1. Department of Family Dentistry, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.
2. Department of Periodontics, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.
3. Department of Prosthodontics, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.
4. School of Dentistry, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
5. Department of Fiber and Composite Materials, Feng Chia University, Taichung, Taiwan.