Yu Hsueh Wu1, Yi-Ping Wang2, Sang-Heng Kok3, Julia Yu Fong Chang4. 1. Graduate Institute of Clinical Dentistry, School of Dentistry, National Taiwan University, Taipei, Taiwan. 2. Graduate Institute of Clinical Dentistry, School of Dentistry, National Taiwan University, Taipei, Taiwan; Department of Dentistry, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan; Graduate Institute of Oral Biology, School of Dentistry, National Taiwan University, Taipei, Taiwan. 3. Graduate Institute of Clinical Dentistry, School of Dentistry, National Taiwan University, Taipei, Taiwan; Department of Dentistry, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan. 4. Graduate Institute of Clinical Dentistry, School of Dentistry, National Taiwan University, Taipei, Taiwan; Department of Dentistry, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan; Graduate Institute of Oral Biology, School of Dentistry, National Taiwan University, Taipei, Taiwan. Electronic address: jyfchang@ntu.edu.tw.