title: Wear at the titanium-titanium and the titanium-zirconia implant-abutment interface: a comparative in vitro study.
abstract: OBJECTIVE
  The purpose of this study was to determine and measure the wear of the interface between titanium implants and one-piece zirconia abutments in comparison to titanium abutments.
  
  
  METHODS
  6 implants were secured into epoxy resin blocks. The implant interface of these implants and 6 corresponding abutments (group Zr: three one-piece zirconia abutments; group Ti: three titanium abutments) were examined by a microscope and scanning electron micrograph (SEM). Also the implants and the abutments were scanned by 3D-Micro Computer Tomography (CT). The abutments were connected to the implants and cyclically loaded with 1,200,000 cycles at 100N in a two-axis fatigue testing machine. Afterwards, all specimens were unscrewed and the implants and abutments again were scanned by microscope, SEM and CT. The microscope and SEM images were compared, the CT data were superimposed and the wear was calculated by inspection software. The statistical analysis was carried out with an unpaired t-test.
  
  
  RESULTS
  Abutment fracture or screw loosening was not observed during cyclical loading. Comparing the microscope and SEM images more wear was observed on the implants connected to zirconia abutments. The maximum wear on the implant shoulder calculated by the inspection software was 10.2μm for group Zr, and 0.7μm for group Ti. The influence of the abutment material on the measured wear was statistically significant (p≤0.001; Levene-test).
  
  
  CONCLUSIONS
  Titanium implants showed higher wear at the implant interface following cyclic loading when connected to one-piece zirconia implant abutments compared to titanium abutments. The clinical relevance is not clear; hence damage of the internal implant connection could result in prosthetic failures up to the need of implant removal.
authors.affiliation: University of Munich, Department of Prosthodontics, Goethestr. 70, 80336 Munich, Germany. michael.stimmelmayr@med.uni-muenchen.de
authors.forename: Michael
authors.initials: M
authors.lastname: Stimmelmayr
authors.forename: Daniel
authors.initials: D
authors.lastname: Edelhoff
authors.forename: Jan-Frederik
authors.initials: JF
authors.lastname: Güth
authors.forename: Kurt
authors.initials: K
authors.lastname: Erdelt
authors.forename: Arndt
authors.initials: A
authors.lastname: Happe
authors.forename: Florian
authors.initials: F
authors.lastname: Beuer
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D003442:Crowns; D045662:Dental Etching / Q000379:methods; D059605:Dental Implant-Abutment Design; D003764:Dental Materials / Q000737:chemistry*; D019554:Dental Restoration Wear; D003799:Dental Stress Analysis / Q000295:instrumentation; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D008853:Microscopy; D008855:Microscopy, Electron, Scanning; D019279:Resin Cements / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013871:Thiones / Q000737:chemistry; D014025:Titanium / Q000737:chemistry*; D055114:X-Ray Microtomography / Q000379:methods; D015040:Zirconium / Q000737:chemistry*
chemical_list: C521707:Alloy Primer; D003188:Composite Resins; D003764:Dental Materials; D008689:Methacrylates; C438843:Panavia-Fluoro; D019279:Resin Cements; D013871:Thiones; C100646:Metal Primer; D015040:Zirconium; D014025:Titanium; D000537:Aluminum Oxide; C028541:zirconium oxide