title: Three-dimensional assessment of teeth first-, second- and third-order position in Caucasian and African subjects with ideal occlusion.
abstract: BACKGROUND
  The aim of this study was to provide an updated version of Andrews' seminal study by exploiting 3D software to analyse the tip, torque and in-out values of two groups of different racial and ethnic background.
  
  
  METHODS
  The analysis was conducted on one Caucasian group (30 individuals) and one of African origin (29). All subjects were adult, in normal occlusion and had no previous history of orthodontic treatment. Rhinoceros™ 3D modelling software was used to identify anatomical reference points, planes and axes and to make the appropriate measurements.
  
  
  RESULTS
  Compared to Andrews' measurements, we found more positive coronal tip values in both African and Caucasian subjects, while the torque values we measured tended to be less negative in the posterior sectors than those reported by Andrews. We measured greater tip values in the lower jaw of Caucasian with respect to African subjects, particularly in the middle sectors.
  
  
  CONCLUSIONS
  Race and ethnicity have a strong influence on values of tip, torque and in-out. This is translated as a more positive tip in Caucasian subjects and a more positive torque in those of African descent (greater proclination of the incisors). Finally, with respect to the values reported by Andrews, we found a tendency to more positive mean tip (except for at the upper second molars and lower incisors) and less negative torque in the posterior sectors.
authors.affiliation: Department of Orthodontics, University of Ferrara, Via montebello, 31, Ferrara, 44100, Italy, lulombardo@tiscali.it.
authors.forename: Luca
authors.initials: L
authors.lastname: Lombardo
authors.forename: Alessandro
authors.initials: A
authors.lastname: Perri
authors.forename: Angela
authors.initials: A
authors.lastname: Arreghini
authors.forename: Michele
authors.initials: M
authors.lastname: Latini
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Siciliani
mesh_terms: D000328:Adult; D059925:Anatomic Landmarks / Q000033:anatomy & histology; D001641:Bicuspid / Q000033:anatomy & histology; D044383:Black People; D017076:Computer-Aided Design; D003481:Cuspid / Q000033:anatomy & histology; D003724:Dental Arch / Q000033:anatomy & histology; D003766:Dental Occlusion; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000706:statistics & numerical data*; D007180:Incisor / Q000033:anatomy & histology; D007574:Jaw Relation Record; D008297:Male; D008334:Mandible / Q000033:anatomy & histology; D008437:Maxilla / Q000033:anatomy & histology; D008963:Molar / Q000033:anatomy & histology; D009811:Odontometry / Q000706:statistics & numerical data*; D012016:Reference Values; D012399:Rotation; D019228:Tooth Crown / Q000033:anatomy & histology*; D019415:Torque; D014584:User-Computer Interface; D044465:White People