Caries status and risk factors among urban and rural primary students in Thua Thien Hue Province, Vietnam

Background: Dental caries is an essential public health problem in most developing countries including Vietnam. This study's aims were to discover the dental caries prevalence in selected areas of Thua Thien Hue province, Vietnam, and to detect the association of sweet food consumption and oral hygiene practices with caries among Vietnamese primary school students. Methods: A cross-sectional study was conducted in Hue City and in Nam Dong District as one urban and one rural areas of Thua Thien Hue province, Vietnam that identifies the dental caries prevalence and to find participants for the matched case-control study. Each child in the dental caries group was matched to a student in the non-caries group using multivariate matched sampling methods that incorporated the propensity score. Practices related to dental hygiene and sweet food consumption were obtained using an intervieweradministered questionnaire for the matched case-control study. Results: Prevalence of dental caries in Hue City was 77.9% and in Nam Dong District was 77.3%, giving no statistically significant difference between two areas. Brushing teeth and replacing toothbrush frequently were related to the presence of dental caries in both urban and rural areas. Children who brushed teeth at least twice a day were less likely to have dental caries compared to those who did not (adjusted odds ratio [aOR], 0.42; 95% CI, 0.29–0.62; P < 0.001). The odds of having dental caries were significantly higher among children who replaced their toothbrush after at least each nine months than among those who replaced toothbrushes less than every three months (aOR, 2.66; 95% CI, 1.77–4.01; P < 0.001). Conclusion: The prevalence of dental caries was equally high among primary students in Hue City and Nam Dong District. Using toothbrush correctly more than twice per day and replacing the toothbrush every three months can reduce dental caries among primary school students.