1. State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Engineering Research Center for Dental Materials and Advanced Manufacture Department of Periodontology School of Stomatology Air Force Medical University Xi'an Shaanxi People's Republic of China
2. State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi International Joint Research Center for Oral Diseases Center for Tissue Engineering School of Stomatology Air Force Medical University Xi'an Shaanxi People's Republic of China