title: Radiographic evaluation of orthodontic treatment by means of four different cephalometric superimposition methods.
abstract: BACKGROUND
  Despite discussion on the merit of various cephalometric superimposition methods, there remains a need to assess which one can be used in daily practice with reasonably accuracy and less working time.
  
  
  OBJECTIVE
  The aim of this study was to investigate four methods of cephalometric superimposition by means of assessing the longitudinal changes in craniofacial morphology caused by growth and response of adolescents with Class I malocclusion to orthodontic treatment involving first premolar extraction.
  
  
  METHODS
  Pretreatment (T1) and post-treatment (T2) standardized lateral cephalometric radiographs of 31 adolescents (20 females and 11 males), with Angle Class I malocclusion and indication of premolar extraction, participated in this study. Radiographs were digitized, traced and had structures identified by means of a cephalometric software. Four superimposition methods were used: Björk structural method, Steiner/Tweed SN line, Ricketts N-Ba line at N-point and Ricketts N-Ba line at CC-point. Positional changes were quantified by horizontal and vertical linear changes in the following cephalometric landmarks: anterior/posterior nasal spine (ANS and PNS), gnathion (Gn), Gonion (Go), Pogonion (Pog), A-point and B-point. Differences between T1 and T2 in horizontal and vertical positional changes for all superimposition methods were assessed by one-way analysis of variance (ANOVA) and Bonferroni correction (p < 0.05).
  
  
  RESULTS
  There were no statistically significant differences among the cephalometric superimposition methods or when patients' sex was considered.
  
  
  CONCLUSIONS
  Björk structural method, Steiner/Tweed SN line, Ricketts N-Ba line at N-point and Ricketts N-Ba line at CC-point methods were reliable and presented similar precision when the overall facial changes due to active growth and/or orthodontic treatment were examined.
authors.affiliation: School of Dentistry, Universidade Federal de Goiás, Goiânia, Goiás, Brazil.
authors.forename: Marcos Augusto
authors.initials: MA
authors.lastname: Lenza
authors.affiliation: Faculdades Unidas do Norte de Minas, Goiânia, Goiás, Brazil.
authors.forename: Adilson Alves de
authors.initials: AA
authors.lastname: Carvalho
authors.affiliation: Faculdades Unidas do Norte de Minas, Goiânia, Goiás, Brazil.
authors.forename: Eduardo Beaton
authors.initials: EB
authors.lastname: Lenza
authors.affiliation: Faculdades Unidas do Norte de Minas, Goiânia, Goiás, Brazil.
authors.forename: Mauricio Guilherme
authors.initials: MG
authors.lastname: Lenza
authors.affiliation: Universidade Federal de Goiás, Goiânia, Goiás, Brazil.
authors.forename: Hianne Miranda de
authors.initials: HM
authors.lastname: Torres
authors.affiliation: School of Dentistry, Universidade Federal de Goiás, Goiânia, Goiás, Brazil.
authors.forename: João Batista de
authors.initials: JB
authors.lastname: Souza
mesh_terms: D000293:Adolescent; D059925:Anatomic Landmarks / Q000000981:diagnostic imaging / Q000254:growth & development; D001641:Bicuspid / Q000601:surgery; D002508:Cephalometry / Q000379:methods*; D002680:Chin / Q000000981:diagnostic imaging / Q000254:growth & development; D005147:Facial Bones / Q000000981:diagnostic imaging / Q000254:growth & development; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008137:Longitudinal Studies; D008297:Male; D008311:Malocclusion, Angle Class I / Q000000981:diagnostic imaging* / Q000628:therapy; D008334:Mandible / Q000000981:diagnostic imaging / Q000254:growth & development; D008437:Maxilla / Q000000981:diagnostic imaging / Q000254:growth & development; D009295:Nasal Bone / Q000000981:diagnostic imaging / Q000254:growth & development; D009971:Orthodontics, Corrective / Q000379:methods*; D019252:Radiography, Dental, Digital / Q000379:methods*; D012189:Retrospective Studies; D012886:Skull / Q000000981:diagnostic imaging / Q000254:growth & development; D014081:Tooth Extraction / Q000379:methods