Abstract: Objective To explore and analyze the status of dental caries among junior high school students in Zhangjiakou and the impact of oral health-related behaviors on dental caries in this population, to provide a basis for the publicity and education of oral health-related behaviors. Methods A stratified and multi-stage random sampling method was used to select middle schools. Oral examination and oral health-related behavior survey were conducted on all junior high school students in the selected schools. The descriptive analysis method was used to analyze the prevalence of dental caries among junior high school students, and univariate and multivariate analysis methods were used to analyze the influence of oral health-related behaviors on dental caries. Results A total of 2 029 junior high school students were investigated in oral examination and oral health-related behaviors, including 1 123 boys and 906 girls, aged 11-14 years; 1 187 only children, 842 non-only children; 1 106 parents with the highest education level of high school or below, 605 parents with the highest education level of technical secondary school / junior college, and 318 parents with the highest education level of bachelor or above. A total of 724 students with dental caries were detected, the prevalence rate was 35.68%, and the mean decayed-missing-filled teeth was （2.48 ± 0.77）. The filling rate of dental caries was 15.67%. The results of multivariate regression analysis showed that eating sweets before bed （OR=4.455）, the frequency of eating desserts≥2 times a day （OR=2.347）, incorrect brushing method （OR=4.754）, and having malocclusion （OR=1.956） were the risk factors of dental caries in junior high school students; brushing times≥2 times a day （OR=0.293）, brushing habit after deciduous tooth eruption （OR=0.262）, parental attention （OR=0.384）, correctly understanding of brushing bleeding （OR=0.304） were the protective factors of dental caries in junior high school students. Conclusion The prevalence of dental caries among junior high school students in Zhangjiakou is still relatively high. Poor eating habits, tooth brushing habits, parents' attention, and knowledge of dental knowledge affect the occurrence of dental caries. Parents and society need to increase their attention to dental caries in junior high school students.

Key words: Dental caries, Oral health, Middle school student, Children, Adolescents, Influencing factor