1. Department of Prosthetic Dentistry, Center for Dental and Oral Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
2. Oral Healthcare DACH, Philips GmbH, Hamburg, Germany
3. Department of Prosthetic Dentistry and Dental Materials and Special Care, Center for Dental and Oral Medicine, University of Leipzig, Leipzig, Germany
4. Department of Prosthetic Dentistry, University Hospital LMU Ludwig-Maximilians, Munich, Germany
5. CMD-Center Hamburg-Eppendorf, Hamburg, Germany
6. Department of Periodontics, Preventive and Restorative Dentistry, University Medical Center Hamburg-Eppendorf, Hamburg, Germany