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; The Fourth Military Medical University; Xi'an Shaanxi P.R.China
2. Department of Stomatology; Chinese PLA 359 Hospital; Zhenjiang P.R. China
3. Stomatology Department; Nanjing Jinling Hospital; Nanjing Jiangsu P.R.China