1. Department of Periodontology Dental Clinic Faculty of Medicine Sigmund Freud University Vienna Vienna Austria
2. Department of Periodontology Faculty of Odontology University of Malmö Malmö Sweden
3. Gastrounit Medical Division Copenhagen University Hospital ‐ Amager and Hvidovre Hvidovre Denmark
4. Copenhagen Center for Inflammatory Bowel Disease in Children Adolescents and Adults Copenhagen University Hospital ‐ Amager and Hvidovre Hvidovre Denmark
5. Department of Orthodontics and Dentofacial Orthopedics School of Dental Medicine University of Bern Bern Switzerland
6. Department of Dental Medicine Division of Oral Diseases Karolinska Institute Stockholm Sweden
7. Division of Conservative Dentistry and Periodontology University Clinic of Dentistry Medical University of Vienna Vienna Austria