title: Development of a digital impression procedure using photogrammetry for complete denture fabrication.
abstract: OBJECTIVE
  We developed an innovative procedure for digitizing maxillary edentulous residual ridges with a photogrammetric system capable of estimating three-dimensional (3D) digital forms from multiple two-dimensional (2D) digital images. The aim of this study was to validate the effectiveness of the photogrammetric system.
  
  
  METHODS
  Impressions of the maxillary residual ridges of five edentulous patients were taken with four kinds of procedures: three conventional impression procedures and the photogrammetric system. Plaster models were fabricated from conventional impressions and digitized with a 3D scanner. Two 3D forms out of four forms were superimposed with 3D inspection software, and differences were evaluated using a least squares best fit algorithm.
  
  
  RESULTS
  The in vitro experiment suggested that better imaging conditions were in the horizontal range of ± 15 degrees and at a vertical angle of 45 degrees. The mean difference between the photogrammetric image (Form A) and the image taken from conventional preliminarily impression (Form C) was 0.52 ± 0.22 mm. The mean difference between the image taken of final impression through a special tray (Form B) and Form C was 0.26 ± 0.06 mm. The mean difference between the image taken from conventional final impression (Form D) and Form C was 0.25 ± 0.07 mm. The difference between Forms A and C was significantly larger than the differences between Forms B and C and between Forms D and C.
  
  
  CONCLUSIONS
  The results of this study suggest that obtaining digital impressions of edentulous residual ridges using a photogrammetric system is feasible and available for clinical use.
authors.forename: Takashi
authors.initials: T
authors.lastname: Matsuda
authors.forename: Takaharu
authors.initials: T
authors.lastname: Goto
authors.forename: Kosuke
authors.initials: K
authors.lastname: Kurahashi
authors.forename: Toshiya
authors.initials: T
authors.lastname: Kashiwabara
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Ichikawa
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D059925:Anatomic Landmarks / Q000473:pathology; D017076:Computer-Aided Design; D003761:Dental Impression Technique; D003779:Denture Design; D003824:Denture, Complete; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007575:Jaw, Edentulous / Q000473:pathology; D008297:Male; D008437:Maxilla / Q000473:pathology; D003765:Models, Dental; D010780:Photogrammetry / Q000379:methods*