralization was confirmed by radiography and insertion of a needle into the crown. [6] The teeth were then rinsed under running water for 4 hours and subsequently were dehydrated using increasing concentrations of ethyl alcohol (Ararat, Tehran, Iran), starting with 80% ethyl alcohol overnight, followed by 90% ethyl alcohol for 1 hour, and finally 100% ethyl alcohol for 1 hour. To make the teeth transparent, they were kept in methyl salicylate (Merck, Darmstadt, Germany) for 2 hours. India ink was injected into the root canals of the transparent teeth and they were then examined under a magnifying glass (Lumagny ® , No 7540, Hong Kong) at ×5 magnification. The root canal configurations were categorized according to the Vertucci classification. [11]


   Results Top


All the incisors in this study had one root. However, 12.08% of the canines (18 out of 149) had two roots [Figure 1]. The configurations of canals according to the Vertucci classification are summarized in [Table 1].
Table 1: Configuration of the canals according to the Vertucci classification


Click here to view
Figure 1: (a) Mandibular central incisor (Vertucci type I), (b) mandibular lateral incisor (Vertucci type II), (c) mandibular incisor (Vertucci type I), (d) mandibular canine (Vertucci type I), (e) two-rooted mandibular canine.

Click here to view



   Discussion Top


Successful endodontic treatment depends mainly on the ability to completely clean and seal the root canal system. [19] Therefore, it is mandatory for the clinician to have thorough knowledge about the canal configuration of the teeth. Various methods have been used to investigate root canal morphology. However, the most detailed information can be obtained by the clearing and staining technique. [6],[11] In this study we used a clearing technique to study the internal anatomy of a sample of mandibular anterior teeth.

Studies on mandibular incisors have shown that about 11%-70% of these teeth possess two canals. [3],[4],[5],[6],[8],[11],[20] The prevalence of two separate apical foramina in these teeth has been reported to be 0.3%-10%. [3],[4],[5],[6],[8],[14],[21] The variations in the results may be attributable to several factors, one of which is the methodology of the study. Studies using radiography alone have generally shown low prevalence of two-canaled incisors (1.3%-18.7%). [7],[13],[22],[23],[24] However, when two radiographs with different angulations were used, or when radiopacifiers were injected into the canals or endodontic files were placed in the canal prior to taking radiographs, higher prevalence (30%-61.5%) of two-canaled incisors were reported. [2],[3],[5],[25] Studies using the clearing and staining technique have also showed high prevalence of two-canaled incisors. [4],[6],[8] In this study, the incidence of two canals in mandibular incisors was 36.62%. This is in accordance with other studies that have used the clearing method or used radiography with opacifiers. [3],[4],[5],[8] Other factors such as differences in race and sex of the study population may be responsible for the slight differences in the results. [6]

The age of the patients is an important factor that has not been considered as a parameter in morphological studies. Secondary dentin deposition may obscure the canals in older teeth and therefore studies carried out on different age-groups may show different results. On the other hand, mandibular incisors are usually the last teeth to be lost by the patients and so it can be assumed that most of the samples have been from older age-groups. We can argue that a greater percentage of two-canaled incisors might be found in studies carried out on younger age-groups. It is recommended that future studies be carried out after categorizing the teeth according to the age of the patients.

In this study, the prevalence of mandibular incisors with two separate apical foramina was 0.64%, which is in agreement with other studies. [3],[5],[8],[21] Because in most of these teeth the canals merge in the apical third of the canal, some clinicians believe that treating one canal should be sufficient since the apical foramen would be sealed. This is probably true in many cases, or else the failure rates in these teeth would be higher. [3] However, it is important to be aware that if only one canal is treated, the pulp remnant in the second canal gradually becomes. Also, the canals usually merge about 1-2 mm from the apex, and if only one canal is treated and the filling does not extend up to the point where the canals merge, then the untreated canal can cause failure.

Mandibular canines usually have one root; however, studies have shown that about 1.7% of these teeth have two separate roots. [15] In this study, 12.08% of the canines had two roots (18 out of 149 teeth). The prevalence of two separate canals in mandibular canines has ranged from 1.96%-6% in various studies. [6],[8],[9],[10],[11],[15] The present study showed a relatively high percentage of two-rooted mandibular canines in North-West Iran.

Comparison of the mandibular canines with the incisors shows a slightly higher prevalence of the second canal in incisors (36.62% vs. 20.48%). However, the probability of there being two separate apical foramina is higher in canines than in incisors (12.08% vs. 0.64%). The clinician should therefore make a thorough search for the second canal in mandibular canines.


   Conclusion Top


In view of the high prevalence of two-canaled mandibular anterior teeth found in this study, it would be prudent to assume that any mandibular anterior tooth being treated is two-canaled until a thorough search proves otherwise.

 
   References Top

1.Sommer RF, Ostrander FD, Crowley M. Clinical endodontics. 2 th ed. Philadelphia: WB Saunders 1965. p. 269-71.  Back to cited text no. 1
    
2.Kaffe I, Kaufman A, Littner MM, Lazarson A. Radiographic study of the root canal system of mandibular anterior teeth. Int Endod J 1985;18:253-9.  Back to cited text no. 2
[PUBMED]    
3.Benjamin KA, Dowson J. Incidence of two root canals in human mandibular incisor teeth. Oral Surg Oral Med Oral Pathol 1974;38:122-6.  Back to cited text no. 3
[PUBMED]    
4.Kartal N, Yanikoglu FC. Root canal morphology of mandibular incisors. J Endod 1992;18:562-4.  Back to cited text no. 4
    
5.Rankine-Wilson RW, Henry P. The Bifurcated Root Canal in Lower Anterior Teeth. J Am Dent Assoc 1965;70:1162-5.  Back to cited text no. 5
[PUBMED]    
6.Sert S, Bayirli GS. Evaluation of the root canal configurations of the mandibular and maxillary permanent teeth by gender in the Turkish population. J Endod 2004;30:391-8.  Back to cited text no. 6
[PUBMED]    
7.Bellizzi R, Hartwell G. Clinical investigation of in vivo endodontically treated mandibular anterior teeth. J Endod 1983;9:246-8.  Back to cited text no. 7
[PUBMED]    
8.Caliskan MK, Pehlivan Y, Sepetcioglu F, Turkun M, Tuncer SS. Root canal morphology of human permanent teeth in a Turkish population. J Endod 1995;21:200-4.  Back to cited text no. 8
    
9.Green D. Double canals in single roots. Oral Surg Oral Med Oral Pathol 1973;35:689-96.  Back to cited text no. 9
[PUBMED]    
10.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. 10
[PUBMED]    
11.Vertucci FJ. Root canal anatomy of the human permanent teeth. Oral Surg Oral Med Oral Pathol 1984;58:589-99.  Back to cited text no. 11
[PUBMED]    
12.Walker RT. The root canal anatomy of mandibular incisors in a southern Chinese population. Int Endod J 1988;21:218-23.  Back to cited text no. 12
[PUBMED]    
13.Klein RM, Blake SA, Nattress BR, Hirschmann PN. Evaluation of X-ray beam angulation for successful twin canal identification in mandibular incisors. Int Endod J 1997;30:58-63.  Back to cited text no. 13
[PUBMED]    
14.Madeira MC, Hetem S. Incidence of bifurcations in mandibular incisors. Oral Surg Oral Med Oral Pathol 1973;36:589-91.  Back to cited text no. 14
[PUBMED]    
15.Pecora JD, Sousa Neto MD, Saquy PC. Internal anatomy, direction and number of roots and size of human mandibular canines. Braz Dent J 1993;4:53-7.  Back to cited text no. 15
    
16.Scheid RC, Woelfel JB. Woelfel's Dental anatomy: Its relevance to dentistry. 7 th ed. Baltimore: Williams and Willkins 2007. p. 158-89.  Back to cited text no. 16
    
17.Rahimi S, Shahi S, Lotfi M, Zand V, Abdolrahimi M, Es'haghi R. Root canal configuration and the prevalence of C-shaped canals in mandibular second molars in an Iranian population. J Oral Sci 2008;50:9-13.  Back to cited text no. 17
[PUBMED]    
18.Rahimi S, Shahi S, Yavari HR, Reyhani MF, Ebrahimi ME, Rajabi E. A stereomicroscopy study of root apices of human maxillary central incisors and mandibular second premolars in an Iranian population. J Oral Sci 2009;51:411-5.  Back to cited text no. 18
[PUBMED]    
19.Hashem AA, Ghoneim AG, Lutfy RA, Fouda MY. The effect of different irrigating solutions on bond strength of two root canal-filling systems. J Endod 2009;35:537-40.  Back to cited text no. 19
[PUBMED]    
20.de Oliveira SH, de Moraes LC, Faig-Leite H, Camargo SE, Camargo CH. In vitro incidence of root canal bifurcation in mandibular incisors by radiovisiography. J Appl Oral Sci 2009;17:234-9.  Back to cited text no. 20
[PUBMED]    
21.Miyashita M, Kasahara E, Yasuda E, Yamamoto A, Sekizawa T. Root canal system of the mandibular incisor. J Endod 1997;23:479-84.  Back to cited text no. 21
[PUBMED]    
22.Miyoshi S, Fujiwara J, Tsuji YT, Yamamoto K. Bifurcated root canals and crown diameter. J Dent Res 1977;56:1425.  Back to cited text no. 22
    
23.Nattress BR, Martin DM. Predictability of radiographic diagnosis of variations in root canal anatomy in mandibular incisor and premolar teeth. Int Endod J 1991;24:58-62.  Back to cited text no. 23
[PUBMED]    
24.Neo J, Chee LF. A retrospective clinical study of endodontically treated mandibular incisors in a selected Chinese population. Oral Surg Oral Med Oral Pathol 1990;70:782-3.  Back to cited text no. 24
[PUBMED]    
25.Hession RW. Endodontic morphology. II. A radiographic analysis. Oral Surg Oral Med Oral Pathol 1977;44:610-20.  Back to cited text no. 25
    

Top
Correspondence Address:
Amin Salem Milani
Dental and Periodontal Research Center, Tabriz University of Medical Sciences, Tabriz
Iran
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0970-9290.116694

Rights and Permissions


    Figures

  [Figure 1]
 
 
    Tables

  [Table 1]

This article has been cited by
1 A Study of the Root Canal Morphology of Mandibular Anterior Teeth Using Cone-beam Computed Tomography in a Chinese Subpopulation
Ting Han,Yue Ma,Lin Yang,Xinyu Chen,Xin Zhang,Yan Wang
Journal of Endodontics. 2014;
[Pubmed] | [DOI]



 

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
    Materials and Me...
   Results
   Discussion
   Conclusion
    References
    Article Figures
    Article Tables

 Article Access Statistics
    Viewed5152    
    Printed63    
    Emailed8    
    PDF Downloaded177    
    Comments [Add]    
    Cited by others 1    

Recommend this journal