title: [Longitudinal changes of crown inclination in juveniles with normal occlusion].
abstract: OBJECTIVE
  To investigate the longitudinal changes in crown inclination of permanent incisors and first molars in juveniles with normal occlusion.
  
  
  METHODS
  The untreated sample comprised 20 subjects (6 males and 14 females) with normal occlusion from the Research Centre for Craniofacial Growth and Development of Peking University School and Hospital of Stomatology. Crown inclination was evaluated with Biaggini Rayset in two stages, stage I with first molars and four incisors in occlusion (mean, 9.5 +/- 0.9 years) and stage II with the second molars in occlusion (mean, 13.7 +/- 1.3 years).
  
  
  RESULTS
  No significant difference was found between sexual groups. The crown inclination of the upper central incisors decreased (P < 0.001). The crown inclination of the lower central and lateral incisors increased (P < 0.01 and P < 0.05, respectively). The crown inclination of maxillary molars decreased with growth (P < 0.001), whereas that of mandibular molars increased with growth (P < 0.001).
  
  
  CONCLUSIONS
  Maxillary molars tended to become upright lingually, whereas mandibular molars upright buccally with growth.
authors.affiliation: Department of Orthodontics, Peking University School and Hospital of Stomatology, Beijing 100081, China.
authors.forename: Hai-ping
authors.initials: HP
authors.lastname: Zhang
authors.forename: Tian-min
authors.initials: TM
authors.lastname: Xu
authors.forename: Xing-zhong
authors.initials: XZ
authors.lastname: Zhang
authors.forename: Jiu-xiang
authors.initials: JX
authors.lastname: Lin
mesh_terms: D002648:Child; D003766:Dental Occlusion; D005260:Female; D006801:Humans; D007180:Incisor / Q000502:physiology*; D008137:Longitudinal Studies; D008297:Male; D008963:Molar / Q000502:physiology*