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Year : 2016  |  Volume : 2  |  Issue : 2  |  Page : 50-52

Single canal in a single-rooted mandibular second molar: An enigma

Department of Pedodontics and Preventive Dentistry, Institute of Dental Sciences,SOA University, Bhubaneswar, Odisha, India

Date of Web Publication15-Mar-2017

Correspondence Address:
Sonu Acharya
HIG-48, Phase-I, 7 Acres, HB Colony, Chandrasekharpur, Bhubaneswar - 751 016, Odisha
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/2454-3160.202221

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The case report here tries to describe the variation of root canal anatomy in a second mandibular molar, which is rare in occurrence in literature. This case report presents a relatively rare case of mandibular second molar with single root and a single root canal in a 45-year-old female patient who had come to dental clinic with a complain of pain in the left lower tooth region. Ambiguity in the canal morphology of the second molar is quite common. Knowledge of variations in internal anatomy of teeth is important for success in endodontic treatment. Root canal morphology is limitless in its variability and clinicians must be aware that anatomic variations constitute a formidable challenge to endodontic success. Hence, clinicians have to take utmost care when these cases with single canal and single root come to clinic.

Keywords: Canal morphology, mandibular second molar, single canal, single root

How to cite this article:
Acharya S. Single canal in a single-rooted mandibular second molar: An enigma. Saint Int Dent J 2016;2:50-2

How to cite this URL:
Acharya S. Single canal in a single-rooted mandibular second molar: An enigma. Saint Int Dent J [serial online] 2016 [cited 2023 Jun 2];2:50-2. Available from: https://www.sidj.org/text.asp?2016/2/2/50/202221

Clinicians should be aware that the main root canals in a tooth may only provide access to the complexities of the root canal system, which must be fully cleaned of all microorganisms.[1] Unless and until the practitioner is familiar with the morphology of the roots of all teeth, and the associated intricate root canal anatomy, effective debridement, and obturation may be impossible. As long ago as 1925, it became clear that teeth had complicated root canal systems rather than the simplified canals that had been previously described.[2] The clinician is confronted daily with a highly complex and variable root canal system. All available armamentaria must be utilized to achieve a successful outcome treatment. Routine periapical radiographs helps us to assess the number, length, curvature, and aberration of the canal system of the tooth rejoin. Weine [3] categorized the root canal systems in any root into four basic types. Vertucci et al.[4] utilizing cleared teeth which had their pulp cavities stained with hematoxylin dye, found a much more complex canal system and identified eight pulp space configurations. General anatomical configuration of mandibular second molar is that of two roots, mesial and distal. This tooth is similar to the mandibular first molar, although a little more compact. The mesial canals tend to lie much closer together, and the incidence of two canals distally is much less. Occasionally, the root canals may join in a buccal fin giving a “C-shaped” canal, which may lead all the way to the apex.[5] C-shaped canal system is commonly found in mandibular molars, especially in Asian population.[6] Walker [7] determined that Asians have different percentages of canal configurations than those reported in studies dominated by Caucasians and Africans. A recent study conducted on Iranian population reported prevalence of 7.2% of C-shaped canals among second mandibular molars and these configuration were mostly seen among single rooted mandibular.[8] A study by Cimilli et al. reported 1.3% of mandibular second molars had single canal configuration.[9] This case report here presents a case of a single-rooted mandibular second molar with a single canal which is quite rare.

  Case Report Top

A 45-year-old female reported to the dental clinic with pain in relation to her mandibular left second molar, whose medical history was noncontributory. The tooth on examination revealed a deep caries. Clinical examination revealed that the tooth responded positively to percussion but not on palpation. Intraoral periapical radiograph revealed radiolucency in the crown involving the pulp suggestive of a pulpal involvement [Figure 1]. The root canal morphology confirmed the presence of a single root with a linear canal, constricting toward the apex. Slight periradicular changes were appreciable. After adequate anesthesia under proper isolation, an access cavity was prepared. Only a single round orifice was located in the middle portion of the floor of the pulp chamber. After pulp extirpation, working length was determined using a pro-file (Dentsply) [Figure 2] as well as apex locater (Propex, Dentsply). Cleaning and shaping was by crown down technique using ProTaper files. A thorough irrigation with sodium hypochlorite and saline was done throughout the procedure. Gutta-percha (GP) ProTaper was selected as a master apical cone to obtain an apical tug back [Figure 3]. As the canal was large, lateral condensation with GP points was done for a good obturation. The obturation was further confirmed with a radiograph [Figure 4]. Postobturation restoration was done with light cure composite.
Figure 1: Preoperative radiograph showing single root

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Figure 2: Working length radiograph

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Figure 3: Master cone radiograph

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Figure 4: Postobturation radiograph

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  Discussion Top

The study of root anatomy of teeth has an endodontic as well as anthropological significance. Mandibular second molars usually have two roots and three root canals but variations in the number of roots as well as canal morphology are not uncommon. In 1979, first description of the term C-shaped root canal was mentioned.[10] C-shaped canals are commonly found in permanent mandibular second molars but they can also be found in maxillary first molars, maxillary second molars, and mandibular first and second premolars, third molars, as well as in mandibular first molars.[10] In a recent study,[11] a 30% prevalence in the Hong Kong population was seen which was lower than that reported by Walker [7] (52%) and Yang et al.[12] (32%) A study of Iranian population reported prevalence of 7.2% of C-shaped canals in second mandibular molars, which were mostly among single rooted mandibular teeth while another study reported type I canals,[13] but very few mention of single canal with a round or oval orifice in a second mandibular molars could be found.[14],[15] In the present case, initial evaluations of the radiographs suggested the presence of single root with a wide canal space suggesting that there may be C-shaped configuration of canals. After access cavity preparation, on observation of the pulpal floor, only one canal with a round orifice was located, suggestive of the presence of a single canal. Further exploration of the pulpal floor did not reveal presence of any additional orifice opening. The canals of these teeth were wide and tapering biomechanical preparation and copies irrigation was done to ensure complete removal of debris. The canal was obturated with GP point and resin based sealer using lateral condensation technique. Here, we used ProTaper GP as master cone and normal GP points for compact obturation. A postobturation radiograph showed a well obturated canal.

  Conclusion Top

A thorough understanding of the complexity of the root canal system is essential for understanding the principles and problems of shaping and cleaning, for determining the apical limits and dimensions of canal preparations, and for performing successful root canal therapy.

It is difficult to determine to which classification of C-shaped canal do the above described canal belong to or they can just be described as Vertucci type I canal system.

Clinical significance

Clinicians ought to be aware of complex root canal structures, of cross-sectional dimensions and of iatrogenic alterations of canal anatomy. Careful interpretation of angled radiographs, proper access preparation, and a detailed exploration of the interior of the tooth, ideally under magnification, are essential prerequisites for a successful treatment outcome.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Carrotte P. Endodontics: part 4. Morphology of the root canal system. Br Dent J 2004;197:379-83.  Back to cited text no. 1
Hess W, Zurcher E. The Anatomy of the Root Canals of the Teeth of the Permanent Dentition and the Anatomy of the Root Canals of the Deciduous Dentition and the First Permanent Molars. London: Basle, Sons and Danielson; 1925.  Back to cited text no. 2
Weine FS. Endodontic Therapy. 5th ed. St. Louis: Mosby-Yearbook Inc.; 1996. p. 243.  Back to cited text no. 3
Vertucci F, Seelig A, Gillis R. Root canal morphology of the human maxillary second premolar. Oral Surg Oral Med Oral Pathol 1974;38:456-64.  Back to cited text no. 4
Ingle J, Bakland I, Baumgartner JC. Ingle's Endodontics. 6th ed. Philadelphia, USA: BC Decker Inc.; 2008. p. 209.  Back to cited text no. 5
Manning SA. Root canal anatomy of mandibular second molars. Part II. C-shaped canals. Int Endod J 1990;23:40-5.  Back to cited text no. 6
Walker RT. Root form and canal anatomy of mandibular first molars in a Southern Chinese population. Endod Dent Traumatol 1988;4:19-22.  Back to cited text no. 7
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. 8
Cimilli H, Cimilli T, Mumcu G, Kartal N, Wesselink P. Spiral computed tomographic demonstration of C-shaped canals in mandibular second molars. Dentomaxillofac Radiol 2005;34:164-7.  Back to cited text no. 9
Cooke HG 3rd, Cox FL. C-shaped canal configurations in mandibular molars. J Am Dent Assoc 1979;99:836-9.  Back to cited text no. 10
Jayasinghe RD, Ka-Lun LT. C-shaped canals in mandibular second molars in the Hong Kong population: A computed tomographic study. Hong Kong Dent J 2008;5:27-30.  Back to cited text no. 11
Yang ZP, Yang SF, Lin YC, Shay JC, Chi CY. C-shaped root canals in mandibular second molars in a Chinese population. Endod Dent Traumatol 1988;4:160-3.  Back to cited text no. 12
Fan W, Fan B, Gutmann JL, Cheung GS. Identification of C-shaped canal in mandibular second molars. Part I: Radiographic and anatomical features revealed by intraradicular contrast medium. J Endod 2007;33:806-10.  Back to cited text no. 13
Fava LR, Weinfeld I, Fabri FP, Pais CR. Four second molars with single roots and single canals in the same patient. Int Endod J 2000;33:138-42.  Back to cited text no. 14
Shetty N, Singh V, Rijal S. Single rooted mandibular second molars with single canal: Rare occurance. Endodontology 2000;2:55-9.  Back to cited text no. 15


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


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