1. Department of Oral Implantology, State Key Laboratory of Military Stomatology; School of Stomatology, The Fourth Military Medical University; Xi'an 710032 People's Republic of China
2. Department of Material Science and Engineering; Xi'an University of Science and Technology; Xi'an Shaan Xi 710054 People's Republic of China
3. Department of Prosthodontics, State Key Laboratory of Military Stomatology; School of Stomatology The Fourth Military Medical University; Xi'an 710032 People's Republic of China