title: In vivo precision of conventional and digital methods of obtaining complete-arch dental impressions.
abstract: BACKGROUND
  Digital impression systems have undergone significant development in recent years, but few studies have investigated the accuracy of the technique in vivo, particularly compared with conventional impression techniques.
  
  
  OBJECTIVE
  The purpose of this in vivo study was to investigate the precision of conventional and digital methods for complete-arch impressions.
  
  
  METHODS
  Complete-arch impressions were obtained using 5 conventional (polyether, POE; vinylsiloxanether, VSE; direct scannable vinylsiloxanether, VSES; digitized scannable vinylsiloxanether, VSES-D; and irreversible hydrocolloid, ALG) and 7 digital (CEREC Bluecam, CER; CEREC Omnicam, OC; Cadent iTero, ITE; Lava COS, LAV; Lava True Definition Scanner, T-Def; 3Shape Trios, TRI; and 3Shape Trios Color, TRC) techniques. Impressions were made 3 times each in 5 participants (N=15). The impressions were then compared within and between the test groups. The cast surfaces were measured point-to-point using the signed nearest neighbor method. Precision was calculated from the (90%-10%)/2 percentile value.
  
  
  RESULTS
  The precision ranged from 12.3 μm (VSE) to 167.2 μm (ALG), with the highest precision in the VSE and VSES groups. The deviation pattern varied distinctly according to the impression method. Conventional impressions showed the highest accuracy across the complete dental arch in all groups, except for the ALG group.
  
  
  CONCLUSIONS
  Conventional and digital impression methods differ significantly in the complete-arch accuracy. Digital impression systems had higher local deviations within the complete arch cast; however, they achieve equal and higher precision than some conventional impression materials.
authors.affiliation: Research Assistant, Division for Computerized Restorative Dentistry, Center of Dental Medicine, University of Zürich, Zürich, Switzerland. Electronic address: andreas.ender@zzm.uzh.ch.
authors.forename: Andreas
authors.initials: A
authors.lastname: Ender
authors.affiliation: Department Head, Clinic for Preventive Dentistry, Periodontology and Cariology, Centre of Dental Medicine, University of Zürich, Zürich, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Attin
authors.affiliation: Department Head, Division for Computerized Restorative Dentistry, Centre of Dental Medicine, University of Zürich, Zürich, Switzerland.
authors.forename: Albert
authors.initials: A
authors.lastname: Mehl
mesh_terms: D017076:Computer-Aided Design; D003724:Dental Arch / Q000033:anatomy & histology*; D003760:Dental Impression Materials; D003761:Dental Impression Technique; D006801:Humans; D021621:Imaging, Three-Dimensional; D003765:Models, Dental
chemical_list: D003760:Dental Impression Materials