Objective To study the risk factors of severe early childhood caries( SECC) among 5 years old children in Guangzhou,and to provide theoretical evidence for developing scientific and effective interventions. Methods 1 ∶1 matched case-control study was conducted in 244 cases with SECC and 244 controls with no caries based on population survey. Univariate and multivariate conditional Logistic regressions were used to analyze the factors influencing SECC.Results Multivariate conditional Logistic regression show...