1. Department of Oral and Maxillofacial Surgery; Klinikum rechts der Isar, Technical University Munich; Ismaninger Str. 22 81675 Munich Germany
2. Institute of Molecular Immunology and Experimental Oncology; Klinikum rechts der Isar, Technical University Munich; Ismaninger Str. 22 81675 Munich Germany
3. Department of Orthopeadic Sports Medicine; Klinikum rechts der Isar, Technical University Munich; Ismaninger Str. 22 81675 Munich Germany
4. Institute of Medical Statistics and Epidemiology; Klinikum rechts der Isar, Technical University Munich; Ismaninger Str. 22 81675 Munich Germany
5. Department of Oral and Maxillofacial Surgery; University Medical Center Hamburg-Eppendorf; Martinistr. 52 Hamburg 20246 Germany