Fig. 1

Standardized path coefficients of the hypothesized model 1 and model 2. Model 1: We assumed that dental caries (dmft) were directly influenced by SES, oral health knowledge, oral health attitudes, dietary behaviours, tooth brushing behaviours and dental attendance. Simultaneously, SES, oral health knowledge and oral health attitudes directly affected dietary behaviours and tooth brushing and dental attendance. Additionally, SES and oral health knowledge directly affected oral health attitudes, and SES directly influenced oral health knowledge. Model 2: based on the model 1, we assumed that oral health knowledge and attitude were directly affected by dental attendance and SES. Meanwhile, SES directly affected dental attendance. Red solid arrows mean significant effect while blue solid arrows indicate insignificant effect (the significant for path coefficients was set at 0.05, * P < 0.05, ** P < 0.01, ***P < 0.001)