title: Clinical evaluation comparing the fit of all-ceramic crowns obtained from silicone and digital intraoral impressions based on wavefront sampling technology.
abstract: OBJECTIVE
  The aim of this study was to compare the fit of ceramic crowns fabricated from conventional silicone impressions with the fit of ceramic crowns fabricated from intraoral digital impressions.
  
  
  METHODS
  Twenty-five participants with 30 posterior teeth with a prosthetic demand were selected for the study. Two crowns were made for each preparation. One crown was fabricated from an intraoral digital impression system (IDI group) and the other crown was fabricated from a conventional two-step silicone impression (CI group). To replicate the interface between the crown and the preparation, each crown was cemented on its corresponding clinical preparation with ultra-flow silicone. Each crown was embedded in acrylic resin to stabilise the registered interface and then cut in 2mm thick slices in a buco-lingual orientation. The internal gap was determined as the vertical distance from the internal surface of the crown to the prepared tooth surface at four points (marginal gap, axial gap, crest gap, and occlusal fossa gap) using stereomicroscopy with a magnification of 40×. Data was analysed by using Wilcoxon signed rank test (α=0.05).
  
  
  RESULTS
  Internal adaptation values were significantly affected by the impression technique (p=0.001). Mean marginal gap was 76.33 ± 65.32 μm for the crowns of the IDI group and 91.46 ± 72.17 μm for the CI group.
  
  
  CONCLUSIONS
  All-ceramic crowns fabricated from intraoral digital impressions with wavefront sampling technology demonstrated better internal fit than crowns manufactured from silicone impressions.
  
  
  CONCLUSIONS
  Impressions obtained from an intraoral digital scanner based on wavefront sampling technology can be used for manufacturing ceramic crowns in the normal clinical practice with better results than conventional impressions with elastomers.
authors.affiliation: Department of Buccofacial Prostheses, Faculty of Dentistry, Complutense University of Madrid, Pza. Ramón y Cajal, s/n Ciudad Universitaria 28040, Madrid, Spain. Electronic address: gpradies@odon.ucm.es.
authors.forename: Guillermo
authors.initials: G
authors.lastname: Pradíes
authors.affiliation: Department of Buccofacial Prostheses, Faculty of Dentistry, Complutense University of Madrid, Pza. Ramón y Cajal, s/n Ciudad Universitaria 28040, Madrid, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Zarauz
authors.affiliation: Department of Buccofacial Prostheses, Faculty of Dentistry, Complutense University of Madrid, Pza. Ramón y Cajal, s/n Ciudad Universitaria 28040, Madrid, Spain.
authors.forename: Arelhys
authors.initials: A
authors.lastname: Valverde
authors.affiliation: Department of Buccofacial Prostheses, Faculty of Dentistry, Complutense University of Madrid, Pza. Ramón y Cajal, s/n Ciudad Universitaria 28040, Madrid, Spain.
authors.forename: Alberto
authors.initials: A
authors.lastname: Ferreiroa
authors.affiliation: Department of Buccofacial Prostheses, Faculty of Dentistry, Complutense University of Madrid, Pza. Ramón y Cajal, s/n Ciudad Universitaria 28040, Madrid, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: Martínez-Rus
mesh_terms: D003442:Crowns; D003761:Dental Impression Technique; D003776:Dental Porcelain / Q000494:pharmacology*; D017267:Dental Prosthesis Design / Q000379:methods*; D006801:Humans; D012828:Silicones / Q000494:pharmacology*; D014070:Tooth / Q000187:drug effects
chemical_list: D012828:Silicones; D003776:Dental Porcelain
keywords: All-ceramic systems; CAD/CAM; Internal gap; Intraoral scanner; Marginal gap; Zirconia