Dental caries status and its associated factors among schoolchildren aged 6–8 years in Hangzhou, China: a cross-sectional study

Abstract Background Dental caries prevalence reaches the first peak around 6 years old. It is necessary to take effective measures to prevent and treat caries at this stage. This study investigated the prevalence and associated factors of dental caries among schoolchildren aged 6–8 years in Hangzhou City, China. Methods A cross-sectional survey was conducted in Hangzhou from October 2017 to May 2018. Oral health status of schoolchildren in 1st and 2nd grades of primary schools aged 6–8 years was examined by well-trained examiners according to the WHO criteria. Questionnaires about potential caries-related factors were distributed to their parents. ANOVA test and logistic regression were conducted for the statistical analyses (α = 0.05). Results A total of 7959 pairs of schoolchildren and their parents were invited to participate, and 5595 were included in this study according to the eligible criteria (response rate: 70.3%). The overall prevalence and mean dmft/DMFT of dental caries in the investigated schoolchildren were 52.78% and 2.11. The prevalence and mean dmft/DMFT were 39.05% and 1.63 in the deciduous teeth, while these were 21.45% and 0.48 in the permanent teeth, respectively. For the first permanent molars (FPMs), the rate of fully eruption and pit and fissure sealing (PFS) were 79.09% and 6.60%, respectively. Multiple logistic regression showed that girl (OR = 1.12, 95% CI 1.01–1.25, p