1. Department of Endodontics and Operative Dentistry; Ninth People's Hospital; Shanghai Key Laboratory of Stomatology; School of Medicine; Shanghai Jiao Tong University; Shanghai; 200011; China
2. Department of Periodontology; Jiangsu Province Stomatological Hospital; Institute of Stomatology; Nanjing Medical University; Nanjing; Jiangsu; 210029; China