J S Chin1, C D Lynch2, J Rees3, M Locke4, M B M Thomas5, L D Addy5. 1. Specialty Registrar in Restorative Dentistry, Cardiff University School of Dentistry, Heath Park, Cardiff. 2. Professor/Consultant in Restorative Dentistry, University College Cork, Wilton, Cork, Ireland. 3. Professor/Honorary Consultant in Restorative Dentistry, Cardiff University School of Dentistry, Heath Park, Cardiff. 4. Senior Clinical Lecturer/Honorary Consultant in Restorative Dentistry, Cardiff University School of Dentistry, Heath Park, Cardiff. 5. Consultant in Restorative Dentistry, Cardiff University School of Dentistry, Heath Park, Cardiff.