title: Three-dimensional cone beam computed tomographic image reorientation using soft tissues as reference for facial asymmetry diagnosis.
abstract: OBJECTIVE
  To investigate discrepancies in results of facial asymmetry analysis using different cone beam computed tomography (CBCT) image reorientation methods and the effectiveness of soft tissue as a reorientation reference for analysis of facial asymmetry.
  
  
  METHODS
  An asymmetric group of 30 patients with 4 mm or more of chin point (menton [Me]) deviation and a symmetric group of 30 patients with less than 4 mm of deviation of Me were chosen as study subjects. Three orientation methods were used to calculate and compare Me deviation values of the 60 subjects. Two methods used only skeletal landmarks for reference, and one method included the soft tissue landmarks around the eye. Preferences of an expert group for the facial midline as determined by each reorientation method were also examined.
  
  
  RESULTS
  The examinations showed significant discrepancies in Me deviation values between the three reorientation methods. The expert group showed the greatest preference for the facial midline reorientation method that incorporated soft tissue landmarks of the eye.
  
  
  CONCLUSIONS
  These study findings suggest that the inclusion of soft tissue landmarks, especially those around the eyes, is effective for three-dimensional CBCT image reorientation for facial asymmetry analysis.
authors.affiliation: a  Resident, Department of Orthodontics, Gachon Medical School, Gil Medical Center, Incheon, South Korea.
authors.forename: Jae-Kyu
authors.initials: JK
authors.lastname: Lee
authors.forename: Pil-Kyo
authors.initials: PK
authors.lastname: Jung
authors.forename: Cheol-Hyun
authors.initials: CH
authors.lastname: Moon
mesh_terms: D059925:Anatomic Landmarks / Q000000981:diagnostic imaging; D002680:Chin / Q000000981:diagnostic imaging; D054893:Cone-Beam Computed Tomography / Q000379:methods*; D004424:Ear Canal / Q000000981:diagnostic imaging; D005004:Ethmoid Bone / Q000000981:diagnostic imaging; D005123:Eye / Q000000981:diagnostic imaging; D005143:Eyelids / Q000000981:diagnostic imaging; D005145:Face / Q000000981:diagnostic imaging*; D005146:Facial Asymmetry / Q000000981:diagnostic imaging*; D005147:Facial Bones / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D009295:Nasal Bone / Q000000981:diagnostic imaging; D009915:Orbit / Q000000981:diagnostic imaging; D012189:Retrospective Studies; D019291:Skull Base / Q000000981:diagnostic imaging; D055815:Young Adult; D015050:Zygoma / Q000000981:diagnostic imaging