1. Department of Oral Surgery; The School of Dentistry; University of Birmingham; Birmingham UK
2. Department of Health Policy and Health Services Research; Boston University Goldman School of Dental Medicine; Boston MA USA
3. Birmingham Dental Hospital; Birmingham Community Healthcare NHS Trust; Birmingham UK
4. Periodontal Research Group; The University of Birmingham; Birmingham UK
5. Department of Periodontology, Endodontology and Cariology; University of Basel; Basel Switzerland
6. Department of Dental Ecology; University of North Carolina; Chapel Hill NC USA