1. Department of Periodontology and Oral Medicine University of Michigan Ann Arbor Michigan USA
2. Department of Periodontology Universitat Internacional de Catalunya Barcelona Spain
3. Department of Periodontology University of Bern Bern Switzerland
4. Private Practice Atelier Dental Madrid Madrid Spain
5. Department of Periodontology Complutense University of Madrid Madrid Spain
6. Department of Oral Medicine, Infection, and Immunity Harvard School of Dental Medicine Boston USA
7. Department of Periodontics University of Iowa College of Dentistry Iowa City Iowa USA