1. Department of Oral Surgery, Shanghai Ninth People's Hospital Shanghai Jiao Tong University School of Medicine Shanghai China
2. Kathmandu Dental Hospital and Research Center Kathmandu Nepal
3. Department of Craniomaxillofacial and Plastic Surgery, Faculty of Dentistry Alexandria University Alexandria Egypt
4. Biostatistics Office of Clinical Research Unit, Shanghai Ninth People's Hospital Shanghai Jiao Tong University School of Medicine Shanghai China