title: [Changes of profile prominence in borderline cases with extraction and non-extraction orthodontic treatment].
abstract: OBJECTIVE
  To compare the treatment effect on the prominence of profile in borderline cases between extraction and non-extraction treatment.
  
  
  METHODS
  The sample consisting of 33 borderline cases based on the judgment of 5 orthodontic specialists was divided into three groups according to the treatment way selected by the doctor in charge of the case. Three groups comprised 12 non-extraction cases, 13 four first premolars extraction cases and 8 four second premolars extraction cases. Structure superimposition was used to measure landmarks displacements which reflect the change of profile prominence before and after orthodontic treatment using pretreatment FH plane as a frame of reference.
  
  
  RESULTS
  Only the prominence of upper and lower incisors showed statistically significance between the extraction and non-extraction treatments. There was no statistically significant difference between the extraction of four first premolars and second premolars.
  
  
  CONCLUSIONS
  The main effect of extraction vs. non-extraction on profile of borderline cases is the prominence of upper and lower incisors, while their influences on upper and lower base bone and soft-tissue profile are not obvious.
authors.affiliation: Dept. of Orthodontics, Hospital of Stomatology, Peking University, Beijing 100081, China.
authors.forename: Tian-min
authors.initials: TM
authors.lastname: Xu
authors.forename: Yan
authors.initials: Y
authors.lastname: Liu
authors.forename: Hai-ping
authors.initials: HP
authors.lastname: Zhang
authors.forename: Jiu-xiang
authors.initials: JX
authors.lastname: Lin
mesh_terms: D002508:Cephalometry; D006801:Humans; D009971:Orthodontics, Corrective; D014081:Tooth Extraction