1. Department of Dentistry, National Yang-Ming University, No. 155, Sec. 2, Linong St., Beitou District, Taipei 112, Taiwan
2. Department of Stomatology, Veterans General Hospital Taipei, No. 201, Section 2, Shipai Road, Beitou District, Taipei City 112, Taiwan
3. Department of Dentistry, Taipei City Hospital, No. 145, Zhengzhou Rd., Datong District, Taipei 103, Taiwan
4. School of Dentistry, Taipei Medical University, No. 250 Wu-Xing Street, Taipei 110, Taiwan