1. University of Michigan School of Dentistry; Ann Arbor MI USA
2. Department of Periodontology and Geriatric Dentistry; Oulu University Institute of Dentistry; Oulu Finland
3. Institute of Dentistry; University of Eastern Finland; Finland
4. Kuopio University Hospital; Unit for Maxillofacial and Oral Surgery; Kuopio Finland
5. Department of Preventive and Restorative Dental Sciences; University of California San Francisco; San Francisco CA USA
6. Departments of Oral Biology and Microbiology; Schools of Dental Medicine and Medicine and Biomedical Sciences; State University of New York at Buffalo; Buffalo NY USA