1. Department of Oral- and Maxillofacial Surgery, University Medical Center Mainz, Augustusplatz 2, 55131 Mainz, Germany
2. Private Praxis Dr. Kühnöl, Bayreuther Straße 30, 01187 Dresden, Germany
3. Institute for Medical Statistics, Epidemiology and Informatics, University Medical Center of the Johannes-Gutenberg-University Mainz, 55131 Mainz, Germany
4. Department of Oral and Maxillofacial Surgery, Federal Armed Forces Hospital, Rübenacherstraße 170, 56072 Koblenz, Germany
5. Department of Oral Surgery and Stomatology, Division of Oral Diagnostic Science, University of Bern, Freiburgstrasse 7, 3010 Bern, Switzerland