*Chi-Hung Chen1, Yung-Chung Chen1,2
(1. School of Dentistry & Institute of Oral Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan, 2. Division of Prosthodontics, Department of Stomatology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan)