The aim of this study was to investigate the relationship between chewing behavior and oral conditions in elementary school children based on an intervention study.

The subjects were allocated into an intervention group (5th grade students, n=81) and a control group (5th grade students, n=39) in 2 elementary schools in Tokushima Prefecture, Japan. Eating habits were self-reported using a questionnaire in both groups. The PMA index (Schour-Massler index) of each subject in the intervention group was assessed. The school lunch program “Chewing 30” was performed 5 times per year using a chewing counter.

After the completion of the program, a significant difference in behavior change regarding “sufficient chewing” was observed between the intervention and control groups (p<0.01). The participants in the intervention group were sub-divided into 2 groups based on the change of “sufficient chewing”. The PMA index of the non-improved group significantly increased (p<0.05), while that of the improved group showed no significant difference.

These results suggest an association between insufficient chewing behavior and gingival inflammation in elementary school children. The program “Chewing 30” might be effective to prevent gingival inflammation in addition to promoting sufficient chewing.

There are 51 remote but inhabited islands in Nagasaki Prefecture. According to the results of a survey of dental disease, those who lived on islands had fewer teeth compared with mainland residents in Nagasaki Prefecture. This might be caused by poor accessibility to dental clinics experienced by residents on islands. However, this has yet to be studied. Nagasaki University surveyed dental disease among 1,053 residents living on Kabashima, Hisakajima, and Saganoshima (remote island with no dentist), Fukuejima, and Narushima in Goto City from 2005 to 2010. Goto City government conducted a questionnaire survey on experience and demand for dental treatment among residents living on Kabashima, Hisakajima, and Saganoshima in October 2010. Questionnaires were sent to all 477 households, and 166 of them responded. A total of 198 residents living on remote islands with no dentists had an average of 10.8 (S.D.=10.5) teeth, and 32.3% of them had lost all of their teeth. In comparison, 855 residents living on islands with dentists had an average of 15.9 (S.D.=10.4) teeth and 15.6% of them had lost all of their teeth. That is, residents who lived on islands with no dentist had fewer teeth and a high rate of edentulism compared with residents who lived on islands with dentists (p<0.01). About half of the residents of islands with no dentist (45.4%) had an experience of tooth extraction based on their own request in order to reduce the frequency of having to visit a dental clinic. Also, about 90% of respondents wanted to receive dental treatment on the island where they lived. It can be suggested that one reason for this is that patients who have acute dental symptoms might prefer tooth extraction rather than conservative treatment because there are temporal and geographical restrictions on remote islands with no dentist. On our targeted islands, a system for improving accessibility to dental clinics should be established urgently.

We investigated the associations among the oral health-related quality of life (OHRQoL) and oral status, health behaviors, and life environment to analyze factors which affect the OHRQoL. As the index of the OHRQoL, we used the General Oral Health Assessment Index (GOHAI).

The subjects were independent elderly people who used the two welfare facilities for the elderly in the city of Chiba, aged between 60 to 86. An anonymous self-administered questionnaire was completed by the subjects. The total number of subjects was 216, and the valid number of responses was 145.

The results of logistic regression analysis showed that a high GOHAI score was associated with higher numbers of remaining teeth, having regular dental check–ups, and a better subjective chewing ability. A better subjective chewing ability was particularly strongly associated with the GOHAI. These findings suggest that maintaining a better subjective chewing ability is important to maintain a good OHRQoL.

In conclusion, we found that a higher number of remaining teeth, having regular dental check–ups, and a better subjective chewing ability are associated with a better OHRQoL.

A reduction in oral health inequalities is required in policies in Japan and those of international academic societies. However, the nationwide status of oral health inequalities through various life-stages among the Japanese is unclear. Thus, a cross-sectional study was conducted using data from national surveys conducted by the government. We linked the Survey of Dental Diseases and Comprehensive Survey of Living Conditions conducted in 2005, and analyzed data of 3,157 individuals. Equivalized family expenditure was included as the variable for the socioeconomic status, while sex, age, and living area were used as covariates for analyses. Stratified analyses were conducted for early childhood (1 to 5 years; n=116), school age (6 to 19 years; n=353), adulthood (20 to 64 years; n=1,606), and an older age (65 years or older, n=1,082), As the independent variables, the presence of deciduous dental caries for early childhood, permanent dental caries for school age, advanced periodontal disease (CPI score 3 or 4) for adulthood, and edentulousness for older people were applied. Whether lower expenditure was associated with a higher prevalence of oral diseases or conditions was determined using Poisson regression analyses. The results demonstrated that periodontal disease in adults (p=0.001) and edentulousness at an older age (p<0.001) are associated with lower expenditure. In lower-expenditure households, permanent dental caries at school age were more prevalent, although this was not significant (p=0.066). We found no significant correlation between expenditure and the presence of deciduous dental caries in early childhood, but this could be attributed to the smaller sample size of the children. Approaches for reducing oral health inequalities by considering broader ranges of social determinants are required.

It is important to prevent lifestyle-related diseases to extend healthy life expectancy. Although maintaining oral health is known to prevent lifestyle-related diseases, the association has not yet been elucidated. Here, we investigated the association between oral health and lifestyle-related diseases in a population of community-dwelling people.

We recruited 2,523 people, aged 40-79　years, from subjects who participated in the 2007 Hisayama study. Each subject received a dental examination. To rate the oral health status, the number of teeth, periodontal pocket depth, and experience of dental caries were assessed. To rate the lifestyle-related disease status, the presence of diabetes, hypertension, and dyslipidemia was assessed. The absence of any disease was defined as “no lifestyle-related disease.” Subjects were stratified into two age groups (40-59 and 60-79 years). We performed logistic regression analysis with the no lifestyle-related disease condition as a dependent variable and the oral health status as the independent variable.

The percentage of subjects with no lifestyle-related disease was 42.0% in the 40-59-year-old group and 17.9% in the 60-79-year-old group. Logistic regression analysis showed that no lifestyle-related disease was associated with a greater number of teeth in the 40-59-year-old group and shallow pocket depth in the 60-79-year-old group, after adjusting for age, sex, body mass index, smoking, alcohol consumption, exercise, and occupational status.

Good oral health was associated with good general health, without lifestyle-related diseases. The results suggest that maintaining oral health may contribute to preventing lifestyle-related diseases.

The aim of this study was to investigate the use of fluoride toothpaste and the oral health behavior among preschool children in Tokushima City, Japan. The survey was carried out with a questionnaire administered to parents of 3-6-year-old children. The subjects consisted of 140 children in 2010 and 116 children in 2013. The rates of children who did not use toothpaste in 2010 and 2013 were 27.9 and 12.1%, respectively. Among users of toothpaste, the rate of users of fluoride toothpaste in 2013 was 100%, and the frequency of mouth rinsing after tooth brushing significantly decreased (p<0.05) compared with data in 2010. These results suggest that favorable behavioral changes regarding the use of fluoride toothpaste in preschool children were revealed by the surveys in 2010 and 2013. However, there were some problems regarding how to use fluoride toothpaste, such as frequent rinsing after tooth brushing.