1. Experimental Dento-Maxillo-Facial Medicine; Center of Dento-Maxillo-Facial Medicine; University of Bonn; Bonn Germany
2. Clinical Research Unit 208; Center of Dento-Maxillo-Facial Medicine; University of Bonn; Bonn Germany
3. Department of Periodontology; Laboratory of Oral Microbiology; University of Bern; Bern Switzerland
4. Department of Oral Surgery; Center of Dento-Maxillo-Facial Medicine; University of Bonn; Bonn Germany