1. Department of General Dentistry, School and Hospital of Stomatology, Peking University, Beijing, People’s Republic of China.
2. Discipline of Periodontics, Faculty of Dentistry, National University of Singapore, Singapore, Republic of Singapore.
3. Department of Endodontics, Jinan Stomatology Hospital, Jinan, Shandong, People’s Republic of China.
4. Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, MI.