title: Facial asymmetry index in normal young adults.
abstract: OBJECTIVE
  To differentiate a symmetric face from an asymmetric face by analyzing a three-dimensional (3D) facial image and plotting the asymmetry index (AI) on a facial symmetry diagram.
  
  
  METHODS
  Sixty healthy Chinese adults (30 men and 30 women, mean age: 27.7 + 4.9 years old) without any craniofacial deformity were recruited on a voluntary basis from a medical center.
  
  
  METHODS
  A 3D facial image of each participant was captured by a GENEX 3D FACE CAM system. Sixteen facial landmarks, as defined by Farkas, were selected on each 3D facial image. The AI was calculated for each landmark.
  
  
  RESULTS
  The norm for the AI varied from 0.76 to 2.82. The landmarks located on the upper face had a smaller AI than the landmarks located on the lower face. A facial symmetry diagram was designed according to the mean, one standard deviation, and 2 standard deviations of AI for each landmark.
  
  
  CONCLUSIONS
  The 3D facial asymmetry can be documented with AI. The landmarks located on the upper face had a smaller AI than the landmarks located on the lower face. The facial symmetry diagram can identify efficiently the location of asymmetry on a face.
authors: Faculty of Dentistry, Craniofacial Research Center, Chang Gung Memorial Hospital, Taipei, Taiwan. sshuang@ms1.hinet.net
authors: C S
authors: CS
authors: Huang
authors: X Q
authors: XQ
authors: Liu
authors: Y R
authors: YR
authors: Chen
mesh_terms: D000328:Adult; D059925:Anatomic Landmarks; D002508:Cephalometry; D005146:Facial Asymmetry / Q000175:diagnosis*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008297:Male; D012016:Reference Values; D055815:Young Adult