2.11. Statistical analysis
caries
CARIES, PLAQUE
After completion of the trial, the obtained data were entered in Epi Data 3.0 and analyzed using Statistical Product and Service Solutions (SPSS) (IBM company, the United States, version 23.0). The level of significance was set at Based on the results of the normality test and homogeneity of variance test, parametric analysis or non-parametric analysis methods were selected:Pearson chi-square test was used to analyze parents' diploma degree, family income, whether one-child, caries risk assessment items, oral health-related behavior, and caries filled rate in two groups before and after a year. Fisher exact probability method was used when the sample size was <40 or the theoretical frequency was <1. For row × list data, if the theoretical frequency of more than 1/5 grids was <5, or one theoretical frequency was <1, the likelihood-ratio test could be used.The Mann-Whitney U test was used to analyze the DMFS index of first permanent molars, plaque index, and the score of oral health knowledge and attitude in two groups before and after 1 year.