|Year : 2019 | Volume
| Issue : 2 | Page : 133-138
|Racial predilection of C-shaped canal configuration in the mandibular second molar
Aishwarya Roy1, Madhusudan Astekar2, Rashmi Bansal1, Anuraag Gurtu1, Mrityunjay Kumar3, Lalit Kumar Agarwal1
1 Department of Conservative Dentistry and Endodontics, Institute of Dental Sciences, Bareilly, Uttar Pradesh, India
2 Department of Oral Pathology and Microbiology, Institute of Dental Sciences, Bareilly, Uttar Pradesh, India
3 Department of Anaesthesiology, Critical Care and Pain Management, Shri Ram Murti Smarak Institute of Medical Sciences, Bareilly, Uttar Pradesh, India
Click here for correspondence address and email
|Date of Submission||28-Aug-2018|
|Date of Decision||20-Nov-2018|
|Date of Acceptance||25-Mar-2019|
|Date of Web Publication||02-May-2019|
| Abstract|| |
Aim: The purpose of this article is to determine the racial predilection of C-shaped canal configuration in a mandibular second molar.
Background: Unusual root canal anatomy always poses a diagnostic and treatment challenge. Identification of such variation is important for the success of root canal treatment outcome. C-shaped canal configuration is such an aberrant morphology of molar teeth that vary in different population and is commonly seen in a mandibular second molar. Thus, knowledge of racial predilection of C-shaped canal configuration in different population for early diagnosis is obligatory.
Materials and Methods: An exhaustive search was undertaken to identify published research articles related to C-shaped canal configuration in mandibular second molars. Forty-three research articles were analyzed which included 12,481 mandibular second molars. Chi-square test using value of P < 0.05 was performed to assess the statistical significance of this anomalous anatomic variation among the different population.
Results: Statistical test revealed a significant variation between the Asian and nonAsian population. The highest incidence of racial predilection was observed in China (Asia) with 93.1%, and the minimum was observed in America with 2.7%.
Conclusion: This research reported that racial predilection of C-shaped canal configuration in mandibular second molar varies significantly.
Keywords: Cross-sectional studies; fused mandibular teeth; mandibular molar; root canal; root canal therapy
|How to cite this article:|
Roy A, Astekar M, Bansal R, Gurtu A, Kumar M, Agarwal LK. Racial predilection of C-shaped canal configuration in the mandibular second molar. J Conserv Dent 2019;22:133-8
|How to cite this URL:|
Roy A, Astekar M, Bansal R, Gurtu A, Kumar M, Agarwal LK. Racial predilection of C-shaped canal configuration in the mandibular second molar. J Conserv Dent [serial online] 2019 [cited 2021 Oct 21];22:133-8. Available from: https://www.jcd.org.in/text.asp?2019/22/2/133/257574
| Introduction|| |
Mandibular molars exhibit different anatomical variations. C-shaped canal configuration is one of the most common anatomical variants observed in a mandibular second molar. It is an aberrant morphology of mandibular second molar in which the horizontal cross section is in the form of a letter C, with canals which may or may not be separate. In this configuration, the canals are connected by ribbon-like structure such as a slit, fin, or web. This configuration develops either due to the fusion between roots or by coalescence due to deposition of cementum with time. The root canal configuration depends on the growth of the Hertwig's epithelial root sheath (HERS), which bends in a horizontal plane below the cementoenamel junction and fuses in the center leaving an opening for roots. Thus, failure of HERS to fuse on the lingual or buccal root surface is the main cause of C-shaped root canal configuration.
Predominantly, this type of configuration occurs in mandibular second molars, but it has also been reported in mandibular first and third molars, maxillary first molars, and in mandibular premolars by various researchers. If the C-shaped canal is present on one side, it may be found in the contralateral tooth in over 70% of individuals. C-shaped canal configuration is difficult to prepare during biomechanical preparation. Therefore, it requires a different regimen of endodontic treatment.
Literature search reveals that C-shaped canal configuration is not uncommon, and this is confirmed by various studies in which prevalence ranges from 2.7 to 41.27%., This prevalence is estimated to be between 2.7 and 9.0% in nonAsian population and is as high as 41.27% among the Asian population such as Chinese, Korean, and Hong Kong Chinese which indicate its racial distribution. With the advent of three-dimensional imaging and dental operating microscope further increase in the detection of C-shaped configuration in the Asian population were also reported.,,
Systematic reviews are a type of literature review that collects and critically analyzes multiple research studies or papers, using methods that are selected before one or more research questions are formulated, and then finding and analyzing studies that relate to and answer those questions in a structured methodology. Therefore, it uses an objective and transparent approach, with the aim of minimizing bias.
As there are very few systematic reviews available in the literature, this study was undertaken to re-evaluate the racial predilection of the C-shaped canal in mandibular second molars. Further, racial predilection in different continents and especially in India as a country in the South Asian geographical location was also studied.
| Materials and Methods|| |
Literature Search and Data Extraction: An exhaustive search was undertaken through MEDLINE/Pub Med/Elsevier/Google Scholar/Web of Science (ISI)/Scopus/IndMED database, various Journals indexed in PubMed/Medline to identify published literature related to the prevalence of C-shaped canal in permanent mandibular second molar by using keywords “mandibular molar,” “root canal,” “fused mandibular teeth,” and “cross-sectional study.” Related research articles were identified, and a literature review was performed for articles dated February 2018 and before.
The data were analyzed according to the geographical population, sample size, prevalence of C-shaped canal configuration, and evaluation technique. The geographical population studied was categorized based on various continents such as Asia and non-Asian such as Australia, Europe, South America, North America, and Africa. Various evaluation techniques have been documented in the literature which includes the routine analysis such as clinical examination and intraoral periapical and panoramic radiography. With the evolution of time, the advanced analysis includes clearing technique, micro/spiral computed tomography (CT), cone-beam CT (CBCT), and stereomicroscopy.
Statistical comparisons were made between different population and within the same population, using Chi-square test with P < 0.05.
| Results|| |
A summary of the findings of these studies based on the geographical population, their sample size, racial predilection percentage, and evaluation technique were tabulated. A total of 43 anatomic studies were analyzed which included 12,768 mandibular second molars.
Among the Asian population, East Asians showed the maximum prevalence of C-shaped canal of 93.1% (Fan et al., 2004) from China, 52% (Walker et al., 1988) from Hong Kong, and 45.5% (Jin et al., 2006) from Korea followed by West Asia of 34.37% (Salma et al., 2013) from UAE, Southeast Asia of 22% (Gulabivala et al. 2001) from Burma and least in the South Asian population of 7.5% (Neelkanthan et al., 2010) from India. However, a minimum of 3% racial predilection was observed in various populations from such as Srilanka (Peiris et al., 2008) and Iran (Jahromi et al., 2013 and Nourmadipour et al., 2007) [Table 1].
|Table 1: Racial predilection of C-shaped canal configuration in Asian races|
Click here to view
Among the nonAsian population, Brazil showed a maximum prevalence of C-shaped canal of 15.9% (Rocha et al., 1996) followed by 12.8% (Manning et al., 1990) from Australia [Table 2].
|Table 2: Racial predilection of C-shaped canal configuration in non-Asian races|
Click here to view
Overall C-shaped canal racial predilection was estimated, it showed 16.41%. When routine and advanced analysis of C-shaped canal racial predilection was assessed, the routine methods such as clinical examination showed 16.56%, radiographic examination showed 14.8%, and when both the clinical and radiographic method was assessed, it showed 19.6%. However when the advanced analysis was estimated, clearing technique showed 10.36%, CBCT showed 26.01%, and micro CT showed 44.15% [Table 3].
|Table 3: Mean percentage of C-shaped canal configuration based on routine and advanced analysis|
Click here to view
When micro CT was compared with all the other techniques in analyzing the racial predilection of C-shaped canal configuration, it showed a statistically highly significant result with P < 0.0001 except when compared with CBCT which showed a significant value of P = 0.0303 [Table 4].
|Table 4: Comparison of average percentage of micro computed tomography to others|
Click here to view
The country-wise the racial predilection of C-shaped canal configuration was assessed as there were more than one studies from the same population, and hence, racial predilection was statistically calculated for each population [Table 5]. This racial predilection was statistically compared between Asian versus nonAsian population using the Chi-square test and this difference was found to be statistically significant. Even in the Asian population, difference in racial predilection between East, West, South, and Southeast Asia was statistically significant [Table 6].
|Table 5: Average percentage of racial predilection of C-shaped canal configuration|
Click here to view
|Table 6: Comparative evaluation of racial predilection of C-shaped canal configuration between Asian population and non-Asian continent and among Asian countries|
Click here to view
| Discussion|| |
The C-shaped canal, which was first documented in endodontic literature by Cooke and Cox in 1979, is so named for the cross-sectional morphology of the root and root canal. Instead of having several discrete orifices, the pulp chamber of the C-shaped canal is a single ribbon-shaped orifice with a 180° arc (or more), which, in mandibular molars, starts at the mesiolingual line angle and sweeps around the buccal to the end at the distal aspect of the pulp chamber. Knowledge and recognition of such canal configuration facilitate more effective canal identification and unnecessary removal of healthy tooth structure in an attempt to search for missing canals. The literature reports that the presence of C-shaped canal is more common in the East Asian population. This co-relates with the study's results, as the sample from China had significantly higher prevalence (93.1%) when compared with other regions.
This systematic review revealed that C-shaped canal configuration varies in the mandibular second molar among the different population. Various techniques were used for the evaluation of this configuration both in vitro,,, and in vivo. To the best of author's knowledge, there is no such study till date where comparison of prevalence for C-shaped canal between the Asian and non-Asian population has been made, moreover comparison of routine and advanced analysis and separate comparison of micro-CT with various other techniques has not been reported. This systemic study has evaluated above-mentioned details.
Among various techniques, clearing technique,,,,, radiography,,,,, and clinical analysis,,,,, were more common. Using these techniques, various studies, had reported the prevalence of this configuration ranging from 2.7% to 41.27%. Among three-dimensional imaging techniques, spiral CT, micro-CT,, and CBCT, were used. The Use of micro-CT resulted in even higher prevalence up to 93.1% in the Chinese population as compared to when clearing technique. This increase in prevalence may also be due to the difference in sample size, increase in knowledge about configuration and decrease in jaw size during evolution leading to fusion of roots. Introduction of magnification and use of ultrasonic tips had further improved the diagnosis of this configuration. More racial predilection was observed in the Asian population as compared to the NonAsian population [Figure 1]. C-shaped configuration is reported to be more prevalent among females (16.5%), as compared to that of males (10.4%). The present study revealed great variability between regions regarding C-shaped canal configuration.
|Figure 1: Map depicting the variation in prevalence of C-shaped canal configuration world-wide|
Click here to view
C-shaped configuration complicates endodontic instrumentation and obturation if not diagnosed at an early stage. As this configuration is common in Asian as compared to European and American population, hence mandibular second molars in Asian must be carefully diagnosed for this configuration before the initiation of endodontic treatment for better prognosis and treatment planning.
| Conclusion|| |
The prevalence of C-shaped anatomy varied from region to region. The highest prevalence was observed in China (93.1%), whereas the lowest was observed in the United States (2.7%). The results from China were significantly higher than any other region. Recent imaging techniques have given a better insight into racial predilection of C-shaped configuration. It is important to be familiar with this variant because ultimately they have both clinical and anthropological significance. In clinical practice, such knowledge can aid in the location and negotiation of canals as well as in their subsequent management.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Kato A, Ziegler A, Higuchi N, Nakata K, Nakamura H, Ohno N, et al.
Aetiology, incidence and morphology of the C-shaped root canal system and its impact on clinical endodontics. Int Endod J 2014;47:1012-33.
Manning SA. Root canal anatomy of mandibular second molars. Part II. C-shaped canals. Int Endod J 1990;23:40-5.
Jafarzadeh H, Wu YN. The C-shaped root canal configuration: A review. J Endod 2007;33:517-23.
Hargreaves KM, Berman LH. Cohen's Pathways of the Pulp. 11th
ed. Missouri: Elsevier Health Sciences; 2016.
Cooke HG 3rd
, Cox FL. C-shaped canal configurations in mandibular molars. J Am Dent Assoc 1979;99:836-9.
Park JB, Kim N, Park S, Kim Y, Ko Y. Evaluation of root anatomy of permanent mandibular premolars and molars in a Korean population with cone-beam computed tomography. Eur J Dent 2013;7:94-101.
Fan B, Cheung GS, Fan M, Gutmann JL, Bian Z. C-shaped canal system in mandibular second molars: Part I – Anatomical features. J Endod 2004;30:899-903.
Jin GC, Lee SJ, Roh BD. Anatomical study of C-shaped canals in mandibular second molars by analysis of computed tomography. J Endod 2006;32:10-3.
Seo DG, Gu Y, Yi YA, Lee SJ, Jeong JS, Lee Y, et al.
Abiometric study of C-shaped root canal systems in mandibular second molars using cone-beam computed tomography. Int Endod J 2012;45:807-14.
Thong YL, Abukasim NH. C-Shaped root canals in single rooted mandibular second molars of Malaysians. J Dent Res 1995;74:533.
Zhang R, Wang H, Tian YY, Yu X, Hu T, Dummer PM, et al.
Use of cone-beam computed tomography to evaluate root and canal morphology of mandibular molars in Chinese individuals. Int Endod J 2011;44:990-9.
Zheng Q, Zhang L, Zhou X, Wang Q, Wang Y, Tang L, et al.
C-shaped root canal system in mandibular second molars in a Chinese population evaluated by cone-beam computed tomography. Int Endod J 2011;44:857-62.
Wang Y, Guo J, Yang HB, Han X, Yu Y. Incidence of C-shaped root canal systems in mandibular second molars in the native Chinese population by analysis of clinical methods. Int J Oral Sci 2012;4:161-5.
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.
Jung HJ, Lee SS, Huh KH, Yi WJ, Heo MS, Choi SC, et al.
Predicting the configuration of a C-shaped canal system from panoramic radiographs. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010;109:e37-41.
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.
Walker RT. Root form and canal anatomy of mandibular second molars in a Southern Chinese population. J Endod 1988;14:325-9.
Jayasinghe R, Li T. C-shaped canals in mandibular second molars in the Hong Kong population: A computed tomographic study. Hong Kong Dent J 2008;5:27-30.
Kotoku K. Morphological studies on the roots of the Japanese mandibular second molars. Dental Sci Rep 1985;1:43–64.
Nourmandipour M, Nasiri M. Prevalence of C-shaped mandibular second molars in Zahedan. Zahedan J Res Med Sci 2008;9:313-8.
Rahimi S, Shahi S, Lotfi M, Zand V, Abdolrahimi M, Es'haghi R, et al.
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.
Hasheminia M, Hashemi A. Frequency of canal configuration in maxillary first premolars and mandibular second premolars. J Isfahan Dent Sch 2005;1:59-64.
Kuzekanani M, Haghani J, Nosrati H. Root and canal morphology of mandibular third molars in an Iranian population. J Dent Res Dent Clin Dent Prospects 2012;6:85-8.
Naseri M, Haghighi AK, Kharazifard MJ, Khavid A. Prevalence of C-shaped root canals in Iranian population: A systematic review. J Dent (Tehran) 2013;10:186-96.
Zare Jahromi M, Jafari Golestan F, Mashhadi Esmaeil M, Moouavizahed SH, Sarami M. Root and canal morphology of mandibular second molar in an Iranian population by clearing method. J Dent (Shiraz) 2013;14:78-81.
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.
Helvacioglu-Yigit D. Endodontic management of C-shaped root canal system of mandibular first molar by using a modified technique of self-adjusting file system. J Contemp Dent Pract 2015;16:77-80.
Al-Fouzan KS. C-shaped root canals in mandibular second molars in a Saudi Arabian population. Int Endod J 2002;35:499-504.
Abdo SB, Alkaisi A. C Shaped root canals in mandibular second molars in UAE nationals. Smile Dent J 2013;8:16-9.
Tamse A, Kaffe I. Radiographic survey of the prevalence of conical lower second molar. Int Endod J 1981;14:188-90.
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.
Ashraf H, Grayeli M. Determine frequency and anatomic form of the C-shaped canals in mandibular second molars. J Dent Sch 2003;21:441-6.
Peiris R, Takahashi M, Sasaki K, Kanazawa E. Root and canal morphology of permanent mandibular molars in a Sri Lankan population. Odontology 2007;95:16-23.
Peiris HR, Pitakotuwage TN, Takahashi M, Sasaki K, Kanazawa E. Root canal morphology of mandibular permanent molars at different ages. Int Endod J 2008;41:828-35.
Neelakantan P, Subbarao C, Subbarao CV, Ravindranath M. Root and canal morphology of mandibular second molars in an Indian population. J Endod 2010;36:1319-22.
Nikita S, Koshy M, Prabhakar V. Root canal morphology of permanent mandibular second molar in South Indian population using computed tomography. Conserv Dent Endod J 2016;1:1-5.
Wadhwani S, Singh MP, Agarwal M, Somasundaram P, Rawtiya M, Wadhwani PK, et al.
Prevalence of C-shaped canals in mandibular second and third molars in a central India population: A cone beam computed tomography analysis. J Conserv Dent 2017;20:351-4.
] [Full text]
Gulabivala K, Aung TH, Alavi A, Ng YL. Root and canal morphology of Burmese mandibular molars. Int Endod J 2001;34:359-70.
Gulabivala K, Opasanon A, Ng YL, Alavi A. Root and canal morphology of Thai mandibular molars. Int Endod J 2002;35:56-62.
Lambrianidis T, Lyroudia K, Pandelidou O, Nicolaou A. Evaluation of periapical radiographs in the recognition of C-shaped mandibular second molars. Int Endod J 2001;34:458-62.
Martins JN, Mata A, Marques D, Caramês J. Prevalence of C-shaped mandibular molars in the Portuguese population evaluated by cone-beam computed tomography. Eur J Dent 2016;10:529-35.
] [Full text]
Rocha S, Barnett F, Saerper A. Mandibular molar with C-shaped canal. Endod Dent Traumatol 1996;2:79-81.
Silva EJ, Nejaim Y, Silva AV, Haiter-Neto F, Cohenca N. Evaluation of root canal configuration of mandibular molars in a Brazilian population by using cone-beam computed tomography: An in vivo
study. J Endod 2013;39:849-52.
Weine FS, Pasiewicz RA, Rice RT. Canal configuration of the mandibular second molar using a clinically orientedin vitro
method. J Endod 1988;14:207-13.
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.
Weine FS. The C-shaped mandibular second molar: Incidence and other considerations. Members of the Arizona Endodontic Association. J Endod 1998;24:372-5.
Sutalo J, Simeon P, Tarle Z, Prskalo K, Pevalek J, Stanicić T, et al.
“C”-shaped canal configuration of mandibular second permanent molar. Coll Antropol 1998;22:179-86.
Kadam N, Ataide ID. Management of C-shaped canals: Two case reports. J Orofac Sci 2013;5:37-41. [Full text]
Sujith R, Dhananjaya K, Chaurasia VR, Kasigari D, Veerabhadrappa AC, Naik S, et al.
Microscope magnification and ultrasonic precision guidance for location and negotiation of second mesiobuccal canal: An in vivo
study. J Int Soc Prev Community Dent 2014;4:S209-12.
von Zuben M, Martins JN, Berti L, Cassim I, Flynn D, Gonzalez JA, et al.
Worldwide prevalence of mandibular second molar C-shaped morphologies evaluated by cone-beam computed tomography. J Endod 2017;43:1442-7.
Dr. Rashmi Bansal
Department of Conservative Dentistry and Endodontics, Institute of Dental Sciences, Bareilly - 243 001, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]
| Article Access Statistics|
| Viewed||1662 |
| Printed||37 |
| Emailed||0 |
| PDF Downloaded||162 |
| Comments ||[Add] |