1. Specialty Registrar in Restorative Dentistry, Department of Restorative Dentistry, Charles Clifford Dental Hospital, 76 Wellesley Road, Sheffield S10 2SZ, UK ()
2. Specialty Registrar in Restorative Dentistry, Department of Restorative Dentistry, Leeds Dental Institute, Clarendon Way, Leeds LS2 9LU, UK
3. Consultant in Restorative Dentistry, Department of Restorative Dentistry, Leeds Dental Institute, Clarendon Way, Leeds LS2 9LU, UK