1. Department of Periodontology, Endodontology and Cariology; University of Basel; Basel Switzerland
2. Department of Oral Surgery; School of Dentistry; University of Birmingham; Birmingham UK
3. Biomaterials Unit; School of Dentistry; University of Birmingham; Birmingham UK
4. Department of Conservative Dentistry; School of Dental Medicine; University of Tubingen; Tubingen Germany
5. Department of Health Policy and Health Services Research; Boston University Goldman School of Dental Medicine; Boston MA USA