Abstract: Objective: To evaluate the effect of 2. 26 mg/mL fluoride varnish(Duraphat) applications on prevention for enamel demineralization during orthodontic treatment with fixed appliance．Methods: The study was based on a random clinical trial. In accordance with inclusion criteria，60 orthodontic patients were randomly selected into a test group and a control group. The patients in test group were used topical application of fluoride varnish at every 6 months during 24 months of orthodontic treatment and follow-up．Results: The enamel demineralization was significantly lower in test group than in control group during orthodontic treatment with fixed appliance(P＜0. 05).Conclusion: The effect of 2. 26 mg/mL fluoride varnish used for prevention of enamel demineralization during orthodontic treatment was remarkable．

Key words: Orthodontics, Fluoride varnish, Enamel demineralization, Remineralization