【名词&注释】
预防措施(preventive measures)、学龄儿童(school children)、口腔卫生习惯(oral hygiene practices)、窝沟龋(fissure caries)、颗粒状(granular)
[单选题]牙拔除后至少多长时间,拔牙创内形成凝血块而将创口封闭
A. 5min B. 10min C. 15min D. 30min E. 45min