氟化钠预防龋齿的研究已有四十余年的历史，大量的临床实践证明，无论全身或局都应用都是有效的。自1988年氟离子透入防朗在我市中小学校中推广使用，至今已有7个年头．这种群防工作，对减少学生的阐齿发病，起到了积极的作用，但其中也存在着一些卫生学问题。1存在细菌污染的 Sodium fluoride to prevent dental caries has been more than 40 years of history, a large number of clinical practice has proved that whether the whole body or the application is effective. Fluoride penetration since 1988, prevention and treatment of primary and secondary schools in our city to promote the use of, has been seven years. This group prevention work has played a positive role in reducing the number of students' articulation, but there are also some health problems. 1 Bacterial contamination