{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,26]],"date-time":"2026-10-26T22:45:37Z","timestamp":1793054737929,"version":"4.5.0"},"reference-count":42,"publisher":"Public Library of Science (PLoS)","issue":"7","license":[{"start":{"date-parts":[[2025,7,31]],"date-time":"2025-07-31T00:00:00Z","timestamp":1753920000000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["www.plosone.org"],"crossmark-restriction":false},"short-container-title":["PLoS One"],"abstract":"<jats:sec id=\"sec001\">\n<jats:title>Objectives<\/jats:title>\n<jats:p>The objective of this study was to evaluate the effectiveness of clinically applicable diagnostic methods such as Direct Vision (DV), Dental Operating Microscope (DOM), and two-dimensional (2D) radiographs in detecting canal orifices and root canal configurations in mandibular first premolars with deep radicular grooves. The study also aimed to compare these methods with micro-computed tomography (micro-CT) to better understand their diagnostic capabilities and to assess the applicability of the Ahmed et al. (2017) classification system across different imaging modalities.<\/jats:p>\n<\/jats:sec>\n<jats:sec id=\"sec002\">\n<jats:title>Methods<\/jats:title>\n<jats:p>A total of 133 mandibular first premolars with deep radicular grooves were scanned using micro-CT. After scanning, two examiners, blinded to micro-CT results, accessed and examined the root canal orifices of the study samples under DV, and DOM. Further evaluation of the root canal configurations was undertaken using exploration and 2D radiographic images. A second round of relocation of canals was undertaken if the radiographic view showed the presence of a missed canal. The data were then compared with the original reconstructed micro-CT images. Descriptive statistical analysis, Kappa and chi-square tests were performed to compare between methods and examiners, and the <jats:italic>p<\/jats:italic>-value was set at 0.05.<\/jats:p>\n<\/jats:sec>\n<jats:sec id=\"sec003\">\n<jats:title>Results<\/jats:title>\n<jats:p>Except for three teeth, all samples exhibited multiple canals. Micro-CT data revealed a wide range of root canal configurations, with the most common being <jats:sup>1<\/jats:sup>MFP<jats:sup>1-2<\/jats:sup> (19.54%), followed by <jats:sup>1<\/jats:sup>MFP<jats:sup>1-2-3<\/jats:sup> (15.78%), <jats:sup>1<\/jats:sup>MFP<jats:sup>1-2-3-2<\/jats:sup> (5.26%), and both <jats:sup>1<\/jats:sup>MFP<jats:sup>1-2-4<\/jats:sup> and <jats:sup>1<\/jats:sup>MFP<jats:sup>1-2-1<\/jats:sup> configurations, each at 4.51%. For both examiners, using the DOM resulted in detection of more canal orifices compared to DV (p\u2009&lt;\u20090.001). A number of root canal configuration types including <jats:sup>1<\/jats:sup>MFP<jats:sup>1-2<\/jats:sup> and <jats:sup>1<\/jats:sup>MFP<jats:sup>1-2-1<\/jats:sup> was identified using exploration and radiographic imaging. Both examiners identified additional canals in the relocation phase. A significant difference was found when the radiographic method is compared with micro-CT results (<jats:italic>p<\/jats:italic>\u2009&lt;\u20090.001), in which the latter method showed more complex root canal configuration types.<\/jats:p>\n<\/jats:sec>\n<jats:sec id=\"sec004\">\n<jats:title>Conclusions<\/jats:title>\n<jats:p>Mandibular first premolars with deep proximal grooves exhibit considerable variability and complexity in their root canal systems. The use of a dental operating microscope (DOM) significantly improves the detection of canal orifices compared to direct vision. The most frequently observed root canal configuration was <jats:sup>1<\/jats:sup>MFP<jats:sup>1-2<\/jats:sup>. A high percentage of additional canals may be missed due to atypical locations of bifurcations along the root. While micro-CT imaging is not applicable in clinical settings, it remains a valuable reference tool in studies for enhancing our understanding of root canal morphology and guiding the development of clinically feasible diagnostic strategies.<\/jats:p>\n<\/jats:sec>","DOI":"10.1371\/journal.pone.0329439","type":"journal-article","created":{"date-parts":[[2025,7,31]],"date-time":"2025-07-31T17:32:42Z","timestamp":1753983162000},"page":"e0329439","update-policy":"https:\/\/doi.org\/10.1371\/journal.pone.corrections_policy","source":"Crossref","is-referenced-by-count":4,"title":["Comparative evaluation of root canal morphology in mandibular first premolars with deep radicular grooves using direct vision, dental operating microscope, 2D radiographic visualisation and micro-computed tomography"],"prefix":"10.1371","volume":"20","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0313-9695","authenticated-orcid":true,"given":"Mohmed Isaqali","family":"Karobari","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hany Mohamed Aly","family":"Ahmed","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mohd Fadhli","family":"Bin Khamis","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Norliza","family":"Ibrahim","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tahir Yusuf","family":"Noorani","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"340","published-online":{"date-parts":[[2025,7,31]]},"reference":[{"issue":"6","key":"pone.0329439.ref001","doi-asserted-by":"crossref","first-page":"871","DOI":"10.1111\/iej.13271","article-title":"Application of a new system for classifying root canal morphology in undergraduate teaching and clinical practice: a national survey in Malaysia","volume":"53","author":"HMA Ahmed","year":"2020","journal-title":"Int Endod J"},{"issue":"1","key":"pone.0329439.ref002","doi-asserted-by":"crossref","first-page":"93","DOI":"10.2334\/josnusd.19-0160","article-title":"Root and canal configurations of maxillary premolars in a South African subpopulation using cone beam computed tomography and two classification systems","volume":"62","author":"GD Buchanan","year":"2020","journal-title":"J Oral Sci"},{"issue":"5","key":"pone.0329439.ref003","doi-asserted-by":"crossref","first-page":"509","DOI":"10.1016\/j.joen.2006.12.004","article-title":"The root and root canal morphology of the human mandibular first premolar: a literature review","volume":"33","author":"BM Cleghorn","year":"2007","journal-title":"J Endod"},{"issue":"5","key":"pone.0329439.ref004","doi-asserted-by":"crossref","first-page":"597","DOI":"10.1590\/0103-6440201601784","article-title":"Micro-CT evaluation of root and canal morphology of mandibular first premolars with radicular grooves","volume":"28","author":"E Boschetti","year":"2017","journal-title":"Braz Dent J"},{"issue":"1","key":"pone.0329439.ref005","doi-asserted-by":"crossref","first-page":"93","DOI":"10.1038\/s41598-020-80046-1","article-title":"Micro-tomographic characterization of the root and canal system morphology of mandibular first premolars in a Chilean population","volume":"11","author":"A Sierra-Cristancho","year":"2021","journal-title":"Sci Rep"},{"issue":"10","key":"pone.0329439.ref006","doi-asserted-by":"crossref","first-page":"932","DOI":"10.1016\/j.joen.2006.04.008","article-title":"Complicated root canal morphology of mandibular first premolar in a Chinese population using the cross section method","volume":"32","author":"T-Y Lu","year":"2006","journal-title":"J Endod"},{"issue":"3","key":"pone.0329439.ref007","doi-asserted-by":"crossref","first-page":"100","DOI":"10.1016\/j.job.2016.05.004","article-title":"Three-dimensional imaging of internal tooth structures: Applications in dental education","volume":"58","author":"A Kato","year":"2016","journal-title":"J Oral Biosci"},{"key":"pone.0329439.ref008","doi-asserted-by":"crossref","first-page":"183","DOI":"10.1007\/978-3-030-16641-0_12","article-title":"Applications of micro-CT technology in endodontics","volume-title":"Micro-computed Tomography (micro-CT) in Medicine and Engineering","author":"MA Versiani","year":"2020"},{"issue":"4","key":"pone.0329439.ref009","doi-asserted-by":"crossref","first-page":"1007","DOI":"10.1007\/s00784-016-1852-x","article-title":"The root canal morphology in mandibular first premolars: a comparative evaluation of cone-beam computed tomography and micro-computed tomography","volume":"21","author":"D Zhang","year":"2017","journal-title":"Clin Oral Investig"},{"key":"pone.0329439.ref010","unstructured":"AAE. 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