{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,3]],"date-time":"2026-10-03T02:57:34Z","timestamp":1790996254490,"version":"4.1.0"},"reference-count":54,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2023,11,17]],"date-time":"2023-11-17T00:00:00Z","timestamp":1700179200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100002383","name":"King Saud University","doi-asserted-by":"publisher","award":["RSPD2023R950"],"award-info":[{"award-number":["RSPD2023R950"]}],"id":[{"id":"10.13039\/501100002383","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Medicina"],"abstract":"<jats:p>Background and Objectives: An understanding of the anatomical complexity of teeth is a significant factor for a successful endodontic treatment outcome. The aim of this study was to explore the frequency and pattern of distribution of radix entomolaris (RE) in mandibular first molars (MFMs) of a Saudi Arabian subpopulation using CBCT scans. Materials and Methods: This study was conducted at dental clinics of Qassim University from February to May 2023 by evaluating CBCT scans that were previously obtained for diagnostic purposes. Scans of Saudi national patients with bilaterally present MFMs and fully formed root apices were included. Conversely, scans with one\/or two missing MFMs, MFMs with incomplete root apices, full- or partial-coverage prosthesis, endodontic treatment, and associated radicular resorption were excluded from study. A total of 303 CBCT scans with 606 bilateral MFMs were analyzed by two calibrated evaluators for the presence of, and type according to Song\u2019s typolgy of RE. The data were analyzed using SPPS-24. The descriptive variables were documented as frequencies and percentages. The chi-square test was used to determine the association between the prevalence of RE with the gender, jaw side and age group. Both inter-rater and intra-rater agreements were estimated for detecting and classifying RE using Cohen\u2019s kappa test. Results: The sample had 63.7% males and 36.3% females. The prevalence of RE was 6.6%, with Song\u2019s type III (57.5%) as the most common variant. Absolute agreement was noted between the raters about the presence of RE and very strong agreement was noted for the classification of the RE. Conclusions: RE is an uncommon finding among the mandibular first molars of the Saudi population without any gender and quadrant predilection. The clinicians\u2019 knowledge of the presence and Song\u2019s type of RE may contribute towards the enhancement of endodontic treatment outcomes.<\/jats:p>","DOI":"10.3390\/medicina59112025","type":"journal-article","created":{"date-parts":[[2023,11,17]],"date-time":"2023-11-17T09:10:38Z","timestamp":1700212238000},"page":"2025","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["A Cone Beam Computed Tomography-Based Investigation of the Frequency and Pattern of Radix Entomolaris in the Saudi Arabian Population"],"prefix":"10.3390","volume":"59","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7586-4319","authenticated-orcid":false,"given":"Muhammad Qasim","family":"Javed","sequence":"first","affiliation":[{"name":"Department of Conservative Dental Sciences, College of Dentistry, Qassim University, P.O. Box 1162, Buraidah 51452, Qassim, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5288-9452","authenticated-orcid":false,"given":"Swati","family":"Srivastava","sequence":"additional","affiliation":[{"name":"Department of Conservative Dental Sciences, College of Dentistry, Qassim University, P.O. Box 1162, Buraidah 51452, Qassim, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Badi Baen Rashed","family":"Alotaibi","sequence":"additional","affiliation":[{"name":"Department of Conservative Dental Sciences, College of Dentistry, Qassim University, P.O. Box 1162, Buraidah 51452, Qassim, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Usman Anwer","family":"Bhatti","sequence":"additional","affiliation":[{"name":"Department of Operative Dentistry, Islamic International Dental College, Riphah International University, Islamabad 44000, Pakistan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7214-0967","authenticated-orcid":false,"given":"Ayman M.","family":"Abulhamael","sequence":"additional","affiliation":[{"name":"Department of Endodontics, Faculty of Dentistry, King Abdulaziz University, P.O. Box 80209, Jeddah 21589, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4398-3479","authenticated-orcid":false,"given":"Syed Rashid","family":"Habib","sequence":"additional","affiliation":[{"name":"Department of Prosthetic Dental Sciences, College of Dentistry, King Saud University, P.O. Box 60169, Riyadh 11545, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,11,17]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1919","DOI":"10.1016\/j.joen.2010.08.055","article-title":"Root anatomy and canal configuration of the permanent mandibular first molar: A systematic review","volume":"36","author":"Estevez","year":"2010","journal-title":"J. Endod."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"45","DOI":"10.1038\/sj.ebd.6400335","article-title":"Better success rate for root canal therapy when treatment includes obturation short of the apex","volume":"6","author":"Toru","year":"2005","journal-title":"Evid. Based Dent."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"212","DOI":"10.1016\/j.joen.2007.11.018","article-title":"The evaluation of root canal morphology of the mandibular first molar in an Indian population using spiral computed tomography scan: An in vitro study","volume":"34","author":"Reuben","year":"2008","journal-title":"J. Endod."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"778","DOI":"10.1016\/0030-4220(71)90304-5","article-title":"Root canal morphology of the human mandibular first molar","volume":"32","author":"Skidmore","year":"1971","journal-title":"Oral Surg. Oral Med. Oral Pathol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"849","DOI":"10.1016\/j.joen.2013.04.030","article-title":"Evaluation of root canal configuration of mandibular molars in a Brazilian population by using cone-beam computed tomography: An in vivo study","volume":"39","author":"Silva","year":"2013","journal-title":"J. Endod."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"185","DOI":"10.1097\/00004770-200403000-00015","article-title":"Middle mesial canal of the mandibular first molar: A case report and literature review","volume":"30","author":"Baugh","year":"2004","journal-title":"J. Endod."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"990","DOI":"10.1016\/j.joen.2010.02.030","article-title":"Root canal morphology of permanent three-rooted mandibular first molars-part I: Pulp floor and root canal system","volume":"36","author":"Gu","year":"2010","journal-title":"J. Endod."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1516","DOI":"10.1016\/j.joen.2013.08.015","article-title":"Morphology of mandibular first molars analyzed by cone-beam computed tomography in a Korean population: Variations in the number of roots and canals","volume":"39","author":"Kim","year":"2013","journal-title":"J. Endod."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"372","DOI":"10.1016\/j.joen.2018.12.016","article-title":"Prevalence studies on root canal anatomy using cone-beam computed tomographic imaging: A systematic review","volume":"45","author":"Martins","year":"2019","journal-title":"J. Endod."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"478","DOI":"10.1111\/j.1365-2591.2010.01702.x","article-title":"Three-dimensional analysis of the root morphology of mandibular first molars with distolingual roots","volume":"43","author":"Huang","year":"2010","journal-title":"Int. Endod. J."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"28","DOI":"10.1016\/j.joen.2014.08.004","article-title":"Middle mesial canals in mandibular molars: Incidence and related factors","volume":"41","author":"Nosrat","year":"2015","journal-title":"J. Endod."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1064","DOI":"10.1016\/j.joen.2017.01.027","article-title":"Complicated root canal configuration of mandibular first premolars is correlated with the presence of the distolingual root in mandibular first molars: A cone-beam computed tomographic study in Taiwanese individuals","volume":"43","author":"Wu","year":"2017","journal-title":"J. Endod."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"2020","DOI":"10.1016\/j.joen.2017.07.022","article-title":"A cone-beam computed tomographic study of apical surgery\u2013related morphological characteristics of the distolingual root in 3-rooted mandibular first molars in a Chinese population","volume":"43","author":"Zhang","year":"2017","journal-title":"J. Endod."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"963","DOI":"10.1111\/j.1365-2591.2012.02075.x","article-title":"Mandibular first molars with disto-lingual roots: Review and clinical management","volume":"45","author":"Abella","year":"2012","journal-title":"Int. Endod. J."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"494","DOI":"10.1111\/aej.12607","article-title":"Frequency of middle mesial canal in mandibular first molars and its association with various anatomic variables","volume":"48","author":"Bhatti","year":"2022","journal-title":"Aust. Endod. J."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"58","DOI":"10.1016\/j.joen.2006.05.007","article-title":"The radix entomolaris and paramolaris: Clinical approach in endodontics","volume":"33","author":"Calberson","year":"2007","journal-title":"J. Endod."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"789","DOI":"10.1111\/j.1365-2591.2004.00870.x","article-title":"The radix entomolaris in mandibular first molars: An endodontic challenge","volume":"37","author":"Deroose","year":"2004","journal-title":"Int. Endod. J."},{"key":"ref_18","unstructured":"Carabelli, G. (1844). Systemntisches Handbueh der Zahnkeilkunde, BraumuUer und Seidel. [2nd ed.]."},{"key":"ref_19","first-page":"605","article-title":"Bemerkungen \u00fcber wurzelvariationen am menschlichen unteren molaren","volume":"3","author":"Bolk","year":"1915","journal-title":"Z. Morphol. Anthropol."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"653","DOI":"10.1016\/j.joen.2009.10.007","article-title":"The prevalence and morphologic classification of distolingual roots in the mandibular molars in a Korean population","volume":"36","author":"Song","year":"2010","journal-title":"J. Endod."},{"key":"ref_21","first-page":"363","article-title":"Radix entomolaris: Identification and morphology","volume":"98","author":"Carlsen","year":"1990","journal-title":"Scan. J. Dent. Res."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"779","DOI":"10.1016\/j.joen.2021.02.006","article-title":"Geometric Analysis of the Distolingual Root and Canal in Mandibular First Molars: A Micro-computed Tomographic Study","volume":"47","author":"Wu","year":"2021","journal-title":"J. Endod."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"400","DOI":"10.1111\/iej.13022","article-title":"Association between missed canals and apical periodontitis","volume":"52","author":"Costa","year":"2019","journal-title":"Int. Endod. J."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"223","DOI":"10.1016\/j.joen.2021.11.009","article-title":"Worldwide Assessment of the Mandibular First Molar Second Distal Root and Root Canal: A Cross-sectional Study with Meta-analysis","volume":"48","author":"Martins","year":"2022","journal-title":"J. Endod."},{"key":"ref_25","first-page":"e1","article-title":"The prevalence of radix molaris in the mandibular first molars of a Saudi subpopulation based on cone-beam computed tomography","volume":"45","author":"Aldosimani","year":"2019","journal-title":"Restor. Dent. Endod."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"481","DOI":"10.1016\/j.sdentj.2019.04.001","article-title":"Anatomical variations and bilateral symmetry of roots and root canal system of mandibular first permanent molars in Saudi Arabian population utilizing cone-beam computed tomography","volume":"31","author":"Mashyakhy","year":"2019","journal-title":"Saudi Dent. J."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"915","DOI":"10.1016\/j.joen.2020.03.020","article-title":"Preferred reporting items for epidemiologic cross-sectional studies on root and root canal anatomy using cone-beam computed tomographic technology: A systematized assessment","volume":"46","author":"Martins","year":"2020","journal-title":"J. Endod."},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Naing, L., Nordin, R.B., Abdul Rahman, H., and Naing, Y.T. (2022). Sample size calculation for prevalence studies using Scalex and ScalaR calculators. BMC Med. Res. Methodol., 22.","DOI":"10.1186\/s12874-022-01694-7"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"83","DOI":"10.4197\/Med.18-4.7","article-title":"The incidence of radix entomolaris in mandibular first permanent molars in a Saudi Arabian sub-population","volume":"18","author":"Bahammam","year":"2011","journal-title":"JKAU Med. Sci."},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"(2015). AAE and AAOMR joint position statement: Use of cone beam computed tomography in endodontics 2015 update. Oral Surg. Oral Med. Oral Pathol. Oral Radiol., 120, 508\u2013512.","DOI":"10.1016\/j.oooo.2015.07.033"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"359","DOI":"10.1046\/j.1365-2591.2001.00399.x","article-title":"Root and canal morphology of Burmese mandibular molars","volume":"34","author":"Gulabivala","year":"2001","journal-title":"Int. Endod. J."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1044","DOI":"10.1111\/j.1365-2591.2009.01619.x","article-title":"Investigation of the root canal configuration of mandibular first molars in a Taiwan Chinese population","volume":"42","author":"Chen","year":"2009","journal-title":"Int. Endod. J."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"102","DOI":"10.1016\/0030-4220(90)90276-X","article-title":"Three-rooted permanent mandibular first molars of Asian and black groups in the Middle East","volume":"69","author":"Younes","year":"1990","journal-title":"Oral Surg. Oral Med. Oral Pathol."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"49","DOI":"10.1046\/j.1365-2591.1999.00188.x","article-title":"Incidence of four canals in root-canal-treated mandibular first molars in a Saudi Arabian sub-population","volume":"32","year":"1999","journal-title":"Int. Endod. J."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"1121","DOI":"10.1016\/j.joen.2007.06.011","article-title":"Endodontic applications of cone-beam volumetric tomography","volume":"33","author":"Cotton","year":"2007","journal-title":"J. Endod."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"1547","DOI":"10.1016\/j.joen.2010.05.008","article-title":"Comparative evaluation of modified canal staining and clearing technique, cone-beam computed tomography, peripheral quantitative computed tomography, spiral computed tomography, and plain and contrast medium-enhanced digital radiography in studying root canal morphology","volume":"36","author":"Neelakantan","year":"2010","journal-title":"J. Endod."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"1786","DOI":"10.1016\/j.joen.2010.08.016","article-title":"Evaluation of the root and canal morphology of mandibular first permanent molars in a western Chinese population by cone-beam computed tomography","volume":"36","author":"Wang","year":"2010","journal-title":"J. Endod."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"990","DOI":"10.1111\/j.1365-2591.2011.01904.x","article-title":"Use of cone-beam computed tomography to evaluate root and canal morphology of mandibular molars in Chinese individuals","volume":"44","author":"Zhang","year":"2011","journal-title":"Int. Endod. J."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"1302","DOI":"10.1016\/j.joen.2010.04.019","article-title":"Prevalence of three-rooted mandibular permanent first molars among the Indian Population","volume":"36","author":"Garg","year":"2010","journal-title":"J. Endod."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"117","DOI":"10.1046\/j.1365-2591.1998.00126.x","article-title":"Study of the number of roots and canals in Senegalese first permanent mandibular molars","volume":"31","author":"Sperber","year":"1999","journal-title":"Int. Endod. J."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"95","DOI":"10.5624\/isd.2015.45.2.95","article-title":"Characterization of mandibular molar root and canal morphology using cone beam computed tomography and its variability in Belgian and Chilean population samples","volume":"45","author":"Torres","year":"2015","journal-title":"Imaging Sci. Dent."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"1308","DOI":"10.1016\/j.joen.2023.06.011","article-title":"Assessment of the Prevalence of Radix Entomolaris and Distolingual Canal in Mandibular First Molars in 15 Countries: A Multinational Cross-sectional Study with Meta-analysis","volume":"49","author":"Elatrash","year":"2023","journal-title":"J. Endod."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"56","DOI":"10.1046\/j.1365-2591.2002.00452.x","article-title":"Root and canal morphology of Thai mandibular molars","volume":"35","author":"Gulabivala","year":"2002","journal-title":"Int. Endod. J."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"1163","DOI":"10.1016\/j.joen.2007.07.020","article-title":"Prevalence of three-rooted mandibular first molars among Taiwanese individuals","volume":"33","author":"Tu","year":"2007","journal-title":"J. Endod."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"434","DOI":"10.1111\/j.1834-7819.1990.tb05426.x","article-title":"Incidence and features of three-rooted permanent mandibular molars","volume":"35","author":"Loh","year":"1990","journal-title":"Aust. Dent. J."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"181","DOI":"10.1177\/00220345730520011901","article-title":"Three-rooted mandibular permanent molars in English Caucasians","volume":"52","author":"Curzon","year":"1973","journal-title":"J. Dent. Res."},{"key":"ref_47","doi-asserted-by":"crossref","unstructured":"Talabani, R.M., Abdalrahman, K.O., Abdul, R.J., Babarasul, D.O., and Hilmi Kazzaz, S. (2022). Evaluation of Radix Entomolaris and Middle Mesial Canal in Mandibular Permanent First Molars in an Iraqi Subpopulation Using Cone-Beam Computed Tomography. BioMed Res. Int., 2022.","DOI":"10.1155\/2022\/7825948"},{"key":"ref_48","first-page":"63","article-title":"Frequency of middle mesial canal and radix entomolaris in mandibular first molars by cone beam computed tomography in a selected Iranian population","volume":"9","author":"Hosseini","year":"2020","journal-title":"Caspian J. Dent. Res."},{"key":"ref_49","doi-asserted-by":"crossref","unstructured":"Qiao, X., Zhu, H., Yan, Y., Li, J., Ren, J., Gao, Y., and Zou, L. (2020). Prevalence of middle mesial canal and radix entomolaris of mandibular first permanent molars in a western Chinese population: An in vivo cone-beam computed tomographic study. BMC Oral Health, 20.","DOI":"10.1186\/s12903-020-01218-z"},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"643","DOI":"10.1016\/j.joen.2009.01.020","article-title":"The morphologic characteristics of the distolingual roots of mandibular first molars in a Taiwanese population","volume":"35","author":"Chen","year":"2009","journal-title":"J. Endod."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"766","DOI":"10.1111\/j.1365-2591.2007.01283.x","article-title":"Root and canal morphology of permanent mandibular molars in a Sudanese population","volume":"40","author":"Ahmed","year":"2007","journal-title":"Int. Endod. J."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"495","DOI":"10.1126\/science.139.3554.495","article-title":"Observation of internal structures of teeth by ultrasonography","volume":"139","author":"Baum","year":"1963","journal-title":"Science"},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"819","DOI":"10.1016\/j.oooo.2013.03.012","article-title":"Recent advances of ultrasound imaging in dentistry\u2014A review of the literature","volume":"115","author":"Marotti","year":"2013","journal-title":"Oral Surg. Oral Med. Oral Pathol. Oral Radiol."},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"20190290","DOI":"10.1259\/dmfr.20190290","article-title":"Diagnostic accuracy of panoramic radiography and ultrasonography in detecting periapical lesions using periapical radiography as a gold standard","volume":"49","author":"Arslan","year":"2020","journal-title":"Dentomaxillofac. Radiol."}],"container-title":["Medicina"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1648-9144\/59\/11\/2025\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T21:24:43Z","timestamp":1760131483000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1648-9144\/59\/11\/2025"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,11,17]]},"references-count":54,"journal-issue":{"issue":"11","published-online":{"date-parts":[[2023,11]]}},"alternative-id":["medicina59112025"],"URL":"https:\/\/doi.org\/10.3390\/medicina59112025","relation":{},"ISSN":["1648-9144"],"issn-type":[{"value":"1648-9144","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,11,17]]}}}