title: [Differences in maxillary growth vector of skeletal class I with various vertical growth types before and after growth spurts].
abstract: OBJECTIVE
  To identify the differences in maxillary growth vector with different vertical skeletal patterns of skeletal class I before and after growth spurts.
  
  
  METHODS
  One hundred and ninety four cases with different vertical skeletal patterns of skeletal class I were selected and categorized into six groups according to their vertical skeletal patterns and cervical vertebral stages: cervical vertebral maturation stage (CVMS)1,2-horizontal pattern (n=30); CVMS1,2-average pattern (n=32); CVMS1, 2-vertical pattern (n=33); CVMS5, 6-horizontal pattern (n=34); CVMS5, 6-average pattern (n=29); and CVMS5, 6-vertical pattern (n=36). Lateral cephalograms were taken on all of the cases. The angle SN-C axis (theta) and angel PP-C axis (alpha) were measured.
  
  
  RESULTS
  (1) The skeletal class I with a vertical growth pattern had larger angle SN-C axis than those with a horizontal or average growth pattern before growth spurts (P(average-vertical) < 0.05, P(horizontal-vertical) < 0.001). (2) The skeletal class I with a vertical growth pattern had the largest angle SN-C axis after growth spurts, followed by those with an average growth pattern. Those with a horizontal growth pattern had the smallest angle SN-C axis. The differences were statistically significant (P(horizontal-average) < 0.05, P(horizontal-vertical) < 0.001, P(average-vertical) < 0.001). (3) The skeletal class I with the same vertical growth pattern had slightly larger angle SN-C axis after growth spurts than before growth spurts, but without statistical significance. (4) The skeletal class I had relatively stable angle PP-C axis and no significant differences were found before and after growth spurts or among those with various vertical skeletal facial types.
  
  
  CONCLUSIONS
  The magnitude of angle SN-C axis is closely associated with vertical growth patterns and is weakly influenced by maxillofacial growth and development.
authors.affiliation: Department of Orthodontics, West China Stomatological Hospital, Sichuan University, Chengdu 610041, China.
authors.forename: Xiao-xia
authors.initials: XX
authors.lastname: Feng
authors.forename: Lin-kun
authors.initials: LK
authors.lastname: Zhang
authors.forename: Wei-peng
authors.initials: WP
authors.lastname: Li
authors.forename: Meng-ting
authors.initials: MT
authors.lastname: Xu
authors.forename: Yi-fan
authors.initials: YF
authors.lastname: Zhang
authors.forename: Rui
authors.initials: R
authors.lastname: Ye
authors.forename: Juan
authors.initials: J
authors.lastname: Li
authors.forename: Jian-hua
authors.initials: JH
authors.lastname: Li
authors.forename: Mei-ying
authors.initials: MY
authors.lastname: Zhao
authors.forename: Zhi-he
authors.initials: ZH
authors.lastname: Zhao
mesh_terms: D002508:Cephalometry; D005260:Female; D006801:Humans; D008297:Male; D008311:Malocclusion, Angle Class I / Q000503:physiopathology*; D008437:Maxilla / Q000254:growth & development*; D008445:Maxillofacial Development; D014716:Vertical Dimension