title: Evaluating the marginal fit of zirconia copings with digital impressions with an intraoral digital scanner.
abstract: BACKGROUND
  Digital impression systems have been developed to overcome the disadvantages associated with conventional impression methods.
  
  
  OBJECTIVE
  The purpose of this study was to compare the marginal fit of zirconia copings designed with the use of an iTero digital scanner with those designed by the conventional impression technique.
  
  
  METHODS
  Thirty identical cast, base-metal dies from 1 maxillary central incisor prepared for a ceramic crown restoration were fabricated. For the conventional impression group (CI), base metal dies (n=10) were replicated as stone dies by means of a conventional impression technique with polyvinyl siloxane material. For the iTero with polyurethane group (iP), base metal dies (n=10) were replicated as polyurethane dies with the iTero digital impression system. For the iTero with no dies group (iNo), base metal dies (n=10) were scanned with the iTero digital impression system, but no dies were fabricated. For each group, 10 zirconia copings were fabricated based on the stone dies (CI group), polyurethane dies (iP group), or stereolithography files (iNo group). The marginal gap of each specimen was measured with a light microscope at ×50 magnification. One-way analysis of variance and the Tukey honestly significant difference test were used for statistical analysis (α=.05).
  
  
  RESULTS
  Statistically significant differences were found between the CI group and iP group (P<.05) and between the CI group and iNo group (P<.05).
  
  
  CONCLUSIONS
  The marginal gap between the restoration and definitive cast base metal die was greater in the groups that used the digital impression method than in the group that used the conventional impression method. However, the marginal discrepancies of all of the groups were clinically acceptable.
authors.affiliation: Clinical Assistant Professor, Advanced Education in General Dentistry, Yonsei University College of Dentistry, Seoul, Korea.
authors.forename: Shinyoung
authors.initials: S
authors.lastname: An
authors.affiliation: Assistant Professor, Department of Periodontology, Dental Research Institute, Seoul National University School of Dentistry, Seoul, Korea.
authors.forename: Sungtae
authors.initials: S
authors.lastname: Kim
authors.affiliation: Graduate student, Department of Prosthodontics, Yonsei University College of Dentistry, Seoul, Korea.
authors.forename: Hyunmin
authors.initials: H
authors.lastname: Choi
authors.affiliation: Associate Professor, Department of Prosthodontics, Yonsei University College of Dentistry, Seoul, Korea.
authors.forename: Jae-Hoon
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Professor, Department of Prosthodontics, Yonsei University College of Dentistry, Seoul, Korea. Electronic address: hsm5@yuhs.ac.
authors.forename: Hong-Seok
authors.initials: HS
authors.lastname: Moon
mesh_terms: D002133:Calcium Sulfate / Q000737:chemistry; D002858:Chromium Alloys / Q000737:chemistry; D017076:Computer-Aided Design; D003442:Crowns; D003761:Dental Impression Technique / Q000295:instrumentation; D018772:Dental Marginal Adaptation; D003764:Dental Materials / Q000737:chemistry*; D017267:Dental Prosthesis Design; D006801:Humans; D008422:Materials Testing; D003765:Models, Dental; D011140:Polyurethanes / Q000737:chemistry; D017973:Tungsten Compounds / Q000737:chemistry; D015040:Zirconium / Q000737:chemistry*
chemical_list: D002858:Chromium Alloys; D003764:Dental Materials; D011140:Polyurethanes; D017973:Tungsten Compounds; C002802:tungsten carbide; D015040:Zirconium; C028541:zirconium oxide; D002133:Calcium Sulfate