1. Unit of Periodontology, Department of Restorative Dentistry, Periodontology and Endodontology; Dental School, Ernst-Moritz-Arndt-University Greifswald; Greifswald; Germany
2. Leibniz-Institute for Plasma Science and Technology e.V.; Greifswald; Germany
3. Deptartment of Cell Biology, Center for Medical Research; Medical Faculty; University of Rostock; Rostock; Germany