JICDRO is a UGC approved journal (Journal no. 63927)

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Year : 2017  |  Volume : 9  |  Issue : 1  |  Page : 28-30

Radix entomolaris: A case report with cone-beam computed tomography evaluation

1 Department of Conservative Dentistry and Endodontics, Government Dental College, Srinagar, Jammu and Kashmir, India
2 Department of Conservative Dentistry and Endodontics, Santosh Dental College, Ghaziabad, Uttar Pradesh, India

Date of Web Publication30-Jun-2017

Correspondence Address:
Shafia Sarfi
House Number 1, Lane B, Rehmatabad Colony, New Airport Road, Hyderpora, Srinagar - 190 014, Jammu and Kashmir
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/2231-0754.201733

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The purpose of this article is to draw the correlation between the morphology of the right and left radix entomoralis (RE) in a bilateral case using CBCT. In this report a case involving root canal treatment of both the mandibular molars (36 & 46) is presented. A correlation between the morphology of the two is drawn using CBCT. During root canal treatment of 46 the presence of RE was identified clinically and then radiographically. Following which, 36 was treated and similar morphologic variation was seen. A CBCT was performed after obturation of both the teeth was completed in order to analyse and compare the morphologic variation and similarity. The morphology of both the radices was found to be similar. Anatomic variations can occur in any tooth, therefore careful clinical and radiographic examination is compulsory for successful outcome. This report describes the similarity of tooth root anatomy in a patient with bilateral RE and hence its clinical implication.

Keywords: Chemomechanical preparation, radix entomolaris, radix paramolaris

How to cite this article:
Sarfi S, Bali D. Radix entomolaris: A case report with cone-beam computed tomography evaluation. J Int Clin Dent Res Organ 2017;9:28-30

How to cite this URL:
Sarfi S, Bali D. Radix entomolaris: A case report with cone-beam computed tomography evaluation. J Int Clin Dent Res Organ [serial online] 2017 [cited 2023 Mar 28];9:28-30. Available from: https://www.jicdro.org/text.asp?2017/9/1/28/201733

   Introduction Top

Entrenched in the privileged anatomic localization of the root canal system, bacteria are beyond the reach of the host defenses and systemically administered antibiotics.[1] Chemomechanical preparation and intracanal medication are the mainstay of endodontic treatment that reduces the bacterial load.[1] An awareness and understanding of the presence of unusual root canal morphology can thus contribute to the successful outcome of root canal treatment.

It is known that the mandibular first molar can display several anatomical variations. First described by Carabelli, the presence of a third root in the permanent first molar is the major and well-known variant in this group.[2] This lingually present additional root is called radix entomolaris (RE). When present on the mesiobuccal side, it is referred to as radix paramolaris (RP) reported by Bolk.[3] RP occurs less frequently than RE. The dimensions of the RE can vary from a mature root to a short conical extension.

Carlsen and Alexandersen [4] classified RE into four different types (A, B, C, and AC) according to the location of the cervical part of the RE. Types A and B refer to distally located cervical part of the RE with two normal and one normal distal root components, respectively. Type C refers to mesially located cervical part, and Type AC refers to central location between the distal and mesial root components. This classification allows for the identification of separate and nonseparate RE.

De Moor et al.[5] described, three types of RE can be based on the curvature of the variant.

  • Type I - refers to a straight root/root canal,
  • Type II - refers to an initially curved entrance which continues as a straight root/root canal
  • Type III - refers to an initial curve in the coronal third of the root canal and a second curve beginning in the middle and continuing to the apical third.

The article describes the morphologic variation as well as correlation between the bilateral radicies.

   Case Report Top

A 46-year-old male reported to the Department of Conservative Dentistry and Endodontics at Santosh Dental College and Hospital, with the chief complaint of pain in right posterior tooth region of lower jaw for 3 days. Pain was continuous in nature and aggravated on chewing food and consumption of cold beverages.

Clinical examination revealed that #46 and #36 were carious and #46 was tender on percussion. Radiographs were exposed and showed caries involving pulp and widening of periodontal ligament with respect to both the teeth. Medical history was noncontributing.

As patients' chief complaint was pain in the right side of jaw, so the root canal treatment of #46 was started. Conventional inferior alveolar nerve block was given, rubber dam was placed, caries was removed, and access opening was performed. Three canal orifices were located, and initial negotiation of the root canals was done with K-file 10 (Dentsply Maillefer, Switzerland). Working length was determined using electronic apex locator (Propex II, Dentsply Maillefer, Switzerland) and confirmed radiographically. The radiograph showed the presence of an extra-root shadow and canal. The access cavity was widened to a trapezoidal access to negotiate the extra-root canal. The extra-canal was located and negotiated, and working length was reconfirmed using 300 mesially angulated radiograph, it showed the radix clearly as a discrete root. Initial instrumentation was done with K-files (Dentsply Maillefer, Switzerland) and Gates-Glidden burs (Brasseler, Germany). The distolingual canal orifice was present more lingually, away from rest of the three orifices. The chemomechanical instrumentation was performed with rotary ProTaper files (Dentsply Maillefer, Ballaigues, Switzerland) and irrigation of sodium hypochlorite (2.5%). The canals were filled with calcium hydroxide and the patient was recalled after 1 week. The patient reported back after 7 days with relief of symptoms, temporary restoration was removed, and canals were irrigated with sodium hypochlorite (2.5%). All four canals were obturated using warm lateral condensation using AH Plus (Dentsply DeTrey, Germany) sealer.

Seven days after completion of randomized control trial in respect to #46, treatment of #36 was started. Access opening was performed, four canal orifices were located carefully, the distolingual orifice was located away from the rest of the three orifices. For this tooth, we were better prepared in advance as a preoperative mesially angulated radiograph was taken beforehand. Initial negotiation of the root canals was done with K-file 10 (Dentsply Maillefer, Switzerland), working length was determined using electronic apex locator (Propex II, Dentsply Maillefer, Switzerland) and confirmed radiographically. After biomechanical preparation and 1 week intracanal medication, all four canals were obturated using lateral compaction.

To study the morphologic variation/correlation between the two RE, a cone-beam computed tomography (CBCT) was performed and morphology studied [Figure 1],[Figure 2],[Figure 3]. The coronal section showed similar location of RE in both #36 and#46, and they fell under Type B of Carlsen and Alexandersen classification. The extra-root was located more lingually and distally in both the teeth. Buccolingual view showed the curvature of the roots and according to De Moor et al.'s classification, both the roots fell under Type III configuration.
Figure 1: axial CBCT scan of bilateral permanent three-rooted mandibular first molars. Arrows indicate bilateral extradistolingual roots

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Figure 2: transaxial CBCT images of #46 L indicate the lingual side and the lingually present radix entomolaris morphology is clear

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Figure 3: transaxial CBCT images of #36 L indicate the lingual side and the lingually present radix entomolaris morphology is clear

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Our report shows a strong similarity in the morphology of RE when present bilaterally.

   Discussion Top

A careful clinical examination of the concerned tooth along with its periodontal and radiographic examination is a must to avoid any iatrogenic mistake. The case report clearly shows that the chances of “missed canal” can be minimized if the operator is aware of unusual anatomic variations.

Looking for an extra-cusp (tuberculum paramolare) or more prominent distolingual lobe in combination with a cervical prominence, using magnifications, ultrasonic tips, or DG 16 probe to locate canal orifices, CBCT imaging, and performing champagne or bubble test will also help identify the missed canal. The operator should be aware not only of the presence of the extra root but also about its various morphologic variance to avoid any mishap, such as instrument separation, perforation, and under preparation.

Curzon suggested that the “three-rooted molar” trait has a high degree of genetic penetrance and he reported its high frequency in pure Eskimos and Keewatin Eskimos (27%).[6] The prevalence of RE in Indian population was reported to be 18.6% and 5.3% by Chandra et al. and Chourasia et al., respectively.[7],[8]

Gulabivala et al.[9] found its incidence to be 13% in Thai population. The incidence of RE is high among Taiwanese (Chinese) population and was found to be ranging from 21.1% to 33.33%, with a bilateral incidence ranging from 53.65% to 68.57% in them.[10]

The morphology of this extra-root has been studied by many and De Moor et al. concluded in their study that the majority of the RE were curved.[5] In this case report, we saw clearly that bilaterally present radices have a very similar morphology and location. Both were present more lingually, so a conventional triangular access opening would not have been sufficient and a trapezoidal access is essential to better locate and access the distolingually located orifice of the additional root. Straight-line access, in this respect, has to be emphasized as the majority of the RE are curved.[5] Proper clinical examination of the tooth and angulation (30° mesial or distal angulation) and interpretation of radiographs help identify root anatomy.

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Conflicts of interest

There are no conflicts of interest.

   References Top

Siqueira JF Jr., Rôças IN. Clinical implications and microbiology of bacterial persistence after treatment procedures. J Endod 2008;34:1291-301.e3.  Back to cited text no. 1
Carabelli G. Systematisches Handbuch der Zahnheilkunde. 2nd ed. Vienna: Braumuller und Seidel; 1844. p. 114.  Back to cited text no. 2
Bolk L. Welcher Gebi_reihe gehören die Molaren an? Z Morphol Anthropol 1914;17:83-116.  Back to cited text no. 3
Carlsen O, Alexandersen V. Radix entomolaris: Identification and morphology. Scand J Dent Res 1990;98:363-73.  Back to cited text no. 4
De Moor RJ, Deroose CA, Calberson FL. The radix entomolaris in mandibular first molars: An endodontic challenge. Int Endod J 2004;37:789-99.  Back to cited text no. 5
Curzon ME, Curzon JA. Three-rooted mandibular molars in the Keewatin Eskimo. J Can Dent Assoc (Tor) 1971;37:71-2.  Back to cited text no. 6
Chandra SS, Chandra S, Shankar P, Indira R. Prevalence of radix entomolaris in mandibular permanent first molars: A study in a South Indian population. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2011;112:e77-82.  Back to cited text no. 7
Chourasia HR, Meshram GK, Warhadpande M, Dakshindas D. Root canal morphology of mandibular first permanent molars in an Indian population. Int J Dent 2012;2012:745152.  Back to cited text no. 8
Gulabivala K, Opasanon A, Ng YL, Alavi A. Root and canal morphology of Thai mandibular molars. Int Endod J 2002;35:56-62.  Back to cited text no. 9
Tu MG, Tsai CC, Jou MJ, Chen WL, Chang YF, Chen SY, et al. Prevalence of three-rooted mandibular first molars among Taiwanese individuals. J Endod 2007;33:1163-6.  Back to cited text no. 10


  [Figure 1], [Figure 2], [Figure 3]

This article has been cited by
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[Pubmed] | [DOI]


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