title: Augmentation of linear facial anthropometrics through modern morphometrics: a facial convexity example.
abstract: BACKGROUND
  The facial region has traditionally been quantified using linear anthropometrics. These are well established in dentistry, but require expertise to be used effectively. The aim of this study was to augment the utility of linear anthropometrics by applying them in conjunction with modern 3-D morphometrics.
  
  
  METHODS
  Facial images of 75 males and 94 females aged 18-25 years with self-reported Caucasian ancestry were used. An anthropometric mask was applied to establish corresponding quasi-landmarks on the images in the dataset. A statistical face-space, encoding shape covariation, was established. The facial median plane was extracted facilitating both manual and automated indication of commonly used midline landmarks. From both indications, facial convexity angles were calculated and compared. The angles were related to the face-space using a regression based pathway enabling the visualization of facial form associated with convexity variation.
  
  
  RESULTS
  Good agreement between the manual and automated angles was found (Pearson correlation: 0.9478-0.9474, Dahlberg root mean squared error: 1.15°-1.24°). The population mean angle was 166.59°-166.29° (SD 5.09°-5.2°) for males-females. The angle-pathway provided valuable feedback.
  
  
  CONCLUSIONS
  Linear facial anthropometrics can be extended when used in combination with a face-space derived from 3-D scans and the exploration of property pathways inferred in a statistically verifiable way.
authors.affiliation: Melbourne Dental School, The University of Melbourne, Victoria, Australia.
authors.forename: R
authors.initials: R
authors.lastname: Wei
authors.forename: P
authors.initials: P
authors.lastname: Claes
authors.forename: M
authors.initials: M
authors.lastname: Walters
authors.forename: C
authors.initials: C
authors.lastname: Wholley
authors.forename: J G
authors.initials: JG
authors.lastname: Clement
mesh_terms: D000293:Adolescent; D000328:Adult; D002508:Cephalometry / Q000379:methods* / Q000706:statistics & numerical data; D002680:Chin / Q000033:anatomy & histology; D015331:Cohort Studies; D003198:Computer Simulation; D005145:Face / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods / Q000706:statistics & numerical data; D008297:Male; D009295:Nasal Bone / Q000033:anatomy & histology; D009666:Nose / Q000033:anatomy & histology; D012737:Sex Factors; D014584:User-Computer Interface; D014716:Vertical Dimension; D044465:White People; D055815:Young Adult