Introduction:

Early childhood caries remains a major public health concern in rapidly urbanizing regions of China, yet age-specific patterns of disease accumulation in preschoolers are not well described. This study aimed to characterize age-related trends in dental caries experience among 3- to 5-year-old children in Shenzhen.

Methods:

A cross-sectional survey was conducted in 2024 using a multistage random sampling method to recruit preschool children from 27 kindergartens in Shenzhen. Two calibrated examiners performed oral examinations in the kindergartens using disposable dental mirrors with LED illumination and ball-ended Community Periodontal Index probes. Dental caries experience was recorded using the decayed, missing, and filled teeth (dmft) index, following World Health Organization recommendations.

Results:

Out of the 4,015 invited children, 3,534 (1,886 boys, 53%) completed the survey (response rate: 88%). The prevalence of caries experience was 31% at age 3, 49% at age 4, and 58% at age 5, indicating that an additional 27% of children developed caries experience over the two-year age span. 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, corresponding to a cumulative increase of 1.6 affected teeth per child. Upper central incisors were the most frequently affected teeth (23%) at age 3 and remained the most susceptible across all ages, while caries in lower molars increased from 7% at age 3 to 24% at age 5.

Conclusions:

Dental caries prevalence and severity among preschool children in Shenzhen increase markedly with age. These findings highlight the urgent need for targeted preventive strategies focusing on high-risk teeth, particularly the upper central incisors and lower molars, to curb the growing burden of early childhood caries in this population.