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CASE REPORT
Year : 2017  |  Volume : 7  |  Issue : 3  |  Page : 181-185

Endodontic management of a permanent mandibular first molar with unusual root canal configurations: Two case reports


1 Department of Dentistry, Ministry of Health, Kuwait City, Kuwait; Department of Restorative Dentistry, College of Dentistry, Riyadh Colleges of Dentistry and Pharmacy, Riyadh, Kingdom of Saudi Arabia
2 Department of Restorative Dentistry, College of Dentistry, Riyadh Colleges of Dentistry and Pharmacy, Riyadh, Kingdom of Saudi Arabia
3 Division of Endodontics, Prince Sultan Military Medical City, Riyadh, Kingdom of Saudi Arabia

Date of Web Publication21-Aug-2017

Correspondence Address:
Mohammad Ahmad Alenezi
Department of Restorative Dentistry, Riyadh Colleges of Dentistry and Pharmacy, P. O. 84891, Riyadh 11681, Kingdom of Saudi Arabia

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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/1658-5984.213476

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  Abstract 

A precise knowledge of the root canal anatomy is the key to successful root canal therapy. Mandibular first molar usually has two roots (mesial and distal) and three to four root canals. In addition, any anatomic variations may occur in these teeth type. This clinical report describes two cases of root canal treatment of mandibular first molar with three root canals in mesial root (3–2) in one case and three root canals in distal root (2–3) of another one. The clinicians should be aware of the anatomical variations of different human dentition and must use all the available tools to detect and treat their clinical cases.

Keywords: Anatomic variation, cone beam computed tomography, mandibular first molar, root canal treatment


How to cite this article:
Alenezi MA, Aldajani M, Al-Qathami HO, Al-Shommrani S. Endodontic management of a permanent mandibular first molar with unusual root canal configurations: Two case reports. Saudi Endod J 2017;7:181-5

How to cite this URL:
Alenezi MA, Aldajani M, Al-Qathami HO, Al-Shommrani S. Endodontic management of a permanent mandibular first molar with unusual root canal configurations: Two case reports. Saudi Endod J [serial online] 2017 [cited 2017 Nov 22];7:181-5. Available from: http://www.saudiendodj.com/text.asp?2017/7/3/181/213476


  Introduction Top


A careful knowledge of the internal anatomy of the root canal system and its variations plays an important role in the endodontic therapy.[1],[2] Thus, the clinicians should have a full understanding of the configuration of the root canal anatomy to improve the predictability of root canal therapy and to increase the success rate.[3]

Mandibular first molar tooth usually has two roots, mesial root and distal root, but sometimes, it has three roots, with 2–4 canals in the mesial root and 1–4 canals in the distal root.[4],[5],[6],[7],[8],[9],[10],[11],[12],[13],[14],[15] In general, this tooth has been evaluated by different methods on different ethnic groups and populations through time.[1],[5],[7],[16],[17],[18],[19]

The main variant in the mandibular molars is the presence of an extra third root, which is called radix; a supernumerary distolingual (DL) root called radix entomolaris while a mesiobuccal (MB) root called radix paramolaris.[20],[21] Furthermore, the root canal variant in this tooth is the existence of extra root canals in the mesial or distal roots. Middle mesial canal (MM) is located between the two main mesial canals, and the percentage ranged from 0% to 37.5%.[12],[22],[23],[24] On the other hand, the percentage of middle distal canal in-between the two distal root canals was 0.2–8%.[6],[7],[13],[25],[26],[27],[28],[29],[30]

The purpose of these clinical case reports was to present a nonsurgical approach of endodontic treatment of two cases of permanent mandibular first molar with unusual anatomic variation of three root canals in mesial root and three root canals in distal root, to highlight the importance of using microscope and cone beam computed tomography as adjuncts for the management of teeth with different anatomic variations, and to discuss the clinical considerations.


  Case Reports Top


Case 1

A 28-year-old Saudi male presented to the Endodontic Clinic in Riyadh Colleges of Dentistry and Pharmacy, Riyadh, Saudi Arabia. His chief complaint was pain on biting of the right mandibular first molar (tooth #46). The medical history was normal. Clinical examination reveals recurrent caries with defective coronal restoration. The tooth was tender to percussion or palpation. Radiographic examination shows substandard root canal treatment and periradicular radiolucency of the mesial root [Figure 1]a. After clinical and radiographic examinations, the tooth was diagnosed as having previously treated, and symptomatic apical periodontitis and nonsurgical endodontic retreatment of tooth were planned.
Figure 1: (a) Preoperative periapical radiograph of tooth #46 showing a substandard root canal treatment, apical radiolucency at the mesial root, and recurrent distal caries. (b) Clinical photograph of access opening showing three mesial root canals

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Local anesthesia with epinephrine was introduced through the inferior alveolar nerve and then the rubber dam was placed for isolation. After removal of temporary filling and caries with large low-speed round bur, the pulpal floor was carefully examined with dental operating microscope (DOM) (Global Dental Microscopes, Global Surgical Corporation, USA). The MB, mesiolingual (ML), distobuccal, and DL canal orifices were identified. The MM canal was detected by careful exploration of the developmental groove between the ML and MB canals. It was identified and negotiated to full length with #8 and #10 K-hand file [Figure 1]b, where the MM canal was joined with MB root canal, and both distal canals were independent.

Cone beam computed tomography (CBCT) was performed to confirm the root canal's anatomy and pathway [Figure 2]a and [Figure 2]b. The old root canal filling was removed, and the working length was determined by Electronic Apex Locator (Root ZX II J. Morita, Tokyo, Japan) and then confirmed by periapical radiographs [Figure 3]a.
Figure 2: (a) Axial plane of cone beam computed tomography at coronal third showing three mesial root canals and two distal root canals. (b) Axial plane of cone beam computed tomography at apical third showing middle mesial and mesiobuccal canals was joined

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Figure 3: (a) Working length determination. (b) Obturation

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Root canals' instrumentation was carried out using ProTaper NEXT files (Dentsply, Maillefer, Ballaigues, Switzerland) until file X3 was reached. Copious irrigation with 2.5% sodium hypochlorite and 17% ethylenediaminetetraacetic acid (EDTA) was achieved during the instrumentation phase. Root canals were dried with paper points and then obturation was achieved by matching gutta-percha cones and AH-Plus Sealer (Dentsply Maillefer, Ballaigues, Switzerland). The access cavity was sealed with temporary filling material (Coltosol ® F, Coltene, Switzerland), and the patient was referred for final restoration [Figure 3]b.

Case 2

A 22-year-old Saudi young female of good health was referred to the Endodontic Clinic in Riyadh Colleges of Dentistry and Pharmacy, Riyadh, Saudi Arabia, from intern clinics after pulp extirpation. Her chief complaint was to continue nonsurgical root canal treatment of the left mandibular first molar (tooth #36). The tooth was not tender to percussion or palpation, and radiograph shows apical rarefaction [Figure 2]a. The tooth was diagnosed as having previously initiated therapy and asymptomatic apical periodontitis.

Local anesthesia was administered, and the tooth was isolated with rubber dam, the coronal filling was removed, and the pulpal floor was carefully examined through DOM. The mesial root has two separated root canals whereas the distal root has three root canals, DB canal was independent canal, while DL started as one canal and then separated with two canal at the apex. In addition, CBCT was achieved to ensure the number of root canals [Figure 4]. The working length was established by Electronic Apex Locator (Root ZX II J. Morita, Tokyo, Japan) and then confirmed by periapical radiographs [Figure 5].
Figure 4: Preoperative periapical radiograph of tooth #36 showing apical radiolucency of the mesial and distal roots

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Figure 5: (a) Axial plane of cone beam computed tomography at coronal third showing two mesial and two distal canals. (b) Axial plane of cone beam computed tomography at apical third showing three distal canals, where distolingual canal was bifid

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Cleaning and shaping were carried out using ProFile. 04 Files Rotary System until file #35 was reached for mesial canals, while file #30 was reached for distal root canals. Copious irrigation with 2.5% NaOCl and 17% EDTA was carried out during all phases of the procedure. Sterile paper points were used to dry the root canals and then obturation was achieved by matching gutta-percha cones and AH-Plus sealer. The access cavity was sealed with Coltsol temporary filling material, and the patient was referred for final restoration [Figure 6].
Figure 6: (a) Working length determination. (b) Obturation

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  Discussion Top


The mandibular first molar is the more considerably endodontically treated tooth among permanent dentitions due to its early eruption in the mouth and lower success rate.[16],[31],[32],[33] This is because of inadequate treatment of the root canal system, incomplete elimination of microorganisms and remnants of the pulp tissues, as well as complicated morphology of its root canal system. Therefore, the clinicians should have a good knowledge of the root canal anatomy to improve the predictability of root canal therapy and success rate.[3],[34]

In fact, the mesial root of the mandibular first molar tooth has two canals such as (2–2) canal type of 52.3% and (2–1) canal type of 35% according to the Vertucci's classification. In contrast, in the distal root, the most common frequent configuration is Type I (62.7%), followed by Type II (14.5%), and Type IV (12.4%).[8] However, Gulabivala et al. in 2001 reported additional root canal types (3–2) and (2–3) on Burmese population.[6] These canal configurations were similar to the finding of the current case report where 3–2 type was in the mesial root of Case #1 and 2–3 type was in the distal root of Case #2.

The reason for the presence of an additional or extra canal (s) in teeth might be due to compression of the connective pulp tissue as a result of the accumulation of secondary dentin during the growth of the root that forms vertical walls.[35] In addition, this phenomenon was reported to be high in younger patients.[14] In 1974, Barker et al.[36] reported a fifth canal with an independent MM canal in the mandibular first molar followed by a similar finding by Vertucci and Williams,[37] while Martinez-Berná and Badanelli [35] stated the third canal in the distal root for the first time.

The anatomical variations that exist in the MM canal of mandibular first and second molar teeth were classified by Pomeranz et al.[38] as a fin when an instrument could pass freely between the MB or ML canal and the MM canal. The MM canal was classified as confluent when the canal originated as a separate orifice but joined the MB or ML canal in the apical third of the canal. The canal was classified as independent if it remained separating from orifice to apex.

Access cavity modifications are necessary (from triangle to rectangle) to locate the additional canals in both mesial and distal roots. Once the main root canals are identified, small bur or ultrasonic tip is utilized to remove a dentinal bridge which connected the main canals and to expose the developmental groove that was considered as an important landmark for the presence of the additional canal (s). An endodontic explorer is used to locate the orifice, then negotiation is carried out by using a small file. In addition, staining the pulp chamber with 1% methylene blue dye or performing the sodium hypochlorite “champagne bubble” test and visualizing root canal's bleeding points, all of these hints will facilitate the location of extra canals.[2] Moreover, the important use of magnification tool such as DOM to improve visualization is very helpful to find the accessory canal.[39] It must be kept in mind the distal concavity of the mesial root during instrumentation of MM canal to avoid strip perforation.[40]

Another complexity of canal morphology that the clinicians face during root canal therapy is isthmus (anastomosis). It could be wide in young patients and decreases by age.[41] In general, the isthmi are more frequent in mesial root reached to 55%, at the same time, it reached to 20% in the distal root.[8] This difficult anatomical configuration has to be taken into account during canal disinfection, endodontic therapy, and surgery.[42],[43]

Conventional periapical radiographs provide two-dimensional images that produce poor data due to limitation regarding the number of roots and canals, periapical lesions status, location of vertical root fracture, and assessment of presurgical procedure. Therefore, to overcome this limitation, the use of advanced imaging techniques such as computed tomography and CBCT that provide the three-dimensional images of the root canal system is of good aid. More recently, CBCT is considered as a vital diagnostic tool in dentistry, particularly in the endodontic field. All endodontists should be familiar with CBCT to improve the root canal treatment outcome.[44],[45],[46],[47] In the present case report, the CBCT technique was used to detect the accessory root canals.


  Conclusion Top


Mandibular first molars might have complex root canal morphology. Using magnifying devices alongside CBCT tools and the knowledge of the root canal system enhanced to identify the additional canal (s), all these factors improve the root canal treatment outcome. The clinicians should be aware of the anatomical variations of different human dentition and use all the available tools to detect and treat their clinical cases.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
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  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]



 

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