1. Department of Periodontology, Faculty of Odontology University of Malmö Malmö Sweden
2. Division of Conservative Dentistry and Periodontology, University Clinic of Dentistry Medical University of Vienna Vienna Austria
3. Division of Oral Surgery, University Clinic of Dentistry Medical University of Vienna Vienna Austria
4. Postgraduate Course Periodontology Medical University of Vienna Vienna Austria
5. Department of Oral Rehabilitation, Faculty of Health and Medical Sciences, School of Dentistry University of Copenhagen Copenhagen Denmark