The American Children's Dental Association defines early childhood caries (ECC) as the presence of one or more cavities, missing teeth (due to caries) or fillings on the surfaces of teeth in children who are younger than 71 months. 1 Over the past few decades, ECC has become the most common oral disease in children, affecting children's health, growth, quality of life and even psychological status. 2 ECC is influenced by many factors, including genetic, dietary and environmental ones. Some studies showed that children's sugar intake and frequency, 3 breast-feeding time, 4,5 brushing frequency, 6 fluoride use, 7 children's body mass index 8 and even parents' smoking history 9 are all possible risk factors for ECC. China has been actively exploring methods to prevent and treat ECC by formulating policies on oral health for children and vigorously promoting oral health-related knowledge. A national oral health epidemiological survey is conducted every ten years. The fourth national survey (2016) showed that the incidence rate of primary tooth caries in children aged 3-5 years was 62.5% with a mean decayed, missing and filled teeth (dmft) score of 3.35. Compared this survey with the

ObjectivesThis work aims to examining the latest early childhood caries situation in children aged 3 and 5 and its related risk factors in Zhejiang Province during the COVID-19 pandemic.MethodThere are 3,537 children and their main caregivers participate in this study. We used chi square test or U-test to analyze whether there were differences in the prevalence of dental caries under different variables. The risk factors on ECC were determined by multivariate logistic analysis.ResultsThe ECC rate of children in this study was 57.51%. The mean decayed missing filled teeth (dmft) scores were 3.01. The result of multivariate logistic analysis showed higher ECC prevalence was found in children as age increasing, with lower district economic level, with high frequency of confectionary consumption, having oral medical treatment behavior and bad evaluation of children's oral health by parents.ConclusionIn general, the prevalence rate of ECC in this study was lower than five years ago, but still higher than those developed countries. And it was associated with age, district economic level, frequency of confectionary consumption, oral medical treatment behavior and evaluation of children's oral health by parents.