1. Oral Medicine, Division of Maxillofacial Diagnostic, Medical & Surgical Sciences, Eastman Dental Institute for Oral Health Care Sciences, UCL, University of London, 256, Gray’s Inn Road, London WC1X 8LD, UK;
2. Community Dental Department, Coventry NHS Primary Care Trust, Abbey View, 271 London Road, Coventry, West Midlands CV3 4AR, UK;
3. Department of Nephrology, University Hospitals Coventry and Warwickshire NHS Trust, Coventry, West Midlands CV2 2DX, UK; and
4. Health Services Research, Eastman Dental Institute for Oral Health Care Sciences, UCL, University of London, 256, Gray’s Inn Road, London WC1X 8LD, UK;