Methods: This research was carried out on 845 primary schoolchildren aged 9 yr in Kerman, Iran, in 2012. Ten variables, including health records, family structure information and a dmft/DMFT index, were collected. Children were categorized into three groups based on the WHO caries severity classification. Low caries level was defined as dmft/DMFT4.4. The Cochran–Armitage test and ordinal logistic regression were employed for data analysis.