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 Table of Contents  
Year : 2016  |  Volume : 6  |  Issue : 3  |  Page : 136-140

Maxillary first molars with six canals confirmed with the aid of cone-beam computed tomography

Department of Endodontic, Dammam Dental Center, Dammam Medical Complex, Dammam, Saudi Arabia

Date of Web Publication29-Aug-2016

Correspondence Address:
Tahra Mohammad Al-Habboubi
Dammam Medical Complex, Damman
Saudi Arabia
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/1658-5984.189357

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The maxillary first molar exhibits unpredictable root canal morphology. Different number of root canals has been reported with the aids of new tools. It is very important to clinically detect all canals for better outcome results. The purpose of the present case is to present a case of the maxillary first molar in a Saudi male patient with an anatomical variation of having six root canals that were confirmed with cone-beam computed tomography.

Keywords: Anatomical variations, cone-beam computed tomography, maxillary first molar, root canal treatment

How to cite this article:
Al-Habboubi TM, Al-Wasi KA. Maxillary first molars with six canals confirmed with the aid of cone-beam computed tomography. Saudi Endod J 2016;6:136-40

How to cite this URL:
Al-Habboubi TM, Al-Wasi KA. Maxillary first molars with six canals confirmed with the aid of cone-beam computed tomography. Saudi Endod J [serial online] 2016 [cited 2023 Feb 5];6:136-40. Available from: https://www.saudiendodj.com/text.asp?2016/6/3/136/189357

  Introduction Top

Thorough mechanical and chemical cleansing of the entire root canal system and filling it with biocompatible filling materials are the main objectives of endodontic therapy. To facilitate the treatment, the clinicians should use all the armamentaria at their disposal to locate and treat the entire root canal system.[1],[2],[3]

The morphology of the maxillary first molar has been extensively studied. It is generally accepted that three roots and four canals in the maxillary first molar should be regarded as the rule rather than the exception.[4] The presence of the fourth canal usually located in the mesiobuccal (MB) root which ranges from 18.6% to 96.1%.[5],[6],[7],[8] Additional canals were reported in the distobuccal (DB) and palatal (P) roots. Case reports with five,[9] six,[10] seven,[11] and even eight canals were reported.[12] Conventional radiograph is usually used during clinical practice which provides a limited two-dimensional (2D) view where detailed morphological information might be missed.[13] Therefore, a 3D view tools such as the cone-beam computed tomography (CBCT) should be used for assessment of root canal morphology.

In the present case, a maxillary first molar with three roots and six canals was located and successfully managed. The canal morphology was confirmed with CBCT.

  Case Report Top

A 35-year-old Saudi male patient referred from a prosthodontic was reported to the Endodontic Department at Dammam Medical Complex Hospital for evaluation of the previous root canal treatment of the right maxillary first molar (#16). The patient's medical history was noncontributory. Clinical examination of tooth #16 did not reveal neither tenderness with palpation nor percussion of the buccal and palatal aspect of the tooth. The tooth was not mobile and periodontal probing was within normal limits [Figure 1]a. A preoperative radiograph [Figure 1]b revealed radiolucency around the apex of MB root and a substandard root canal treatment where the root canal filling of the mesial root is not centered. The case was diagnosed as a previously treated root canal with asymptomatic apical periodontitis, and a nonsurgical root canal retreatment was suggested to the patient.
Figure 1: (a) Clinical view of tooth #16 restored with temporary filling. (b) Preoperative radiograph showing radiolucency at the apex of the mesiobuccal root and substandard root canal treatment

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The tooth was anesthetized with 1.8 ml 2% lidocaine containing 1:80,000 epinephrine. Amalgam restoration was removed and access cavity was refined under rubber dam isolation. The internal anatomy was evaluated using a surgical operating microscope (Carl Zeiss AG, Oberkochen, Germany) with the aid of DG-16 endodontic explorer, orifice micro-opener size #10 0.04 (Dentsply Maillefer, Ballaigues, Switzerland), and ultrasonic troughing using Endo tip 2 (ProUltra, Dentsply), which revealed three (MB1, MB2, and MB3) canals, two (DB1 and DB2) canals, and one P canal [Figure 2]a. The Gutta-percha was removed using ProTaper retreatment rotary nickel-titanium files (Dentsply, Maillefer, Ballaigues, Switzerland) and a stainless steel size #25 H-files (DENTSPLY Maillefer); the coronal enlargement was done with a nickel-titanium ProTaper series orifice shaper SX to improve the straight-line access. In the DB1 canal, there was a ledge that was successfully managed using a size #15 k-file with a distinct curve in the apical 2 mm using slight rotation motion of the file combined with a “picking” motion, which was repeated until the file bypassed the ledge. After the use of #15 k-file, a ProTaper hand files size S1, S2, and F1 were used to remove the ledge.
Figure 2: (a) Clinical view of the access opening showing six canal orifices. (b) Working length determination

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Working length was determined using electronic apex locator (Root ZX; Morita, Tokyo, Japan) and confirmed with radiograph [Figure 2]b. The cleaning and shaping were performed using ProTaper universal nickel-titanium rotary instruments (Dentsply Maillefer, Ballaigues, Switzerland) with copious irrigation with 2.5% sodium hypochlorite (NaOCl) solution and 17% ethylenediaminetetraacetic acid (EDTA) (Master-Dent, USA). The canals were dried with paper points and dressed with calcium hydroxide (Promedica, Neumunster, Germany); intracanal medication and Cavit (EasyFill, Hoffmann, Germany) were used as a temporary restoration.

After 1 week and under rubber dam isolation, the Cavit and calcium hydroxide were removed and the canals were irrigated with 2.5% NaOCl and 17% EDTA and ultrasonic activation using EndoActivator system (Dentsply Tulsa Dental Specialties, Tulsa, OK). The canals were dried with paper points, and obturation was performed using continuous wave compaction of Gutta-percha (Dentsply Maillefer) and AH Plus resin sealer (Maillefer, Dentsply, Konstanz, Germany) [Figure 3]a and [Figure 3]b. The tooth was then restored with a composite resin restoration and the patient was advised to have a full-coverage porcelain crown. The patient was asymptomatic during the follow-up period of 3 months [Figure 4]a,[Figure 4]b,[Figure 4]c.
Figure 3: (a) Clinical view of the access opening showing six canal orifices after filling with Gutta-percha. (b) Periapical radiograph after filling the root canals

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Figure 4: (a) A 3-month follow-up radiograph. (b and c) Clinical view after final coronal restoration

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The CBCT images (WhiteFox Imaging Ver. 3.1, de Götzen, S.r.l. via Roma, 45 21057 Olgiate Olona (VA), Italy) confirmed the presence of six canals. The scans showed three MB, two DB, and one palatal canals. The MB root was broad buccolingually and the DB root fused to the P root [Figure 5]a,[Figure 5]b,[Figure 5]c.
Figure 5: (a) Axial section of cone-beam computed tomography image showing six canals. The distal root is fused to the palatal root. (b) Note the three canals in the mesial root (c) and curvature of the distobuccal 1 canal in transverse section

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  Discussion Top

Based on the literature, it has been apparent that the maxillary first molar commonly has anatomical aberration. In the present case report, three canals in the mesial and two in the distal root were located and treated. Al-Nazhan [14] and Al-Fouzan et al.[15] studied the morphology of the permanent maxillary first molar in a Saudi Arabian population using conventional radiographs. Only one canal in the distal and palatal root and two in the mesial root were reported. The incidence of having three canals in the mesial root and two in the distal root in Saudi citizen was not reported.

The presence of the third canal in the mesial root has been recently reported. Kim et al.[16] analyzed CBCT images of 814 maxillary first molars in a Korean population. The incidence of the third MB canal was reported to be 0.12%. Another study investigated 145 extracted human maxillary first molars by Kim et al.[17] The MB roots were scanned by micro-computed tomography, and the canals were reconstructed by 3D modeling software found the incidence of three canals to be 12%.

Görduysus et al.[18] studied the location and pathway of the MB2 canal in the maxillary first and second molars using the dental operating microscope (DOM) and found that the location of the MB2 canal varied considerably in relation to the main MB and P canal orifices. The MB2 canal was located either mesial to, or directly on the mesiopalatal line, within 3.5 mm palatally and 2 mm mesially of the main MB canal. Negotiation of the MB2 canal is often difficult due to a ledge of dentin that covers its orifices; the MB inclination of its orifices on the pulpal floor and its pathway which often takes one or two abrupt curves in the coronal part of the root. Most of these obstructions can be eliminated by “troughing or countersinking” with ultrasonic tips mesially and apically along the MB-palatal groove.[2]

The routine use of the DOM and specific instruments are necessary to increase the efficiency and the effectiveness of the clinical procedure.[19] Stropko in 1999 gave some guidelines to help locate the MB2 by scheduling adequate clinical time, using the recent magnification and detection instrumentation aids, and having thorough knowledge of how and where to search for MB2.[20] According to Stropko,[20] the rate of location MB2 can approach 93% in the maxillary first molars when DOM was used.

The incidence of having two canals in the DB root has been reported to be between 1.6% and 9.5%.[21],[22] The presence of the third canal was reported too.[12],[23] The presence of multiple canals in the MB and DB roots in the current case could possibly be due to the root morphology being broad buccolingually or fusion between two roots.[24] This was observed in the axial and transverse sections of the CBCT image of the present case where the MB and DB roots were broad buccolingually with DB root fused with the P root. Axial images showed that the MB root presented a Gulabivala Type II canal pattern [25] where the DB root presented a Vertucci Type IV canal pattern.[1]

Diagnostic measures such as multiple preoperative radiographs, examination of the pulp floor with a sharp explorer, troughing of grooves with ultrasonic tips, staining the chamber floor with 1% methylene blue dye, performing the hypochlorite champagne bubble test, and visualizing canal bleeding points are important aids in locating canal orifices.[2] In the presented case, examination of the pulpal floor to follow the dentinal map and exploration with the orifice opener was the first indication to hint at the presence of extra orifices and canals.

Conventional radiographic examination is an essential tool for management of endodontic problems. It produces a 2D image of a 3D object resulting in superimposition of images.[26] In contrast, CBCT is a valuable method for initial identification and effective evaluation of internal morphology of teeth.[5],[27] According to American association of endodontics in 2011, the use of CBCT in endodontics should be limited to the assessment and treatment of complex endodontic conditions such as identification of root canal system anomalies and determination of root curvature.[28]

Good knowledge of tooth morphology, careful interpretation of angled radiographs, proper access preparation, and detailed exploration of the interior of the tooth are important for a successful treatment outcome. Magnification and illumination are essential aids that must be utilized to achieve this goal.

  Conclusion Top

Clinicians should be aware of the complex root canal anatomy and should carefully interoperate angled radiographs, have proper access preparation and detailed exploration of the interior of the tooth, ideally under magnification, for a successful treatment outcome.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Vertucci FJ. Root canal anatomy of the human permanent teeth. Oral Surg Oral Med Oral Pathol 1984;58:589-99.  Back to cited text no. 1
Vertucci FJ. Root canal morphology and its relationship to endodontic procedures. Endod Topics 2005;10:3-29.  Back to cited text no. 2
Slowey RR. Radiographic aids in the detection of extra root canals. Oral Surg Oral Med Oral Pathol 1974;37:762-72.  Back to cited text no. 3
Pineda F, Kuttler Y. Mesiodistal and buccolingual roentgenographic investigation of 7,275 root canals. Oral Surg Oral Med Oral Pathol 1972;33:101-10.  Back to cited text no. 4
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Shetty K, Yadav A, Babu VM. Endodontic management of maxillary first molar having five root canals with the aid of spiral computed tomography. Saudi Endod J 2014;4:149-53.  Back to cited text no. 9
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Badole GP, Warhadpande MM, Shenoi PR, Lachure C, Badole SG. A rare root canal configuration of bilateral maxillary first molar with 7 root canals diagnosed using cone-beam computed tomographic scanning: A case report. J Endod 2014;40:296-301.  Back to cited text no. 11
Kottoor J, Velmurugan N, Surendran S. Endodontic management of a maxillary first molar with eight root canal systems evaluated using cone-beam computed tomography scanning: A case report. J Endod 2011;37:715-9.  Back to cited text no. 12
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Al-Nazhan S. The prevalence of two canals in mesial root of endodontically treated maxillary first molars among a Saudi Arabian sub-population. Saudi Dent J 2005;17:24-8.  Back to cited text no. 14
Al-Fouzan KS, Ounis HF, Merdad K, Al-Hezaimi K. Incidence of canal systems in the mesio-buccal roots of maxillary first and second molars in Saudi Arabian population. Aust Endod J 2013;39:98-101.  Back to cited text no. 15
Kim Y, Lee SJ, Woo J. Morphology of maxillary first and second molars analyzed by cone-beam computed tomography in a Korean population: Variations in the number of roots and canals and the incidence of fusion. J Endod 2012;38:1063-8.  Back to cited text no. 16
Kim Y, Chang SW, Lee JK, Chen IP, Kaufman B, Jiang J, et al. A micro-computed tomography study of canal configuration of multiple-canalled mesiobuccal root of maxillary first molar. Clin Oral Investig 2013;17:1541-6.  Back to cited text no. 17
Görduysus MO, Görduysus M, Friedman S. Operating microscope improves negotiation of second mesiobuccal canals in maxillary molars. J Endod 2001;27:683-6.  Back to cited text no. 18
Alrejaie M, Ibrahim NM, Malur MH, AlFouzan K. The use of dental operating microscopes by endodontists in the Middle East: A report based on a questionnaire. Saudi Endod J 2015;5:134-7.  Back to cited text no. 19
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Stropko JJ. Canal morphology of maxillary molars: Clinical observations of canal configurations. J Endod 1999;25:446-50.  Back to cited text no. 20
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Karthikeyan K, Mahalaxmi S. New nomenclature for extra canals based on four reported cases of maxillary first molars with six canals. J Endod 2010;36:1073-8.  Back to cited text no. 23
Cleghorn BM, Christie WH, Dong CC. Root and root canal morphology of the human permanent maxillary first molar: A literature review. J Endod 2006;32:813-21.  Back to cited text no. 24
Gulabivala K, Aung TH, Alavi A, Ng YL. Root and canal morphology of Burmese mandibular molars. Int Endod J 2001;34:359-70.  Back to cited text no. 25
Patel S, Dawood A, Whaites E, Pitt Ford T. New dimensions in endodontic imaging: Part 1. Conventional and alternative radiographic systems. Int Endod J 2009;42:447-62.  Back to cited text no. 26
Nair MK, Nair UP. Digital and advanced imaging in endodontics: A review. J Endod 2007;33:1-6.  Back to cited text no. 27
Endodontics: Colleagues for Excellence. Cone Beam-computed Tomography in Endodontics; Summer, 2011. Available from: http://www.aae.org/uploadedfiles/publications_and_research/endodontics_colleagues_for_excellence_newsletter/ecfe%20summer%2011%20final.pdf. [Last accessed on 2015 Dec 01].  Back to cited text no. 28


  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]

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