1. Department of Periodontics and Oral Medicine University of Michigan School of Dentistry Ann Arbor MI USA
2. Department of Oral‐ and Maxillofacial Surgery Medical Center – University of Freiburg Faculty of Medicine University of Freiburg Germany
3. Laboratory of Epithelial Biology Department of Periodontics and Oral Medicine University of Michigan School Ann Arbor MI USA
4. Department of Periodontology School of Dentistry Oregon Health & Science University Portland OR USA
5. Department of Periodontology Institute of Odontology University of Gothenburg Gothenburg Sweden