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ORIGINAL ARTICLE
Year : 2017  |  Volume : 5  |  Issue : 1  |  Page : 11-15

Radix entomolaris in the permanent mandibular first molars of davangere children: A prevalence study


Department of Pedodontics and Preventive Dentistry, College of Dental Sciences, Davangere, Karnataka, India

Date of Web Publication28-Sep-2018

Correspondence Address:
Dr. N B Nagveni
Department of Pedodontics and Preventive Dentistry, College of Dental Sciences, Davangere, Karnataka
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/njecp.njecp_28_15

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  Abstract 


Purpose: The aim of this study is to determine the prevalence of radix entomolaris (RE) in permanent mandibular first molars among the Davangere children, India, using periapical radiographs. Materials and Methods: A total of 199 (94 boys and 105 girls) patient's bilateral periapical radiographs were examined using magnifying lens. The prevalence, gender distribution, and symmetry of RE were recorded and analyzed using the Chi-squared test. Results: The prevalence of RE in permanent mandibular first molars was 4.5% for all patients examined and 2.5% for all teeth evaluated. The prevalence of RE seen in boys was 6.38% (6 of 94), and in females, it was 2.85% (3 of 105) which is statistically found insignificant (P = 1.232). Eight cases occurred unilaterally, and only one case of bilateral presence of RE was found. Among unilateral cases, 7 teeth showed the presence of RE on the left side, and only in one case, RE was present on the right side. This was found statistically highly significant (P = 0.001). Conclusion: Awareness of the high racial prevalence of RE (an unusual root variation) in permanent mandibular first molars among Davangere children is highly essential before and during the root canal treatment to achieve successful treatment outcome.

Keywords: Endodontic treatment, permanent mandibular first molar, radix entomolaris


How to cite this article:
Nagveni N B, Poornima P, Mathew MG. Radix entomolaris in the permanent mandibular first molars of davangere children: A prevalence study. Niger J Exp Clin Biosci 2017;5:11-5

How to cite this URL:
Nagveni N B, Poornima P, Mathew MG. Radix entomolaris in the permanent mandibular first molars of davangere children: A prevalence study. Niger J Exp Clin Biosci [serial online] 2017 [cited 2018 Dec 16];5:11-5. Available from: http://www.njecbonline.org/text.asp?2017/5/1/11/242443




  Introduction Top


Root canal anatomy and the confounding nature of the human pulpal system pose a great clinical challenge in rendering successful endodontic treatment in children. Permanent teeth exhibit anatomical differences regarding size, shape, external, and internal morphology. The main objective of root canal treatment is thorough chemomechanical debridement of all root canals and their complete obturation with a suitable material, and a coronal filling, preventing the ingress of microorganisms. One of the main reasons for the failure of root canal treatment is the inadequate removal of pulp tissue and microorganisms from the root canal system.

Permanent mandibular first molars (PMFMs) usually have two roots located mesially and distally, with three root canals. Occasionally, they have an additional third root requiring special attention when root canal treatment is being considered. The permanent mandibular first molar with three-rooted variants, which feature the presence of the additional third root, i.e., the supernumerary root, seen distolingually, was first described by Carabelli in 1844.[1] The “Radix Entomolaris” is the term used extensively to describe this distolingual root according to Bolk.[2]

The RE is considered as a normal racial and morphological variation rather than an abnormality in certain populations due to its high frequency. The prevalence of RE reported to be more common in races of Mongoloid origin,[3] including, European,[4] Eskimo[5] Chinese,[6] German,[7] and Taiwanese populations.[8]

To the best of the current knowledge, there are only case reports[9],[10] on RE in the permanent dentition of the Indian population. However, studies of the prevalence of these teeth are very few in number.[11],[12] Therefore, the present study was undertaken to determine the prevalence of RE in permanent mandibular first molars, using periapical radiographic images obtained in the Davangere children. The study evaluated the incidence, gender, and symmetry-related differences among these children population which could be interest to clinical dentists, dental morphologists, and dental anthropologists.


  Materials and Methods Top


The periapical radiographs of 199 patients who visited the Outpatient Department of Pedodontics and Preventive Dentistry for the treatment of either pain or caries in the permanent mandibular molars were considered for this study. Patients found with missing unilateral molars were excluded from the study. All patients included in this study were of Davangere origin belonging to the same race, and the study protocol was approved by the Institutional Ethics Committee. Patients found with unilateral intraoral periapical (IOPA) radiograph were advised to take contra lateral IOPA to obtain bilateral IOPAs after taking signed informed consent from their parents. The periapical radiographs were taken using Kodak, size 1, ultra-speed films (Kodak Rochester, NY, USA). The periapical radiographs were taken using a Rinn XCP (Dentsply, USA) for each patient. After exposure, the films were developed, fixed, and dried in an automatic processor.

The bilateral radiographs (398 radiographs) of 199 patients (94 boys and 105 girls) were examined for the presence of RE using the magnifying lens (×3). The radiographs were placed on a viewing box, and the light surrounding the radiograph was blocked. Each radiograph was separately viewed by two authors (A and B). The criteria for the presence of a RE were employed from recent studies.[7],[8],[11],[12] The presence of RE was indicated by the crossing of the translucent lines defining the pulp space and periodontal ligament in mandibular first molars with respect to the distal root [Figure 1], [Figure 2], [Figure 3], [Figure 4]. Disagreement in the interpretation of radiographs was discussed between two investigators until a consensus was reached. Finally, the demographic details such as the total prevalence, gender ratio, the prevalence of unilateral or bilateral occurrence of RE in PMFMs of these patients were studied. The data obtained was subjected to statistical analysis using the Chi-squared test.
Figure 1: Periapical radiograph showing radix entomolaris in pemanent mandibular first molar on left side (arrow)

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Figure 2: Periapical radiograph showing radix entomolaris on left side (arrow)

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Figure 3: Picture of radix entomolaris present on right mandibular first molar (arrow)

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Figure 4: Radiograph showing radix entomolarison left side (arrow)

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  Results Top


A total of 199 patients, 94 boys and 105 girls, aged between 9 and 14 years were examined for this study. A total of 398 radiographs consisting of the same number of PMFM were evaluated. The results of this study showed that among 199 patients, the RE was observed in 10 patients. Hence, the total prevalence found from this study is 4.5%, when we considered the total number of patients, and it was of 2.5% when the total number of teeth studied, i.e., 398 [Table 1].
Table 1: Number and percentages of permanent mandibular first molars with radix entomolaris

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Gender-wise distribution of radix entomolaris

The prevalence of RE seen in boys was 6.38% (6 of 94), and in females, it is 2.85% (3 of 105) which is statistically found insignificant (P = 1.232) [Table 2].
Table 2: Gender wise distribution of radix entomolaris in permanent mandibular first molars

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Symmetrical distribution of radix entomolaris

When symmetry of occurrence of RE was analyzed, it was found that eight cases occurred unilaterally and only one case of bilateral presence of RE was found. Among unilateral cases, 7 teeth showed the presence of RE, and only in one case, RE was present on the right side. This was found statistically highly significant (P = 0.001) [Table 3].
Table 3: Side wise distribution of radix entomolaris in permanent mandibular first molars

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  Discussion Top


An extensive review of scientific literature shows only case reports[9],[10] on the occurrence of RE in PMFMs among the Indian population. However, studies of the prevalence of these teeth are very few in number.[11],[12] From this study, the total prevalence of RE in PMFMs found in Davangere children was 4.5%. This figure was higher than the study carried out by Tratman[13] in the Indian population in 1938 who studied 453 extracted teeth and found a prevalence of 0.2% three-rooted mandibular first molars. However compared to a recent study done by Garg et al.,[11] in 2010 who examined 1054 periapical radiographs shows a prevalence of 5.97% which is higher than the present study. One more recent study carried out in Indians also showed a higher prevalence of 7.67%.[12] Whereas, a study done in American Indians[14] and Canadian Indians[15] revealed a prevalence of 5.8% and 15.6%, respectively. These contradictory results may be due to marked differences in the sample size, case selection, and the methods used. Hence, further investigations are highly mandatory to clarify the issue.

Gender wise distribution of RE did not show any significant difference in the prevalence in this study. This finding appeared similar to other Indian studies[11],[12] and studies done in German[7] and Taiwanese population.[8] When symmetry of occurrence of RE was examined, most of the RE occurred unilaterally (8 cases) which was statistically significant. Among unilateral cases, seven occurred on the left with one being on the right. This figure was in agreement with other recent studies,[16],[17] but opposite to the findings of Indian studies.[11],[12] However, majority studies reported no significant difference according to the gender or side distribution of RE.[6],[7],[11],[12] Only one case of bilateral presence of RE was recorded in our study. Whereas Karale et al.[12] showed 3.72% bilateral prevalence of three-rooted molars.

The exact prevalence of RE reported is based on extracted teeth studied for racial difference.[13],[18] It is, therefore, not possible to evaluate inter-study comparisons relating to gender and bilateral occurrence of RE in PMFMs from extracted teeth unless detailed investigations were carried out before extraction. However, availability of extracted teeth for research purposes has progressively decreased due to improvements in diagnostic aids and treatment procedures. The use of radiographs can be a valuable tool for research purposes. In the present study, radiographic method was employed to estimate the prevalence of RE which is a noninvasive and allows for inter-study comparisons about gender and symmetrical distribution of RE in PMFMs.

All dental surgeons, especially a pediatric dentist should be aware of this anatomic root variation when diagnosing and managing any pathology associated with PMFMs, especially during endodontic treatment. Since the presence of RE has clinical implications in endodontic treatment. An accurate diagnosis of this root variation can avoid complications or a “missed canal” during root canal treatment.[9],[19],[20] Since the RE is mostly situated in the same buccolingual plane as the distobuccal root, a superimposition of both roots can appear on the preoperative radiograph, making an inaccurate interpretation of particular marks or characteristics, such as unclear view or outline of the distal root contour or the root canal, can indicate the presence of a “hidden” RE. Therefore, to make it evident, a second radiograph should be taken from a more mesial or distal angle usually in 30 degrees.[9],[10],[19],[20]

Successful root canal treatment always depends on the important basic principles such as cleaning and shaping followed by obturation of the entire root canal system. Of the three, the most important is the principle of “straight-line” access. Moreover, the location of the orifice of the root canal of the RE has significant implications during the access opening also. As RE is located distolingually, a modification of the conventional triangular opening should be changed to a trapezoidal form to better locate and access the root canal as well as to obtain straight line access as the majority of RE are curved.[18],[19],[20]

Other difficulties encountered with respect to RE are during extraction and orthodontic procedures. The curved RE may render extraction difficult or tend to fracture or make movement difficult due to its presence.[9],[10],[18],[20]


  Conclusion Top


Knowledge about the high racial prevalence of RE which is an unusual root morphology seen in permanent mandibular first molars is highly essential among clinicians. Every possible effort should be made for locating this extra root while treating Indian patients because it might be useful for successful endodontic treatment.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Nagaveni NB, Poornima P, Valsan A, Mathew MG. Prevalence of three-rooted primary mandibular second molars in Karnataka (South Indian) population. Int J Pedod Rehabil 2018;3:33-5.  Back to cited text no. 1
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2.
Nagaveni NB, Yadav S, Poornima P, Bharath KP, Mathew MG, Naveen Kumar PG. Volumetric evaluation of various obturation techniques in primary teeth using cone beam computed tomography – An in vitro study. J Indian Soc Pedod Prev Dent 2017;35:244-8.  Back to cited text no. 2
[PUBMED]  [Full text]  
3.
Ferraz JA, Pécora JD. Three-rooted mandibular molars in patients of Mongolian, Caucasian and Negro origin. Braz Dent J 1993;3:113-7.  Back to cited text no. 3
    
4.
Sperber GH, Moreau JL. Study of the number of roots and canals in Senegalese first permanent mandibular molars. Int Endod J 1998;31:117-22.  Back to cited text no. 4
    
5.
Curzon ME. Miscegenation and the prevalence of three-rooted mandibular first molars in the Baffin Eskimo. Community Dent Oral Epidemiol 1974;2:130-1.  Back to cited text no. 5
    
6.
Walker RT, Quackenbush LE. Three-rooted lower first permanent molars in Hong Kong Chinese. Br Dent J 1985;159:298-9.  Back to cited text no. 6
    
7.
Schäfer E, Breuer D, Janzen S. The prevalence of three-rooted mandibular permanent first molars in a German population. J Endod 2009;35:202-5.  Back to cited text no. 7
    
8.
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. 8
    
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Nagaveni NB, Umashankar KV. Radix entomolaris in permanent mandibular first molars: Case reports and literature review. Gen Dent 2009;57:e25-9.  Back to cited text no. 9
    
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Nagaven NB, Umashankara KV. Radix entomolaris and paramolaris in children: A review of the literature. J Indian Soc Pedod Prev Dent 2012;30:94-102.  Back to cited text no. 10
    
11.
Garg AK, Tewari RK, Kumar A, Hashmi SH, Agrawal N, Mishra SK, et al. Prevalence of three-rooted mandibular permanent first molars among the Indian population. J Endod 2010;36:1302-6.  Back to cited text no. 11
    
12.
Karale R, Chikkamallaiah C, Hegde J, Aswathanarayana S, Santhosh L, Bashetty K, et al. The prevalence of bilateral three-rooted mandibular first molar in Indian population. Iran Endod J 2013;8:99-102.  Back to cited text no. 12
    
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Tratman EK. Three-rooted lower molars in man and their racial distribution. Br Dent J 1938;64:264-74.  Back to cited text no. 13
    
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Turner CG 2nd. Three-rooted mandibular first permanent molars and the question of American Indian origins. Am J Phys Anthropol 1971;34:229-41.  Back to cited text no. 14
    
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Somogyi-Csizmazia W, Simons AJ. Three-rooted mandibular first permanent molars in Alberta Indian children. J Can Dent Assoc (Tor) 1971;37:105-6.  Back to cited text no. 15
    
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Curzon ME. Three-rooted mandibular permanent molars in English Caucasians. J Dent Res 1973;52:181.  Back to cited text no. 16
    
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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. 17
    
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Carlsen O, Alexandersen V. Radix entomolaris: Identification and morphology. Scand J Dent Res 1990;98:363-73.  Back to cited text no. 18
    
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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. 19
    
20.
Nagaveni NB, Umashankar KV, Radhika NB, Satisha TS. Third root (Radix Entomolaris) in permanent mandibular first molars in pediatric patients – An endodontic challenge. J Oral Health Comm Dent 2011;5:49-51.  Back to cited text no. 20
    


    Figures

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

  [Table 1], [Table 2], [Table 3]



 

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