title: Topographic relationship between root apex of mesially and horizontally impacted mandibular third molar and lingual plate: cross-sectional analysis using CBCT.
abstract: The present study was aimed to determine the topographic relationship between root apex of the mesially and horizontally impacted mandibular third molar and lingual plate of mandible. The original cone beam computed tomography (CBCT) data of 364 teeth from 223 patients were retrospectively collected and analyzed. The topographic relationship between root apex and lingual plate on cross-sectional CBCT images was classified as non-contact (99), contact (145) and perforation (120). The cross-sectional morphology of lingual plate at the level of root apex was defined as parallel (28), undercut (38), slanted (29) and round (4). The distribution of topographic relationship between root apex and lingual plate significantly associated with gender, impaction depth, root number and lingual plate morphology. Moreover, the average bone thickness of lingual cortex and distance between root apex and the outer surface of lingual plate were 1.02 and 1.39 mm, respectively. Furthermore, multivariate regression analyses identified impaction depth and lingual plate morphology as the risk factors for the contact and perforation subtypes between root apex and lingual plate. Collectively, our findings reveal the topographic proximity of root apex of impacted mandibular third molar to the lingual plate, which might be associated with intraoperative and postoperative complications during tooth extraction.
authors.affiliation: Department of Oral and Maxillofacial Surgery, College of Stomatology, Nanjing Medical University, Nanjing 210029, China.|Jiangsu Key Laboratory of Oral Disease, Nanjing Medical University, Nanjing 210029, China.
authors.forename: Dongmiao
authors.initials: D
authors.lastname: Wang
authors.affiliation: Department of Oral and Maxillofacial Surgery, College of Stomatology, Nanjing Medical University, Nanjing 210029, China.
authors.forename: Xiaotong
authors.initials: X
authors.lastname: He
authors.affiliation: Department of oral prosthodontics, College of Stomatology, Nanjing Medical University, Nanjing 210029, China.
authors.forename: Yanling
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Oral and Maxillofacial Radiology, College of Stomatology, Nanjing Medical University, Nanjing 210029, China.
authors.forename: Guangchao
authors.initials: G
authors.lastname: Zhou
authors.affiliation: Department of Oral and Maxillofacial Radiology, College of Stomatology, Nanjing Medical University, Nanjing 210029, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Sun
authors.affiliation: Department of Oral and Maxillofacial Radiology, College of Stomatology, Nanjing Medical University, Nanjing 210029, China.
authors.forename: Lianfeng
authors.initials: L
authors.lastname: Yang
authors.affiliation: Department of Biomedical Statistics, College of Public Health, Nanjing Medical University, Nanjing 210029, China.
authors.forename: Jianling
authors.initials: J
authors.lastname: Bai
authors.affiliation: Jiangsu Key Laboratory of Oral Disease, Nanjing Medical University, Nanjing 210029, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Gao
authors.affiliation: Department of Oral and Maxillofacial Surgery, College of Stomatology, Nanjing Medical University, Nanjing 210029, China.
authors.forename: Yunong
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Department of Oral and Maxillofacial Surgery, College of Stomatology, Nanjing Medical University, Nanjing 210029, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Cheng
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D054893:Cone-Beam Computed Tomography; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging / Q000502:physiology; D008875:Middle Aged; D008964:Molar, Third / Q000000981:diagnostic imaging / Q000502:physiology*; D015999:Multivariate Analysis; D012189:Retrospective Studies; D014092:Tooth Root / Q000000981:diagnostic imaging / Q000502:physiology*; D014095:Tooth, Impacted / Q000000981:diagnostic imaging; D055815:Young Adult