1. Department of Operative Dentistry and Periodontology, Faculty of Medicine University of Freiburg Freiburg Germany
2. Private Practice Alzenau Germany
3. Private Practice Demmin Germany
4. Institute of Medical Biometry and Statistics, Faculty of Medicine and Medical Center University of Freiburg Freiburg Germany
5. Policlinic of Operative Dentistry, Periodontology, and Pediatric Dentistry, Medical Faculty Carl Gustav Carus Technische Universität Dresden Dresden Germany