{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,5]],"date-time":"2026-10-05T23:13:12Z","timestamp":1791241992030,"version":"4.1.0"},"reference-count":52,"publisher":"Springer Science and Business Media LLC","issue":"1","license":[{"start":{"date-parts":[[2023,6,2]],"date-time":"2023-06-02T00:00:00Z","timestamp":1685664000000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"},{"start":{"date-parts":[[2023,6,2]],"date-time":"2023-06-02T00:00:00Z","timestamp":1685664000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"funder":[{"DOI":"10.13039\/501100019652","name":"British University in Egypt","doi-asserted-by":"crossref","id":[{"id":"10.13039\/501100019652","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["Sci Rep"],"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>A well-protected microbial habitat may be present in the root and canal morphology, which is varied and complicated. Before initiating effective root canal treatment, a detailed knowledge of the root and canal anatomical variances in each tooth is a must. This study aimed to investigate the root canal configuration, apical constriction anatomy, location of the apical foramen, dentine thickness, and prevalence of accessory canals in mandibular molar teeth in an Egyptian subpopulation using micro-computed tomography (microCT). A total of 96 mandibular first molars were scanned using microCT, and 3D reconstruction was performed using Mimics software. The root canal configurations of each of the mesial and distal root were classified with two different classification systems. The prevalence and dentin thickness around middle mesial and middle distal canals were investigated. The number, location and anatomy of major apical foramina and the apical constriction anatomy analysed. The number and location of accessory canals were identified. Our findings showed that two separate canals (15%) and one single canal (65%) were the most common configuration in the mesial and distal roots, respectively. More than half of the mesial roots had complex canal configurations and 51% had middle mesial canals. The single apical constriction anatomy was the most common for both canals followed by the parallel anatomy. Disto-lingual and distal locations of the apical foramen are the most common location for both roots. Mandibular molars in Egyptians show a wide range of variations in root canal anatomy with high prevalence of middle mesial canals. Clinicians should be aware of such anatomical variations for successful root canal treatment procedures. A specific access refinement protocol and appropriate shaping parameters should be designated for each case to fulfil the mechanical and biological objectives of root canal treatment without compromising the longevity of treated teeth.<\/jats:p>","DOI":"10.1038\/s41598-023-36005-7","type":"journal-article","created":{"date-parts":[[2023,6,2]],"date-time":"2023-06-02T08:08:52Z","timestamp":1685693332000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":19,"title":["A microcomputed tomographic analysis of the morphological variabilities and incidence of extra canals in mandibular first molar teeth in an Egyptian subpopulation"],"prefix":"10.1038","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1465-3198","authenticated-orcid":false,"given":"Shehabeldin Mohamed","family":"Saber","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mohamed Mohamed","family":"Elashiry","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shaimaa Mohamed Abu El","family":"Sadat","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nawar Naguib","family":"Nawar","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2023,6,2]]},"reference":[{"key":"36005_CR1","doi-asserted-by":"publisher","first-page":"3","DOI":"10.1111\/j.1601-1546.2005.00129.x","volume":"10","author":"F Vertucci","year":"2005","unstructured":"Vertucci, F. Root canal morphology and its relationship to endodontic procedures. Endod. Topics. 10, 3\u201329. https:\/\/doi.org\/10.1111\/j.1601-1546.2005.00129.x (2005).","journal-title":"Endod. Topics."},{"key":"36005_CR2","doi-asserted-by":"publisher","first-page":"3","DOI":"10.1111\/j.1601-1546.2009.00240.x","volume":"15","author":"G Cantatore","year":"2006","unstructured":"Cantatore, G., Berutti, E. & Castellucci, A. Missed anatomy: Frequency and clinical impact. Endod. Topics. 15, 3\u201331. https:\/\/doi.org\/10.1111\/j.1601-1546.2009.00240.x (2006).","journal-title":"Endod. Topics."},{"key":"36005_CR3","doi-asserted-by":"publisher","first-page":"589","DOI":"10.1016\/0030-4220(84)90085-9","volume":"58","author":"F Vertucci","year":"1984","unstructured":"Vertucci, F. Root canal anatomy of the human permanent teeth. Oral Surg. Oral Med. Oral Pathol. 58, 589\u2013599. https:\/\/doi.org\/10.1016\/0030-4220(84)90085-9 (1984).","journal-title":"Oral Surg. Oral Med. Oral Pathol."},{"key":"36005_CR4","doi-asserted-by":"publisher","first-page":"130","DOI":"10.1016\/j.archoralbio.2015.10.020","volume":"61","author":"M Versiani","year":"2016","unstructured":"Versiani, M. et al. Middle mesial canals in mandibular first molars: A micro-CT study in different populations. Arch. Oral Biol. 61, 130\u2013137. https:\/\/doi.org\/10.1016\/j.archoralbio.2015.10.020 (2016).","journal-title":"Arch. Oral Biol."},{"key":"36005_CR5","doi-asserted-by":"publisher","first-page":"1013","DOI":"10.1111\/iej.12724","volume":"50","author":"J Martins","year":"2017","unstructured":"Martins, J., Marques, D., Mata, A. & Caram\u00eas, J. Root and root canal morphology of the permanent dentition in a Caucasian population: A cone-beam computed tomography study. Int. Endod J. 50, 1013\u20131026. https:\/\/doi.org\/10.1111\/iej.12724 (2017).","journal-title":"Int. Endod J."},{"key":"36005_CR6","doi-asserted-by":"publisher","first-page":"159","DOI":"10.14744\/eej.2020.88942","volume":"5","author":"H Ahmed","year":"2020","unstructured":"Ahmed, H. & Rossi-Fedele, G. Preferred reporting items for root and canal anatomy in the human dentition (PROUD 2020)\u2014A systematic review and a proposal for a standardized protocol. Eur. Endod. J. 5, 159\u2013176. https:\/\/doi.org\/10.14744\/eej.2020.88942 (2020).","journal-title":"Eur. Endod. J."},{"key":"36005_CR7","doi-asserted-by":"publisher","first-page":"524","DOI":"10.1111\/iej.13025","volume":"52","author":"R Ordinola-Zapata","year":"2019","unstructured":"Ordinola-Zapata, R., Martins, J., Versiani, M. & Bramante, C. Micro-CT analysis of danger zone thickness in the mesiobuccal roots of maxillary first molars. Int. Endod. J. 52, 524\u2013529. https:\/\/doi.org\/10.1111\/iej.13025 (2019).","journal-title":"Int. Endod. J."},{"key":"36005_CR8","doi-asserted-by":"publisher","first-page":"240","DOI":"10.1111\/iej.12842","volume":"51","author":"A Kele\u015f","year":"2018","unstructured":"Kele\u015f, A. & Keskin, C. Micro-computed tomographic study of band-shaped root canal isthmuses, having their floor in the apical third of mesial roots of mandibular first molars. Int. Endod. J. 51, 240\u2013246. https:\/\/doi.org\/10.1111\/iej.12842 (2018).","journal-title":"Int. Endod. J."},{"key":"36005_CR9","doi-asserted-by":"publisher","first-page":"994","DOI":"10.1016\/j.joen.2019.04.001","volume":"45","author":"T Xu","year":"2019","unstructured":"Xu, T., Fan, W., Tay, F. & Fan, B. Micro-computed tomographic evaluation of the prevalence, distribution, and morphologic features of accessory canals in Chinese permanent Teeth. J. Endod. 45, 994\u2013999. https:\/\/doi.org\/10.1016\/j.joen.2019.04.001 (2019).","journal-title":"J. Endod."},{"key":"36005_CR10","doi-asserted-by":"publisher","first-page":"36501","DOI":"10.1038\/srep36501","volume":"6","author":"X Gao","year":"2016","unstructured":"Gao, X. et al. Micro-CT evaluation of apical delta morphologies in human teeth. Sci. Rep. 6, 36501. https:\/\/doi.org\/10.1038\/srep36501 (2016).","journal-title":"Sci. Rep."},{"key":"36005_CR11","doi-asserted-by":"publisher","first-page":"151","DOI":"10.1038\/ijos.2017.29","volume":"9","author":"T Wolf","year":"2017","unstructured":"Wolf, T., Paqu\u00e9, F., Sven Patyna, M., Willershausen, B. & Brise\u00f1o-Marroqu\u00edn, B. Three-dimensional analysis of the physiological foramen geometry of maxillary and mandibular molars by means of micro-CT. Int. J. Oral Sci. 9, 151\u2013157. https:\/\/doi.org\/10.1038\/ijos.2017.29 (2017).","journal-title":"Int. J. Oral Sci."},{"key":"36005_CR12","doi-asserted-by":"publisher","first-page":"231","DOI":"10.1016\/j.joen.2014.09.024","volume":"41","author":"C Filpo-Perez","year":"2015","unstructured":"Filpo-Perez, C. et al. Micro-computed tomographic analysis of the root canal morphology of the distal root of mandibular first molar. J. Endod. 41, 231\u2013236. https:\/\/doi.org\/10.1016\/j.joen.2014.09.024 (2015).","journal-title":"J. Endod."},{"key":"36005_CR13","doi-asserted-by":"publisher","first-page":"33","DOI":"10.1038\/ijos.2016.53","volume":"9","author":"T Wolf","year":"2017","unstructured":"Wolf, T. et al. Root canal morphology and configuration of 123 maxillary second molars by means of micro-CT. Int. J. Oral Sci. 9, 33\u201337. https:\/\/doi.org\/10.1038\/ijos.2016.53 (2017).","journal-title":"Int. J. Oral Sci."},{"key":"36005_CR14","doi-asserted-by":"publisher","first-page":"761","DOI":"10.1111\/iej.12685","volume":"50","author":"H Ahmed","year":"2017","unstructured":"Ahmed, H., Versiani, M., De-Deus, G. & Dummer, P. A new system for classifying root and root canal morphology. Int. Endod. J. 50, 761\u2013770. https:\/\/doi.org\/10.1111\/iej.12685 (2017).","journal-title":"Int. Endod. J."},{"key":"36005_CR15","doi-asserted-by":"publisher","first-page":"164","DOI":"10.1111\/iej.12800","volume":"51","author":"H Ahmed","year":"2018","unstructured":"Ahmed, H., Neelakantan, P. & Dummer, P. A new system for classifying accessory canal morphology. Int. Endod. J. 51, 164\u2013176. https:\/\/doi.org\/10.1111\/iej.12800 (2018).","journal-title":"Int. Endod. J."},{"key":"36005_CR16","doi-asserted-by":"publisher","first-page":"389","DOI":"10.1111\/iej.12867","volume":"51","author":"H Ahmed","year":"2018","unstructured":"Ahmed, H. & Dummer, P. A new system for classifying tooth, root and canal anomalies. Int. Endod. J. 51, 389\u2013404. https:\/\/doi.org\/10.1111\/iej.12867 (2018).","journal-title":"Int. Endod. J."},{"key":"36005_CR17","doi-asserted-by":"publisher","first-page":"9","DOI":"10.5152\/eej.2017.17064","volume":"3","author":"H Ahmed","year":"2017","unstructured":"Ahmed, H. & Dummer, P. Advantages and applications of a new system for classifying roots and canal systems in research and clinical practice. Euro. Endod. J. 3, 9\u201317. https:\/\/doi.org\/10.5152\/eej.2017.17064 (2017).","journal-title":"Euro. Endod. J."},{"key":"36005_CR18","doi-asserted-by":"publisher","first-page":"267","DOI":"10.1111\/iej.13016","volume":"52","author":"S Saber","year":"2019","unstructured":"Saber, S., Ahmed, M., Obeid, M. & Ahmed, H. Root and canal morphology of maxillary premolar teeth in an Egyptian subpopulation using two classification systems: A cone beam computed tomography study. Int. Endod. J. 52, 267\u2013278. https:\/\/doi.org\/10.1111\/iej.13016 (2019).","journal-title":"Int. Endod. J."},{"key":"36005_CR19","doi-asserted-by":"publisher","first-page":"871","DOI":"10.1111\/iej.13271","volume":"53","author":"H Ahmed","year":"2020","unstructured":"Ahmed, H. et al. Application of a new system for classifying root canal morphology in undergraduate teaching and clinical practice: A national survey in Malaysia. Int. Endod. J. 53, 871\u2013879. https:\/\/doi.org\/10.1111\/iej.13271 (2020).","journal-title":"Int. Endod. J."},{"key":"36005_CR20","doi-asserted-by":"publisher","first-page":"147","DOI":"10.1111\/iej.13439","volume":"54","author":"H Salas","year":"2021","unstructured":"Salas, H., Torres, J., Pauro, J. & Ahmed, H. A new coding system for root and canal morphology\u2014An online survey from Peru. Int. Endod. J. 54, 147\u2013149. https:\/\/doi.org\/10.1111\/iej.13439 (2021).","journal-title":"Int. Endod. J."},{"key":"36005_CR21","doi-asserted-by":"publisher","first-page":"223","DOI":"10.1111\/iej.12814","volume":"51","author":"T Connert","year":"2018","unstructured":"Connert, T. et al. Evaluation of the accuracy of nine electronic apex locators by using Micro-CT. Int. Endod. J. 51, 223\u2013232. https:\/\/doi.org\/10.1111\/iej.12814 (2018).","journal-title":"Int. Endod. J."},{"key":"36005_CR22","doi-asserted-by":"publisher","first-page":"70","DOI":"10.1055\/s-0040-1701393","volume":"14","author":"M Elashiry","year":"2020","unstructured":"Elashiry, M., Saber, S. & Elashry, S. Comparison of shaping ability of different single-file systems using microcomputed tomography. Euro J. Dent. 14, 70\u201376. https:\/\/doi.org\/10.1055\/s-0040-1701393 (2020).","journal-title":"Euro J. Dent."},{"key":"36005_CR23","doi-asserted-by":"publisher","first-page":"565","DOI":"10.1016\/S0099-2399(81)80216-6","volume":"7","author":"H Pomeranz","year":"1981","unstructured":"Pomeranz, H., Eidelman, D. & Goldberg, M. Treatment considerations of the middle mesial canal of mandibular first and second molars. J. Endod. 7, 565\u2013568. https:\/\/doi.org\/10.1016\/S0099-2399(81)80216-6 (1981).","journal-title":"J. Endod."},{"key":"36005_CR24","doi-asserted-by":"publisher","first-page":"724","DOI":"10.1016\/j.joen.2019.03.007","volume":"45","author":"K Divine","year":"2019","unstructured":"Divine, K., McClanahan, S. & Fok, A. Anatomic analysis of palatal roots of maxillary molars using micro-computed tomography. J. Endod. 45, 724\u2013728. https:\/\/doi.org\/10.1016\/j.joen.2019.03.007 (2019).","journal-title":"J. Endod."},{"key":"36005_CR25","doi-asserted-by":"publisher","first-page":"264","DOI":"10.14744\/eej.2021.40427","volume":"6","author":"SE Saber","year":"2021","unstructured":"Saber, S. E., Abu El Sadat, S., Taha, A., Nawar, N. N. & Abdel Azim, A. Anatomical analysis of mandibular posterior teeth using CBCT: An endo-surgical perspective. Eur. Endod. J. 6, 264\u2013270. https:\/\/doi.org\/10.14744\/eej.2021.40427 (2021).","journal-title":"Eur. Endod. J."},{"key":"36005_CR26","doi-asserted-by":"publisher","first-page":"800","DOI":"10.1111\/iej.12061","volume":"46","author":"M Versiani","year":"2013","unstructured":"Versiani, M., P\u00e9cora, J. & Sousa-Neto, M. Microcomputed tomography analysis of the root canal morphology of single-rooted mandibular canines. Int. Endod. J. 46, 800\u2013807. https:\/\/doi.org\/10.1111\/iej.12061 (2013).","journal-title":"Int. Endod. J."},{"key":"36005_CR27","doi-asserted-by":"publisher","first-page":"198","DOI":"10.1016\/S0099-2399(83)80092-2","volume":"9","author":"D Swartz","year":"1983","unstructured":"Swartz, D., Skidmore, A. & Griffin, J. Twenty years of endodontic success and failure. J. Endod. 9, 198\u2013202. https:\/\/doi.org\/10.1016\/S0099-2399(83)80092-2 (1983).","journal-title":"J. Endod."},{"key":"36005_CR28","first-page":"113","volume":"72","author":"P Vyver","year":"2017","unstructured":"Vyver, P. & Vorster, M. Radix Entomolaris: Literature review and case report. S. Afr. Dent. J. 72, 113\u2013117 (2017).","journal-title":"S. Afr. Dent. J."},{"key":"36005_CR29","doi-asserted-by":"publisher","first-page":"164","DOI":"10.1016\/j.joen.2014.09.013","volume":"41","author":"A Azim","year":"2015","unstructured":"Azim, A., Deutsch, A. & Solomon, C. Prevalence of middle mesial canals in mandibular molars after guided troughing under high magnification: An in vivo investigation. J. Endod. 41, 164\u2013168. https:\/\/doi.org\/10.1016\/j.joen.2014.09.013 (2015).","journal-title":"J. Endod."},{"key":"36005_CR30","doi-asserted-by":"publisher","first-page":"92","DOI":"10.4103\/0970-7212.195425","volume":"28","author":"S Chavda","year":"2016","unstructured":"Chavda, S. & Garg, S. Advanced methods for identification of middle mesial canal in mandibular molars: An in vitro study. Endodont. 28, 92. https:\/\/doi.org\/10.4103\/0970-7212.195425 (2016).","journal-title":"Endodont."},{"key":"36005_CR31","doi-asserted-by":"publisher","first-page":"1919","DOI":"10.1016\/j.joen.2010.08.055","volume":"36","author":"O de Pablo","year":"2010","unstructured":"de Pablo, O., Estevez, R., P\u00e9ix S\u00e1nchez, M., Heilborn, C. & Cohenca, N. Root anatomy and canal configuration of the permanent mandibular first molar: A systematic review. J. Endod. 36, 1919\u20131931. https:\/\/doi.org\/10.1016\/j.joen.2010.08.055 (2010).","journal-title":"J. Endod."},{"key":"36005_CR32","doi-asserted-by":"publisher","first-page":"1080","DOI":"10.1016\/j.joen.2017.02.008","volume":"43","author":"M Tahmasbi","year":"2017","unstructured":"Tahmasbi, M., Jalali, P., Nair, M., Barghan, S. & Nair, U. Prevalence of middle mesial canals and isthmi in the mesial root of mandibular molars: An in vivo cone-beam computed tomographic study. J. Endod. 43, 1080\u20131083. https:\/\/doi.org\/10.1016\/j.joen.2017.02.008 (2017).","journal-title":"J. Endod."},{"key":"36005_CR33","doi-asserted-by":"publisher","first-page":"216","DOI":"10.4103\/jomfp.JOMFP_194_17","volume":"22","author":"R Bansal","year":"2018","unstructured":"Bansal, R., Hegde, S. & Astekar, M. Morphology and prevalence of middle canals in the mandibular molars: A systematic review. J. Oral Maxillofac. Pathol. 22, 216\u2013226. https:\/\/doi.org\/10.4103\/jomfp.JOMFP_194_17 (2018).","journal-title":"J. Oral Maxillofac. Pathol."},{"key":"36005_CR34","doi-asserted-by":"publisher","first-page":"610","DOI":"10.1016\/j.joen.2016.01.004","volume":"42","author":"T Wolf","year":"2016","unstructured":"Wolf, T., Paqu\u00e9, F., Zeller, M., Willershausen, B. & Brise\u00f1o-Marroqu\u00edn, B. Root canal morphology and configuration of 118 mandibular first molars by means of micro-computed tomography: An ex vivo study. J. Endod. 42, 610\u2013614. https:\/\/doi.org\/10.1016\/j.joen.2016.01.004 (2016).","journal-title":"J. Endod."},{"key":"36005_CR35","doi-asserted-by":"publisher","first-page":"1757","DOI":"10.21608\/edj.2018.78432","volume":"64","author":"N Roshdy","year":"2018","unstructured":"Roshdy, N. & ElKhodary, S. Prevalence of middle mesial canals in the mesial root of first permanent mandibular molars in Egyptian population: an in vivo cohort retrospective cone-beam computed tomographic study. Egy. Dent. J. 64, 1757\u20131761. https:\/\/doi.org\/10.21608\/edj.2018.78432 (2018).","journal-title":"Egy. Dent. J."},{"key":"36005_CR36","doi-asserted-by":"publisher","first-page":"1467","DOI":"10.1016\/j.joen.2021.06.002","volume":"47","author":"Y K\u0131l\u0131\u00e7","year":"2021","unstructured":"K\u0131l\u0131\u00e7, Y., Karata\u015fl\u0131o\u011flu, E. & Kaval, M. The effect of root canal preparation size and taper of middle mesial canals on fracture resistance of the mandibular molar teeth: An in vitro study. J. Endod. 47, 1467\u20131471. https:\/\/doi.org\/10.1016\/j.joen.2021.06.002 (2021).","journal-title":"J. Endod."},{"key":"36005_CR37","doi-asserted-by":"publisher","first-page":"1374","DOI":"10.1016\/j.joen.2013.06.034","volume":"39","author":"S Harris","year":"2013","unstructured":"Harris, S., Bowles, W., Fok, A. & McClanahan, S. An anatomic investigation of the mandibular first molar using micro-computed tomography. J. Endod. 39, 1374\u20131378. https:\/\/doi.org\/10.1016\/j.joen.2013.06.034 (2013).","journal-title":"J. Endod."},{"key":"36005_CR38","doi-asserted-by":"publisher","first-page":"93","DOI":"10.2334\/josnusd.19-0160","volume":"62","author":"G Buchanan","year":"2020","unstructured":"Buchanan, G., Gamieldien, M., Tredoux, S. & Vally, Z. Root and canal configurations of maxillary premolars in a South African subpopulation using cone beam computed tomography and two classification systems. J. Oral Sci. 62, 93\u201397. https:\/\/doi.org\/10.2334\/josnusd.19-0160 (2020).","journal-title":"J. Oral Sci."},{"key":"36005_CR39","doi-asserted-by":"publisher","first-page":"300","DOI":"10.2334\/josnusd.22-0239","volume":"64","author":"G Buchanan","year":"2022","unstructured":"Buchanan, G., Gamieldien, M., Fabris-Rotelli, I., van Schoor, A. & Uys, A. A study of mandibular premolar root and canal morphology in a Black South African population using cone-beam computed tomography and two classification systems. J. Oral Sci. 64, 300\u2013306. https:\/\/doi.org\/10.2334\/josnusd.22-0239 (2022).","journal-title":"J. Oral Sci."},{"key":"36005_CR40","doi-asserted-by":"publisher","first-page":"93","DOI":"10.1038\/s41598-020-80046-1","volume":"11","author":"A Sierra-Cristancho","year":"2021","unstructured":"Sierra-Cristancho, A. et al. Micro-tomographic characterization of the root and canal system morphology of mandibular first premolars in a Chilean population. Sci. Rep. 11, 93. https:\/\/doi.org\/10.1038\/s41598-020-80046-1 (2021).","journal-title":"Sci. Rep."},{"key":"36005_CR41","doi-asserted-by":"publisher","first-page":"1866","DOI":"10.1016\/j.joen.2010.08.030","volume":"36","author":"B Fan","year":"2010","unstructured":"Fan, B. et al. Three-dimensional morphologic analysis of isthmuses in the mesial roots of mandibular molars. J. Endod. 36, 1866\u20131869. https:\/\/doi.org\/10.1016\/j.joen.2010.08.030 (2010).","journal-title":"J. Endod."},{"key":"36005_CR42","first-page":"75","volume":"22","author":"U Asijavi\u010dien\u0117","year":"2020","unstructured":"Asijavi\u010dien\u0117, U., Drukteinis, S. & Suduiko, A. Microcomputed tomography evaluation of the root canals morphology of the mandibular first molars. Stomatologija 22, 75\u201379 (2020).","journal-title":"Stomatologija"},{"key":"36005_CR43","doi-asserted-by":"publisher","first-page":"321","DOI":"10.1097\/00004770-200405000-00005","volume":"30","author":"B Marroqu\u00edn","year":"2004","unstructured":"Marroqu\u00edn, B., El-Sayed, M. & Willershausen-Z\u00f6nnchen, B. Morphology of the physiological foramen: I Maxillary and mandibular molars. J. Endod. 30, 321\u2013328. https:\/\/doi.org\/10.1097\/00004770-200405000-00005 (2004).","journal-title":"J. Endod."},{"key":"36005_CR44","doi-asserted-by":"publisher","first-page":"41","DOI":"10.1016\/j.gien.2014.05.001","volume":"28","author":"F Citterio","year":"2014","unstructured":"Citterio, F. et al. Analysis of the apical constriction using micro-computed tomography and anatomical sections. G. Ital. Endod. 28, 41\u201345. https:\/\/doi.org\/10.1016\/j.gien.2014.05.001 (2014).","journal-title":"G. Ital. Endod."},{"key":"36005_CR45","doi-asserted-by":"publisher","first-page":"329","DOI":"10.1111\/j.1365-2591.2008.01513.x","volume":"42","author":"J Martos","year":"2009","unstructured":"Martos, J., Ferrer-Luque, C., Gonz\u00e1lez-Rodr\u00edguez, M. & Castro, L. Topographical evaluation of the major apical foramen in permanent human teeth. Int. Endod. J. 42, 329\u2013334. https:\/\/doi.org\/10.1111\/j.1365-2591.2008.01513.x (2009).","journal-title":"Int. Endod. J."},{"key":"36005_CR46","doi-asserted-by":"publisher","first-page":"798","DOI":"10.1016\/j.joen.2016.02.006","volume":"42","author":"T Xu","year":"2016","unstructured":"Xu, T. et al. Micro-computed tomography assessment of apical accessory canal morphologies. J. Endod. 42, 798\u2013802. https:\/\/doi.org\/10.1016\/j.joen.2016.02.006 (2016).","journal-title":"J. Endod."},{"key":"36005_CR47","doi-asserted-by":"publisher","first-page":"437","DOI":"10.1111\/iej.13272","volume":"53","author":"V Nagendrababu","year":"2020","unstructured":"Nagendrababu, V., Duncan, H. & Dummer, P. Research that matters: Systematic reviews and meta-analyses. Int. Endod. J. 53, 437\u2013439. https:\/\/doi.org\/10.1111\/iej.13272 (2020).","journal-title":"Int. Endod. J."},{"key":"36005_CR48","doi-asserted-by":"publisher","first-page":"229","DOI":"10.1111\/iej.13702","volume":"55","author":"H Ahmed","year":"2022","unstructured":"Ahmed, H. A critical analysis of laboratory and clinical research methods to study root and canal anatomy. Int. Enodod. J. 55, 229\u2013280. https:\/\/doi.org\/10.1111\/iej.13702 (2022).","journal-title":"Int. Enodod. J."},{"key":"36005_CR49","doi-asserted-by":"publisher","first-page":"2917","DOI":"10.21608\/edj.2022.133181.2071","volume":"68","author":"M Elhousiny","year":"2022","unstructured":"Elhousiny, M. & Farid, Z. Prevalence of three rooted mandibular first molars in Egyptian population: Cross-sectional Study. Egy. Dent. J. 68, 2917\u20132922. https:\/\/doi.org\/10.21608\/edj.2022.133181.2071 (2022).","journal-title":"Egy. Dent. J."},{"key":"36005_CR50","doi-asserted-by":"publisher","first-page":"191","DOI":"10.1111\/j.1600-0528.1981.tb01053.x","volume":"9","author":"P Reichart","year":"1981","unstructured":"Reichart, P. & Metah, D. Three-rooted permanent mandibular first molars in the Thai. Community Dent. Oral Epidemiol. 9, 191\u2013192. https:\/\/doi.org\/10.1111\/j.1600-0528.1981.tb01053.x (1981).","journal-title":"Community Dent. Oral Epidemiol."},{"key":"36005_CR51","doi-asserted-by":"publisher","first-page":"19","DOI":"10.1111\/j.1600-9657.1988.tb00287.x","volume":"4","author":"R Walker","year":"1988","unstructured":"Walker, R. Root form and canal anatomy of mandibular first molars in a southern Chinese population. Endod. Dent. Traumatol. 4, 19\u201322. https:\/\/doi.org\/10.1111\/j.1600-9657.1988.tb00287.x (1988).","journal-title":"Endod. Dent. Traumatol."},{"key":"36005_CR52","doi-asserted-by":"publisher","first-page":"434","DOI":"10.1111\/j.1834-7819.1990.tb05426.x","volume":"35","author":"H Loh","year":"1990","unstructured":"Loh, H. Incidence and features of three-rooted permanent mandibular molars. Aust. Dent. J. 35, 434\u2013437. https:\/\/doi.org\/10.1111\/j.1834-7819.1990.tb05426.x (1990).","journal-title":"Aust. Dent. J."}],"container-title":["Scientific Reports"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.nature.com\/articles\/s41598-023-36005-7.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/www.nature.com\/articles\/s41598-023-36005-7","content-type":"text\/html","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/www.nature.com\/articles\/s41598-023-36005-7.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,6,2]],"date-time":"2023-06-02T08:10:26Z","timestamp":1685693426000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.nature.com\/articles\/s41598-023-36005-7"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,6,2]]},"references-count":52,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2023,12]]}},"alternative-id":["36005"],"URL":"https:\/\/doi.org\/10.1038\/s41598-023-36005-7","relation":{},"ISSN":["2045-2322"],"issn-type":[{"value":"2045-2322","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,6,2]]},"assertion":[{"value":"7 February 2023","order":1,"name":"received","label":"Received","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"27 May 2023","order":2,"name":"accepted","label":"Accepted","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"2 June 2023","order":3,"name":"first_online","label":"First Online","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"The authors declare no competing interests.","order":1,"name":"Ethics","group":{"name":"EthicsHeading","label":"Competing interests"}}],"article-number":"8985"}}