title: The location of midfacial landmarks according to the method of establishing the midsagittal reference plane in three-dimensional computed tomography analysis of facial asymmetry.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the influence of methods of establishing the midsagittal reference plane (MRP) on the locations of midfacial landmarks in the three-dimensional computed tomography (CT) analysis of facial asymmetry.
  
  
  METHODS
  A total of 24 patients (12 male and 12 female; mean age, 22.5 years; age range, 18.2-29.7 years) with facial asymmetry were included in this study. The MRP was established using two different methods on each patient's CT image. The x-coordinates of four midfacial landmarks (the menton, nasion, upper incisor, and lower incisor) were obtained by measuring the distance and direction of the landmarks from the MRP, and the two methods were compared statistically. The direction of deviation and the severity of asymmetry found using each method were also compared.
  
  
  RESULTS
  The x-coordinates of the four anatomic landmarks all showed a statistically significant difference between the two methods of establishing the MRP. For the nasion and lower incisor, six patients (25.0%) showed a change in the direction of deviation. The severity of asymmetry also changed in 16 patients (66.7%).
  
  
  CONCLUSIONS
  The results of this study suggest that the locations of midfacial landmarks change significantly according to the method used to establish the MRP.
authors.affiliation: School of Dentistry, Dental Science Research Institute, Chonnam National University, Gwangju, Korea.
authors.forename: Min Sun
authors.initials: MS
authors.lastname: Kim
authors.affiliation: Department of Oral Anatomy, School of Dentistry, Dental Science Research Institute, Chonnam National University, Gwangju, Korea.
authors.forename: Eun Joo
authors.initials: EJ
authors.lastname: Lee
authors.affiliation: Department of Nursing, Kwangju Women's University, Gwangju, Korea.
authors.forename: In Ja
authors.initials: IJ
authors.lastname: Song
authors.affiliation: Department of Oral and Maxillofacial Radiology, School of Dentistry, Dental Science Research Institute, Chonnam National University, Gwangju, Korea.
authors.forename: Jae-Seo
authors.initials: JS
authors.lastname: Lee
authors.affiliation: Department of Oral and Maxillofacial Radiology, School of Dentistry, Dental Science Research Institute, Chonnam National University, Gwangju, Korea.
authors.forename: Byung-Cheol
authors.initials: BC
authors.lastname: Kang
authors.affiliation: Department of Oral and Maxillofacial Radiology, School of Dentistry, Dental Science Research Institute, Chonnam National University, Gwangju, Korea.
authors.forename: Suk-Ja
authors.initials: SJ
authors.lastname: Yoon
keywords: Anatomic Landmarks; Facial Asymmetry; Tomography, X-Ray Computed