1. Department of Restorative, Preventive and Pediatric Dentistry University of Bern Bern Switzerland
2. Department of Operative Dentistry and Periodontology Faculty of Medicine Center for Dental Medicine Medical Center – University of Freiburg Freiburg im Breisgau Germany
3. Clinic of Preventive Dentistry, Periodontology and Cariology Center of Dental Medicine University of Zürich Zürich Switzerland
4. Department of Medical Biometry and Statistics Medical Center – University of Freiburg Freiburg im Breisgau Germany
5. Department of Microbiology and Hygiene Institute of Medical Microbiology and Hygiene Medical Center – University of Freiburg Freiburg im Breisgau Germany