1. Department of Periodontics and Oral Medicine University of Michigan School of Dentistry Ann Arbor Michigan USA
2. Department of Periodontology, Institute of Odontology, Sahlgrenska Academy University of Gothenburg Gothenburg Sweden
3. Perelman School of Medicine University of Pennsylvania Philadelphia Pennsylvania USA
4. Department of Periodontics and Oral Medicine and Laboratory of Epithelial Biology University of Michigan School of Dentistry Ann Arbor Michigan USA
5. Department of Oral Medicine, Infection and Immunity Harvard School of Dental Medicine Boston Massachusetts USA