Journal of Conservative Dentistry
Home About us Editorial Board Instructions Submission Subscribe Advertise Contact e-Alerts Login 
Users Online: 1158
Print this page  Email this page Bookmark this page Small font sizeDefault font sizeIncrease font size

Table of Contents   
Year : 2015  |  Volume : 18  |  Issue : 5  |  Page : 419-422
Endodontic management of a mandibular first molar with six root canal systems

Department of Conservative Dentistry and Endodontics, Sri Sai College of Dental Surgery, Hyderabad, Telangana, India

Click here for correspondence address and email

Date of Submission13-Apr-2015
Date of Decision17-Jun-2015
Date of Acceptance11-Jul-2015
Date of Web Publication1-Sep-2015


Internal anatomy of pulp is complex. The first mandibular molars typically have two roots, one mesial with two root canals and another distal root, which contains one or two canals. A 20-year-old female patient reported with intermittent pain and incomplete root canal treatment in left lower back region since 1-week. Refined access cavity revealed initially two canals in mesial and two canals in the distal root. With operating microscope and cone beam computerized tomography, two additional canals (L-mesio-buccal and B-mesio-lingual) were identified in mesial root. One-year follow-up showed patient was asymptomatic and complete healing of periapical radiolucency.

Keywords: Cone beam computerized tomography; extra canals; mandibular first molar; operating microscope

How to cite this article:
Jain D, Reddy S, Venigalla BS, Kamishetty S. Endodontic management of a mandibular first molar with six root canal systems. J Conserv Dent 2015;18:419-22

How to cite this URL:
Jain D, Reddy S, Venigalla BS, Kamishetty S. Endodontic management of a mandibular first molar with six root canal systems. J Conserv Dent [serial online] 2015 [cited 2023 May 28];18:419-22. Available from:

   Introduction Top

A major cause of failure in endodontic treatment is the incomplete debridement of root canal system. [1] Pulp tissue remnants due to the inability to locate canals can affect and compromise the treatment outcome. [2] Thus, a better understanding of tooth morphology and anatomy is essential to attain this purpose. The mandibular first molar is considered to be the most common tooth to involve in the endodontic procedure because it is earliest permanent tooth to erupt. [3] Because of the greater number of endodontic treatments involving this tooth, the clinician may be confronted in many cases of mandibular first molars with variation in root (single root, [4] four roots, [5] taurodontism, [6] radix entomolaris, [7] Radix paramolaris [8] ) and internal anatomy (middle mesial, [9],[10],[11],[12],[13],[14] middle distal, [5],[9],[13],[14],[15],[16] and C-shape [17],[18] ). However, presence of four canals in the mesial root is extremely rare. [9],[10],[11],[12],[13],[14] This case report describes the endodontic management of mandibular first molar with four independent mesial canals (mesio-buccal [MB], L-MB, B-mesio-lingual [ML], ML) and two distal canals (disto-buccal [DB], disto-lingual [DL]) using operating microscope and cone beam computerized tomography (CBCT). [19]

   Case Report Top

A 20-year-old female patient reported to Department of Conservative Dentistry and Endodontics, with an intermittent type of pain and incomplete root canal treatment in left lower back region since 1-week. Clinical examination revealed attempted root canal treatment in tooth #19 with no signs of pain or tenderness on percussion. The temporary restoration within the access cavity had been missing [Figure 1]a. Radiographic examination revealed periapical radiolucency in relation to the distal root. From clinical and radiographic examination, a diagnosis of chronic apical abscess was made on tooth #19.
Figure 1: (a) Preoperative (b) working length (c) cone beam computerized tomography (d) pulp chamber picture

Click here to view

Under rubber dam isolation, access cavity was modified with endo access bur (Dentsply, Switzerland). Earlier two canals in mesial- and distal roots were identified. Working length was determined with the help of ISO 10 K-file. Under a dental operative microscope (7X, Seiler IQ, Chicago, USA) additional two more canals were identified in the mesial root (L-MB and B-ML) [Figure 1]b. A total six root canals were identified that is, MB, L-MB, B-ML, ML in the mesial root with (Type XIV) according to Sert and Bayirli's classification [20] and DB, DL in distal root (Type II) according to Vertucci classification. [21] An apex locator (Root ZX, J Morita Mfg. Corp., Japan) was used to verify the working length in all six identified root canals. An additional operative radiograph [Figure 1]c was then taken to confirm the independent presence of four canals in mesial root. Root canals were instrumented with ProTaper rotary Ni-Ti instruments (Dentsply, Maillefer) using crown down technique and alternate irrigation with 5.25% sodium hypochlorite and 17% ethylenediaminetetraacetic acid (EDTA). Cleaning and shaping was done till F 2 in mesial canals and F 3 in distal canals. After completion of the chemo-mechanical preparation, cavity was sealed with zinc oxide eugenol temporary cement (Dental products of India).

CBCT (Kodak 9000 3D, Carestream Dental LLC Vaughan, Canada) images were taken with the informed consent of the patient. Axial CBCT images, revealed independent four root canals in coronal and middle part of the mesial root and with only two canals in the apical axial image [Figure 1]d and [Figure 3] indicating a Type XIV canal pattern. Calcium hydroxide dressing placed and patient recalled after a week. After a week, intra-canal dressing was removed with alternate instrumentation and irrigation with 5.25% sodium hypochlorite. The canal was finally rinsed with saline and EDTA. The root canals were dried with paper points and obturated with sealer (Apexit, Ivoclar Vivadent) and respective Gutta-percha cones (Dentsply, Maillefer, Switzerland) using lateral condensation technique [Figure 2]a and [Figure 2]b. Temporary cement (Dental products of India) was placed and a postoperative radiograph was taken to assess the quality of obturation [Figure 2]c. One year follow-up showed patient is asymptomatic, and there is complete healing of periapical radiolucency [Figure 2]d.
Figure 2: (a) Master cone X-ray (b) obturation (c) post endodontic restoration (d) 1-year follow-up

Click here to view
Figure 3: An axial cone beam computerized tomography showing four canals in mesial root and two canals in distal root #19

Click here to view

   Discussion Top

The mandibular first molar is the first permanent tooth to develop at the age of 6 years. It is the most heavily restored teeth and also common to undergo root canal treatment in adult dentition. Normally, mandibular first and second molars have two roots, that is, mesial and distal root. The percentage of mandibular molars, with two canals in the mesial and one in the distal root is 65% and the presence of two canals in the distal root is 30%. Middle mesial or multiple canals in the mesial root of mandibular molars have been reported in the literature as having an incidence of 2.07-13.3% of the examined cases. [22],[23] The incidence of middle mesial canal (MMC) and middle distal canal in mandibular first one molar are 1-15% and 0.2-3%, respectively. [4],[20],[24] However, only six case reports have reported showing four canals in the mesial root of mandibular molars. [9],[10],[11],[12],[13],[25]

Figures have been named according to Valerian Albuquerque et al. Earlier Reeh described the nomenclature as MB1, MB2, ML1, ML2, DB, DL, but lacked the clarity based on their location. [9] However, the proposed naming system is an anatomically based nomenclature which takes into account the root-to-root-canal relationship in mandibular molars and its location. [26]

The existence of two MM canal is sometimes observed in horizontally angulated radiographs. Conventional radiograph exhibits two-dimensional views, whereas CBCT shows three-dimensional imaging with accuracy and precision and a promising tool for investigating the occurrences and morphology of root canal anatomy. Main disadvantage of CBCT compared to conventional radiograph is high radiation dose, but with proper precautions like lead sheath and thyroid collar its effect can be reduced. In this situation, CBCT provides additional information to detect extra canals. De Toubes et al., [27] in an in-vitro study demonstrated that CBCT was an accurate method of identifying accessory mesial canals in mandibular first molars. In the present case, CBCT was used to confirm the two MMCs with separate orifices but joined with other canals before exiting.

Nosrat et al. studied the frequency distribution of MMCs in mandibular molars and according to him, there were no significant differences in the incidence of MM canals based on sex, ethnicity, or molar type. There was no significant difference in the presence of a second distal canal between the teeth with a MM canal and those without MM canal which is evident in [Table 1] mentioned above. Among 15 MM canals, 7 showed confluent anatomy, 3 independent anatomy, and 5 showed fin anatomy. Overall, 4% (2/50) of mandibular first molars had a second distal (DL) root and 8% (2/25) of mandibular second molars had C-shaped anatomy. [28]
Table 1: Reported case with four canals in mesial or distal of mandibular molar

Click here to view

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

Sundqvist G, Figdor D. Endodontic treatment of apical periodontitis. In: Orstarik D, Pitt Ford TR, editors. Essential Endodontology. Oxford, England: Black-Well; 1998. p. 242.  Back to cited text no. 1
Nair PN. On the causes of persistent apical periodontitis: A review. Int Endod J 2006;39:249-81.  Back to cited text no. 2
Vertucci JF, Haddix EJ, Britto RL. Tooth morphology and access cavity preparation. In: Cohen S, Hargreaves MK, editors. Pathways of the Pulp. 9 th ed. St Louis, MO: Mosby, Inc.; 2006. p. 220.  Back to cited text no. 3
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;34:212-5.  Back to cited text no. 4
Ghoddusi J, Naghavi N, Zarei M, Rohani E. Mandibular first molar with four distal canals. J Endod 2007;33:1481-3.  Back to cited text no. 5
Tsesis I, Shifman A, Kaufman AY. Taurodontism: An endodontic challenge. Report of a case. J Endod 2003;29:353-5.  Back to cited text no. 6
Naidu GM, Kandregula CR, Koya S. Bilateral radix endomolaris (third root): A rare Endoexperience. J Adv Oral Res 2013;4:29-33.  Back to cited text no. 7
Acharya N, Singh A, Samant PS, Gautam V. Endodontic management of radix paramolaris with six canals: A clinical case report. Kathmandu Univ Med J (KUMJ) 2013;11:338-41.  Back to cited text no. 8
Reeh ES. Seven canals in a lower first molar. J Endod 1998;24:497-9.  Back to cited text no. 9
Kontakiotis EG, Tzanetakis GN. Four canals in the mesial root of a mandibular first molar. A case report under the operating microscope. Aust Endod J 2007;33:84-8.  Back to cited text no. 10
Aminsobhani M, Shokouhinejad N, Ghabraei S, Bolhari B, GhorbanzadehA. Retreatment of a 6-canalled mandibular first molar with four mesial canals: A case report. Iran Endod J 2010;5:138-40.  Back to cited text no. 11
Subbiya A, Kumar KS, Vivekanandhan P, Prakash V. Management of mandibular first molar with four canals in mesial root. J Conserv Dent 2013;16:471-3.  Back to cited text no. 12
[PUBMED]  Medknow Journal  
Kottoor J, Paul KK, Mathew J, George S, Mathew J, Roy A. A permanent mandibular second molar with seven root canal systems. Quintessence Int 2014;45:381-3.  Back to cited text no. 13
Arora A, Acharya SR, Sharma P. Endodontic treatment of a mandibular first molar with 8 canals: A case report. Restor Dent Endod 2015;40:75-8.  Back to cited text no. 14
Baziar H, Daneshvar F, Mohammadi A, Jafarzadeh H. Endodontic management of a mandibular first molar with four canals in a distal root by using cone-beam computed tomography: A case report. J Oral Maxillofac Res 2014;5:e5.  Back to cited text no. 15
Sinha N, Singh B, Langaliya A, Mirdha N, Huda I, Jain A. Cone beam computed topographic evaluation and endodontic management of a rare mandibular first molar with four distal canals. Case Rep Dent 2014;2014:306943.  Back to cited text no. 16
Shemesh A, Katzenell V, Itzhak JB, Solomonov M. C-shaped canal in mandibular first molar: A case report. ENDO (Lond Engl) 2014;8:47-52.  Back to cited text no. 17
Bolger WL, Schindler WG. A mandibular first molar with a C-shaped root configuration. J Endod 1988;14:515-9.  Back to cited text no. 18
Scarfe WC, Farman AG, Sukovic P. Clinical applications of cone-beam computed tomography in dental practice. J Can Dent Assoc 2006;72:75-80.  Back to cited text no. 19
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. 20
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. 21
Baugh D, Wallace J. Middle mesial canal of the mandibular first molar: A case report and literature review. J Endod 2004;30:185-6.  Back to cited text no. 22
Ballullaya SV, Vemuri S, Kumar PR. Variable permanent mandibular first molar: Review of literature. J Conserv Dent 2013;16:99-110.  Back to cited text no. 23
[PUBMED]  Medknow Journal  
Ahmed HA, Abu-bakr NH, Yahia NA, Ibrahim YE. Root and canal morphology of permanent mandibular molars in a Sudanese population. Int Endod J 2007;40:766-71.  Back to cited text no. 24
Gu Q, Liu G, Yang X. Report of a first mandibular molar with four mesial root canals. Zhonghua Kou Qiang Yi Xue Za Zhi 2014;49:127.  Back to cited text no. 25
Valerian Albuquerque D, Kottoor J, Velmurugan N. A new anatomically based nomenclature for the roots and root canals-part 2: Mandibular molars. Int J Dent 2012;2012:814789.  Back to cited text no. 26
De Toubes KM, Cortes MI, Valadares MA, Fonseca LC, Nunes E, Silveira FF. Comparative analysis of accessory mesial canal identification in mandibular first molars by using four different diagnostic methods. J Endod 2012;38:436-41..  Back to cited text no. 27
Nosrat A, Deschenes RJ, Tordik PA, Hicks ML, Fouad AF. Middle mesial canals in mandibular molars: Incidence and related factors. J Endod 2015;41:28-32.  Back to cited text no. 28

Correspondence Address:
Dr. Dilip Jain
15-1-305, Old Feel Khana, Hyderabad - 500 012, Telangana
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0972-0707.164060

Rights and Permissions


  [Figure 1], [Figure 2], [Figure 3]

  [Table 1]

This article has been cited by
1 Endodontic treatment of various palatal roots in maxillary molars
Chengshi Wei, Keyi Li, Lili Shen, Guangliang Bai, Xiufen Tian
The Journal of the American Dental Association. 2021; 152(12): 1044
[Pubmed] | [DOI]
2 Endodontic Management of a Permanent Mandibular First Molar with Five Root Canals Aided by Cone-beam Computed Tomography: A Case Report
Rakesh Mittal, Monika Tandan, Aditi Kohli
Conservative Dentistry and Endodontic Journal. 2021; 5(2): 48
[Pubmed] | [DOI]


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

   Case Report
    Article Figures
    Article Tables

 Article Access Statistics
    PDF Downloaded259    
    Comments [Add]    
    Cited by others 2    

Recommend this journal