title: Effects of Computer-Aided Manufacturing Technology on Precision of Clinical Metal-Free Restorations.
abstract: OBJECTIVE
  The purpose of this study was to investigate the marginal fit of metal-free crowns made by three different computer-aided design/computer-aided manufacturing (CAD/CAM) systems.
  
  
  METHODS
  The maxillary left first premolar of a dentiform was prepared for all-ceramic crown restoration. Thirty all-ceramic premolar crowns were made, ten each manufactured by the Lava system, Cercon, and Cerec. Ten metal ceramic gold (MCG) crowns served as control. The marginal gap of each sample was measured under a stereoscopic microscope at 75x magnification after cementation. One-way ANOVA and the Duncan's post hoc test were used for data analysis at the significance level of 0.05.
  
  
  RESULTS
  The mean (standard deviation) marginal gaps were 70.5 (34.4) μm for the MCG crowns, 87.2 (22.8) μm for Lava, 58.5 (17.6) μm for Cercon, and 72.3 (30.8) μm for Cerec. There were no significant differences in the marginal fit among the groups except that the Cercon crowns had significantly smaller marginal gaps than the Lava crowns (P < 0.001).
  
  
  CONCLUSIONS
  Within the limitation of this study, all the metal-free restorations made by the digital CAD/CAM systems had clinically acceptable marginal accuracy.
authors.affiliation: Department of Prosthodontics, School of Dentistry and Dental Research Institute, Seoul National University, Daehak-ro, Jongno-gu, Seoul 110-749, Republic of Korea.
authors.forename: Ki-Hong
authors.initials: KH
authors.lastname: Lee
authors.affiliation: Department of Prosthodontics, School of Dentistry and Dental Research Institute, Seoul National University, Daehak-ro, Jongno-gu, Seoul 110-749, Republic of Korea.
authors.forename: In-Sung
authors.initials: IS
authors.lastname: Yeo
authors.affiliation: Division of Advanced Prosthodontics, UCLA School of Dentistry, Los Angeles, CA 90095, USA.
authors.forename: Benjamin M
authors.initials: BM
authors.lastname: Wu
authors.affiliation: Department of Prosthodontics, School of Dentistry and Dental Research Institute, Seoul National University, Daehak-ro, Jongno-gu, Seoul 110-749, Republic of Korea.
authors.forename: Jae-Ho
authors.initials: JH
authors.lastname: Yang
authors.affiliation: Department of Prosthodontics, School of Dentistry and Dental Research Institute, Seoul National University, Daehak-ro, Jongno-gu, Seoul 110-749, Republic of Korea.
authors.forename: Jung-Suk
authors.initials: JS
authors.lastname: Han
authors.affiliation: Department of Prosthodontics, School of Dentistry and Dental Research Institute, Seoul National University, Daehak-ro, Jongno-gu, Seoul 110-749, Republic of Korea.
authors.forename: Sung-Hun
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Department of Prosthodontics, School of Dentistry and Dental Research Institute, Seoul National University, Daehak-ro, Jongno-gu, Seoul 110-749, Republic of Korea.
authors.forename: Yang-Jin
authors.initials: YJ
authors.lastname: Yi
authors.affiliation: Department of Dentistry, St. Vincent Hospital, Catholic University of Korea, Ji-dong, Paldal-gu, Suwon 442-723, Republic of Korea.
authors.forename: Taek-Ka
authors.initials: TK
authors.lastname: Kwon
mesh_terms: D002484:Cementation / Q000379:methods; D002516:Ceramics / Q000737:chemistry; D017076:Computer-Aided Design; D018772:Dental Marginal Adaptation; D003764:Dental Materials / Q000737:chemistry*; D003776:Dental Porcelain / Q000737:chemistry; D006801:Humans; D008670:Metals / Q000737:chemistry*; D003765:Models, Dental; D013499:Surface Properties; D013674:Technology, Dental / Q000379:methods*
chemical_list: D003764:Dental Materials; D008670:Metals; D003776:Dental Porcelain; C074543:Cerec