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Case Report 

Aziza Al Turki, 2019;3(11):967–970.

International Journal of Medicine in Developing Countries

Mandibular first molar with multiple roots: a case report

Aziza Al Turki1*

Correspondence to: Azizah Abdulaziz Al Turki

*National Guard Hospital, Ministry of National Guard-Health Affairs, Kingdom of Saudi Arabia.

Email: dr.aziza.alturki [at] gmail.com

Full list of author information is available at the end of the article.

Received: 08 August 2019 | Accepted: 13 August 2019



A mandibular first molar with two distal roots is an interesting example of anatomic variation.

Case Presentation:

This report describes a case of mandibular first molar with four roots (two mesial and two distal). The canals were shaped with K3 instrument (Sybron Endo, West Collins, CA, USA) and irrigated with 2.5% sodium hypochlorite. The canals were then obturated with gutta-percha and AH 26 sealer.


This case report shows an anatomic variation of external morphology of the tooth. This report presents a successful treatment of a mandibular first molar with four-rooted, two mesial and two distal roots.


Mandibular first molar, two mesial and two distal root, case report.


Endodontic therapy involves treating vital and necrotic dental pulps so that patients can retain their natural teeth in function and esthetics. The main reasons for endodontic failure are apical percolation, incomplete canal obturation, and the presence of untreated canals [1]. Failure to recognize any unusual canal configuration would eventually lead to an unsuccessful treatment outcome. Although successful therapy depends on many factors, one of the most important is a missing canal. It can lead to infection years after treatment and cause the tooth to require further treatment.

Thus, a thorough knowledge of the root and root canal morphology, along with the various anatomical variations, is essential to reach this goal [2].

All dental clinicians could benefit from regular continuing education that focuses on anatomy. A thorough knowledge of root and root canal morphology and good anticipation of their possible morphological variations will help reduce endodontic failure caused by incomplete debridement and obturation. The mandibular first molar can display several anatomical differences. The common morphology that first mandibular molars exhibit is two-rooted with two mesial and one distal canal [3,4]. Recent studies (Table 1) reported a higher incidence of second canals in distal roots of mandibular permanent first molar than earlier studies [58]. The identification and external morphology of these root complexes, containing a lingual or buccal supernumerary root, are described by Carlsen and Alexandersen [9,10].

Case Presentation

A 20-year-old female referred to our department for root canal treatment of right mandibular first molar tooth (#30) at the King Abdulaziz Dental Center in Riyadh. The patient’s medical history as well. A general practitioner had started the root canal treatment but could not find all the root canals.

The diagnostic radiograph by Radio Viso Graphy revealed the presence of periapical radiolucency around both mesial and distal roots. This radiograph also showed that the tooth had an additional distolingual root (Figure 1).

A clinical examination, the tooth restored with a temporary filling. It was not tender to percussion and palpation. The tooth was not mobile, and periodontal probing around the tooth was within physiological limits. The diagnosis was asymptomatic apical periodontitis, and root canal treatment was recommended.

The tooth was anaesthetized with 1.8 ml (30 mg) 2% lidocaine containing 1:80,000 epinephrine followed by rubber dam isolation. An endodontic access cavity was established well.

Clinical examination with an endodontic explorer revealed four canal openings in each of the mesiobuccal (MB), mesiolingual (ML), and distobuccal (DB), distolingual (DL), where the fourth distolingual canal orifice was present distolingually (Figure 2). The working lengths were estimated using an apex locator (Root ZX, Morita, Tokyo, Japan). The canals were instrumented and shaped through extended access preparations, and with the crown-down technique using Gates-Glidden drills and K3 Endo rotary file system (Sybron Endo, Orange, California, USA). The canals were irrigated frequently with 2.5% sodium hypochlorite solution. The canals were dried with absorbent points (Dentsply Maillefer).

Table 1. Incidence of two canals in distal root of mandibular first molar (Parolia et al., 2009).

Author/Year Incidence (%) Population group
Skidmore and Bjorndal (1971) 28.9 Caucasians
Vertucci and Williams (1974) 30 Caucasians
Yew and Chan (1993) 31.5 Chinese
Zaatar et al. (1997) 29.9 Middle East
Gulabivala et al. (2001) 20 Burmes
Gulabivala et al. (2002) 33.4 Thai
Sen et al. (2004) 46 Turkish

Figure 1. Diagnostic X-ray for Mandibular right first molar tooth.

Calcium hydroxide intracanal medicament was given to the canals and coronally sealed with glass ionomer cement (Ketac Molar, Espe, Seefeld, Germany).

At the second appointment, the patient was asymptomatic, and all canals were irrigated and recapitulated with the final instruments. Master cones were selected, and the canals were dried with paper points. Obturation was performed using cold lateral compaction of gutta-percha and AH2 sealer (Figure 3).

At the 6-months and 10 months follow up examination, tooth #30 was functional and asymptomatic, with no clinical signs. There was radiographic evidence of periapical osseous healing (Figure 4)

Post endodontic restoration was placed, and the patient was recalled for follow up and full coverage crown (Figures 5 and 6).


Based on the literature and the clinical case, it is evident that the knowledge of the anatomical variations of the mandibular molars is essential for the success of endodontic treatment. Most of the dentists treat all the roots with similar tactics; as a result, many failures occur. However, it must be noticed that abnormalities are rare, but it is possible that a patient referred may have one of these rare anatomic variations.

Figure 2. Clinical view of the canal orifices.

An awareness and understanding of the presence of unusual root canal morphology can thus contribute to the successful outcome of root canal treatment [11]. This report describes the success of endodontic therapy in a four-rooted right mandibular permanent first molar. The fourth root canal, which occurred in a supernumerary distolingual root, was identified during the first treatment because periapical radiography was performed. Eventual treatment success was achieved by endodontic therapy of this extra canal of the distolingual canal.

Figure 3. Postoperative radiographs. Root canals were filled with gutta-percha and sealer.

Figure 4. Post endodontic restoration.

Figure 5. Full coverage crown.

Figure 6. The anomaly is more frequent on the left side.

The presence of four canals is relatively frequent [6], but the presence of two distal roots is uncommon (Prabhu and Munshi, 1995). The prevalence of an extra root is about equal in males and females, but the anomaly is more frequent on the left side [12]. An additional distolingual root occurred unilaterally in approximately 40% of the cases summarized by Quackenbush [13] predominantly on the right side. The extra root is smaller than the distobuccal root and is usually curved [14]. In the case reported here, the trait occurred bilaterally, and both of the extra distolingual roots seemed to be similar sizes of the other roots. The number of roots in the mandibular first molar may be increased not only by the presence of a distolingual root but also through the bifurcation of the mesial root, a trait found in 0.5% of mandibular permanent first molars [15].

A comparison of the findings of AI Nazhan [5] study with previous investigations reinforces the view that the incidence of four root canals in the Saudi Arabian population appears to be high. Supernumerary roots, its formation could be related to external factors during odontogenesis or presence of an atavistic gene or polygenetic system [5].


A clinician should have complete knowledge of the anatomic variation of macrostructure and internal and external root canal anatomy. The possibility of an extra root should also be considered and looked for carefully. An accurate diagnosis of these supernumerary roots can avoid complications that arise during canal negotiation and enlargement.

This case has been reported to share our experience and increase the awareness of clinicians on tooth morphology of mandibular first molar teeth for a more predictable treatment outcome.

Conflict of interest

The author declares that there is no conflict of interest regarding the publication of this article.



Consent for publication

Informed consent was obtained from the patient.

Ethical approval

Ethical approval is not required at our institute to publish an anonymous case report.

Author details

Aziza Al Turki1

  1. National Guard Hospital, Riyadh, Ministry of National Guard-Health Affairs, Kingdom of Saudi Arabia


  1. Ingle JI, Beveridge EE, Glick DH, Weichman JA. Modern endodontic therapy. In: Ingle JI, Beveridge EE, editors. Endodontics. 2nd ed. Philadelphia: Lea & Febiger; 1976. pp 1–57.
  2. Vertucci FJ. Root canal morphology and its relationship to endodontic procedures. Endo Topics. 2005;10:3–29. https://doi.org/10.1111/j.1601-1546.2005.00129.x
  3. Barker BC, parson KC, Mills PR, Williams GL. Anatomy of root canals, III. Permanent mandibular molars. Aust Dent J. 1974;19:403–13. https://doi.org/10.1111/j.1834-7819.1974.tb02372.x
  4. Vertucci FJ, Root canal anatomy of the human permanent teeth. Oral SurgOral MedOral Pathol. 1984;58;589–99. https://doi.org/10.1016/0030-4220(84)90085-9
  5. Al Nazhan S. Incidence of fourth canal in root canal treated mandibular first molars in a Saudi Arabian subpopulation. Intl Endod J. 1999;32:49–52. https://doi.org/10.1046/j.1365-2591.1999.00188.x
  6. Gulabivala K, Aung TH, Alavi A, Ng YL. Root and canal morphology of Burmese mandibular molars. Int Endod J. 2001; 34:359–70. https://doi.org/10.1046/j.1365-2591.2001.00399.x
  7. Gulabivala K, Opasanon A, Ng YL, Alavi A. Root and canal morphology of Thai mandibular molars. Int Endod J. 2002; 35:56–62. https://doi.org/10.1046/j.1365-2591.2002.00452.x
  8. Sert S, Aslanalp V, Tanalp J. Investigation of the root canal configurations of mandibular permanent teeth in the Turkish population. Int Endod J. 2004;37:494–9. https://doi.org/10.1111/j.1365-2591.2004.00837.x
  9. Carlsen O, Alexandesen V. Radixentomolaris: identification and morphology Scan J Dent Res. 1990;98:363–73. https://doi.org/10.1111/j.1600-0722.1990.tb00986.x
  10. Carlsen O, Alexandersen V. Radix paramolaris in permanent mandibular molars: identification and morphology. Scan J Dent Res 1991; 99:6189–95. https://doi.org/10.1111/j.1600-0722.1991.tb01884.x
  11. Calberson FL, De Moor RJ, Deroose CA. The Radix Entomolaris and Paramolaris: clinical approach in endodontics. J Endod. 2007;33:58–63. https://doi.org/10.1016/j.joen.2006.05.007
  12. Loh HS. Incidence and features of three-rooted permanent mandibular molars. Aust Dent J 1990; 35(5):434–7. https://doi.org/10.1111/j.1834-7819.1990.tb05426.x
  13. Quackenbush LE. Mandibular molar with three distal root canals. Dent traumatol. 1986;2:48–9. https://doi.org/10.1111/j.1600-9657.1986.tb00123.x
  14. Weine FS. Access cavity preparation and initiating treatment. In: Weine FS, editor. Endodontic therapy. 3rd ed. St. Louis, MO: The C. V. Mosby Company; 1982. pp 207–55.
  15. Onda S, Minemura R, Masaki T, Funatsu S. Shape and number of the roots of the permanent molar teeth. Bull Tokyo Dent Coll. 1989;30(4):221–31.

How to Cite this Article
Pubmed Style

Azizah Abdulaziz Al Turki. Mandibular first molar with multiple roots: a case report. IJMDC. 2019; 3(11): 967-970. doi:10.24911/IJMDC.51-1565259046

Web Style

Azizah Abdulaziz Al Turki. Mandibular first molar with multiple roots: a case report. https://www.ijmdc.com/?mno=60686 [Access: October 15, 2021]. doi:10.24911/IJMDC.51-1565259046

AMA (American Medical Association) Style

Azizah Abdulaziz Al Turki. Mandibular first molar with multiple roots: a case report. IJMDC. 2019; 3(11): 967-970. doi:10.24911/IJMDC.51-1565259046

Vancouver/ICMJE Style

Azizah Abdulaziz Al Turki. Mandibular first molar with multiple roots: a case report. IJMDC. (2019), [cited October 15, 2021]; 3(11): 967-970. doi:10.24911/IJMDC.51-1565259046

Harvard Style

Azizah Abdulaziz Al Turki (2019) Mandibular first molar with multiple roots: a case report. IJMDC, 3 (11), 967-970. doi:10.24911/IJMDC.51-1565259046

Turabian Style

Azizah Abdulaziz Al Turki. 2019. Mandibular first molar with multiple roots: a case report. International Journal of Medicine in Developing Countries, 3 (11), 967-970. doi:10.24911/IJMDC.51-1565259046

Chicago Style

Azizah Abdulaziz Al Turki. "Mandibular first molar with multiple roots: a case report." International Journal of Medicine in Developing Countries 3 (2019), 967-970. doi:10.24911/IJMDC.51-1565259046

MLA (The Modern Language Association) Style

Azizah Abdulaziz Al Turki. "Mandibular first molar with multiple roots: a case report." International Journal of Medicine in Developing Countries 3.11 (2019), 967-970. Print. doi:10.24911/IJMDC.51-1565259046

APA (American Psychological Association) Style

Azizah Abdulaziz Al Turki (2019) Mandibular first molar with multiple roots: a case report. International Journal of Medicine in Developing Countries, 3 (11), 967-970. doi:10.24911/IJMDC.51-1565259046