Impact of migration on oral health outcomes of children in multi-beneficial kindergartens in Nanning, Southern China: a cross-sectional study.

Objective: To explore the effect of children's migration on their oral health outcomes in multi-beneficial kindergartens in Jiangnan District, Nanning, China, and to provide a basis for improving the oral health of migrant children.

Methods: A cross-sectional study was conducted among 470 children aged 5 years in Jiangnan District, Nanning, Guangxi. A questionnaire was used to collect information on their demographic and socioeconomic background, migration experience, eating habits, oral hygiene behaviours and utilization of dental care services. Dental caries of primary teeth was examined using the decayed, missing, and filled teeth (dmft) index recommended by the World Health Organization. Dental caries experience and oral health-related behaviours were compared between migrant and resident children. The impact of children's migration attributes on their oral health outcomes was examined by univariate and multivariate analyses.

Results: Among the examined children, 52.3% were migrant children. The prevalence of caries among the children in multi-beneficial kindergartens was 78.3%, and the mean number of dmft was 5.73 ± 5.00. The prevalence of caries was 81.7% for migrant children and 74.6% for resident children (p = 0.060). No significant difference was found in the mean numbers of DMFT between migrant children and resident children (5.96 ± 4.81 vs. 5.47 ± 5.20, p = 0.139). There were significant differences in the frequency of tooth brushing (p = 0.023) and parental help with tooth brushing (p = 0.008), typical use of fluoride (p = 0.012), regular dental check-ups (p = 0.003) and experience of dental fillings for caries (p < 0.001) between migrant and resident children. The multivariate logistic regression analysis showed that among the children with caries, the proportion of resident children who had regular dental check-ups was 1.720 times higher than that of migrant children (95% CI = 1.155 ~ 2.560), and resident children were more likely to have caries filled than migrant children (OR = 3.313, 95% CI = 1.585 ~ 6.927).

Conclusion: Oral health status and oral health behaviours were poor among children in multi-beneficial kindergartens in Nanning, China, and migration might be a significant predictive indicator for the poor utilization of dental care services by children. The government departments should make special policy to promote the children's oral health in multi-beneficial kindergartens, and invest more to cover the migrant children's utilization of oral health services.