1. Department of Dentistry, Tzu Chi General Hospital – Xindian Branch, New Taipei City, Taiwan, Republic of China.
2. School of Dentistry, Tri-Service General Hospital, Taipei City, Taiwan, Republic of China.
3. Department of Periodontology, School of Dentistry, National Defense Medical Center, Taipei City, Taiwan, Republic of China.
4. School of Public Health, National Defense Medical Center.