1. Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, MI, USA
2. Department of Periodontology, Institute of Odontology, University of Gothenburg, Gothenburg, Sweden
3. Periodontology Unit and Department of Clinical Research, UCL Eastman Dental Institute, London, UK
4. Department of Biomedical Engineering, College of Engineering, University of Michigan, Ann Arbor, MI, USA