Prevalence of Middle Mesial Canal and Radix Entomolaris of Mandibular First Permanent Molars in a Western Chinese Population: an in Vivo Cone-beam Computed Tomographic Study

Overview

Journal BMC Oral Health

Publisher Biomed Central

Specialty Dentistry

Date 2020 Aug 19

PMID 32807171

Citations 14

Authors

Xin Qiao

Hualing Zhu

Yujia Yan

Jinglin Li

Jiayin Ren

Yuan Gao

Ling Zou

Affiliations

Soon will be listed here.

Abstract

Background: The aim of this study was to investigate the prevalence of the middle mesial canal (MMC) and radix entomolaris (RE) in mandibular first permanent molars in a western Chinese population using cone-beam computed tomography (CBCT).

Methods: A total of 1174 CBCT images of the mandibular first molars were collected from West China Hospital of Stomatology, Sichuan University. The following information was recorded and evaluated: the detection rate and location of the MMC and RE, the curvature of the RE, the canal configuration and bilateral symmetry.

Results: The detection rates of the MMC and RE were 3.41 and 25.04%, respectively, as calculated by individuals, and 1.79 and 22.15%, respectively, as calculated by total teeth. The average curvature in the buccolingual (BL) orientation (40.63 ± 14.39°) was significantly larger than that in the mesiodistal (MD) orientation (17.64 ± 7.82°) (p < 0.05). Of 587 patients, 71.72% (421/587) had bilateral symmetry according to the root canal morphology. The prevalence of three-rooted mandibular first molars was higher in males than in females, while the prevalence of two-rooted mandibular first molars was higher in females than in males.

Conclusions: Our results showed that the RE could be detected in almost 1/4 of the western Chinese population; thus, RE detection requires special attention and careful assessment in endodontic treatment.

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References

Calberson F, De Moor R, Deroose C . The radix entomolaris and paramolaris: clinical approach in endodontics. J Endod. 2006; 33(1):58-63. DOI: 10.1016/j.joen.2006.05.007. View

Souza-Flamini L, Leoni G, Chaves J, Versiani M, Cruz-Filho A, Pecora J . The radix entomolaris and paramolaris: a micro-computed tomographic study of 3-rooted mandibular first molars. J Endod. 2014; 40(10):1616-21. DOI: 10.1016/j.joen.2014.03.012. View

De Moor R, Deroose C, Calberson F . The radix entomolaris in mandibular first molars: an endodontic challenge. Int Endod J. 2004; 37(11):789-99. DOI: 10.1111/j.1365-2591.2004.00870.x. View

Ahmed H, Versiani M, De-Deus G, Dummer P . A new system for classifying root and root canal morphology. Int Endod J. 2016; 50(8):761-770. DOI: 10.1111/iej.12685. View

Mukhaimer R . Evaluation of Root Canal Configuration of Mandibular First Molars in a Palestinian Population by Using Cone-Beam Computed Tomography: An Ex Vivo Study. Int Sch Res Notices. 2016; 2014:583621. PMC: 4897246. DOI: 10.1155/2014/583621. View

Wang Y, Zheng Q, Zhou X, Tang L, Wang Q, Zheng G . Evaluation of the root and canal morphology of mandibular first permanent molars in a western Chinese population by cone-beam computed tomography. J Endod. 2010; 36(11):1786-9. DOI: 10.1016/j.joen.2010.08.016. View

Grande N, Plotino G, Pecci R, Bedini R, Malagnino V, Somma F . Cyclic fatigue resistance and three-dimensional analysis of instruments from two nickel-titanium rotary systems. Int Endod J. 2006; 39(10):755-63. DOI: 10.1111/j.1365-2591.2006.01143.x. View

Silva E, Nejaim Y, Silva A, 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(7):849-52. DOI: 10.1016/j.joen.2013.04.030. View

Huang R, Cheng W, Chen C, Lin C, Lai T, Shen E . Three-dimensional analysis of the root morphology of mandibular first molars with distolingual roots. Int Endod J. 2010; 43(6):478-84. DOI: 10.1111/j.1365-2591.2010.01702.x. View

10.

Nosrat A, Deschenes R, Tordik P, Hicks M, Fouad A . Middle mesial canals in mandibular molars: incidence and related factors. J Endod. 2014; 41(1):28-32. DOI: 10.1016/j.joen.2014.08.004. View

11.

Tahmasbi M, Jalali P, Nair M, Barghan S, Nair U . Prevalence of Middle Mesial Canals and Isthmi in the Mesial Root of Mandibular Molars: An In Vivo Cone-beam Computed Tomographic Study. J Endod. 2017; 43(7):1080-1083. DOI: 10.1016/j.joen.2017.02.008. View

12.

Xu S, Dao J, Liu Z, Zhang Z, Lu Y, Zeng X . Cone-beam computed tomography investigation of middle mesial canals and isthmuses in mandibular first molars in a Chinese population. BMC Oral Health. 2020; 20(1):135. PMC: 7206827. DOI: 10.1186/s12903-020-01126-2. View

13.

Karunakaran J, Shobana R, Kumar M, Kumar S, Mankar S . Management of middle mesial canal in mandibular second molar. J Pharm Bioallied Sci. 2012; 4(Suppl 2):S161-4. PMC: 3467889. DOI: 10.4103/0975-7406.100259. View

14.

Bond J, Hartwell G, Donnelly J, Portell F . Clinical management of middle mesial root canals in mandibular molars. J Endod. 1988; 14(6):312-4. DOI: 10.1016/S0099-2399(88)80033-5. View

15.

Chen G, Yao H, Tong C . Investigation of the root canal configuration of mandibular first molars in a Taiwan Chinese population. Int Endod J. 2009; 42(11):1044-9. DOI: 10.1111/j.1365-2591.2009.01619.x. View

16.

Skidmore A, BJORNDAL A . Root canal morphology of the human mandibular first molar. Oral Surg Oral Med Oral Pathol. 1971; 32(5):778-84. DOI: 10.1016/0030-4220(71)90304-5. View

17.

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. DOI: 10.1016/j.joen.2007.11.018. View

18.

Zhang R, Wang H, Tian Y, Yu X, Hu T, Dummer P . Use of cone-beam computed tomography to evaluate root and canal morphology of mandibular molars in Chinese individuals. Int Endod J. 2011; 44(11):990-9. DOI: 10.1111/j.1365-2591.2011.01904.x. View

19.

Naito T . Better success rate for root canal therapy when treatment includes obturation short of the apex. Evid Based Dent. 2005; 6(2):45. DOI: 10.1038/sj.ebd.6400335. View

20.

Alfouzan K, Jamleh A . Fracture of nickel titanium rotary instrument during root canal treatment and re-treatment: a 5-year retrospective study. Int Endod J. 2017; 51(2):157-163. DOI: 10.1111/iej.12826. View