title: Comparison of internal fit between implant abutments and cast metal crowns vs laser-sintered crowns.
abstract: OBJECTIVE
  A common problem related to cemented single crowns is the internal misfit, which may cause inadequate retention, especially when seated on the implant abutment. The aim of this study was to compare the internal fit of Co-Cr crowns using a traditional lost-wax casting technique from laser-sintered Co-Cr alloy crowns.
  
  
  METHODS
  Twelve metallic crowns per each technique were fabricated. The effect of the thickness of cement, originated internal gap was evaluated. Crowns were cemented on the implant abutments with resin cement, and the internal fit of crowns was measured at five areas with an optical microscope. The data were analyzed, and the means were compared with a t-test (p<0.05).
  
  
  RESULTS
  The internal gap width measurements for the laser-sintered group (min. 52.19 ± 11.61 μm and max. 140.01 ± 31.84 μm) indicated the presence of a significantly closed internal gap compared to the crowns obtained through the lost wax method (min. 65.50 ± 9.54 μm and max. 313.46 ± 48.12 μm).
  
  
  CONCLUSIONS
  The fit of the metal crown likely varies with the fabrication technique. The use of techniques that enable the adjustment of crown parameters, such as the laser sintering technique, maintains the desired fit between casting and implant abutments.
  
  
  CONCLUSIONS
  This study investigated which technique affects the internal fit of cemented implant-supported crowns, comparing the use of lost wax casting and laser-sintered metal dental alloys. The results of this study indicate that the use of laser-sintered crowns can improve for crown accuracy.
authors.affiliation: Professor and Vice Dean, Department of Prosthodontics, Faculty of Dentistry, Ankara University, Ankara, Turkey, e-mail: mmkilicarslan@yahoo.com.
authors.forename: Mehmet Ali
authors.initials: MA
authors.lastname: Kiliçarslan
authors.affiliation: Profesor, Department of Prosthodontics, Faculty of Dentistry, Ankara University, Ankara, Turkey.
authors.forename: Pelin
authors.initials: P
authors.lastname: Özkan
authors.affiliation: Profesor, Department of Prosthodontics, Faculty of Dentistry, Ankara University, Ankara, Turkey.
authors.forename: Bülent
authors.initials: B
authors.lastname: Uludag
authors.affiliation: Resarch Assistant, Department of Prosthodontics, Eskisehir Osmangazi University, Eskisehir, Turkey.
authors.forename: Emre
authors.initials: E
authors.lastname: Mumcu
mesh_terms: D002858:Chromium Alloys / Q000737:chemistry*; D003442:Crowns; D003734:Dental Casting Investment / Q000737:chemistry*; D003735:Dental Casting Technique / Q000295:instrumentation; D059605:Dental Implant-Abutment Design; D019250:Dental Implants, Single-Tooth; D018772:Dental Marginal Adaptation; D017267:Dental Prosthesis Design; D017268:Dental Prosthesis Retention; D006801:Humans; D007834:Lasers; D008422:Materials Testing; D019279:Resin Cements / Q000737:chemistry; D013499:Surface Properties
chemical_list: D002858:Chromium Alloys; D003734:Dental Casting Investment; D019279:Resin Cements