1. Section of Periodontology; Department of Conservative Dentistry, Clinic for Oral, Dental and Maxillofacial Diseases, University Hospital Heidelberg; Heidelberg Germany
2. Muenster University Hospital; Institute of Physiological Chemistry and Pathobiochemistry; Waldeyerstr. 15 D-48129 Muenster Germany
3. Hylitis; Rudolf-Harbig-Str. 5 D-48301 Nottuln Germany