d e n t a l m a t e r i a l s 3 1 ( 2 0 1 5 ) 1415–1426 Available online at www.sciencedirect.com ScienceDirect jo ur nal home p ag e: www.intl.elsevierhealth.com/journals/dema Fatigue induced changes in conical implant–abutment connections Kai Blum a,1 , Wolfram Wiest b,1 , Christian Fella b , Andreas Balles b , Jonas Dittmann b , Alexander Rack c , Dominik Maier a , Ralf Thomann d , Benedikt Christopher Spies a , Ralf Joachim Kohal a , Simon Zabler b , Katja Nelson a,∗ a Universitätsklinikum Freiburg, Klinik für MKG-Chirurgie, Hugstetter Str. 55, 79106 Freiburg, Germany b Lehrstuhl für Röntgenmikroskopie der Universität Würzburg, Josef-Martin-Weg 63 Hubland Nord, 97074 Würzburg, Germany c X-ray Imaging Group European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex, France d FMF (Freiburger Materialforschungszentrum), Stefan-Meier-Str. 21, 79104 Freiburg, Germany a r t i c l e i n f o Article history: Received 26 February 2015 Received in revised form 23 June 2015 Accepted 8 September 2015 Keywords: Dental implants Titanium Deformation Fatigue induced IAC Stability Ankylos a b s t r a c t Objectives. 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 radio- graphy (SRX) and scanning electron microscopy (SEM). The implant–abutment assemblies were then subjected to cyclic loading at 98 N and their microgap was evaluated after 100,000, 200,000 and 1 million cycles using SRX, synchrotron micro-tomography (CT). Wear mech- anisms 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). ∗ Corresponding author at: University Hospital Freiburg, Center for Dental Medicine, Department of Oral and Maxillofacial Surgery, Albert- Ludwigs-University, Freiburg, Germany. Tel.: +49 76127049400; fax: +49 76127048000. E-mail addresses: blumkai@gmx.de (K. Blum), wolfram.wiest@physik.uni-wuerzburg.de (W. Wiest), christian.fella@physik.uni-wuerzburg.de (C. Fella), andreas.balles@physik.uni-wuerzburg.de (A. Balles), jonas.dittmann@physik.uni-wuerzburg.de (J. Dittmann), alexander.rack@esrf.fr (A. Rack), maier.dominik@gmx.de (D. Maier), ralf.thomann@fmf.uni-freiburg.de (R. Thomann), benedikt.spies@uniklinik-freiburg.de (B.C. Spies), ralf.kohal@uniklinik-freiburg.de (R.J. Kohal), simon.zabler@physik.uni-freiburg.de (S. Zabler), katja.nelson@uniklinik-freiburg.de (K. Nelson). 1 These authors contributed equally to this work. http://dx.doi.org/10.1016/j.dental.2015.09.004 0109-5641/© 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.