1. House officer, Newcastle Dental Hospital and School, Framlington Place, Newcastle upon Tyne, NE2 4BW, UK
2. Professor of Restorative Dentistry, Newcastle Dental Hospital and School, Framlington Place, Newcastle upon Tyne, NE2 4BW, UK
3. Consultant in Oral Medicine, Newcastle Dental Hospital and School, Framlington Place, Newcastle upon Tyne, NE2 4BW, UK