Low Stimulated Salivary Rate Associated with Increasing Dental Caries in Caries-free Permanent Teeth among School-aged Children: Two-year Prospective Cohort Study

Abstract

 The purpose of this study was to investigate whether saliva is associated with the occurrence of dental caries in caries-free teeth among primary school children. Two public primary schools participated in this study. The study population of the cohort study was 100 primary school pupils with caries-free permanent teeth, aged 9 to 10 years old (38 boys and 62 girls), followed up for 2 years. This survey was conducted from 2013 to 2015 in one school and from 2014 to 2016 in another school. The association between the occurrence of dental caries (dependent variable) in caries-free teeth and salivary flow rate as a continuous value (independent variable) was assessed using multiple logistic regression analysis. During the observation period, dental caries occurred in 30 pupils (30%). Multiple logistic regression analysis showed that a low salivary flow rate was significantly correlated with the occurrence of dental caries in primary school children who were initially caries-free (odds ratio: 0.38, 95% confidence interval: 0.16-0.90). Therefore, attention should be paid to children with low salivary flow rates even if their permanent teeth are caries-free.