Journal of Conservative Dentistry
Home About us Editorial Board Instructions Submission Subscribe Advertise Contact e-Alerts Login 
Users Online: 892
Print this page  Email this page Bookmark this page Small font sizeDefault font sizeIncrease font size
 


 
Table of Contents   
ORIGINAL ARTICLE  
Year : 2011  |  Volume : 14  |  Issue : 4  |  Page : 346-350
Morphologic characteristics of root canal of mandibular incisors in North-East Indian population: An in vitro study


1 Department of Dentistry, FAA Govt Medical College, Jonia Road, Barpeta, India
2 Department of Conservative Dentistry, Regional Dental College, Guwahati, Assam, India

Click here for correspondence address and email

Date of Submission05-Dec-2010
Date of Decision20-Dec-2010
Date of Acceptance02-Sep-2011
Date of Web Publication5-Nov-2011
 

   Abstract 

Aim : To aim of this study is to investigate the root canal characteristics of mandibular incisors in a North East Indian population using a canal staining and tooth-clearing technique.
Materials and Methods : Four hundred and eighty extracted mandibular incisors, collected from dental clinics within North East India were selected for this study. Following pulp tissue removal, the teeth were decalcified with 5% nitric acid, dehydrated with ascending concentrations of alcohol and rendered clear by immersion in methyl salicylate. After staining of the canal systems with India ink, cleared teeth were examined under 5X magnification and the following features were evaluated: (i) number and type of root canals; (ii) presence and location of lateral canals and intercanal communications; (iii) location of apical foramina; and, (iv) Bifurcation of canals.
Results : The majority of mandibular incisors had a single canal (63.75% of teeth possessed a Type I canal system). Although 36.25% of the roots possessed two canals, only 6.25% had two separate apical foramina.
Conclusions : The prevalence of two canals in this group (of North East Indians) of mandibular incisors was 36.25% and is within the range of previous studies performed on populations of different racial origin.

Keywords: Canal staining; mandibular incisors; morphology; root canal; Vertucci′s classification

How to cite this article:
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

How to cite this URL:
Boruah LC, Bhuyan AC. Morphologic characteristics of root canal of mandibular incisors in North-East Indian population: An in vitro study. J Conserv Dent [serial online] 2011 [cited 2019 Sep 21];14:346-50. Available from: http://www.jcd.org.in/text.asp?2011/14/4/346/87195

   Introduction Top


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. [1] This applies to mandibular incisor teeth as well, as many dentists fail to recognize the presence of a second canal. Current knowledge of pulp space anatomy is based on research findings and individual case reports. Many studies have examined the root canal systems of mandibular incisors. There is a lack of consistency in the reported prevalence of second canals in mandibular incisors. [1],[2],[3],[4],[5] The differences may be related to study design (in vivo versus ex vivo), technique of canal identification (radiographic examination, sectioning and clearing) or to racial divergence.

It is important to be familiar with variations in tooth anatomy and characteristic features in various racial groups, since such knowledge can aid location and negotiation of canals, as well as their subsequent management. Additionally, a number of studies have shown different trends in shape and number of roots and canals amongst the different races. [1],[3],[6],[7],[ 8] These variations appear to be genetically determined and are important in tracing the racial origins of populations. [7] Descriptions of the frequently occurring root canal systems of permanent teeth are based largely on studies conducted in Europe and North America, and relate to teeth of mainly Caucasian origin. These descriptions may not be fully applicable to teeth of non- Caucasian origin. There are no published reports on the root canal anatomy of mandibular incisors in North East Indian population. However, some studies have examined an Indian population. [9] The North-Eastern population in India is mostly comprised of Indo-Aryans (Caucasoid) Mongoloids (Tibeto-Burman and Paleo-mangoloid sub race) and Dravidian sub populations. The population of North-East India is nearly 38 million, out of which tribal mongoloid population accounts for almost 42-45% of the total population.


   Materials and Methods Top


A total of five hundred and thirty six extracted mandibular incisors were randomly collected from general dental clinics within North-Eastern India.Out of the collected teeth, fifty six teeth were excluded because of immature or resorbed apices and four hundred and eighty teeth were selected for the present study. The gender and age of patients was not known, and no attempt was made to differentiate between central and lateral incisors. The samples were stored in 5.25% sodium hypochlorite (Organo Bio tech laboratories Pvt Ltd New Delhi, India) for 30 minutes for the removal of organic debris, and then in 10% formaldehyde until use. The teeth were cleaned under running water, access cavities were prepared and the coronal pulp tissue extirpated in the canal orifices. The samples were stored in 5% nitric acid solution (Aries Laboratories, India) for 5 days. The solution was changed each day. Demineralization was assessed by the insertion of a paper pin in the crown and with the help of radiographs. The samples were then rinsed under running water for 4 hours and placed in 70, 80 and 95% ethyl alcohol successively, for 1 day. At the end of this period, no opacity remained. The clearing procedure was completed by placing the samples in methyl salicylate (Regent Chemicals, Mumbai)). At the end of the third day, complete transparency was achieved. India ink (United Ink and Varnishes Pvt Ltd, Mumbai, India) was injected into the root canals of the transparent teeth using syringes with 27 gauge needle (Shree Uniya Surgical, India).

After the ink had dried, root canal morphology was examined by a magnifying glass of 5X magnification [Figure 1], and the following observations were made:
Figure 1: Transparent specimen showing canal bifurcation

Click here to view


  1. number and type of root canals,
  2. presence and location of lateral canals and intercanal communications,
  3. location of apical foramina, and
  4. bifurcation of canals.
  5. Canals were categorized into the first five types of Vertucci's classification [10] as follows:


  • Type I: A single canal is present from the pulp chamber to the apex.
  • Type II: Two separate canals leave the pulp chamber, but join to form one canal to the site of exiting.
  • Type III: One canal leaves the pulp chamber, divides into two within the root, and then merges to exit in one canal.
  • Type IV: Two separate and distinct canals are present from the pulp chamber to the apex.
  • Type V: Single canal leaving the pulp chamber but dividing into two separate canals with two separate apical foramina.



   Results Top


Results of this investigation indicate that one third of the teeth exhibit two canal system (36%). Of the teeth with two canals, Type III configuration was most common followed by Type II and Type V [Figure 2]. None of the teeth were seen with Type IV canal system. It was found that 63.75% of mandibular incisors possessed a single root canal. Although two canals were found in 36% of teeth, only 6.25% of canals exited in two separate foramina (Type V) [Table 1]. Out of all the canals showing two canal configuration,around 83% joined and exited in single foramen (Type II and III) and remaining 17% exited in two separate foramina (Type V) [Table 1].The apical foramen was found to coincide with the apical root tip in 47.2% of teeth [Table 2]. In the present study, lateral canals were observed in around 13% of the cases[Figure 3] [Table 3]. Anastomosis were found only in type III canals which accounts for 2.5% of all the teeth [Table 4]. Apical ramifications were seen in around 7.42% of the teeth, out of which 75.7% were with two rami, 24.3%with three rami, and none with four rami [Table 4] [Figure 4]. In teeth with two canals, bifurcations were seen maximum in middle third (64%) followed by in cervical third 23.3% and in apical third 1.25 % [Table 5]. Intercanal communications were observed in 28.4% of all teeth and in 70.2% of teeth with two canals [Table 6].
Table 1: Number and percentage of canal system types in mandibular incisors (n=480) in the study

Click here to view
Table 2: Distribution of apical foramen in mandibular incisors (n=480) in the study

Click here to view
Table 3: Distribution of lateral canals in mandibular incisors in the study

Click here to view
Table 4: Distribution of apical ramification in mandibular incisors in the study

Click here to view
Table 5: Distribution of position of canal bifurcation in mandibular incisors in the study

Click here to view
Table 6: Distribution of intercanal communications in mandibular incisors in the study

Click here to view
Figure 2: Canal confi guration (From left to right) Types I, II, III and V

Click here to view
Figure 3: Curvatures in Type I canal confi gurations- Straight, S shaped and J shaped

Click here to view
Figure 4: Type I variations- apical ramifi cation, reticular structure and lateral canals

Click here to view



   Discussion Top


Various methods have been used to study root canal morphology including radiographic examination, [2] root sectioning, [4] staining and clearing techniques, [11] direct observation with microscope,th[12] sectioning and macroscopic observation ,th[13] stereo microscope, [14] spiral computed tomography, [15] and cone beam computed tomography. [16],[17] Vertucci [1] used the clearing technique to study the root canal morphology of extracted mandibular anterior teeth. It has been reported that fine details of the root canal system can be visualized by staining and clearing[Figure 1]. [11] This technique also makes canal negotiation with instruments unnecessary, thereby maintaining the original form and relation of canals, and provides a three-dimensional view of root canal.th[1]

The process of changing the tooth into a transparent object involves many physical and chemical changes. The inorganic constituents of the tooth are first dissolved by decalcification, and further water, air, and lipid components are removed by dehydration and by subsequent immersion in the clearing agents,th[18] and this method was used in the present study as well. The literature on mandibular incisors reveals that 11-68% of mandibular incisors possess two canals, although in many of these cases, the canals merge into one in the apical 1-3 mm of the root. [1],[4],[5],[19],[20] Vertucci [1] examined the root canal morphology of 300 mandibular anterior teeth and reported a second canal in 27.5% of mandibular incisors. Miyashita et al., [20] reported that 12.4% of mandibular incisors contained two canals; however, only 3% had two foramina. Sert et al., [5] noted that two canals were present in 68% of mandibular central incisors. Mauger et al., [4] evaluated the canal morphology at different root levels in one hundred mandibular incisors, and reported that 98-100% of the teeth had one canal in the area 1-3 mm from the apex. The differences between these morphology studies may be related to variations of examination methods, classification systems, sample sizes and ethnic background of tooth sources. In a study in Jordanian population, it was found that 73.8% of the mandibular incisors possessed a single root canal, and 26.2% of teeth were with two canals. [21] The results of the present study indicate that one third of the teeth exhibit two canal system (36%) [Table 2] [Figure 2]. It was found that 63.75% of mandibular incisors possessed a single root canal (Type I) with straight, J and S shaped curvatures [Figure 3] as well as frequent apical ramifications, lateral canals and reticular structures [Figure 4]. Only 6.25% of canals exited in two separate foramina (Type V). Of the teeth with two canals, Type III configuration was most common followed by Type II and Type V. Therefore, the frequency of two canals in the present study was within the range of previous reports. This proportion is not found clinically by practitioners during root canal treatment. [22] This is due to failure of the dentist to recognize the presence of the second canal, and the need for access cavities to have appropriate inciso-gingival extension to facilitate the location of lingual canals. None of the teeth were seen with Type IV canal system, which may be due to smaller number of samples examined in the present study and any conclusion drawn needs to be based on study of a larger population.

The apical foramen was found to coincide with the apical root tip in 47.2% of teeth [Table 2]. This is higher than reported in previous studies that demonstrated that the apical foramen coincided with the anatomical apex in 17-46% of cases. [5],[22],[23] In the present study, total apical foramen count stands at 510 (n=480), which is because of type V canal configuration and apical ramifications. This finding may be of significance in working length determination which often depends on the average position of the apical constriction relative to root apex. In the present study, lateral canals were observed in around 13% of teeth and were found most frequently in the middle of the canal [Table 3] [Figure 4]. Lateral canals in the apical third account for 2.94%.This is consistent with the findings of Miyashita et al.[20] ; however, much lower than that reported by Vertucci. [10] Anastomoses were found only in type III canals which accounts for 2.5% of all the teeth. Apical ramifications were seen in around 7.42% of the teeth out of which 75.7% were with two rami, and 24.3% with three rami, and none with four rami [Table 4]. In teeth with two canals, bifurcations were seen maximum in middle third (64%) followed by the cervical third 23.3%; and, the apical third 1.25% [Table 5].This requires an individualized procedure for preparation and filling in each of these conditions to obtain the most desirable results.

Pulp space anatomy of mandibular incisors in an Indian population show high incidence of complexity which includes variations in canal configuration, number of canals and presence of isthmus. [9] Intercanal communications were observed in 28.4% of all teeth, and in 70.2% of teeth with two canals [Table 6]. The high percentage of intercanal communications in teeth with two canals may be of clinical significance, because it may be difficult to debride and fill these communications adequately.


   Conclusions Top


Within the limitations of the present study, it can be concluded that overall, 36% of mandibular incisors in this North-East Indian population had two canals. In the teeth with two canals, the Type III canal system was the most prevalent followed by Type II.Type V was the lEast prevalent. None of the teeth exhibited Type IV canal configuration in the present study.

 
   References Top

1.Vertucci FJ. Root canal morphology and its relationship to endodontic procedures. Endod Top 2005;10:3-29.  Back to cited text no. 1
    
2.Kaffe I, Kaufman A, Littner MM, Lazarson A. Radiographic study of root canal system of mandibular anterior teeth. Int Endod J 1985;18:253-9.  Back to cited text no. 2
[PUBMED]    
3.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. 3
[PUBMED]    
4.Mauger MJ, Schindler WG, Walker WA. An evaluation of canal morphology at different levels of root resection in mandibular incisors. J Endod 1998;24:607-9.  Back to cited text no. 4
    
5.Sert S, Aslanalp V, Tanalp J. Investigation of the root canal configurations of mandibular permanent teeth in the Turkish population. Int Endod J 1985;37:494-9.  Back to cited text no. 5
    
6.Somogyi-Csimazia W, Simmons AJ. Three-rooted mandibular first molars in Alberta Indian children. Can Dent Assoc J 1971;37:105-6.  Back to cited text no. 6
    
7.Curzon ME. Miscegenation and the prevalence of three rooted mandibular first molars in the Baffin Eskimo. Comm Dent Oral Epidem 1974;2:130-1.  Back to cited text no. 7
    
8.Reichart PA, Metah D. Three-rooted permanent mandibular first molars in the Thai population. Comm Dent Oral Epidem 1981;9:191-2.  Back to cited text no. 8
    
9.Uma CH, Ramachandran S, Indira R, Shankar P. Canal and isthmus morphology in mandibular incisors - An in vitro study. Endodontology 2004;16:7-11.  Back to cited text no. 9
    
10.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. 10
[PUBMED]    
11.Robertson D, Leeb J, McKee M, Brewer E. A clearing technique for the study of root canal systems. J Endod 1980;6:421-4.  Back to cited text no. 11
    
12.Sempire 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. 12
    
13.Lu TY, Yang SF, Pai SF. Complicated root canal morphology of mandibular first premolar in a Chinese population using the cross section method. J Endod 2006;32:932-6.  Back to cited text no. 13
[PUBMED]  [FULLTEXT]  
14.Raj UJ, Mylswamy S. Root canal morphology of maxillary second premolars in an Indian population. J Conserv Dent 2010;13:148-51.  Back to cited text no. 14
[PUBMED]  Medknow Journal  
15.Reuben J, Velmurugan N, Kandaswamy D. The evaluation of root canal morphology of the mandibular first molar in an Indian population using spiral computed tomography scan: An in vitro study. J Endod 2008;34:121-249.  Back to cited text no. 15
    
16.Neelakantan P, Subbarao C, Ahuja R, Subbarao CV, Gutmann JL. Cone-beam computed tomography study of root and canal morphology of maxillary first and second molars in an Indian population. J Endod 2010;36:1622-7   Back to cited text no. 16
    
17.Zheng QH, Wang Y, Zhou XD, Wang Q, Zheng GN, Huang DM. A cone-beam computed tomography study of maxillary first permanent molar root and canal morphology in a Chinese population. J Endod 2010;36:1480-4  Back to cited text no. 17
    
18.Shivapathasundharam B, Berti A. Transparent tooth model system. An aid in the study of root canal anatomy. Indian J Dent Res 2000;11:89-94  Back to cited text no. 18
    
19.Kartal N, Yanikoglu F. Root canal morphology of mandibular incisors. J Endod 1992;18:562-4.  Back to cited text no. 19
    
20.Miyashita M, Kasahara E, Yasuda E, Yamamoto A. Root canal system of the mandibular incisor. J Endod 1997;23:479-84.   Back to cited text no. 20
    
21.Al-Qudah AA, Awawdeh LA. Root canal morphology of mandibular incisors in a Jordanian population. Int Endod J 2006;39:873-7.   Back to cited text no. 21
[PUBMED]  [FULLTEXT]  
22.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. 22
[PUBMED]    
23.Pineda F, Kuttler Y. Mesiodistal and buccolingual roentgenographic investigation of 7275 root canals. Oral Surg Oral Med Oral Pathol 1972;33:101-10.  Back to cited text no. 23
[PUBMED]    

Top
Correspondence Address:
Lalit C Boruah
Department of Dentistry, FAA Govt. Medical College, Jonia Road, Barpeta, Assam - 781301
India
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0972-0707.87195

Rights and Permissions


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4]
 
 
    Tables

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

This article has been cited by
1 micro-computed tomography analysis of the root canal anatomy and prevalence of oval canals in mandibular incisors
milanezi de almeida, m. and bernardineli, n. and ordinola-zapata, r. and villas-bôas, m.h. and amoroso-silva, p.a. and brandão, c.g. and guimarães, b.m. and gomes de moraes, i. and húngaro-duarte, m.a.
journal of endodontics. 2013; 39(12): 1529-1533
[Pubmed]
2 using a dental operating microscope for endodontic management of a mandibular central incisor with 3 root canals
aswinkumar, v. and nandini, s. and velmurgan, n.
general dentistry. 2013; 61(5): 30-32
[Pubmed]
3 In-depth morphological study of mesiobuccal root canal systems in maxillary first molars: review
Seok-Woo Chang,Jong-Ki Lee,Yoon Lee,Kee-Yeon Kum
Restorative Dentistry & Endodontics. 2013; 38(1): 2
[Pubmed] | [DOI]
4 evaluation of the apical adaptation performance of various root canal instruments
ceyhanli, k.t. and turkun, m. and erdilek, n. and peskersoy, c. and kose, t.
european journal of dentistry. 2013; 7(5 suppl.): s41-s44
[Pubmed]



 

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

 Article Access Statistics
    Viewed3157    
    Printed132    
    Emailed1    
    PDF Downloaded227    
    Comments [Add]    
    Cited by others 4    

Recommend this journal