title: [Double scanning method for computer aided design and computer aided manufacture all-ceramic restorations].
abstract: OBJECTIVE
  To introduce the double scanning for producing computer aided design and computer aided manufacture (CAD-CAM) zirconia crowns, and to compare Procera with Everest CAD-CAM system by observing clinical effects of the crowns.
  
  
  METHODS
  Forty CAD-CAM zirconia crowns (10 crowns by Procera, and 30 crowns by Everest) were evaluated, and the examination criteria included: marginal fit, aesthetics, gingival health, retention, and fracture. All of the zirconia copings were produced using double scanning. Procera system and Everest system use contact scanner and optical scanner respectively.
  
  
  RESULTS
  The observation time for the crowns ranged from 6 to 24 months. The results of clinic evaluation were acceptable in all restorations.
  
  
  CONCLUSIONS
  Double scanning could be used to produce complicated zirconia copings by CAD-CAM in order to get proper symmetrical porcelain length. It was easier to make complicated coping with contact scanner than with optical scanner.
authors.affiliation: Department of Prosthodontics, Peking University School and Hospital of Stomatology, Beijing 100081, China.
authors.forename: Yi-Hong
authors.initials: YH
authors.lastname: Liu
authors.forename: Hai-Lan
authors.initials: HL
authors.lastname: Feng
authors.forename: Hai-Tao
authors.initials: HT
authors.lastname: Wang
authors.forename: Lin
authors.initials: L
authors.lastname: Wang
authors.forename: Yu-Guang
authors.initials: YG
authors.lastname: Nie
authors.forename: Tao
authors.initials: T
authors.lastname: Wang
mesh_terms: D000328:Adult; D000368:Aged; D017076:Computer-Aided Design; D003442:Crowns; D003776:Dental Porcelain; D017267:Dental Prosthesis Design; D019554:Dental Restoration Wear; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010783:Photometry; D013499:Surface Properties; D015040:Zirconium
chemical_list: D003776:Dental Porcelain; D015040:Zirconium; C028541:zirconium oxide