1. Department of Periodontics; the First Affiliated Hospital; Harbin Medical University; Harbin Heilongjiang China
2. Longjiang Scholar Laboratory; the First Affiliated Hospital; Harbin Medical University; Harbin Heilongjiang China
3. Department of Biomedical Sciences and Center for Craniofacial Research and Diagnosis; Texas, A&M University, Baylor College of Dentistry; Dallas TX USA