1. Doctoral student, Dept. of Clinical Dental Sciences, Faculty of Medicine, The University of Liverpool, GB.
2. Lecturer, Honorary consultant, Unit of Prosthodontics, University Dental Hospital of Manchester, GB.
3. Emeritus professor, Senior Research Fellow, Dept. of Clinical Dental Sciences, Faculty of Medicine, The University of Liverpool, GB.
4. Senior lecturer, Dept. of Clinical Dental Sciences, Faculty of Medicine, The University of Liverpool, GB.