1. Department of Periodontics, School of Stomatology, China Medical University, Shenyang 110002, China
2. Department of Periodontics, Jinan Stomatological Hospital, Jinan 250001, China
3. Shenyang Dental Hospital, Shenyang 110002, China
4. Institute of Biotechnology and Department of Medical Science, National Tsing Hua University, Hsinchu 300, Taiwan