1. Department of Operative Dentistry and Endodontology, Medical Center for Dentistry and Oral Medicine, University of Marburg , Marburg , Germany
2. University Hospital Giessen and Marburg, Campus Marburg , Marburg , Germany
3. Department of Periodontology and Peri-Implant Diseases, Medical Center for Dentistry and Oral Medicine, University of Marburg , Marburg , Germany
4. Department of Oral and Maxillofacial Diseases, University of Helsinki, Helsinki University Hospital , Helsinki , Finland
5. Section of Periodontology and Dental Prevention, Division of Oral Diseases, Department of Dental Medicine, Karolinska Institutet , Stockholm , Sweden
6. Private Practice , Heilbronn , Germany
7. Dental Hygiene and Prevention Management, European University of Applied Sciences , Cologne , Germany
8. Institute of Empirical Health Economics , B urscheid , Germany