1. School of Dentistry, College of Oral Medicine, Taipei Medical University, Taipei City 110301, Taiwan
2. Department of Dentistry, Shuang Ho Hospital, Taipei Medical University, New Taipei City 235041, Taiwan
3. School of Dentistry and Graduate Institute of Dental Science, National Defense Medical Center, Taipei City 114201, Taiwan
4. School of Oral Hygiene, College of Oral Medicine, Taipei Medical University, Taipei City 110301, Taiwan
5. Department of Periodontics, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO 64108, USA
6. Division of Prosthodontics, Department of Dentistry, Taipei Medical University Hospital, Taipei City 11031, Taiwan