title: An In Vitro Study of Factors Influencing the Performance of Digital Intraoral Impressions Operating on Active Wavefront Sampling Technology with Multiple Implants in the Edentulous Maxilla.
abstract: OBJECTIVE
  To evaluate the performance (accuracy and repeatability) and the factors affecting the clinical performance of a recently released intraoral scanner based on active wavefront sampling technology.
  
  
  METHODS
  A single resin model of an edentulous maxilla fitted with six implants inserted at various depths and angulations was measured with a coordinated measuring machine (CMM) at 3 to 5 μm, and this acted as the "true," or reference, values of the study. Six corresponding cylindrical PEEK scanbodies were then mounted onto the implants, and four calibrated observers independently repeated the digital intraoral scan five times with a True Definition (TrueDef) scanner. Using implant position #15 as a reference, five linear and angular measurements were compared with the reference values (CMM), and the data were analyzed via one-way ANOVA and two-sample t-test.
  
  
  RESULTS
  Mean linear and angular deviations for the TrueDef from CMM measurements were from 5.38 ± 12.61 μm to -26.97 ± 50.56 μm and from 0.16º ± 0.04º to -0.43º ± 0.1º, respectively. Experienced observers performed significantly better than inexperienced ones (p = 0.006), and scan distance (quadrant) significantly affected scanning accuracy (p = 0.003). Visible length of the scanbody affected measurement accuracy (p = 0.0001), while implant angulation did not (p = 0.757).
  
  
  CONCLUSIONS
  The TrueDef scanner provides measurements within clinically accepted limits. Yet scanbody visibility, observer experience, and scan length remain relevant factors affecting accuracy.
authors.affiliation: Department of Oral Implantology and Prosthetic Dentistry at the Academic Centre for Dentistry Amsterdam (ACTA), Amsterdam, The Netherlands.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Gimenez-Gonzalez
authors.affiliation: Department of Oral Implantology and Prosthetic Dentistry at the Academic Centre for Dentistry Amsterdam (ACTA), Amsterdam, The Netherlands.
authors.forename: Bassam
authors.initials: B
authors.lastname: Hassan
authors.affiliation: University of Zurich, Dental Materials Unit, Center for Dental and Oral Medicine, Clinic for Fixed and Removable Prosthodontics and Dental Materials Science, Zurich, Switzerland.
authors.forename: Mutlu
authors.initials: M
authors.lastname: Özcan
authors.affiliation: Department of Buccofacial Prostheses (Stomatology I), Faculty of Odontology, Complutense University of Madrid, Madrid, Spain.
authors.forename: Guillermo
authors.initials: G
authors.lastname: Pradíes
mesh_terms: D017076:Computer-Aided Design; D015921:Dental Implants; D003761:Dental Impression Technique; D006801:Humans; D007091:Image Processing, Computer-Assisted; D066298:In Vitro Techniques; D007575:Jaw, Edentulous; D008437:Maxilla; D009055:Mouth
chemical_list: D015921:Dental Implants
keywords: CAD/CAM; Intraoral scanner; accuracy; dental implants; digital impression