1. Department of Stomatology, Fourth Affiliated Hospital, Hebei Medical University, Shijiazhuang, 050000, China
2. Department of Stomatology, Affiliated Hospital of Hebei University, Baoding, Hebei, 071000, China
3. Department of Stomatology, Second Hospital of Shijiazhuang, Shijiazhuang, Hebei, 050000, China
4. Department of Stomatology, First Outpatient Department of Hebei Province, Shijiazhuang, Hebei, 050000, China