1. Department of Pediatric Dentistry, University Medical Center Carl Gustav Carus, Technical University of Dresden, Fetscherstrasse 74, D-01307, Dresden, Germany;
2. Department of Operative Dentistry and Periodontology, City Centre University Clinics, University of Munich, Germany;
3. Dental Clinic 1 - Operative Dentistry and Periodontology, University Clinics, University Medical Center, University of Erlangen-Nuremberg, Glückstrasse 11, D-91054 Erlangen, Germany; and
4. Bioscience Research Center, College of Dental Medicine, 3200 South University Drive, Fort Lauderdale, FL 33328-2018, USA