title: Measuring abutment convergence angles using stereovision dental image processing system.
abstract: OBJECTIVE
  The purpose of this study was to develop a dental image processing system using a three-dimensional (3D) camera and stereovision technology. The reliability of the system for measuring axial wall convergence angles was evaluated.
  
  
  METHODS
  The new system predicted 3D coordinate points from 2D images and calculated distances and angles between points. Two examiners measured axial wall convergence angles for seven artificial abutments using a traditional tracing-based method (TBM) and the stereovision-based method (SVBM). Five wax abutment models of simplified abutment forms were made and axial wall convergence angles of wax models were measured by both methods. The data were statistically analyzed at the level of significance, 0.05.
  
  
  RESULTS
  Intraclass correlation coefficients showed excellent intra-examiner and inter-examiner reliabilities for both methods. Bland-Altman plots and paired t-tests showed significant differences between measurements and true values using TBM; differences were not significant with SVBM.
  
  
  CONCLUSIONS
  This study found that the SVBM reflected true angle values more accurately than a TMB and illustrated an example of 3D computer science applied to clinical dentistry.
authors.affiliation: Seoul National University School of Dentistry, Seoul, Republic of Korea.
authors.forename: Hong-Seok
authors.initials: HS
authors.lastname: Yang
authors.affiliation: Department of Dental Prosthodontics, Ewha Womans University, Seoul, Republic of Korea.
authors.forename: Ji-Man
authors.initials: JM
authors.lastname: Park
authors.affiliation: Department of Prosthodontics and Dental Research Institute, Seoul National University School of Dentistry, Seoul, Republic of Korea.
authors.forename: Jung-Suk
authors.initials: JS
authors.lastname: Han
authors.affiliation: Department of Prosthodontics and Dental Research Institute, Seoul National University School of Dentistry, Seoul, Republic of Korea.
authors.forename: Jai-Bong
authors.initials: JB
authors.lastname: Lee
authors.affiliation: Department of Prosthodontics and Dental Research Institute, Seoul National University School of Dentistry, Seoul, Republic of Korea.
authors.forename: Sung-Hun
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Department of Prosthodontics and Dental Research Institute, Seoul National University School of Dentistry, Seoul, Republic of Korea.
authors.forename: In-Sung
authors.initials: IS
authors.lastname: Yeo
keywords: Axial wall convergence angle; Stereovision dental image system; Three-dimensional; Tracing; abutment