Year : 2013 | Volume : 1 | Issue : 2 | Page : 69 - 72  

Case Reports
A report of three independent mesial canals in the mesial root of a mandibular second molar.

Shilpa Reddy M 1, Mamta Kaushik 2, Yellamma Bai 3, Chiyadu Padmini 4

1Associate professor of Conservative Dentistry and Endodontics, 3Principal, Professor and Head of Pedodontics & Preventive Dentistry, 4Senior Lecturer, Dept. of Pedodontics & Preventive Dentistry, Malla Reddy Institute of Dental Sciences, Hyderabad, AP.

2Professor of Conservative Dentistry and Endodontics, Army College of Dental Sciences, Secunderabad, AP.


The root canal treatment of a mandibular molar with aberrant canal configuration can be diagnostically and technically challenging. This case report presents the clinical management of a mandibular second molar with three separate mesial canals including middle mesial canal, which was confirmed by operating microscope. There are reports that deal with three orifices in the mesial root, but very rare describe three independent canals, indicating a rare anatomical configuration. This case report highlights the very rare occurrence of independent medial mesial canal in mandibular second molar

Keywords: Mandibular second molar, mesial canals, operating microscope.

Corresponding Author: Dr. Shilpa Reddy M, Associate Professor, Dept. of Conservative Dentistry & Endodontics, Malla Reddy Institute of Dental Sciences, Hyderabad, AP. E-mail:



The main objective of root canal treatment is the thorough mechanical and chemical

cleansing of the entire pulp space followed by complete obturation with inert filling material. [1] Therefore, it is imperative that aberrant anatomy is identified before and during root canal treatment of such teeth. Since Vertucci and Williams [2] first reported the presence of a middle mesial (MM) canal in a mandibular molar with a separate orifice and a separate apical foramen, there have been multiple case reports of aberrant canal morphology in the mesial root. [3-7] In a clinical evaluation of 100 mandibular molars, Pomeranz et al [4] found that 12 molars had MM canals in their mesial roots and classified them into three morphologic categories as follows:

fin, confluent, and independent. According to their classification, an independent canal implies the canal originated as a separate orifice and terminated as a separate foramen, and only two cases were identified as independent. Goel et al [7] reported mandibular first molars had MM canals in 15.0% of specimens. Among these MM canals, only 6.7% of MM canals were independent. In a study by Ahmed et al. using a clearing technique, the prevalence of three mesial canals was 4% in mandibular first molars and 10% in mandibular second molars in Sudanese population. [8]

Reuben et al. evaluated root canal morphology of 125 extracted mandibular first molars in an Indian population using spiral computed tomography; they did not find mesial roots of mandibular molars with three mesial canals. [9] In a clinical study of 145 mandibular first molars, Fabra-Campos found four molars (2.07%) with five canals- three in mesial root and two in distal. [3] In the four cases, the MM canal did not show an independent apical foramen. On the other hand, very few mandibular first and second molars with three separated canals in mesial root have been reported. [4, 5] The present report describes root canal treatment in a mandibular second molar containing three independent canals in its mesial root.

Case report:

A 48-year old male patient reported to the Department of Conservative Dentistry and Endodontics, ACDS with complaint of pain on the lower left posterior region since three days. Pain was moderate, intermittent and increased while chewing food. The patient was taking medication (analgesics) for same. The patient’s medical history was non-contributory. Dental history revealed that he had undergone extraction of left mandibular first molar one month earlier by a general dental practitioner. On clinical examination, mandibular first molar of left side was missing and in mandibular second molar caries was present in disto-occlusal aspect. There was no evidence of swelling or sinus tract in relation to it. The involved tooth was tender on percussion and no periodontal pockets were present. Radiographic evaluation of the concerned tooth (Fig.1) revealed carious destruction on the distal aspect involving the pulp and widening of the lamina dura for the distal root. Based on clinical and radiographic findings the tooth was diagnosed for irreversible pulpitis with apical periodontitis. Endodontic treatment was planned for the same. After administering local anaesthesia, and rubber dam isolation, all carious tissue was removed and an access cavity was prepared. Four orifices and canals (three mesial and one distal) were located in the first appointment. Working lengths were estimated by using an electronic apex locator (Propex II, Dentsply) and then confirmed with a radiograph (Fig.2). All canals were cleaned and shaped with Mtwo instruments (VDW) under copious irrigation with 5.25% sodium hypochlorite. The access cavity was sealed with a cotton pellet and temporary restoration placed. On the next appointment, using the surgical operating microscope with 8x magnification, the middle mesial canal was identified as independent by Pormeranz’s classification. A gutta-percha cone fit radiograph was made and the canals were obturated (Fig.4) using cold lateral compaction of gutta- percha and a resin sealer (AH Plus, Dentsply, Germany). The patient experienced no post-treatment discomfort and the tooth was referred for a full coverage restoration.


Before root canal treatment is performed, the clinician should ideally have adequate knowledge of the pulp chamber and internal anatomy of the teeth. All canals should be accessed, cleaned, and shaped to achieve a hermetic obturation of the entire root canal space. There are abundant reports that relate the anatomic variations of mandibular molars.[10] This should induce the clinician to accurately observe the pulpal floor to locate extra canal orifices. Searching for additional canal orifices should be standard practice for clinicians. A round bur or an ultrasonic tip can be used to remove any protuberance from the mesial axial wall which could prevent direct access to the developmental groove between MB and ML orifices. This developmental groove should be carefully checked with the sharp tip of an endodontic explorer. If depression or orifices are located, the groove can be troughed with ultrasonic tips at its mesial aspect until a small file can negotiate this intermediate canal. New technologies, such as the dental operating microscope and dental loupes, offer magnification and illumination of the operating field and substantially improve the visualization of root canal orifices. The morphology of the mesial root canals in mandibular molars is complex and difficult to find, with a high frequency of inter-canal communications and or isthmuses. [1, 7] The presence of a third canal (middle mesial) in the mesial root of the mandibular molars has been reported to have an incidence of 0.95%-15%. [1, 3]In almost all of the clinical cases reported, the middle mesial canal joined the mesiobuccal or mesiolingual canal in the apical third. [3, 4] However, a few mandibular first molars that had three independent canals in their mesial root have been reported; and further less in the mandibular second molar. [4, 5, 6] Most of the reported and reviewed cases in literature are of first mandibular molars and only a few clinical cases of the second mandibular molars have been reported. Also, mostly it is related to the mesial root. The larger mesiodistal dimension of the distal root, compared to that of the mesial root , may account for the rare incidence of third canal created by dentin apposition in distal roots.Careful evaluation of research material has, however, shown deviations from the norm in tooth morphology are not uncommon.


When root canal treatment is to be performed, the clinician should be aware that the root canal anatomy may be abnormal. Every attempt should be made to find and treat all root canals to ensure successful endodontic treatment. The importance of an accurate clinical evaluation of root canal number and morphology in mandibular molars cannot be overemphasized.


  1. Vertucci FJ. Root canal anatomy of the human permanent teeth. Oral Surg Oral Med Oral Pathol. 1984 Nov;58(5):589-99.
  2. Vertucci FJ, Williams RG. Root canal anatomy of the mandibular first molar. JNJ Dent Assoc 1974 ;48:27–8.
  3. Fabra-Campos H. Unusual root anatomy of mandibular first molars. J Endod 1985; 11(12):568–72.
  4. Pomeranz HH, Eidelman DL, Goldberg MG. Treatment considerations of the middle mesial canal of mandibular first and second molars. J Endod 1981;7(12):565–8.
  5. Min KS. Clinical management of a mandibular first molar with multiple mesial canals: a case report. J Contemp Dent Pract 2004;5(3):142–9.
  6. Ricucci D. Three independent canals in the mesial root of a mandibular first molar. Endod Dent Traumatol 1997;13(1):47–9.
  7. Goel NK, Gill KS, Taneja JR. Study of root canals configuration in mandibular first permanent molar. J Indian Soc Pedod Prev Dent 1991;8(1):12–4.
  8. 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(10):766-71.
  9. 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(2):212-5.
  10. Cleghorn BM, Goodacre CJ, Christie WH. Morphology of teeth and their root canal system. In: Ingle JI,Barkland LK and Baumgathner JC, editors. Endodontics, 6th BC Decker Inc, 2008: 151-210.


Source of Support: Nil. Conflict of Interest: None.


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