Abstract: PURPOSE: To investigate the prevalence of dental caries in primary teeth among school-age children through oral health examination of 8 primary schools in Xuhui District of Shanghai, and to provide a scientific basis for the prevention and control of caries. METHODS: A multi-stage cluster sampling method was used to select 11 344 school-age children aged 6-11 from eight public elementary schools in Xuhui District, Shanghai, as the survey subjects. Oral examinations were conducted according to the protocol of the Fourth National Oral Health Epidemiological Survey. The incidence of caries and the decayed, missing, and filled teeth(DMFT) index were analyzed by SAS 9.4 software package. RESULTS: The caries prevalence among the 11 344 school-age children was 30.61%, with a mean DMFT score of 0.97±1.96. The caries prevalence in primary teeth was 25.43%, with a mean DMFT score of 0.85±1.87; while the caries prevalence in permanent teeth was 7.58%, with a mean DMFT score of 0.12±0.47. There was no statistically significant difference in caries prevalence and DMFT scores of primary teeth between boys and girls. However, girls had a higher caries prevalence and DMFT score in permanent teeth compared to boys, and the differences were statistically significant(P<0.05). In different age groups, the caries prevalence in primary teeth initially increased with age and then decreased, with 8-year-old children having the highest prevalence. The caries prevalence in permanent teeth increased with age, and the differences were statistically significant(P<0.001). Regarding the position of the caries, the most affected primary teeth were the maxillary primary central incisors, primary molars, and mandibular primary molars; while the first permanent molars were the most affected permanent teeth. CONCLUSIONS: The prevalence of dental caries in both primary and permanent teeth among school-age children in Xuhui District of Shanghai is relatively high, and the affected teeth are concentrated. Early prevention and control of dental caries in school-age children should be strengthened.

Key words: School-age children, Dental caries, Prevalence of caries, DMFT score, Epidemiological investigation