Correlation analysis of the permanent caries, primary caries and caries filling among Guangzhou primary and middle school students

Objective To evaluate the relationship among the number of primary caries and filled caries and dental caries,and toprovide the reference and basis for the prevention of dental caries.Methods A total of 5 272 students aged 7,9,12 and 14 in primary and middle schools of Guangzhou were offered with oral examination to record the situation of primary and permanent teeth and caries filling.And the negative binomial regression to analyze the impact of primary caries and filled caries on dental caries.Results The caries rates of deciduous teeth among students aged 7,9,12 in Guangzhou were 48.24%,45.21%,6.10%,respectively,and those of permanent teeth among students aged 7,9,12,14 were 0.61%,2.85%,10.14% and 14.28%,respectively.The caries rates of boys and girls were 35.04% and 34.08%,respectively,and the prevalence rates of permanent teeth were 4.88% and 8.82%,respectively.With a constant number of caries outcome variables,the research analyzed the impact of caries of constant caries,and after adjusting their age,gender and urban and rural areas,the estimated value in the negative two discrete parameter K regression modelwas 16.37(95%CI=9.27-28.90),the girls were usually more susceptible to constant caries.The older the students were,the higher intensity of their constant caries,and there were statistically significant (x2 =41.09,13.32,19,40,P <0.01);Two teeth fitting negative regression model showed that after adjustment for age,gender and urban and rural areas,association between students of caries filling of decidous and permanent teeth and permanent teeth caries were statistically significant(β =1.00,2.76,P<0.05).The dental caries of deciduous teeth caries filling had a protective effect on permanent teeth caries after incoporating deciduous and permanent teeth caries repair and compensation into the model (β =-1.09,95% CI=-1.72--0.46,P<0.01).And the association between permanent teeth caries filling and deciduous teeth caries was of statistical significance(β=2.99,3.02,95%CI=2.65-3.39,P<0.01).Conclusion The more serious denatl caries students in primary and middle schools suffer from,the more serious caries they have.Filling the deciduous teeth caries can reduce caries effectively.