The prevalence of radix molaris in the mandibular first molars of a Saudi subpopulation based on cone-beam computed tomography

Hassan AL-Alawi; Saad Al-Nazhan; Nassr Al-Maflehi; Mazen A. Aldosimani; Mohammed Nabil Zahid; Ghadeer N. Shihabi

doi:10.5395/rde.2018.45.e1

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AL-Alawi, Al-Nazhan, Al-Maflehi, Aldosimani, Zahid, and Shihabi: The prevalence of radix molaris in the mandibular first molars of a Saudi subpopulation based on cone-beam computed tomography

Research Article

Restor Dent Endod 2020;45(1):e1.

Published online: 4 February 2020

DOI: https://doi.org/10.5395/rde.2018.45.e1

The prevalence of radix molaris in the mandibular first molars of a Saudi subpopulation based on cone-beam computed tomography

Hassan AL-Alawi¹, Saad Al-Nazhan^2,^*, Nassr Al-Maflehi³, Mazen A. Aldosimani⁴, Mohammed Nabil Zahid⁵, Ghadeer N. Shihabi⁶

¹Dental Department, Ministry of Health Endodontist, Huraymala General Hospital, Riyadh, Saudi Arabia

²Department of Restorative Dentistry-Endodontics, College of Dentistry, Riyadh Elm University, Riyadh, Saudi Arabia

³Department of Preventive Dental Sciences-Biostatistics, College of Dentistry, King Saud University, Riyadh, Saudi Arabia

⁴Department of Oral Medicine and Diagnostic Sciences, College of Dentistry, King Saud University, Riyadh, Saudi Arabia

⁵Department of Preventive Dental Sciences, College of Dentistry, Prince Sattam Bin AbdulAziz University, Al Kharj, Saudi Arabia

⁶General Practitioner, Riyadh, Saudi Arabia

^*Correspondence to Saad Al-Nazhan, BDS, MSD Professor, Department of Restorative Dentistry-Endodontics, College of Dentistry, Riyadh Elm University, Riyadh 11681, Saudi Arabia. E-mail: saad.alnazhan@riyadh.edu.sa

Received 17 July 2019 Revised 25 September 2019 Accepted 1 October 2019

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Objectives

The purpose of this study was to determine the incidence of radix molaris (RM) (entomolaris and paramolaris) in the mandibular first permanent molars of a sample Saudi Arabian subpopulation using cone-beam computed tomography (CBCT).

Materials and Methods

A total of 884 CBCT images of 427 male and 457 female Saudi citizens (age 16 to 70 years) were collected from the radiology department archives of 4 dental centers. A total of 450 CBCT images of 741 mature mandibular first molars that met the inclusion criteria were reviewed. The images were viewed at high resolution by 3 examiners and were analyzed with Planmeca Romexis software (version 5.2).

Results

Thirty-three (4.5%) mandibular first permanent molars had RM, mostly on the distal side. The incidence of radix entomolaris (EM) was 4.3%, while that of radix paramolaris was 0.3%. The RM roots had one canal and occurred more unilaterally. No significant difference in root configuration was found between males and females (p > 0.05). Types I and III EM root canal configurations were most common, while type B was the only RP configuration observed.

Conclusions

The incidence of RM in the mandibular first molars of this Saudi subpopulation was 4.5%. Identification of the supernumerary root can avoid missing the canal associated with the root during root canal treatment.

Keywords: Cone-beam CT, Mandibular first molar, Radix entomolaris, Radix molaris, Root canal morphology

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Figure 1.

(A) Cone-beam computed tomography (CBCT) images of mandibular first molar showing 4 canals (arrow). (B) CBCT showing disto-buccal root with one canal (arrow). (C) Separated distal roots with one canal each (arrow).

Figure 2.

(A) Cone-beam computed tomography (CBCT) images of mandibular first molar showing disto-lingual root bilateral entomolaris (arrow). (B) Bilateral separated roots with one canal (arrow).

Table 1.

Prevalence of supernumerary root in mandibular first molar

Author/reference	Origin	Incidence (%)	Evaluation method
Curzon and Curzon [4]	Mongoloid Keewatin Eskimo (Canada)	27	In vitro (extracted teeth)
Reichart and Metah [5]	Thai (Thailand)	19.2	In vitro (extracted teeth)
Walker [6]	Chinese (Hong Kong)	15	In vitro (extracted teeth)
Younes et al. [7]	African (Egypt)	0.7	In vitro (extracted teeth)
	Asian (Saudi Arabia)	2.3
Zaatar et al. [8]	Kuwait	2.7	In vivo (periapical radiographs)
Sperber and Moreau [9]	Senegal	3.1	In vitro (extracted teeth)
Al-Nazhan [10]	Saudi Arabia	5.97	In vivo (periapical radiographs)
Ahmed et al. [11]	Sudan	3	In vitro (extracted teeth)
Schäfer et al. [12]	Germany	0.7	In vivo (periapical radiographs)
Al-Qudah and Awawdeh [13]	Jordan	3.9	In vitro (extracted teeth)
Song et al. [14]	Korea (Mongoloid origin)	33.1	In vivo (periapical radiographs)
Zhang et al. [15]	China	29	In vivo (CBCT)
Demirbuga et al. [16]	Turkey	2.06	In vivo (CBCT)
Mukhaimer and Azizi [17]	Palestine	3.73	In vivo (periapical radiographs)
Rodrigues et al. [18]	Brazil	2.58	In vivo (CBCT)
Rahimi et al. [19]	Iran	3.00	In vivo (CBCT)
Gupta et al. [20]	Haryana (North India)	13.00	In vivo (periapical radiographs and CBCT)

CBCT, cone-beam computed tomography.

Table 2.

Total number of evaluated cone-beam computed tomography images

Dental center	Grand total			Total fit criteria
Dental center	Male	Female	Total	Total fit criteria
Riyadh Elm University	105	160	265	82
King Saud University	134	135	269	193
Prince Sattam Bin Abdulaziz University	144	81	225	116
Uranus Dental Center	44	81	125	59
Total	427	457	884	450

Table 3.

Number of roots of mandibular first molar in relation to sex and jaw side

Sex	Jaw side	Total No. of patients	Total No. of teeth	No. of roots
Sex	Jaw side	Total No. of patients	Total No. of teeth	1	2	3
Male	Bilateral	165	330	0	326 (44.0%)	4 (0.5%)
	Unilateral	87	87	0	77 (10.4%)	10 (1.4%)
Female	Bilateral	126	252	1 (0.1%)	245 (33.1%)	6 (0.8%)
	Unilateral	72	72	0	59 (8.0%)	13 (1.8%)
Total		450	741	1 (0.1%)	707 (95.4%)	33 (4.5%)

Table 4.

Number and percentages of patients with entomolaris (distolingual root) and paramolaris (mesiobuccal root) in mandibular first molars according to sex and jaw side (n = 741)

Sex	Jaw side	Total No. of patients	Total No. of teeth	Radix molaris
Sex	Jaw side	Total No. of patients	Total No. of teeth	Entomolaris	Paramolaris
Male	Bilateral	2	4	4 (0.5%)	0
	Unilateral	10	10	8 (1.1%)	2 (0.3%)
	Total	12	14	12 (1.6%)	2 (0.3%)
Female	Bilateral	3	6	6 (0.8%)	0
	Unilateral	13	13	13 (1.8%)	0
	Total	16	19	19 (2.6%)	0
Grand total		28	33 (4.5%)	31 (4.2%)	2 (0.3%)

Table 5.

Morphology of the distolingual root (entomolaris) based on Song et al. [30] classification. (n = 741)

Sex	Jaw side	Total No. of patients	Total No. of teeth	Song et al. [30] classification
Sex	Jaw side	Total No. of patients	Total No. of teeth	Type I	Type II	Type III	Small type	Conical type
Male	Bilateral	2	4	0	2	2	0	0
	Unilateral	8	8^*	2	2	3	1	0
	Total	10	12	2	4	5	1	0
Female	Bilateral	3	6	2	2	2	0	0
	Unilateral	13	13	7	2	3	1	0
	Total	16	19	9	4	5	1	0
Grand total		26^*	31 (4.2%)	11 (1.5%)	8 (1.1%)	10 (1.3%)	2 (0.3%)	0

* The other 2 teeth of 2 patients were type B of Carlsen and Alexandersen [29] classification.

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