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 Table of Contents  
ORIGINAL ARTICLE
Year : 2022  |  Volume : 34  |  Issue : 1  |  Page : 50-54

Prevalence of middle mesial canal in the Indian subpopulation of Greater Noida and the related variations in the canal anatomy of mandibular molars using cone-beam computed tomography


Department of Conservative Dentistry and Endodontics, ITS Dental College, Greater Noida, Uttar Pradesh, India

Date of Submission25-Aug-2021
Date of Decision01-Nov-2021
Date of Acceptance14-Jan-2022
Date of Web Publication25-Mar-2022

Correspondence Address:
Dr. Sana Iqbal
Department of Conservative Dentistry and Endodontics, ITS Dental College, Greater Noida, Uttar Pradesh
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/endo.endo_108_21

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  Abstract 


Aim: Missed canals are one of the imperative reasons for failure of endodontic treatment of molars. This study aimed to determine the prevalence of middle mesial canal (MMC) in mandibular molars (1st and 2nd) in the population of Greater Noida and also to find relationship of intracanal distance between mesiobuccal (MB) and mesiolingual (ML) canals with the presence or absence of MMC.
Materials and Methods: Previous cone-beam computed tomography (CBCT) scans of mandibular molars from patients were included. The following data were collected: Identification of MMC, the distance between MB and ML orifices, whether MMC was more prevalent in mandibular 1st or 2nd molar, whether MMC was prevalent in mandibular molars of right or left side. The results were analyzed using the Chi-square test and independent Student's t-test.
Results: The overall prevalence of MMC was 21.8% (P < 0.05). MMC was more prevalent in mandibular first molar (29.7%) than mandibular second molar (16%) and overall prevalence of MMC was higher on the left side (24.3%) than on the right side (18.8%). The mean distance between MB and ML orifices was 2.9 mm and 3.4 mm with and without MMC respectively, (P < 0.05), i.e., the MB-ML intraorifice distance was inversely related with the presence of MMC. Binary logistic regression was used to determine the possible association between predictor (independent variable) the MB-ML orifice distance and the occurrence of the outcome variable, which was the presence of an MM canal.
Conclusion: MMC is a common finding in the population of Greater Noida. Along with the use of CBCT, careful exploration of the pulpal floor between canal orifices is crucial to prevent missing the MMC.

Keywords: Cone-beam computed tomography, mesiobuccal and mesiolingual canal, middle mesial canal, missed canal


How to cite this article:
Iqbal S, Kochhar R, Kumari M. Prevalence of middle mesial canal in the Indian subpopulation of Greater Noida and the related variations in the canal anatomy of mandibular molars using cone-beam computed tomography. Endodontology 2022;34:50-4

How to cite this URL:
Iqbal S, Kochhar R, Kumari M. Prevalence of middle mesial canal in the Indian subpopulation of Greater Noida and the related variations in the canal anatomy of mandibular molars using cone-beam computed tomography. Endodontology [serial online] 2022 [cited 2022 May 23];34:50-4. Available from: https://www.endodontologyonweb.org/text.asp?2022/34/1/50/340829




  Introduction Top


Accomplishment of the root canal treatment depends upon effective reduction of microbial load from the root canal system configuration.[1] Untreated root canals may have a direct effect on the prognosis of root canal treatment.[2] An untreated canal in an endodontically treated tooth could be outcome of an operator's inadequate knowledge of tooth anatomy, complexities in canal configuration, or procedural errors (such as inadequate access cavity design).[3],[4] Missed canals may have a reservoir of microorganisms, which is one of the major cause of persistent apical periodontitis.[5] For root canal treatment to be effective, it is necessary to locate all root canals, debride them meticulously and seal them completely with an inert root filling material.

Mandibular molars requiring endodontic therapy are often encountered in dental practice. The mesial root of a mandibular molar generally presents with a mesiobuccal (MB) and a mesiolingual (ML) canal, while distal root often contains one canal. Barker et al. and Vertucci and Williams were the primary researchers to demonstrate the presence of an extra and independent canal in the region of the mesial root of mandibular molar known as the “Middle mesial canal.”[6],[7] According to Pomeranz et al., middle mesial canal (MMC) can be classified into three categories: Fin, confluent, or independent.[8] Fin is when an instrument can pass freely amid the MB or ML canal and the MMC. Confluent is when the MMC initiates as a distinct orifice but apically joins with the MB or ML canal, and independent is when the MMC initiates as a separate orifice and terminates as a separate foramen. A broad single mesial canal in which three mastercones could be cemented to the apex at the same time was also counted in as an independent MMC.

Complex anatomy is often seen in the mesial root of mandibular molar, with the incidence of MMC being 46.2%[9] in the same. According to the literature, the prevalence of MMC in various races has been reported up to 53.8%.[9] Thus, knowledge of the morphology of this MMC in mandibular molars is important.

Conventional radiographs, because of their two-dimensional nature, present limitations when searching for missed canals. The introduction of cone-beam computed tomography (CBCT) imaging has significantly improved the visualization of pulpal anatomy by providing a more accurate three-dimensional representation. CBCT provides fine details about the root canal morphology and is more sensitive to the detection of supplementary canals than are than the 2D radiographic images.[10],[11]

Thus, the primary outcome was to find the prevalence of MMC in mandibular molars (1st and 2nd) in the Indian subpopulation of Greater Noida and to find the relationship of intracanal distance between MB and ML canals with the presence or absence of MMC. The secondary outcome was to find the rate of prevalence of MMC in mandibular 1st and 2nd molar and whether MMC was prevalent in mandibular molars of the right or left side. The null hypothesis is that there is no correlation of intracanal distance between MB and ML canals and the presence or absence of MMC.


  Materials and Methods Top


Source of data

The present study is carried out in the Department of Conservative and Endodontics in collaboration with the Department of Oral Medicine and Radiology at the dental institute, in Greater Noida.

Sample selection

CBCT scans of patients who visited the dental institute, in Greater Noida between January 2016 and December 2019 were reviewed. The study design was approved by the Institutional Ethical Committee and Review Board (Ref. No. IEC/CONS/15/19). The power analysis was done before at priori at a power of 0.8 (α = 0.5), and the sample size was calculated using the nMaster software (version 2, CMC, Vellore, Tamil Nadu, India). All CBCT images taken for diagnostic purposes such as oral surgery, orthodontic treatment, implant treatment planning, and maxillofacial diagnosis were drawn out from the Archive in the Department of Oral Medicine and Radiology. OPD is by and large of the local population which was checked and verified by the permanent address details given by the patient at the time of registration and thus, confirmed that the patient was from Greater Noida. Five hundred CBCT records of patients, between the age group of 15–40 years, containing mandibular first molars and second molars were collected and reviewed.

Imaging method

CBCT scan was performed with CS 9300 scanner at resolution (0.18 mm × 0.18 mm × 0.18 mm) and with FOV-10*5. Panoramic, 3D and cross-sectional images at an interval of 1 mm were done. Images were examined using Carestream 3D imaging software. The level of the images was adjusted using the image processing tool in the software to ensure optimal visualization.

CBCT scans of mandibular first and second molars that were – nonfractured, had fully formed apices and without resorption were included in the study. CBCT scans of teeth with-previous endodontic treatment, immature and open apices, root resorption, restorative material below the roof of the pulp chamber, developmental disorders, and pathologies were excluded from the study.

Image evaluation and data extraction

All the CBCT scans under evaluation were analyzed in three planes (coronal, sagittal, and axial) using Carestream 3D imaging software [Figure 1]. The MMC was identified at the level of the pulpal floor and was tracked till it ended. Using in-vivo software's built-in measuring tool, with the MMC orifice as a reference point the middle mesial orifice distance to the MB and ML orifice was measured and when middle mesial was absent the distance between orifices of MB and ML canals was measured.
Figure 1: Three different cone-beam computed tomography scan, showing an axial cone-beam computed tomography section with the presence of an MMC. For all the images, first arrow from top = MB canal. Middle arrow = MMC. Bottom arrow = ML canal

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The following data were collected for further analysis:

  1. Identification of any MMC (present/absent); distinct orifices within the range of 0–2 mm below the pulpal floor were considered as MMCs
  2. Using Carestream 3D imaging software distance between orifices of MB and ML was measured
  3. Whether MMC is more prevalent in mandibular first or second molar
  4. Whether MMC was prevalent in mandibular molars of the right or left side.


Evaluation was performed individually by two calibrated endodontists, twice within a 2-month interval between the assessments. To confirm the reliability of the data, intraexaminer calibration was performed before the experiment. In cases of disagreement, CBCT images were reviewed by a specialist in department of oral medicine and radiology until a final consensus was reached among the three evaluators. To avoid bias, the above-mentioned protocol was followed, and then using a Cohen kappa coefficient during the calibration period in study the intraobserver and interobserver reliability was calculated which yielded a cohen kappa score of 0.91 which was found to be near perfect agreement.

Statistical analysis

Data were entered into MS Excel spreadsheet. Data were analyzed using the Statistical Package for the Social Sciences software (SPSS) version 21 (IBM SPSS Statistics for Windows, version 21.0, Armonk, NY, USA: IBM Corp.). The independent Student's t-test was used to assess the prevalence of MMC in the study population and Chi-square test was used to assess whether it was higher in mandibular 1st or 2nd molars and also to compare whether it was higher on the left side or right side mandibular molars. Binary logistic regression was used to determine the possible association between predictor (independent variable) the MB-ML orifice distance and the occurrence of the outcome variable, which was the presence of an MM canal. The level of statistical significance was set at 0.05, i.e., P > 0.05.


  Results Top


A total sample of 500 mandibular molars (212 mandibular 1st molar and 288 mandibular 2nd molars) were included in this study. This sample was collected from the CBCT scans of 500 patients (294 males and 206 females) with a mean age of 28 and 26 in males and females, respectively.

Of the 500 CBCT scans of mandibular molars, the MMC was identified in 109 of the scans. The overall prevalence of the MMC in mandibular molars, in the population of Greater Noida, was found to be 21.8%.

Out of 212 mandibular first molars, the MMC was found in 63 cases (29.7%), and out of 288 mandibular second molars, the MMC was found in 46 cases (16%) [Table 1].
Table 1: Prevalence of middle mesial canal according to tooth type

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Comparing the right and left mandibular 1st and 2nd molars, it was found that the MMC was found to be most prevalent in mandibular left first molar (30.3%) and least prevalent in mandibular right second molar (10.7%) and the overall prevalence of MMC was higher on the left side (24.3%) than on the right side (18.8%) in the population of Greater Noida (P < 0.05).

The mean distance between MB and ML orifices was 2.9 mm in the samples in which the MMC was identified. The mean distance was 3.4 mm in samples in which middle mesial could not be identified (P < 0.05) [Table 2]. Binary logistic regression was used to determine the possible association between predictor (independent variable) the MB-ML orifice distance and the occurrence of the outcome variable, which was the presence of an MM canal, which showed that the MB-ML intraorifice distance was inversely related with the presence of MMC (P < 0.05). In other words, the incidence of MMC was two times less likely to be recognizable in mandibular molars with every 1-mm increase in the distance of MB-ML orifices.
Table 2: Mean distance between orifices of mesiobuccal and mesiolingual canal

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  Discussion Top


Numerous dental clinicians tend to remark, that a given tooth will contain a predetermined number of roots or canals. However, a careful assessment of the literature shows deviations from the norm in that tooth morphology is not infrequent.[12] Among these anatomic variances, the presence of MMC in mandibular molars has been reported in the literature with the prevalence ranging from 0.26% to 53.8% in various populations, according to a recent systematic review.[9]

In the present study, the prevalence of MMC was determined in the population of Greater Noida which was found to be 21.8%. It was also observed that mandibular first molars had higher prevalence (29.7%) of MMC than mandibular second molars (16%) which is in accordance with the study done by Tahmasbi et al. and Shakeri et al.[12],[13] In contrast to our finding, Azim and others reported a higher prevalence in mandibular second molar than mandibular first molars.[14]

For the detection of MMC, knowing in advance that the intermediate canal usually joins the lingual or buccal canal might be helpful in detecting its orifice. According to the finding of Karapinar-Kazandag et al.,[15] it is proposed to start from the ML canal orifice and progress systematically along the subpulpal groove towards the MB canal. Furthermore, de Carvalho and Zuolo[16] showed in their study that the middle mesial orifice approaches the ML more frequently than the MB orifice.

There are many factors such as genes, race, gender, and age which affect the morphology of mandibular molars.[17] Various authors have suggested that MMCs are most commonly found in younger patients.[18],[19] In this study, CBCT scans of patients within the age group of 15–40 years were analyzed, and it was seen that the presence of MMC in this age group was statistically significant with a mean age being 28 and 26 in males and females, respectively. In case of gender comparison, the prevalence of middle mesial was not found to be statistically significant in males and females in the study population, and this result was similar to the result of study done by Sherwani et al. and Srivastava et al.[19],[20]

In the current study, it is shown that the overall prevalence of MMC is higher on the left side than on the right side of the jaw in the population of Greater Noida, but another study done on the Kerman population[21] shows higher prevalence on the right side than on the left side. Thus, the prevalence of MMC varies with race and the region associated.

Another important factor which could be used as a significant predictor for the presence of MMC is the intracanal distance between MB and ML canals in mandibular molars. In this study, we have correlated the relation between the intracanal distance between the MB and ML canal orifices when the MMC was present or absent. In the current study, it was found that the MB-ML intraorifice distance was inversely related with the presence of MMC (P < 0.05). Specifically, for every 1 mm increase in MB-ML intraorifice distance, the probability of MMC identification becomes two times lesser. However, this result of the study is not in accordance with a recent study done by Weinberg et al.,[22] which states that there does not appear to be a statistically significant difference in the mesial intracanal distance in teeth with and without MMC and the result of same study showed that there is no correlation between the presence of MMC and an increased or decreased mesial intracanal distance.

Treating additional unusual canals can be challenging, but the inability to find these canals may lead to failure of endodontic treatment. The evaluation of CBCT images results in better understanding of root canal anatomy, which enables the clinician to examine the root canal system and to clean, shape, and obturate it more competently. CBCT imaging is an excellent tool in identifying complex root canal system configurations; however, dentists must keep in mind that exposing patients to added radiation from CBCT imaging should only be done in cases in which it is clinically justifiable. As per Akbarzadeh and others,[23] the visibility of MMC in CBCT does not necessarily mean that they will be negotiable by the operator and also there is not enough evidence proving that the identification and instrumentation of MMC affects the success of endodontic treatment and so the relevance of preoperative CBCT scans of mandibular molars holds no relevance in all the cases. However, by the judicious removal of any mesial dentinal protuberance of the pulpal wall and slight troughing with steadfast ultrasonic tips within the developmental groove joining the MB and ML canals discloses any additional canal. Troughing in the pulp chamber floor with visualization through dental operating microscope has been recommended by many authors to improve accessory root canal identification.[14],[15] Second, in consideration of the complex anatomy of the mesial roots in mandibular molars, it is necessary to meticulously instrument and thoroughly irrigate root canals during root canal preparation, to improve the chances of any irrigants going into the isthmi. Passive ultrasonic irrigation, EndoVac, and laser-activated irrigation techniques have been used to increase the efficacy of irrigation solutions since they effectively remove smear and debris from the complex root canal system.[24] Therefore, while treating mandibular molars, specifically the mesial root canals, special and effective irrigation systems should be considered as a routine procedure.


  Conclusion Top


Within the limitations of the study, it can be concluded that the MMC is not an uncommon morphological finding in the population of Greater Noida and should be anticipated in both first and second mandibular molars with mandibular first molar having higher prevalence than mandibular second molar. Second, the overall prevalence of MMC is higher on the left side than on the right side in the population of Greater Noida. Finally, the intracanal distance between MB and ML canals in mandibular molars can be used a significant predictor to detect the presence or absence of the MMC.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Sjögren U, Figdor D, Persson S, Sundqvist G. Influence of infection at the time of root filling on the outcome of endodontic treatment of teeth with apical periodontitis. Int Endod J 1997;30:297-306.  Back to cited text no. 1
    
2.
Baruwa AO, Martins JNR, Meirinhos J, Pereira B, Gouveia J, Quaresma SA, et al. The influence of missed canals on the prevalence of periapical lesions in endodontically treated teeth: A cross-sectional study. J Endod 2020;46:34-9.e1.  Back to cited text no. 2
    
3.
Cantatore G, Berutti E, Castellucci A. Missed anatomy: Frequency and clinical impact. Endod Topics 2006;15:3-31.  Back to cited text no. 3
    
4.
Witherspoon DE, Small JC, Regan JD. Missed canal systems are the most likely basis for endodontic retreatment of molars. Tex Dent J 2013;130:127-39.  Back to cited text no. 4
    
5.
Nair PN. On the causes of persistent apical periodontitis: A review. Int Endod J 2006;39:249-81.  Back to cited text no. 5
    
6.
Barker BC, Lockett BC, Parsons KC. The demonstration of root canal anatomy. Aust Dent J 1969;14:37-41.  Back to cited text no. 6
    
7.
Vertucci FJ, Williams RG. Root canal anatomy of the mandibular first molar. J N J Dent Assoc 1974;45:27-8.  Back to cited text no. 7
    
8.
Pomeranz HH, Eidelman DL, Goldberg MG. Treatment considerations of the middle mesial canal of mandibular first and second molars. J Endod 1981;7:565-8.  Back to cited text no. 8
    
9.
Bansal R, Hegde S, Astekar M. Morphology and prevalence of middle canals in the mandibular molars: A systematic review. J Oral Maxillofac Pathol 2018;22:216-26.  Back to cited text no. 9
[PUBMED]  [Full text]  
10.
Patel S, Durack C, Abella F, Shemesh H, Roig M, Lemberg K. Cone beam computed tomography in Endodontics – A review. Int Endod J 2015;48:3-15.  Back to cited text no. 10
    
11.
D'Addazio PS, Campos CN, Özcan M, Teixeira HG, Passoni RM, Carvalho AC. A comparative study between cone-beam computed tomography and periapical radiographs in the diagnosis of simulated endodontic complications. Int Endod J 2011;44:218-24.  Back to cited text no. 11
    
12.
Shakeri F, Azizi H, Razian F, Haghanifar S, Hoshyari N. Prevalence of mid-mesial canal and isthmuses in mandibular first and second molars in an Iranian population. J Res Dent Maxillofac Sci 2019;4:30-5.  Back to cited text no. 12
    
13.
Tahmasbi M, Jalali P, Nair MK, Barghan S, Nair UP. 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;43:1080-3.  Back to cited text no. 13
    
14.
Azim AA, Deutsch AS, Solomon CS. Prevalence of middle mesial canals in mandibular molars after guided troughing under high magnification: An in vivo investigation. J Endod 2015;41:164-8.  Back to cited text no. 14
    
15.
Karapinar-Kazandag M, Basrani BR, Friedman S. The operating microscope enhances detection and negotiation of accessory mesial canals in mandibular molars. J Endod 2010;36:1289-94.  Back to cited text no. 15
    
16.
de Carvalho MC, Zuolo ML. Orifice locating with a microscope. J Endod 2000;26:532-4.  Back to cited text no. 16
    
17.
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.  Back to cited text no. 17
    
18.
Nosrat A, Deschenes RJ, Tordik PA, Hicks ML, Fouad AF. Middle mesial canals in mandibular molars: Incidence and related factors. J Endod 2015;41:28-32.  Back to cited text no. 18
    
19.
Sherwani OA, Kumar A, Tewari RK, Mishra SK, Andrabi SM, Alam S. Frequency of middle mesial canals in mandibular first molars in North Indian population – An in vivo study. Saudi Endod J 2016;6:66-70.  Back to cited text no. 19
  [Full text]  
20.
Srivastava S, Alrogaibah NA, Aljarbou G. Cone-beam computed tomographic analysis of middle mesial canals and isthmus in mesial roots of mandibular first molars-prevalence and related factors. J Conserv Dent 2018;21:526-30.  Back to cited text no. 20
[PUBMED]  [Full text]  
21.
Kuzekanani M, Walsh LJ, Amiri M. Prevalence and distribution of the middle mesial canal in mandibular first molar teeth of the Kerman population: A CBCT study. Int J Dent 2020;2020:8851984.  Back to cited text no. 21
    
22.
Weinberg EM, Pereda AE, Khurana S, Lotlikar PP, Falcon C, Hirschberg C. Incidence of middle mesial canals based on distance between mesial canal orifices in mandibular molars: A clinical and cone-beam computed tomographic analysis. J Endod 2020;46:40-3.  Back to cited text no. 22
    
23.
Akbarzadeh N, Aminoshariae A, Khalighinejad N, Palomo JM, Syed A, Kulild JC, et al. The association between the anatomic landmarks of the pulp chamber floor and the prevalence of middle mesial canals in mandibular first molars: An in vivo analysis. J Endod 2017;43:1797-801.  Back to cited text no. 23
    
24.
Adcock JM, Sidow SJ, Looney SW, Liu Y, McNally K, Lindsey K, et al. Histologic evaluation of canal and isthmus debridement efficacies of two different irrigant delivery techniques in a closed system. J Endod 2011;37:544-8.  Back to cited text no. 24
    


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