Department of Dentistry, Far Eastern Memorial Hospital, New Taipei City, Taiwan; 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. 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. Department of Dentistry, Far Eastern Memorial Hospital, New Taipei City, Taiwan; Graduate Institute of Clinical Dentistry, School of Dentistry, National Taiwan University, Taipei, Taiwan. 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 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. Electronic address: andysun7702@yahoo.com.tw.