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Year : 2017  |  Volume : 8  |  Issue : 1  |  Page : 34-36

C-shaped single canaled mandibular second molar: A rare case report

1 Department of Conservative Dentistry and Endodontics, Darshan Dental College and Hospital, Udaipur, Rajasthan, India
2 Department of Conservative Dentistry and Endodontics, N.S.V.K. College, Bengaluru, Karnataka, India
3 Department of Orthodontics, Darshan Dental College and Hospital, Udaipur, Rajasthan, India
4 Department of Orthodontics, People's College of Dental Sciences, Bhopal, Madhya Pradesh, India

Date of Web Publication30-Mar-2017

Correspondence Address:
Rahul Bhargava
Department of Conservative Dentistry and Endodontics, Darshan Dental College and Hospital, Udaipur, Rajasthan
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/srmjrds.srmjrds_21_16

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This case report presents a rare root canal system in a mandibular second molar tooth, a single root with a single canal. C-shaped canals with varying configuration are commonly observed in single-rooted mandibular second molars. The access cavity displayed only one round/oval canal orifice which is very rare. The knowledge of dental anatomy is an essential tool for the success of endodontic treatment. The early recognition of these configurations facilitates cleaning, shaping, and obturation of the root canal system. Therefore, a clinician thus requires to have adequate knowledge about root morphology and its variation. Thorough knowledge of the root canal anatomy is necessary to perform a successful endodontic treatment.

Keywords: C-shaped canal, mandibular molar, root canal anomaly

How to cite this article:
Bhargava R, Chandana A S, Punia SK, Dungarwal N, Prakash A. C-shaped single canaled mandibular second molar: A rare case report. SRM J Res Dent Sci 2017;8:34-6

How to cite this URL:
Bhargava R, Chandana A S, Punia SK, Dungarwal N, Prakash A. C-shaped single canaled mandibular second molar: A rare case report. SRM J Res Dent Sci [serial online] 2017 [cited 2023 Jan 29];8:34-6. Available from:

  Introduction Top

A thorough knowledge of the anatomy of teeth involved in root canal treatment is essential for successful debridement and obturation of the root canal system.[1] Recognition of unusual variations in the canal configuration is critical because it has been established that the root with a single tapering canal and apical foramen is the exception rather than the rule.[2] As with most of posterior teeth, the mandibular second molar has several variants in its canal configuration. According to the endodontic literature, a C-shaped root canal is most frequently seen in mandibular second molar. The so-called C-shaped canal system can occur in mandibular first and maxillary molars but is most commonly found in mandibular second molars.[1],[2]

The C-shaped canal was first documented in endodontic literature by Cooke and Cox in 1979. C-shaped canal system is commonly found in mandibular molars, especially in Asian population.[3]

In 2005, Cimilli et al. using spiral computed tomographic imaging concluded that the prevalence of C-shaped canals in single-rooted mandibular second molars was 8%. Vertucci Type I canals were most frequently seen in these C-shaped molars.[4]

Gao et al. described the presence of Type II merging type of canals, where canals merged into one major canal before exiting at the apical foramen; partial dentin fusion areas may appear in the coronal or middle portion of the canal.[5]

A recent study conducted on Iranian population reported the prevalence of 7.2% of C-shaped canals among second mandibular molars and these configurations were mostly seen among single-rooted mandibular.[6] A study by Weine et al. reported 1.3% of mandibular second molars had single canal configuration. The purpose of this case report is to report occurrence of single canal in single-rooted mandibular second molars that required endodontic therapy.[7]

  Case Report Top

A 35-year-old female patient reported at Apex Dental Clinic, Udaipur (Rajasthan), with pain in relation to her right mandibular second molar.

Intraoral examination revealed deep caries and lack of swelling of the surrounding tissue. The patient had pain on percussion. Intraoral periapical radiograph revealed radiolucency in the crown involving the pulp suggestive of a pulpal involvement. The root canal morphology confirmed the presence of a single root with a linear canal, constricting toward the apex. Slight periradicular changes were appreciable [Figure 1].
Figure 1: Preoperative radiograph

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Intraoral periapical radiograph of tooth revealed deep caries approximating the pulp without any associated periapical change. A detailed examination of the radiograph revealed the presence of a single root with a wide canal. Therefore, C-shaped canal configuration was anticipated. Clinical and radiographical examination revealed irreversible pulpitis due to dental caries.

After the administration of local anesthesia (Lignox 2%, Indoco Remedies, Warren, Goa, India), the access cavity was prepared. The pulp chamber was irrigated with 5% sodium hypochlorite to debride the chamber fully and to identify the nature of the canal system present. In the present case, a single round orifice was located in the middle portion of the floor of the pulp chamber. Working length was determined using apex locator (Root ZX, J. Morita USA, Irvine, CA, USA) and confirmed by the radiographs [Figure 2].
Figure 2: Working length radiograph

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Cleaning and shaping were done with K-files (Dentsply Maillefer, Ballaigues, Switzerland) and apical third was shaped to size 80 with K-files. In between the instrumentation, thorough irrigation with sodium hypochlorite and saline was done throughout the procedure. A ISO #80 GP was selected as a master apical cone to obtain an apical tug back [Figure 3].
Figure 3: Master cone radiograph

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The canal was then obturated with AH-Plus sealer using lateral condensation technique. A postobturation radiograph showed a well-obturated canal [Figure 4].
Figure 4: Postobturation radiograph

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  Discussion Top

The study of root and canal anatomy has endodontic and anthropologic significance.[8],[9],[10],[11]

In fact, it is important to be familiar with variations in tooth anatomy and characteristic features in various racial groups because such knowledge can aid location and negotiation of canals as well as their subsequent management.[1]

The variability of the root canal system of multirooted teeth represents a challenge to both endodontic diagnosis and treatment. The preoperative awareness of potential anatomic variations is essential for the success of the endodontic treatment.

The C-shaped canal is not uncommon and this is confirmed by studies, in which frequencies ranging from 2.7% to 8% have been reported.[3] Studies on mandibular second molars have shown a high incidence of C-shaped roots and canals (10%–31.5%).[1] The prevalence is higher in the middle Asia up to 10.6% in Saudi Arabians [12] and 19.14% in Lebanese.[11] In Northeast Asia, the prevalence is 31.5% in Chinese [10] and 32.7% in Koreans.[13] This variation may occur in mandibular first molars,[14] maxillary molars,[15] mandibular first premolars,[16],[17] and even in maxillary lateral incisors,[18] but it is most commonly found in mandibular second molars.[8] When present on one side, C-shaped canal may be found in contralateral tooth in over 70% of individuals.[18]

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 the presence of any additional orifice opening. The root canal of tooth was wide and tapering. Biomechanical preparation and copious irrigation were done to ensure complete removal of debris. A postobturation radiograph showed a well-obturated canal.

  Conclusion Top

Central to successful endodontics is knowledge, respect, and appreciation for root canal anatomy and careful, thoughtful, meticulously performed cleaning and shaping procedures. Knowledge and recognization of canal configuration can facilitate more effective canal identification and unnecessary removal of healthy tooth structure in an attempt to search for missing canals. Therefore, careful location and negotiation of canals and meticulous mechanical and chemical debridement of the pulp tissue should be carried out to successfully treat a C-shaped canal.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Jafarzadeh H, Wu YN. The C-shaped root canal configuration: A review. J Endod 2007;33:517-23.  Back to cited text no. 1
Fan B, Cheung GS, Fan M, Gutmann JL, Fan W. C-shaped canal system in mandibular second molars: Part II – Radiographic features. J Endod 2004;30:904-8.  Back to cited text no. 2
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. 3
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. 4
Gao Y, Fan B, Cheung GS, Gutmann JL, Fan M. C-shaped canal system in mandibular second molars part IV: 3-D morphological analysis and transverse measurement. J Endod 2006;32:1062-5.  Back to cited text no. 5
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. 6
Weine FS, Pasiewicz RA, Rice RT. Canal configuration of the mandibular second molar using a clinically oriented in vitro method. J Endod 1988;14:207-13.  Back to cited text no. 7
Jerome CE. C-shaped root canal systems: Diagnosis, treatment, and restoration. Gen Dent 1994;42:424-7.  Back to cited text no. 8
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. 9
Walker RT. Root form and canal anatomy of mandibular second molars in a Southern Chinese population. J Endod 1988;14:325-9.  Back to cited text no. 10
Haddad GY, Nehme WB, Ounsi HF. Diagnosis, classification, and frequency of C-shaped canals in mandibular second molars in the Lebanese population. J Endod 1999;25:268-71.  Back to cited text no. 11
Al-Fouzan KS. C-shaped root canals in mandibular second molars in a Saudi Arabian population. Int Endod J 2002;35:499-504.  Back to cited text no. 12
Seo MS, Park DS. C-shaped root canals of mandibular second molars in a Korean population: Clinical observation and in vitro analysis. Int Endod J 2004;37:139-44.  Back to cited text no. 13
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. 14
Yilmaz Z, Tuncel B, Serper A, Calt S. C-shaped root canal in a maxillary first molar: A case report. Int Endod J 2006;39:162-6.  Back to cited text no. 15
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. 16
Sikri VK, Sikri P. Mandibular premolars: Aberrations in pulp space morphology. Indian J Dent Res 1994;5:9-14.  Back to cited text no. 17
Bóveda C, Fajardo M, Millán B. Root canal treatment of an invaginated maxillary lateral incisor with a C-shaped canal. Quintessence Int 1999;30:707-11.  Back to cited text no. 18


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


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