Case Report

Journal of Taibah University Medical Sciences (2014) 9(1), 81–84

Taibah University

Journal of Taibah University Medical Sciences

www.sciencedirect.com

Clinical management of amandibular first molar with supernumerary distal

root (radix entomolaris)

Mothanna Alrahabi, PhD

Department of Restorative Dentistry, College of Dentistry, Taibah University, Medina, Kingdom of Saudi Arabia

Received 14 August 2013; revised 28 October 2013; accepted 1 November 2013

صخلملا

يفةيحيرشتلاتافالتخالادحأةيصاقلاةيناسللاةهجلايفدئازلايوحرلارذجلاربتعيةصاخةيانعىلإيحيرشتلافالتخالااذهجاتحيو،يلفسلاكفلابىلوألاىحرلاهذهفصت.نانسألاروذجقافنأةجلاعمللاعحاجنىوتسمىلعظافحللكلذويسنإرذج(روذجةثالثبيلفسلاكفلابىلوألاىحرللةيجالعلاتاءارجإلاةلاقملارذجلايفةانقويسنإلارذجلايفناتانق(تاونقةعبرأو)نايصاقنارذجوةيمهأةلاحلاهذهريرقترهظي)يصاقلايقدشلارذجلايفةانقويصاقلايناسللاروذجلاةجلاعملبقيعاعشلاريوصتلاةيمهأوةيرذجلاتاونقلااحيرشتةفرعم.ايحارج

حيرشتلاملع;رذجلاةانق;يلفسلاكفلا;ىحرلا;دئازلايوحرلارذجلا:حاتفملاتاملكلا

Abstract

Radix entomolares, a supernumerary root on a mandibular

molar, located distolingually, is an anatomical variation of

the mandibular first molar. This variation requires special

care in order to maintain a high success rate of root canal

treatment. This paper describes the procedure for treatment

of a mandibular first molar with three roots (one mesial and

two distal) and four canals (two mesial and one in each dis-

tobuccal and distolingual root). This case report reveals the

importance of anatomical knowledge of root canals and

preoperative radiographs.

Keywords: Anatomy; Mandibular; Molar; Radix entomolares;

Root canal

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Introduction

Thorough knowledge of root canal anatomy, both normal andabnormal, is essential for successful root canal treatment.1 The

mandibular first molar typically has two well-defined roots: amesial root characterised by a flattened mesiodistal surfaceand widened buccolingual surface, and a distal root, which is

usually straight with a wide oval canal or two round canals.2

Sometimes, however, the morphology and number of rootsof the mandibular first molar vary; the major variant is the

presence of supernumerary roots distolingually. This variant,mentioned for the first time by Carabelli,3 is known as radixentomolaris.4

The prevalence of supernumerary roots is less than 3% inAfrican populations, 4.2% in whites, less than 5% in Eurasianand Asian populations and greater than 5% in populations

Corresponding address: Department of Operative Dentistry & Endodontic, College of Dentistry, Taibah University, Medina, Kingdom of Saudi

Arabia. Tel.: +966 597674522.

E-mail: mrahabi@taibahu.edu.sa (M. Alrahabi)

Peer review under responsibility of Taibah University.

Production and hosting by Elsevier

1658-3612 � 2014 Taibah University. Production and hosting by Elsevier Ltd. All rights reserved.

http://dx.doi.org/10.1016/j.jtumed.2013.11.001

with Mongolian traits.5 Radix entomolaris was classified byCarlsen and Alexandersen6 according to the location of its cer-vical part, resulting in four types. A and B refer to a distally

located cervical part of the radix entomolaris with two normaland one normal distal root components, respectively; C refersto a mesially located cervical part, while AC refers to a central

location between the distal and mesial root components. Thisclassification allows identification of separate and non-sepa-rate radix entomolaris.

This report describes endodontic therapy on a three-rootedmandibular first molar.

Case report

A 22-year-old Syrian male patient presented to the clinic of thedental school at Taibah University with a history of severe

pain in the lower-right posterior tooth for a few days. The painkept him awake at night and was radiating up the side of hisface. Clinical examination revealed bad amalgam restorationon tooth no. 30 with recurrent caries on the mesial

(Figure 1). The tooth was very sensitive to percussion andwas nonresponsive to Endo Ice (Hygienic Corp., Akron, Ohio,USA). The medical history of the patient was non-

contributory.A diagnosis of necrotic pulp with acute apical periodontitis

was performed. Emergency treatment involved access cavity

preparation, irrigation with NaOCl and placement of a drycotton pellet for temporization. The patient was then referredto an endodontic specialty clinic. Diagnostic X-rays weretaken from various horizontal angles (Figures 2 and 3), which

showed an additional distal root. Local anaesthesia wasadministered, and the tooth was isolated by a rubber dam.Access was prepared with an endo access bur no. E0123

and Endo Z (Dentsply Maillefer, Ballaigues, Switzerland).As the first distal canal was buccal, access was modified to lo-cate the other distal canal, on the lingual side. The root canals

were explored with a precurved K-file ISO number 15 (Dents-ply Maillefer). The working length was determined electroni-cally with an apex locator (Root ZXII. JMorita, Suita City,

Osaka, Japan) and confirmed by periapical radiography(Figure 4).

The root canals were shaped with ProTaper rotary instru-ments (Dentsply Maillefer). During preparation, Glyde

(Dentsply Maillefer) was used as the lubricant, and the root

Figure 1: OPG X-ray reveal recurrent caries under amalgam restoration on tooth No.30.

Figure 2: Diagnostic X-ray.

Figure 3: Diagnostic X-ray with horizontal angulation.

82 M. Alrahabi

canals were disinfected with NaOCl solution (2.5%). The ca-nals were prepared with an F1 instrument and then dried

and filled with CaOH2 paste (Metapast, Meta Biomed Co.,Seoul, Republic of Korea). The access was closed with a cottonpellet and temporary restoration.

Two weeks later, the patient returned for completion of end-odontic therapy. Local anaesthesia was again administered,

and the tooth was isolated under a rubber dam. The CaOH2

paste was removed by irrigation, and the canals were shapedwith F2 and F3 instruments. The canals were dried, and a gut-

ta-percha master cone was confirmed radiographically (Figure5). Then, the canals were obturated (Figure 6) by vertical com-paction with an Obtura III device and AH26 Sealer (Dentsply

Maillefer), and the access was closed with glass ionomer cement(Ketac Fil, 3M ESPE, Seefeld, Germany). The patient was re-ferred to an operative clinic for permanent restoration.

Discussion

There have been several reports of the occurrence of supernu-

merary roots (an extra distolingual root) in permanent man-dibular molars. The anatomical variant radix entomolarishas been considered by some authors to be a genetic trait

rather than a developmental anomaly.7,8

Radix entomolaris is commonly found distolingually. Itmay be a short conical extension or a full-length root. In thiscase, the supernumerary root was distolingual, full length

and contained pulpal tissue. A third root can be detectedradiographically in 90% of cases,9 but sometimes additionalX-rays from different horizontal angles are required.10,11

In a distolingually located orifice of a radix entomolaris, theaccess cavity should be modified to establish straight-line ac-cess. Following orifice location will help in conserving the

tooth structure,12 and using an electronic apex locater withX-ray to determine the increases in the accuracy of the work-ing length. It is preferable to use nickel–titanium rotary instru-ments and copious irrigation to improve cleaning and shaping

the root canal system.13 Prior treatment should be strict toavoid procedural accidents.

Conclusion

In conclusion, to ensure successful root canal treatment, threefactors should be considered: thorough knowledge of root ca-

nal anatomy and treatment procedures, accurate diagnosis andgood skill.

Conflict of interest

We have no conflict of interest to declare.

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Figure 4: Working length confirmation by periapical radiography.

Figure 5: Master cone confirmation by periapical radiography.

Figure 6: Final root obturation X-ray.

Clinical management 83

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84 M. Alrahabi