title: Accuracy and mechanical performance of passivated and conventional fabricated 3-unit fixed dental prosthesis on multi-unit abutments.
abstract: OBJECTIVE
  The aim of this study was to evaluate the fit and mechanical stability of conventional versus passive fitting 3-unit fixed dental prosthesis (FDP) screw-retained on implants.
  
  
  METHODS
  Twenty acrylic models, each with two embedded implants, were fabricated and functioned as patient-models. Impressions were taken and 20 all-ceramic FDPs were pre-fabricated on the plaster casts. Respectively 10 FDPs were fixed on the plaster casts (group 1) and on the patient-models for passive fitting (group 2). The fit of each FDP was checked on the patient-model by means of visual control (grades 1-10) and microscopic examination. Furthermore, specimens were artificially aged for possible prosthodontic failures, followed by a fracture strength test.
  
  
  RESULTS
  Group 2 [1.4 (±0.3)] showed significantly (p<0.001) better results in the visual examination of the marginal fit compared to group 1 [6.3 (±2.4)]. The microscopic marginal misfit was 160μm (±80μm) at the abutment margin and 150μm (±80μm) at the axial wall of the abutment for group 1, respectively, 0μm and 0μm up to 17μm for group 2 (p<0.001). No failure of the FDPs could be observed during artificial aging in both groups. The fracture load showed no significant difference (p=0.60) between group 1 [2583N (±664N)] and group 2 [2465N (±238N)].
  
  
  CONCLUSIONS
  Visual and microscopic examination detected huge differences in marginal fit between groups 1 and 2. However, no statistically verifiable differences could be detected in long-term stability of implant-supported FDPs irrespective of the fit.
authors.affiliation: Private Practice for Oral Surgery, Josef-Heilingbrunnerstr. 2, 93413 Cham, Germany; University of Munich, Department of Prosthodontics, Goethestr. 70, 80336 Munich, Germany. Electronic address: michael.stimmelmayr@med.uni-muenchen.de.
authors.forename: Michael
authors.initials: M
authors.lastname: Stimmelmayr
authors.affiliation: University of Munich, Department of Prosthodontics, Goethestr. 70, 80336 Munich, Germany.
authors.forename: Julian
authors.initials: J
authors.lastname: Groesser
authors.affiliation: University of Berlin, Department of Prosthodontics and Gerontostomtology, Assmannshauser Strasse 4-6, 14197 Berlin, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Beuer
authors.affiliation: University of Munich, Department of Prosthodontics, Goethestr. 70, 80336 Munich, Germany.
authors.forename: Kurt
authors.initials: K
authors.lastname: Erdelt
authors.affiliation: University of Vienna, Dental School, Sensengasse 2a, 1090 Wien, Austria.
authors.forename: Gerald
authors.initials: G
authors.lastname: Krennmair
authors.affiliation: University of Munich, Department of Prosthodontics, Goethestr. 70, 80336 Munich, Germany.
authors.forename: Caroline
authors.initials: C
authors.lastname: Sachs
authors.affiliation: University of Munich, Department of Prosthodontics, Goethestr. 70, 80336 Munich, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Edelhoff
authors.affiliation: University of Munich, Department of Prosthodontics, Goethestr. 70, 80336 Munich, Germany.
authors.forename: Jan-Frederik
authors.initials: JF
authors.lastname: Güth
mesh_terms: D002516:Ceramics; D000044:Dental Abutments; D059605:Dental Implant-Abutment Design; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D003765:Models, Dental
keywords: 3-unit FDP; Cyclic loading; Fatigue testing; Implant; Passive fit