1. Oral and Maxillofacial Diseases University of Helsinki and Helsinki University Hospital Helsinki Finland
2. Institute of Dentistry University of Eastern Finland Kuopio Finland
3. Oral and Maxillofacial Diseases Kuopio University Hospital Kuopio Finland
4. Division of Periodontology Department of Dental Medicine Karolinska Institutet Huddinge Sweden
5. Heart and Lung Center Helsinki University Hospital Helsinki Finland