1. The School of Dentistry, The University of Adelaide, Adelaide, Australia
2. Department of Periodontics, Preventive and Restorative Dentistry, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
3. Institute of Pharmaceutical Biology and Phytochemistry, University of Muenster, Muenster, Germany
4. Faculty of Dentistry, University of Hong Kong, Hong Kong, Hong Kong
5. Department of Periodontics, Preventive and Restorative Dentistry, University Medical Center Eppendorf, Hamburg, Germany