1. UCL Eastman Dental Institute; Unit of Periodontology and International Centre for Evidence-Based Oral Healthcare; 256 Gray's Inn Road London UK WC1X 8LD
2. School of Dentistry, The University of Manchester; Cochrane Oral Health Group; Coupland III Building, 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