1. Department of Conservative Dentistry,
2. Department of Surgical Research, and
3. Institute of Physiological Chemistry, Dresden University of Technology, Medical Faculty, Fetscherstrasse 74, 01307, Dresden, Germany;
4. Department of Periodontology, Ernst Moritz Arndt University, Greifswald, Germany; and
5. Institute of Medical Biometry and Statistics, University at Lübeck, Germany