title: Angular photogrammetric analysis of the soft tissue profile in 12-year-old southern Chinese.
abstract: BACKGROUND
  To quantify average angular measurements that define the soft tissue profiles of 12-year-old southern Chinese and to determine gender differences.
  
  
  METHODS
  A random population sample of 514 12-year-old children was recruited (about 10% of a Hong Kong Chinese birth cohort). Photographs were taken in natural head posture and 12 soft tissue landmarks were located on the photos to measure 12 angular measurements using ImageJ (V1.45s) for Windows. Approximately 10% of photographs were reanalyzed and method error was calculated. Angular norm values for the 12 parameters were determined and gender differences were assessed using 2 sample T-test with 95% confidence interval.
  
  
  RESULTS
  The response rate was 54.1% (278/514). Norm values for the 12 angular measurements were generated. The greatest variability was found for the nasolabial (Cm-Sn-Ls) and labiomental (Li-Sm-Pg) angles. Gender differences were found in 4 angular parameters: vertical nasal angle (N-Prn/TV) (p < 0.05), cervicomental angle (G-Pg/C-Me) (p < 0.001), facial convexity angle (G-Sn-Pg) (p < 0.01) and total facial convexity angle (G-Prn-Pg)(p < 0.01).
  
  
  CONCLUSIONS
  Norm values for 12 angular measurements among 12-year-old southern Chinese children were provided and some variability noted. Gender differences were apparent in several angular measurements. This study has implications in developing norm values for southern Chinese and for comparison with other ethnic groups.
authors.affiliation: Paediatric Dentistry and Orthodontics, Faculty of Dentistry, The University of Hong Kong, Hong Kong, HKSAR, China. cindileung@gmail.com.
authors.forename: Cindi Sy
authors.initials: CS
authors.lastname: Leung
authors.affiliation: Paediatric Dentistry and Orthodontics, Faculty of Dentistry, The University of Hong Kong, Hong Kong, HKSAR, China. yangyanq@hku.hk.
authors.forename: Yanqi
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Department of Dentistry Maxillofacial Surgery, United Christian Hospital, Hong Kong, HKSAR, China. drwongwingkit@gmail.com.
authors.forename: Ricky Wk
authors.initials: RW
authors.lastname: Wong
authors.affiliation: Paediatric Dentistry and Orthodontics, Faculty of Dentistry, The University of Hong Kong, Hong Kong, HKSAR, China. euohagg@hku.hk.
authors.forename: Urban
authors.initials: U
authors.lastname: Hägg
authors.affiliation: Oral and Maxillofacial surgery, Faculty of Dentistry, The University of Hong Kong, Hong Kong, HKSAR, China. juno2999@gmail.com.
authors.forename: John
authors.initials: J
authors.lastname: Lo
authors.affiliation: Periodontology and Public Health, Faculty of Dentistry, The University of Hong Kong; Prince Philip Dental Hospital, 34 Hospital Road, Hong Kong, SAR, China. mcgrathc@hkucc.hku.hk.
authors.forename: Colman
authors.initials: C
authors.lastname: McGrath
mesh_terms: D002508:Cephalometry / Q000379:methods*; D002648:Child; D004954:Esthetics; D005145:Face / Q000033:anatomy & histology*; D005260:Female; D006723:Hong Kong; D006801:Humans; D008297:Male; D010780:Photogrammetry / Q000379:methods*; D012737:Sex Factors