Objective  To examine the status of oral health among preschool children in Shenzhen city and to provide evidences for formulating oral health strategies and promoting oral health in preschool children.

  Methods  Using stratified multistage isometric random sampling, we carried out a survey among 1 892 children aged 3 − 5 years recruited at 12 kindergartens in 4 districts of Shenzhen city from October 30 to November 23, 2018. Examination methods and standards for the Fourth National Oral Health Survey were adopted in detections of deciduous tooth caries among the children and face-to-face interviews on the children′s oral health behaviors were conducted among the parents of the children.

  Results  Totally 1 834 children completed the survey. Among the children aged 3, 4 and 5 years, the prevalence rate of dental caries was 47.54%, 58.77% and 72.3%; the decayed-missing-filled tooth (dmft) index was 2.06, 3.27 and 4.52; and the caries filling rate was 2.67%, 6.09% and 15.02%, respectively. The 4 and 5 years old children in regions with good economic development had significantly lower dmft compared to the children of same age group in regions with poor economic development (t = 2.76, P = 0.01 and t = 3.36, P = 0.001). No significant differences in prevalence rate of deciduous tooth caries and dmft index were observed between the children of other age groups in regions with good and poor economic development (P > 0.05 for all). Unconditional multivariate logistic regression analysis revealed that age, economic development of living region, frequency of sugar intake and dessert intake before going to bed were correlated significantly with the prevalence of deciduous tooth caries among the children (P < 0.05 for all).

  Conclusion  The prevalence of deciduous tooth caries is relatively high among 3 – 5 years old children in Shenzhen city and measures for prevention and treatment of the dental disease should be promoted in the children.