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.

 This study was conducted to clarify factors associated with tooth loss during a 10 - year period among adult community residents with a wide age range.

 In a small village in Aichi Prefecture, of the 766 participants who underwent an oral examination in fiscal 2001, 382 underwent the same examination in 2011. A multivariate logistic regression model was used to quantify individual risk factors for the loss of one or more and three or more teeth, which were considered as dependent variables. In order to clarify risk factors for tooth loss per tooth unit, multi-level multivariate logistic regression analysis was performed using tooth loss per tooth unit as a dependent variable, and using independent variables for individual and tooth-level factors.

 The results of analysis for individual tooth loss showed that tooth loss was significantly correlated with the age, number of teeth present, and awareness of gum swelling. The age, number of teeth present, periodontal condition, awareness of gum bleeding, and smoking habit were all significantly correlated with the loss of three or more teeth. The results of analysis showed that the age, sex, number of teeth present, periodontal condition, and awareness of gum swelling as individual factors were significantly correlated with tooth loss per tooth unit, and regarding tooth-level factors, decayed or filled teeth compared with healthy teeth, and molars or premolars compared with lower incisors showed a significantly higher risk of tooth loss per tooth unit.

 This retrospective cohort study using data from oral examinations in a single municipality revealed factors associated with tooth loss among adults. The results suggest that it is necessary to recommend oral hygiene guidance and periodic dental checkups for persons with a high risk of tooth loss during dental examinations in the future.

Abstract in Japaneses

Abstract in Japaneses

Abstract in Japaneses