1. Department of Periodontics and Oral Medicine University of Michigan School of Dentistry Ann Arbor Michigan USA
2. Department of Periodontology and Oral Medicine School of Dentistry University of Michigan Ann Arbor Michigan USA
3. Department of Periodontology School of Dental Medicine University of Bern Bern Switzerland
4. ETEP (Etiology and Therapy of Periodontal and Peri‐Implant Diseases) Research Group University Complutense Madrid Spain
5. Department of Periodontology School of Dentistry International University of Catalonia Barcelona Spain