1. Department of Oral Sciences; Kristianstad University; Kristianstad Sweden
2. School of Dental Sciences; Trinity College; Dublin Ireland
3. Blekinge Institute of Technology; Karlskrona Sweden
4. Uppsala Käkkirurgiska Centrum; Uppsala Sweden
5. Department of Periodontology; Maxillofacial Unit; Hospital of Halland; Halmstad Sweden
6. Departments of Periodontics and Oral Medicine; University of Washington; Seattle WA USA
7. Department of Periodontology; University of Bern; Bern Switzerland