1. Department of Oral Surgery, The School of Dentistry, University of Birmingham, Birmingham, UK
2. Department of Periodontology, Endodontology, and Cariology, School of Dentistry, University of Basel, Basel, Switzerland
3. Department of Epidemiology, German Institute of Human Nutrition, Potsdam-Nuthetal, Germany
4. Department of Periodontology and Synoptic Dentistry, Charité–University Medicine Berlin, Berlin, Germany