Abstract: PURPOSE: To investigate the prevelence of early childhood caries (ECC) and its related risk factors in children aged 3 to 5 years old in Shanghai. METHODS: According to the requirements of the Fourth National Epidemiological Survey of Oral Health, multistage, stratified, equal capacity and simple random sampling method was performed. A total of 1 296 children aged 3, 4 and 5 years old in 12 kindergartens in Shanghai were selected to calculate the prevalence and the mean dmft(decayed-missing-filled tooth). Their parents were surveyed with questionnaire on oral hygiene habit and consciousness of oral health and related factors. Statistical analysis were performed using SPSS 21.0 software package. RESULTS: The prevalence of ECC were 58.07% in children aged 3 to 5 years old in Shanghai, with dmft index of 2.99 in average. There were significant differences in the mean dmft and the prevalence between male and female and among different age groups(P<0.05). In multivariate logistic regression analysis, more frequent sweet drinks, eating sweets before sleep, less daily tooth brushing, starting tooth brushing after 2 years old and low level of parents' education and oral health knowledge were risk factors for dental caries. CONCLUSIONS: The prevalence of ECC in children aged 3 to 5 years old in Shanghai is severe. There is an urgent need for implementation of a systematic education on diet habit and oral health behavior, and the parental education on oral hygiene needs to be further improved.

Key words: The Fourth National Epidemiological Survey of Oral Health, Early childhood caries, Risk factors