1. State Key Laboratory of Military Stomatology, Department of Oral Implantology, School of Stomatology; The Fourth Military Medical University; Xi'an 710032 People's Republic of China
2. State Key Laboratory of Military Stomatology, Department of Prosthodontics, School of Stomatology; The Fourth Military Medical University; Xi'an 710032 People's Republic of China
3. Department of Applied Chemistry, School of Science; Northwestern Polytechnical University; Xi'an 710072 People's Republic of China