Abstract: Objective: To understand the oral health status of preschool children in Minhang District during 2017-2021, to evaluate the effect of oral primary prevention, and to provide scientific reference for caries prevention. Methods: Forty public kindergartens in Minhang District were selected in 2017. From 2017 to 2021, oral examination, oral health education, fluoride varnish, and oral health status notification were carried out to obtain the oral health condition data of children and establish their personal oral health record. Results: During 2017-2021, the prevalence of caries and the mean dmft of children aged 3-5 increased with age (P<0.01). The prevalence of caries and the mean dmft of preschool children showed a downward trend from 2018 to 2020 (P<0.01) due to the effect of oral primary prevention. The caries filling rate of preschool children was low, which was less than 20% in 2021. Conclusion: For preschool children, the prevention and intervention of dental caries is the key, and oral primary prevention has a significant effect on dental caries prevention. Early filling of dental caries should be strengthened to improve the filling rate in preschool children.

Key words: preschool children, caries, oral primary prevention, fluoride varnish