1. Department of Dental Medicine, Karolinska Institutet, Stockholm, Sweden
2. Institute of Dentistry, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
3. Department of Microbiology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
4. Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit, Amsterdam, The Netherlands