title: Evaluation of marginal/internal fit of chrome-cobalt crowns: Direct laser metal sintering versus computer-aided design and computer-aided manufacturing.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the internal and marginal fit of chrome cobalt (Co-Cr) crowns were fabricated with laser sintering, computer-aided design (CAD) and computer-aided manufacturing, and conventional methods.
  
  
  METHODS
  Polyamide master and working models were designed and fabricated. The models were initially designed with a software application for three-dimensional (3D) CAD (Maya, Autodesk Inc.). All models were fabricated models were produced by a 3D printer (EOSINT P380 SLS, EOS). 128 1-unit Co-Cr fixed dental prostheses were fabricated with four different techniques: Conventional lost wax method, milled wax with lost-wax method (MWLW), direct laser metal sintering (DLMS), and milled Co-Cr (MCo-Cr). The cement film thickness of the marginal and internal gaps was measured by an observer using a stereomicroscope after taking digital photos in ×24.
  
  
  RESULTS
  Best fit rates according to mean and standard deviations of all measurements was in DLMS both in premolar (65.84) and molar (58.38) models in μm. A significant difference was found DLMS and the rest of fabrication techniques (P < 0.05). No significant difference was found between MCo-CR and MWLW in all fabrication techniques both in premolar and molar models (P > 0.05).
  
  
  CONCLUSIONS
  DMLS was best fitting fabrication techniques for single crown based on the results.The best fit was found in marginal; the larger gap was found in occlusal.All groups were within the clinically acceptable misfit range.
authors.affiliation: Department of Prosthodontics, Faculty of Dentistry, Near East University, Nicosia, Northern Cyprus, Mersin 10, Turkey.
authors.forename: S
authors.initials: S
authors.lastname: Gunsoy
authors.affiliation: Department of Prosthodontics, Faculty of Dentistry, Near East University, Nicosia, Northern Cyprus, Mersin 10, Turkey.
authors.forename: M
authors.initials: M
authors.lastname: Ulusoy
mesh_terms: D001641:Bicuspid; D002858:Chromium Alloys; D003035:Cobalt; D017076:Computer-Aided Design; D003442:Crowns; D003735:Dental Casting Technique; D003738:Dental Cements; D018772:Dental Marginal Adaptation; D017267:Dental Prosthesis Design / Q000379:methods*; D006801:Humans; D007834:Lasers; D008963:Molar
chemical_list: D002858:Chromium Alloys; D003738:Dental Cements; D003035:Cobalt