Age-Related Trends of Caries Experience Among Preschool Children in Shenzhen, China: A Cross-Sectional Study

Objectives: This study aimed to characterize the age-related trends of caries experience among preschool children in Shenzhen, China. Methods: This cross-sectional study recruited 3- to 5-year-old preschool children in Shenzhen via a multistage random sampling method in 2024. Two calibrated examiners conducted oral examinations in kindergartens using disposable dental mirrors with LED illumination and ball-ended Community Periodontal Index probes. Caries experience was recorded using the dmft index, as recommended by the World Health Organization. Results: This study invited 4015 children from 27 selected kindergartens, and 3534 children (1886 boys, 53%) completed the survey. The response rate was 88%. The prevalence of caries experience was 31% at age 3, 49% at age 4, and 58% at age 5, representing a 27% higher prevalence in 5-year-olds than in 3-year-olds. The mean dmft scores (±SD) were 1.2 ± 2.5 for 3-year-olds, 2.2 ± 3.2 for 4-year-olds, and 2.8 ± 3.5 for 5-year-olds, indicating a 1.6 affected teeth higher mean dmft in 5-year-olds than in 3-year-olds. The upper central incisors were the most affected teeth (23%) in 3-year-olds and remained the most susceptible across all age groups, while the prevalence of caries in lower molars increased progressively from 7% at age 3 to 24% at age 5. Conclusions: Dental caries prevalence and severity among preschool children in Shenzhen increase significantly with age. These findings highlight the need for targeted preventive strategies focusing on high-risk teeth, including the upper central incisors and lower molars, to address the rising burden of early childhood caries in this population.