RÉSUMÉ
Objective @#To investigate the effectiveness of fluoride varnish in preventing first permanent molars caries inschool-age children and provide necessary information for oral health instruction. @*Methods@#378 children aged 6-7 years old in the first grade of primary school in dahua country, hechi city, Guangxi province (1 053 first permanent molars) were randomly recruited into 2 groups. The test group (542 first permanent molars in 191 children) was treated with fluoride varnish one time in a half year and given oral hygiene instruction 3 times; The control group (511 first permanent molars in 187 children) was only given oral hygiene instruction 3 times. All first permanent molars were checked after 18 months later for caries. @*Results@#After intervention, the caries prevalence rate in the test group raised from 21.99% to 27.75% compared with the control group from 24.60% to 37.43%. The caries incidence rate in test and control group was 5.76% and 12.83% respectively. There was a significant difference between 2 groups regardless of caries prevalence, caries incidence, the DMFT reduction, the DMFs reduction, the occlusal caries prevalence, the pit and fissure caries prevalence, the proximal caries prevalence. @*Conclusion @#Semi-annual application of fluoride varnish is effective in the prevention of dental caries in first permanent molars , which was worth of being popularized in clinic.