1. Interdisciplinary Department of Oral Surgery and Implantology, Department of Craniomaxillofacial and Plastic Surgery, University Cologne
2. Pre-clinical Departmen of Dental Center, Cologne University
3. Department of Craniomaxillofacial and Plastic Surgery, Johannes Wesling Klinikum Minden
4. Praxis für Zahnheilkunde, Dres. Bayer, Kistler und Elbertzhagen