1. Department of Prosthodontics; School of Stomatology; China Medical University; Shenyang China
2. Center of Implant Dentistry; School of Stomatology; China Medical University; Shenyang China
3. Section of Removable Prosthodontics; Division of Oral Rehabilitation; Faculty of Dental Science; Kyushu University; Fukuoka Japan
4. Department of Oral Implantology; School and Hospital of Stomatology; Peking University; Beijing China