1. Department of Oral and Maxillofacial Surgery; University Medical Center Hamburg-Eppendorf; Hamburg Germany
2. Department of Oral and Maxillofacial Surgery; Schleswig-Holstein University Hospital; Kiel Germany
3. Department of Oral and Maxillofacial Surgery; University Hospital Erlangen-Nürnberg; Erlangen Germany
4. Institute of Medical Informatics and Statistics; Schleswig-Holstein University Hospital; Kiel Germany