title: Reproducibility and reliability of three-dimensional soft tissue landmark identification using three-dimensional stereophotogrammetry.
abstract: OBJECTIVE
  To evaluate the intraexaminer repeatability and interexaminer reproducibility of soft tissue landmarks on three-dimensional (3-D) stereophogrammetric images.
  
  
  METHODS
  Thirty-four stereophotogrammetric images were taken and 19 soft tissue points were identified. The images were obtained using the 3-DMD Face (3-DMD TM Ltd, Atlanta, Ga) system. Two examiners marked 34 images manually with a mouse-driven cursor 4 weeks apart. Intraexaminer marking differences were calculated and classified as <0.5 mm, 0.5-1 mm, and >1 mm. Intraclass correlation coefficients were calculated for intraexaminer reliability. A paired-samples t-test was used to evaluate the difference between the examiners. Interexaminer reproducibility was evaluated by kappa analysis. Statistical significance was set at P < .05.
  
  
  RESULTS
  Only one landmark (labiale superior) had an intraexaminer marking difference less than 0.5 mm. Existing landmarks had an intraexaminer difference less than 1 mm, but higher than 0.5 mm. The intraclass correlation coefficients (ICCs) indicated good intraexaminer repeatability for both observers. The ICC range for examiners 1 and 2 was 0.986-1.000 and 0.990-1.000, respectively. Kappa scores showed good interexaminer agreement, especially on the z-axis.
  
  
  CONCLUSIONS
  Except labiale superior, the soft tissue landmarks used in this study were shown to have moderate reproducibility, but the difference between the landmarks was less than 1 mm, and they had clinically acceptable reproducibility.
authors.forename: Asli
authors.initials: A
authors.lastname: Baysal
authors.forename: Ahmet Oguz
authors.initials: AO
authors.lastname: Sahan
authors.forename: Mehmet Ali
authors.initials: MA
authors.lastname: Ozturk
authors.forename: Tancan
authors.initials: T
authors.lastname: Uysal
mesh_terms: D002508:Cephalometry; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D015588:Observer Variation; D010780:Photogrammetry; D015203:Reproducibility of Results
keywords: 3-D stereophotogrammetry; Cephalometry; Computer-assisted three-dimensional imaging; Orthodontics; Reproducibility