title: Three-dimensional fit of CAD/CAM-made zirconia copings.
abstract: OBJECTIVE
  CAD/CAM-technologies aim for a standardized, accurate production of dental restorations out of high strength materials (zirconia). The three-dimensional internal fit of CAD/CAM-manufactured zirconia copings was evaluated in vitro to verify the realizability of this aim.
  
  
  METHODS
  The analysis was based on ceramic master dies of prepared teeth and corresponding virtual CAD surfaces. Five copings per die were manufactured with two different CAD/CAM-technologies: milling and grinding. The internal fit was determined by a three-dimensional replica technique by optical digitization and computer-assisted analysis.
  
  
  RESULTS
  Mean internal gaps were 134/84μm (SD 78/28) for molar and 93/69μm (SD 56/35) for premolar copings (milling/grinding) using a digitizable silicone for the replicas representing the cement space; they were statistically significant regarding tooth and CAD/CAM-system (p<0.001).
  
  
  CONCLUSIONS
  All zirconia copings showed an internal accuracy of fit where the gap widths ranged within the current clinical recommendations. However, there still is room for improvement and further standardization of CAD/CAM-technologies.
authors: Department of Dentistry, Prosthetic Dentistry and Material Sciences, University Hospital Ulm, Albert-Einstein-Allee 11, Ulm, Germany. ovidiu.moldovan@gmail.com
authors: Ovidiu
authors: O
authors: Moldovan
authors: Ralph G
authors: RG
authors: Luthardt
authors: Nicoleta
authors: N
authors: Corcodel
authors: Heike
authors: H
authors: Rudolph
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry; D001641:Bicuspid; D017076:Computer-Aided Design; D003442:Crowns; D003738:Dental Cements / Q000737:chemistry; D018772:Dental Marginal Adaptation; D003776:Dental Porcelain / Q000737:chemistry*; D017267:Dental Prosthesis Design / Q000379:methods*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D008422:Materials Testing; D003765:Models, Dental; D008963:Molar; D010781:Photography / Q000379:methods; D016628:Replica Techniques; D012828:Silicones / Q000737:chemistry; D013499:Surface Properties; D019246:Tooth Preparation / Q000379:methods; D014584:User-Computer Interface; D015019:Yttrium / Q000737:chemistry*; D015040:Zirconium / Q000737:chemistry*
chemical_list: D003738:Dental Cements; C485633:In-Ceram Zirconia; D012828:Silicones; C499362:yttria stabilized tetragonal zirconia; D003776:Dental Porcelain; D015019:Yttrium; D015040:Zirconium; D000537:Aluminum Oxide