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Cover page of the Journal of Health Sciences

 Table of Contents  
Year : 2014  |  Volume : 7  |  Issue : 2  |  Page : 121-124

Mandibular molar with six canals: Report of cases

Department of Conservative Dentistry and Endodontics, KLE VK Institute of Dental Sciences, Belgaum, Karnataka, India

Date of Web Publication7-Jan-2015

Correspondence Address:
Dr. Sheetal B Ghivari
4A, Basav Colony, Bauxite Road, Nehru Nagar, Belgaum - 590 010, Karnataka
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/2349-5006.148815

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A mandibular molar with more than four canals is an interesting example of anatomic variations. This case report describes a mandibular first molar with six canals, three canals located in the mesial root and three canals in distal root. The canals were instrumented with rotary system and irrigated with NaOCl (5.25%) and normal saline as the final irrigant. The canals were filled with gutta-percha (Denstply, Maillefer, Switzerland) and AH-plus sealer (Dentsply DeTrey GmbH Konstanz, Germany). This case shows a rare anatomic configuration and points out the importance of search for additional canals.

Keywords: Anatomic variation, mandibular molar, six root canals

How to cite this article:
Ghivari SB, Patil AC. Mandibular molar with six canals: Report of cases. Indian J Health Sci Biomed Res 2014;7:121-4

How to cite this URL:
Ghivari SB, Patil AC. Mandibular molar with six canals: Report of cases. Indian J Health Sci Biomed Res [serial online] 2014 [cited 2022 Aug 15];7:121-4. Available from: https://www.ijournalhs.org/text.asp?2014/7/2/121/148815

  Introduction Top

The aim of root canal therapy is thorough mechanical and chemical cleaning of entire pulp space and its three dimensional seal to prevent ingress of microorganisms. [1] Failure to detect root canals leads to persistent microbial infection and failure of root canal procedure. It is important to be familiar with variations in root canal anatomy because such knowledge can aid in location and negotiation of canals as well as their subsequent management. [2]

The mandibular first molar is the first posterior tooth that erupts in the oral cavity and frequently requires root canal treatment. This tooth has two roots but occasionally it has three roots with two or three canals in the mesial root and one, two or three canals in the distal root. [3]

Over the years there have been numerous reports that described the morphology of teeth including mandibular first molar. The major variant in this group is mandibular molar with five, six and seven canals. [4] Martinez-Berna and Badanelli reported a mandibular molar with six canals, three in mesial root that were independent throughout the root and three canals in distal root with independent orifices in the pulpal floor but join immediately to form two canals. [5] Ghoddusi, et al. reported a mandibular molar with two mesial and four distal canals. [3]

The morphology of mesial roots of mandibular molars is complex with high frequency of intracanal communications. The presence of the third canal in the mesial root of mandibular molar has been reported to have an incidence of 1-15%. The occurrence of three root canals in the mesial root is frequently reported in the literature but with three independent canals in distal root is a rare anatomic configuration with incidence of 1.3%. [6],[7] The present article reports successful management of mandibular first molars with six canals.

  Case Reports Top

Case report 1

A 45-year-old male presented to the clinic with the chief complaint of a sore tooth on the lower right jaw since 8 days [[Figure 1] Case 1a]. Medical history was noncontributory. His dental history indicated that incomplete root canal treatment which was initiated 6 months ago on mandibular right first molar tooth (46) and left uncompleted as treatment was discontinued by the patient. The tooth was sensitive to percussion on all the cusps and noticeably elevated when he bites on it. Sleep was disturbed because of the constant ache emanating from lower dental arch. Radiographic examination indicated widening of apical periodontal ligament space. The tooth was unusually broad its bucco-lingual dimension equals it's mesiodistal dimension.
Figure 1: Case 1 - (a) Preoperative. (b) Acess opening. (c) Working length. (d) Determinationd master cone

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Written consent was obtained from the patient before beginning root canal procedure. Local anesthetic was administered and the area was isolated with dental-dam. An endodontic access cavity was prepared in the usual manner but required modification to locate four orifices in pulpal floor corresponding to mesiobuccal, mesiolingual, distobuccal and distolingual canals using K-flex (Mani, Japan) hand file. Careful exploration of pulp chamber floor using an endodontic explorer (DG16, Hu Friedy, Rockwell, Chicago, USA) located a third canal (middle distal) in the distal root apart from distobuccal and distolingual canals. An isthmus was verified between the entrance orifice of distobuccal and distolingual canals [[Figure 1] Case 1b]. K-files no. 10 inserted to the apical termination in all three canals to confirm the presence of separate canals. Similarly, mesial root was explored for the presence of extra canal using an endodontic explorer and middle mesial canal was detected. K-file no. 10 was inserted to confirm the presence of separate canal [[Figure 1] Case 1c].

The canals were instrumented with Protaper Ni-Ti rotary system and irrigated with copious amounts of sodium hypochlorite (NaOCl) and 17% ethylene diaminotetracetic acid. The canals were prepared using Protaper F2 as the final file. Master gutta-percha cones (Dentsply, Maillefer, Switzerland) were selected corresponding to the size of the final file used [[Figure 1] Case 1d] and the canals obturated using AH-plus (Dentsply DeTrey GmbH, Konstanz, Germany) as a sealer. The access cavity was filled with amalgam restoration. Postoperative radiograph was obtained in 35° mesial angulation [[Figure 2] Case 1a] and 20° mesial angulation [[Figure 2] Case 1b] which showed five independent canals with middle distal canal and distolingual canal joined in the region of apical third. The patient was asymptomatic after 1-year follow-up [Figure 3].
Figure 2: (a) Case 1 - postobturation 35° mesial angulation. (b) Case 1 - 20° mesial angulation. (c) Case 2 - 20° mesial. (d) Case 2 - 20° distal angulation

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Figure 3: Case 1 - postoperative 1-year follow-up

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Case report 2

An 18-year-old male reported to the clinic with the chief complaint of pain in lower back region of the jaw since 5 days. The medical history was noncontributory. Dental history revealed root canal treatment with lower left first molar tooth (no. 36) 3 months back. On clinical examination, the tooth no. 36 was tender on percussion and revealed a large cavity with a temporary restoration [[Figure 4] Case 2a]. Re-endodontic treatment was advised as a measure for successful management of the case. After administration of local anesthetic and rubber dam isolation, the access cavity was modified, and four canals were located. Isthmus was found joining the mesiobuccal and mesio lingual orifices. Careful exploration using DG-16 explorer (Hu Friedy, Rockwell, Chicago, USA) additional canal was located in the middle of the isthmus. Similarly while exploring the isthmus running between distal orifices the middle distal orifice was also located [[Figure 4] Case 2c]. Working length was determined using K-file no. 10 [[Figure 4] Case 2b]. Root canals were instrumented with Protaper rotary system. Obturation consisted of gutta-percha (Denstply, Maillefer, Switzerland) with AH-plus sealer (Dentsply DeTrey GmbH Konstanz, Germany) [[Figure 4] Case 2d]. The access cavity was restored with amalgam. Postobturation periapical radiographs were obtained at 20° mesial [[Figure 2] Case 2c] and 20° distal [[Figure 2] Case 2d] angulation. At regular follow-up of 6 months and 1-year, patient had no recurrence of swelling and pain. Radiographically, tooth showed evidence of periapical healing [Figure 5].
Figure 4: Case 2 - (a) Preoperative. (b) Working length. (c) Location of middle distal canal. (d) Postobturation

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Figure 5: Case 2 - postoperative 1-year follow-up

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  Discussion Top

Anticipating the variations in root canal configurations, shape and size is of great importance during root canal treatment procedures. Endodontic failure occurs mainly due to failure in detection of the extra canals. Early detection of root canal variations and thorough and proper instrumentation is the key in successful endodontic therapy. [6]

Case reports are valuable because they remind us that the situation is not always normal, and during each treatment, we must expect many variations. Hence, it is important to know when to be suspicious. We know to look for canals if files are not well centered in the canal on the radiograph or clinically as they protrude from the canal orifice. Additional canals can be located using additional off angle radiographs and pulpal footprints and other adjunctive techniques. [8]

This case describes mandibular molar with three mesial and three distal canals. Previous reports have represented mandibular molar with three mesial canals and two distal canals, but very few have reported mandibular first molar with more than two distal canals. A radiographic study of extracted mandibular first molars revealed the occurrence of 3 mesial canals 13.3%, 4 mesial canals 3.3% of the time, 3 distal canals 1.7% of the time. [8],[9]

This report has demonstrated separate and distinct three mesial and three distal root canal orifices with distobuccal, distolingual and middle, distal canal exit in single apical foramen.

  Conclusion Top

The clinician should give particular attention to thoroughly observe the pulp chamber floor to locate the possible accessory canal orifices. This will increase the long term success of endodontic therapy.

  References Top

Plotino G. A mandibular third molar with three mesial roots: A case report. J Endod 2008;34:224-6.  Back to cited text no. 1
de Pablo OV, Estevez R, Péix Sánchez M, Heilborn C, Cohenca N. Root anatomy and canal configuration of the permanent mandibular first molar: A systematic review. J Endod 2010;36:1919-31.  Back to cited text no. 2
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. 3
Gu Y, Lu Q, Wang H, Ding Y, Wang P, Ni L. Root canal morphology of permanent three-rooted mandibular first molars - part I: Pulp floor and root canal system. J Endod 2010;36:990-4.  Back to cited text no. 4
Martinez-Berna A, Badanelli P. Mandibular first molars with six root canals. J Endod 1985;11:348-52.  Back to cited text no. 5
Kottoor J, Sudha R, Velmurugan N. Middle distal canal of the mandibular first molar: A case report and literature review. Int Endod J 2010;43:714-22.  Back to cited text no. 6
Ryan JL, Bowles WR, Baisden MK, McClanahan SB. Mandibular first molar with six separate canals. J Endod 2011;37:878-80.  Back to cited text no. 7
Jacobsen EL, Dick K, Bodell R. Mandibular first molars with multiple mesial canals. J Endod 1994;20:610-3.  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


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


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