1. UCL Eastman Dental Institute; Unit of Periodontology and International Centre for Evidence-Based Oral Health; 256 Gray's Inn Road London UK WC1X 8LD
2. Division of Dentistry, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester; Cochrane Oral Health; Coupland Building 3 Oxford Road Manchester UK M13 9PL
3. UCL Eastman Dental Institute; Unit of Periodontology, Division of Restorative Dental Sciences; 256 Gray's Inn Road London UK WC1X 8LD