title: Classification of the Root Position of the Maxillary Central Incisors and its Clinical Significance in Immediate Implant Placement.
abstract: OBJECTIVE
  The aim was to classify the relationship of the sagittal root positions of the maxillary central incisor to alveolar bone using cone beam computed tomography (CBCT).
  
  
  METHODS
  CBCT images of 934 maxillary central incisors were retrospectively reviewed included 542 men and 392 women. The sagittal root position in the alveolar bone was classified as buccal, middle, or palatal. The sagittal buccal type was further classified into 3 subtypes: I, II, and III.
  
  
  RESULTS
  The root position type was buccal in 95.4% of the 934 incisors, middle in 4.4%, and palatal in 0.2%. In the buccal type, 47.5%, 44.2%, and 8.3% were subtypes I, II, and III, respectively. There was no significant difference in the major and subtypes of root position between the male and female subjects (both P > 0.05).
  
  
  CONCLUSIONS
  In Chinese adults, the predominant type of sagittal root position of the maxillary central incisor is buccal. This classification system is useful in planning the implant site for immediate placement in the maxillary esthetic zone.
authors.affiliation: *Department of Stomatology, Longgang District Central Hospital, Affiliated to Zunyi Medical College, Shenzhen, Guangdong, China. †College of Mechanical and Engineering, Key Laboratory of E&M (Zhejiang, University of Technology), Ministry of Education & Zhejiang Province, Hangzhou, China. ‡Department of Oral Radiology, Peking University School and Hospital of Stomatology, Beijing, China.
authors.forename: Duoling
authors.initials: D
authors.lastname: Xu
authors.forename: Zhao
authors.initials: Z
authors.lastname: Wang
authors.forename: Lei
authors.initials: L
authors.lastname: Sun
authors.forename: Zhenyan
authors.initials: Z
authors.lastname: Lin
authors.forename: Linzi
authors.initials: L
authors.lastname: Wan
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.forename: Xuan
authors.initials: X
authors.lastname: Lin
authors.forename: Wei
authors.initials: W
authors.lastname: Peng
authors.forename: Zuyan
authors.initials: Z
authors.lastname: Zhang
authors.forename: Yongbo
authors.initials: Y
authors.lastname: Gao
mesh_terms: D000328:Adult; D000539:Alveolar Process / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D002965:Classification; D054893:Cone-Beam Computed Tomography; D005260:Female; D006801:Humans; D057893:Immediate Dental Implant Loading / Q000379:methods; D007180:Incisor / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D008297:Male; D008437:Maxilla / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D008875:Middle Aged; D012189:Retrospective Studies; D012737:Sex Factors; D014092:Tooth Root / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D055815:Young Adult