1. Department of Orofacial Sciences, School of Dentistry, University of California San Francisco, San Francisco, CA, USA
2. State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Periodontology, West China School of Stomatology, Sichuan University, Chengdu, China
3. Department of Periodontology, Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-sen University, Guangzhou, China
4. Department of Life Science Dentistry, The Nippon Dental University, Tokyo, Japan
5. Department of Periodontology, The Nippon Dental University School of Life Dentistry at Tokyo, Tokyo, Japan