Abstract: Abstract: Objective To investigate the caries prevalence of permanent teeth among the Yi students aged 7~14 years old at Liangshan prefecture, Sichuan, and to provide scientific basis for the prevention and treatment of caries for the primary and middle school students in the area. Methods According to the caries diagnostic criteria of WHO, stratified sampling, random sampling and cluster sampling were used in the survey. The caries status of 954 Yi students aged 7, 9, 12 and 14 years old was examined. The result was statistically analyzed by SPSS 13.0. Results The total caries prevalence rate of the permanent teeth was 43.50% and DMFT was 1.21. The prevalence rate of girls was 50.52%, which was higher than that of boys (36.48%). The difference was statistically significant (P＜0.01). The permanent teeth caries prevalence increased obviously with age. The dental caries concentrated in the first permanent molar, and it occurred more in the mandibles than in the maxillaries. The total filling rate of dental caries is zero. Conclusions The caries status of the permanent teeth among Yi students at Liangshan prefecture is serious, and there are no prevention and treatment, so that their oral health care should be paid great attention.

Key words: permanent tooth , dental caries , Yi students , Liangshan Prefecture