title: Measurement of root surface area of permanent teeth with root variations in a Chinese population-A micro-CT analysis.
abstract: OBJECTIVE
  This study investigated the influence of root variations on the root surface area (RSA) by using micro-CT scans.
  
  
  METHODS
  A total of 228 extracted permanent teeth (2-rooted and single-rooted maxillary first premolars, mandibular first premolars with non-Tomes' and Tomes' roots, 2-rooted and 3-rooted mandibular first molars, and 2-rooted and C-shaped mandibular second molars) were collected in a Chinese population and scanned using a micro-CT. In Mimics 15.01, 3D tooth models were generated, and the net and percent remaining RSA at various simulated attachment levels were measured. The data corresponding to attachment level were fitted to a linear function.
  
  
  RESULTS
  The mean total RSA for different root forms decreased in the following order: 3-rooted>2-rooted>C-shaped>single-rooted. However, the differences were statistically significant (p<0.01) only for 2-rooted vs. single-rooted maxillary first premolars, and 2-rooted vs. C-shaped mandibular second molars. Linear functions can perfectly fit in relating the attachment level to the net and percent remaining RSA.
  
  
  CONCLUSIONS
  Micro-CT combined with Mimics software offers simple and precise technique for quantitative analysis of the RSA. Root variations may affect the total amount and vertical distribution of the net RSA. However, the degree of influence varies with the tooth type.
authors.affiliation: Department of Dentistry, First People's Hospital of Wujiang District, Nantong University, Suzhou, China; Central Lab, First People's Hospital of Wujiang District, Nantong University, Suzhou, China. Electronic address: guyc7152@163.com.
authors.forename: Y
authors.initials: Y
authors.lastname: Gu
authors.affiliation: Central Lab, First People's Hospital of Wujiang District, Nantong University, Suzhou, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Tang
authors.affiliation: Department of Dentistry, First People's Hospital of Wujiang District, Nantong University, Suzhou, China.
authors.forename: Q
authors.initials: Q
authors.lastname: Zhu
authors.affiliation: Department of Orthodontics, Affiliated Hospital of Nantong University, Nantong, China.
authors.forename: X
authors.initials: X
authors.lastname: Feng
mesh_terms: D001641:Bicuspid / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D002681:China; D019229:Dentition, Permanent; D006801:Humans; D066298:In Vitro Techniques; D008963:Molar / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D011857:Radiographic Image Interpretation, Computer-Assisted; D012984:Software; D014092:Tooth Root / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D055114:X-Ray Microtomography / Q000379:methods*
keywords: Micro-computed tomography; Periodontal attachment loss; Root surface area; Root variations