ABSTRACT
Background: Dental caries are the most common diseases in Vietnam and the World. There are some risk factors influencing diseases.Objectives: (1) describe dental caries prevalence in first and second molars, and (2) risk factors of the first molars. Subjects and method: The cross sectional study was applied with sample size of 377 students in Khuong Thuong primary school in 2005. Structured questionnaries were used to collect information on individual characteristics, eating habits and dental hygienic practices. Results: prevalence of the below first molars was highest (35,3%-36,5%). The prevalence of the above first molars was 8,4%. The logistic regression analysis show that students who had poor tooth brushed practice have higher dental caries prevalence significantly. Hygiennic dental education is important and needed to reduce dental caries.Conclusion:The prevalence of the first molars was higher than the prevalence of the second molars. The prevalence of the first below molars was higher than that in the first above molars. Wrong tooth brushing was a determinant of dental caries.