title: In vitro evaluation of marginal, axial, and occlusal discrepancies in metal ceramic restorations produced with new technologies.
abstract: BACKGROUND
  Marginal and axial discrepancies of metal ceramic restorations are key to their long-term success. Little information is available for metal ceramic restorations fabricated with soft metal milling and laser sintering technologies.
  
  
  OBJECTIVE
  The purpose of this in vitro study was to compare the marginal, axial, and occlusal discrepancies in single-unit metal ceramic restorations fabricated with new production techniques with those in a single-unit restoration fabricated using a conventional technique.
  
  
  METHODS
  After the artificial tooth was prepared, impressions were made, and 40 dies were obtained. Dies were randomly divided into 4 groups (n=10). Cobalt-chromium (Co-Cr) cast (C), hard metal milled (HM), laser sintered (LS), and soft metal milled (SM) copings were fabricated. Marginal, axial, and occlusal discrepancies of these copings were measured using the silicone replica technique before and after the application of veneering ceramic. Data were analyzed with repeated measurements 2-way ANOVAs and Bonferroni post hoc tests (α=.05).
  
  
  RESULTS
  Significant differences were found in the increase of marginal discrepancy after the application of veneering ceramic in the LS group (P=.016). However, no significant differences in marginal discrepancy were found whether veneering ceramic was applied to copings before or after in the other groups (P>.05). With regard to marginal and occlusal discrepancies, significant differences were found among the production techniques (P<.001 and P<.05, respectively). No significant differences in axial discrepancies were found among the groups (P>.05).
  
  
  CONCLUSIONS
  This in vitro study showed that metal ceramic restorations produced with HM and newly introduced SM techniques exhibited better marginal adaptations than those produced with the LS or C technique.
authors.affiliation: Assistant Professor, Department of Prosthodontics, Faculty of Dentistry, Pamukkale University, Denizli, Turkey. Electronic address: hasankocaagaoglu@hotmail.com.
authors.forename: Hasan
authors.initials: H
authors.lastname: Kocaağaoğlu
authors.affiliation: Assistant Professor, Department of Prosthodontics, Faculty of Dentistry, Erciyes University, Kayseri, Turkey.
authors.forename: Halil İbrahim
authors.initials: Hİ
authors.lastname: Kılınç
authors.affiliation: Assistant Professor, Department of Prosthodontics, Faculty of Dentistry, Erciyes University, Kayseri, Turkey.
authors.forename: Haydar
authors.initials: H
authors.lastname: Albayrak
authors.affiliation: Specialist Dentist, Kıbrıs Şehitler Oral and Dental Health Center, Denizli, Turkey.
authors.forename: Meryem
authors.initials: M
authors.lastname: Kara
mesh_terms: D002858:Chromium Alloys / Q000627:therapeutic use; D017076:Computer-Aided Design; D018772:Dental Marginal Adaptation / Q000592:standards; D003766:Dental Occlusion; D017267:Dental Prosthesis Design / Q000295:instrumentation / Q000379:methods* / Q000592:standards; D003793:Dental Restoration, Permanent / Q000295:instrumentation / Q000379:methods* / Q000592:standards; D006801:Humans; D066298:In Vitro Techniques; D016876:Metal Ceramic Alloys / Q000627:therapeutic use*; D014093:Tooth, Artificial
chemical_list: D002858:Chromium Alloys; D016876:Metal Ceramic Alloys