1. Department of Oral and Maxillofacial Surgery, Medical Center—University of Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
2. AO Research Institute Davos, Clavadelerstrasse 8, 7270 Davos, Switzerland
3. Department of Oral and Maxillofacial Surgery, Ludwig-Maximilians-University Munich, Lindwurmstr. 2a, 80337 Munich, Germany