儿童和青少年时期是人体生长发育的重要阶段。口腔颌面的生长发育,也是随着年龄的增长,而不断变化。如乳牙和恒牙在一定时期交替,又时常出现各类异常(有乳牙滞留致继承牙错位,前牙拥挤恒齿萌出困难等);乳牙和恒牙的钙化程度低,牙木质小管较粗大、牙髓腔也大,加上他们的饮食和口腔卫生习惯差,他们的龋齿患病率高,龋蚀发展快。据我国84年调查城市中小学生龋齿、牙周病患病率 Children and adolescents are an important stage of human growth and development. Oral and maxillofacial growth and development, but also with age, and constantly changing. Such as deciduous teeth and permanent teeth alternating at a certain period of time, they often appear all kinds of abnormalities (with deciduous teeth caused by inherited teeth dislocation, anterior teeth crowded permanent eruption difficulties); deciduous teeth and permanent teeth of low calcification, Endodontic cavity is also large, coupled with their poor diet and oral health habits, their dental caries prevalence rate, rapid development of caries. According to China’s 84-year survey of urban primary and secondary school students dental caries, the prevalence of periodontal disease