title: Fatigue induced changes in conical implant-abutment connections.
abstract: OBJECTIVE
  Based on the current lack of data and understanding of the wear behavior of dental two-piece implants, this study aims for evaluating the microgap formation and wear pattern of different implants in the course of cyclic loading.
  
  
  METHODS
  Several implant systems with different conical implant-abutment interfaces were purchased. The implants were first evaluated using synchrotron X-ray high-resolution radiography (SRX) and scanning electron microscopy (SEM). The implant-abutment assemblies were then subjected to cyclic loading at 98N and their microgap was evaluated after 100,000, 200,000 and 1 million cycles using SRX, synchrotron micro-tomography (μCT). Wear mechanisms of the implant-abutment connection (IAC) after 200,000 cycles and 1 million cycles were further characterized using SEM.
  
  
  RESULTS
  All implants exhibit a microgap between the implant and abutment prior to loading. The gap size increased with cyclic loading with its changes being significantly higher within the first 200,000 cycles. Wear was seen in all implants regardless of their interface design. The wear pattern comprised adhesive wear and fretting. Wear behavior changed when a different mounting medium was used (brass vs. polymer).
  
  
  CONCLUSIONS
  A micromotion of the abutment during cyclic loading can induce wear and wear particles in conical dental implant systems. This feature accompanied with the formation of a microgap at the IAC is highly relevant for the longevity of the implants.
authors.affiliation: Universitätsklinikum Freiburg, Klinik für MKG-Chirurgie, Hugstetter Str. 55, 79106 Freiburg, Germany. Electronic address: blumkai@gmx.de.
authors.forename: Kai
authors.initials: K
authors.lastname: Blum
authors.affiliation: Lehrstuhl für Röntgenmikroskopie der Universität Würzburg, Josef-Martin-Weg 63 Hubland Nord, 97074 Würzburg, Germany. Electronic address: wolfram.wiest@physik.uni-wuerzburg.de.
authors.forename: Wolfram
authors.initials: W
authors.lastname: Wiest
authors.affiliation: Lehrstuhl für Röntgenmikroskopie der Universität Würzburg, Josef-Martin-Weg 63 Hubland Nord, 97074 Würzburg, Germany. Electronic address: christian.fella@physik.uni-wuerzburg.de.
authors.forename: Christian
authors.initials: C
authors.lastname: Fella
authors.affiliation: Lehrstuhl für Röntgenmikroskopie der Universität Würzburg, Josef-Martin-Weg 63 Hubland Nord, 97074 Würzburg, Germany. Electronic address: andreas.balles@physik.uni-wuerzburg.de.
authors.forename: Andreas
authors.initials: A
authors.lastname: Balles
authors.affiliation: Lehrstuhl für Röntgenmikroskopie der Universität Würzburg, Josef-Martin-Weg 63 Hubland Nord, 97074 Würzburg, Germany. Electronic address: jonas.dittmann@physik.uni-wuerzburg.de.
authors.forename: Jonas
authors.initials: J
authors.lastname: Dittmann
authors.affiliation: X-ray Imaging Group European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex, France. Electronic address: alexander.rack@esrf.fr.
authors.forename: Alexander
authors.initials: A
authors.lastname: Rack
authors.affiliation: Universitätsklinikum Freiburg, Klinik für MKG-Chirurgie, Hugstetter Str. 55, 79106 Freiburg, Germany. Electronic address: maier.dominik@gmx.de.
authors.forename: Dominik
authors.initials: D
authors.lastname: Maier
authors.affiliation: FMF (Freiburger Materialforschungszentrum), Stefan-Meier-Str. 21, 79104 Freiburg, Germany. Electronic address: ralf.thomann@fmf.uni-freiburg.de.
authors.forename: Ralf
authors.initials: R
authors.lastname: Thomann
authors.affiliation: Universitätsklinikum Freiburg, Klinik für MKG-Chirurgie, Hugstetter Str. 55, 79106 Freiburg, Germany. Electronic address: benedikt.spies@uniklinik-freiburg.de.
authors.forename: Benedikt Christopher
authors.initials: BC
authors.lastname: Spies
authors.affiliation: Universitätsklinikum Freiburg, Klinik für MKG-Chirurgie, Hugstetter Str. 55, 79106 Freiburg, Germany. Electronic address: ralf.kohal@uniklinik-freiburg.de.
authors.forename: Ralf Joachim
authors.initials: RJ
authors.lastname: Kohal
authors.affiliation: Lehrstuhl für Röntgenmikroskopie der Universität Würzburg, Josef-Martin-Weg 63 Hubland Nord, 97074 Würzburg, Germany. Electronic address: simon.zabler@physik.uni-freiburg.de.
authors.forename: Simon
authors.initials: S
authors.lastname: Zabler
authors.affiliation: Universitätsklinikum Freiburg, Klinik für MKG-Chirurgie, Hugstetter Str. 55, 79106 Freiburg, Germany. Electronic address: katja.nelson@uniklinik-freiburg.de.
authors.forename: Katja
authors.initials: K
authors.lastname: Nelson
mesh_terms: D000044:Dental Abutments; D059605:Dental Implant-Abutment Design; D015921:Dental Implants; D008855:Microscopy, Electron, Scanning; D014025:Titanium
chemical_list: D015921:Dental Implants; D014025:Titanium
keywords: Ankylos; Astra Tech; Bone level; Deformation; Dental implants; Fatigue induced; IAC; Nobel Active; Stability; Titanium