1. Hebei Key Laboratory of Stomatology, School and Hospital of Stomatology, Hebei Medical University, Shijiazhuang, PR China
2. Department of Dental Pulp, School and Hospital of Stomatology, Hebei Medical University, Shijiazhuang, PR China
3. Department of Oral Mucosa, School and Hospital of Stomatology, Hebei Medical University, Shijiazhuang, PR China
4. School and Hospital of Stomatology, Hebei Medical University, Shijiazhuang, PR China