title: Facial movement in 3 dimensions: average templates of lip movement in adults.
abstract: OBJECTIVE
  To construct 3-dimensional (3D) templates of average lip movement based on a group of normal healthy subjects.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  School of Dentistry, Cardiff University, United Kingdom.
  
  
  METHODS
  One hundred fifteen white subjects were asked to perform 2 reproducible verbal gestures (/puppy/ and /rope/) in a normal relaxed manner. The sequences were captured using a noninvasive, 3D motion scanner (3dMDFace Dynamic System). Mesh-registration software was used to align sequential facial shells to a standardized reference plane. Lip movement during the verbal facial gestures was quantified using the displacement vectors (x, y, z coordinates) of 6 lip landmarks of sequential 3D facial shells subtracted from the reference or rest shell. Descriptive statistics were used to build references for average lip movement, and independent t tests were used to compare lip movement between men and women.
  
  
  RESULTS
  Mean reference movements were created for lip opening, lip stretch, and lip purse that corresponded to the visemes /pu/ /ppy/ and /rope/, respectively. There were statistically significant differences in the lip movement between genders for the visemes /pu/ and /ppy/, although when quantified these were found not to be of clinical significance. Men favored left-sided movement and women right-sided movement, although only slightly--again, when quantified, this was considered to be within symmetrical limits.
  
  
  CONCLUSIONS
  It was possible to quantify and create normal templates of lip movement for the words /puppy/ and /rope/. Men and women show similar standardized lip movements for these 2 words.
authors.affiliation: Applied Clinical Research and Public Health, School of Dentistry, Cardiff University, Cardiff, UK. popath@cardiff.ac.uk
authors.forename: Hashmat
authors.initials: H
authors.lastname: Popat
authors.forename: Stephen
authors.initials: S
authors.lastname: Richmond
authors.forename: David
authors.initials: D
authors.lastname: Marshall
authors.forename: Paul L
authors.initials: PL
authors.lastname: Rosin
mesh_terms: D000328:Adult; D005149:Facial Expression; D005152:Facial Muscles / Q000502:physiology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008046:Lip / Q000502:physiology*; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D010699:Phonation / Q000502:physiology*; D012016:Reference Values; D015203:Reproducibility of Results; D012984:Software; D014741:Video Recording / Q000379:methods*; D055815:Young Adult