title: Does powdering of the dentition increase the accuracy of fusing 3D stereophotographs and digital dental casts.
abstract: The shiny vestibular surfaces of teeth make it difficult to match digital dental casts to 3D stereophotogrammetric images of patient teeth. This study tested whether reducing this shininess by coating the teeth with titanium-oxide powder might improve the accuracy of the matching procedure.
  
  
  
  Twenty patients participated in the study. For each patient, 3D stereophotogrammetric images were taken without and with a powder coating. Separately, digital dental casts were created. Next, the digital dental casts were fused with the 3D stereophotogrammetric images of either non-powdered or powdered dentition. Distance maps were created to evaluate the inter-surface distance between the digital dental cast and the 3D images. The matching accuracy was compared for dentition with and without powdering.
  
  
  
  Of all recorded distances between corresponding points, 95% was smaller than 0.84mm for the powdered dentition and smaller than 0.90mm for the non-powdered dentition. Although powdered dentition showed significantly better matching than non-powdered dentition, the difference was less than 0.1mm. Intra-observer statistics showed that five out of 24 repetitions gave significantly different results, but only for dentition that was not powdered.
  
  
  
  The patients did not have any major malocclusions. Severe malocclusions might cause greater difficulty in matching the dentition without powder. Only one type of powder was used, but it effectively reduced shininess.
  
  
  
  Powdering the dentition had a small, but significant, positive effect on matching. However, this effect was of minor clinical importance. Therefore, we do not recommend powdering the dentition for 3D stereophotogrammetric images used for matching procedures.
authors.affiliation: Department of Orthodontics and Craniofacial Biology, Radboud University Medical Centre, Nijmegen, The Netherlands.
authors.forename: Frits A
authors.initials: FA
authors.lastname: Rangel
authors.affiliation: Division of Craniofacial Orthodontics, Department of Dentistry, Chang Gung Memorial Hospital, Taipei, Taiwan.
authors.forename: Yu-Ting
authors.initials: YT
authors.lastname: Chiu
authors.affiliation: Department of Oral and Craniomaxillofacial Surgery, Radboud University Medical Centre, Nijmegen, The Netherlands, and.
authors.forename: Thomas J J
authors.initials: TJ
authors.lastname: Maal
authors.affiliation: Department of Preventive and Restorative Dentistry, Radboud University Medical Centre, Nijmegen, The Netherlands.
authors.forename: Ewald M
authors.initials: EM
authors.lastname: Bronkhorst
authors.affiliation: Department of Oral and Craniomaxillofacial Surgery, Radboud University Medical Centre, Nijmegen, The Netherlands, and.
authors.forename: Stefaan J
authors.initials: SJ
authors.lastname: Bergé
authors.affiliation: Department of Orthodontics and Craniofacial Biology, Radboud University Medical Centre, Nijmegen, The Netherlands, orthodontics@dent.umcn.nl.
authors.forename: Anne Marie
authors.initials: AM
authors.lastname: Kuijpers-Jagtman
mesh_terms: D003761:Dental Impression Technique; D003817:Dentition; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008310:Malocclusion / Q000175:diagnosis*; D003765:Models, Dental; D010780:Photogrammetry / Q000379:methods*; D023861:Photography, Dental / Q000379:methods; D011208:Powders; D014025:Titanium; D014070:Tooth / Q000473:pathology
chemical_list: D011208:Powders; C009495:titanium dioxide; D014025:Titanium