1. Plymouth University Peninsula Schools of Medicine and Dentistry; Peninsula Dental School; The John Bull Building, Tamar Science Park, Plymouth UK PL6 8BU
2. Cochrane; Bahrain Branch; Box 25438 Awali Bahrain
3. KCL Dental Institute; Division of Health and Social Care Research; Bessemer Road London UK SE5 9RW
4. Dental School of Shahid Beheshti University of Medical Sciences; Orthodontic Department; Evin Tehran Iran 19834