title: Evaluation of castable and premachined metal base abutment/implant interfaces before and after cyclical load.
abstract: OBJECTIVE
  The purpose of this study was to compare the vertical fit of the castable abutment/implant and premachined base metal abutment/implant interface, before and after cyclic loading.
  
  
  METHODS
  Ten UCLA abutments were distributed in 2 groups: castable and premachined with a cobalt-chromium metal base. The abutments were cast in cobalt-chromium alloy and were screwed onto implants (3.75 × 13 mm, external hexagon) with a 32 N·cm torque. The vertical gap (in micrometers) at the interface abutment/implant was evaluated by linear microscope 2 times: after torque and after cyclic load (1 million cycles, 400 N).
  
  
  RESULTS
  The mean values of the vertical gap at the castable abutment/implant and premachined abutment/implant interfaces before and after cyclic load were 5.33 to 6.64 µm and 7.36 to 8.16 µm, respectively. The mean values of the vertical gap were statistically analyzed (ANOVA and t test, P ≤ 0.05). Vertical gap values of the castable abutment/implant interface were not significantly different from those of the premachined abutment/implant interface, before (P = 0.154) and after (P = 0.471) cyclical loading.
  
  
  CONCLUSIONS
  Castable and premachined base metal abutments showed similar gaps at the implant/abutment interface, both after applying torque and after cyclic loading.
authors.affiliation: *Professor, Department of Prosthesis, São Leopoldo Mandic College, Vitória, Brazil. †Graduate Student, Department of Prosthodontics, University of Taubate, São Paulo, Brazil. ‡Associate Professor, Department of Prosthodontics, University of Taubate, São Paulo, Brazil.
authors.forename: Renato
authors.initials: R
authors.lastname: De Mori
authors.forename: Cyntia Ferreira
authors.initials: CF
authors.lastname: Ribeiro
authors.forename: Laís Regiane
authors.initials: LR
authors.lastname: da Silva-Concílio
authors.forename: Ana Christina
authors.initials: AC
authors.lastname: Claro Neves
mesh_terms: D002858:Chromium Alloys / Q000627:therapeutic use; D000044:Dental Abutments; D003735:Dental Casting Technique; D059605:Dental Implant-Abutment Design; D015921:Dental Implants; D003799:Dental Stress Analysis; D006801:Humans; D019415:Torque
chemical_list: D002858:Chromium Alloys; D015921:Dental Implants