The surface layer of the mucosa, which, in adult humans, is estimated to have a surface area over 200 times greater than that of the skin, is constantly in contact with foreign antigens, against which non-specific defense (innate immune mechanisms) and specific defense (acquired immune mechanisms) systems are activated. In the mucosal areas that are entry points for foreign antigens, the efficient production and secretion of secretory IgA (SIgA) antibodies, comprising the main form of specific defense, and mucosal vaccines, which are efficient antigen delivery systems for inducing and promoting antibody production, may offer strategic tools for preventing not only infections, but also the development of non-communicable diseases (NCDs). We have previously undertaken research and development of an immunostimulating agent (adjuvant) for use with mucosal vaccines based on mucosal immunity, particularly nasal vaccines that are administered to the nasal cavity. More specifically, a double DNA adjuvant (dDA) system that targets dendritic cells, which are antigen-presenting cells, was developed, and basic research was conducted using a number of different antigens, including a comparison of the immune response to these antigens when they were introduced into the nasal cavities of young and old experimental animals (mice). Recently, we have been working toward the development of a mucosal vaccine capable of preventing infection or NCDs that can also be used by older people. In this review article, I will introduce the advantages of mucosal vaccines as well as recent findings in our group. We anticipate the development of an effective tool in the near future whereby mucosal vaccines could prevent NCDs as well as various infectious diseases and fulfil the national goals of “the extension of healthy life expectancies” and “reduction of health disparities”. In addition, we hope that mucosal vaccines will markedly contribute to the oral health service in the super-aging society.

 The aim of this study was to compare factors related to the periodontal condition between pregnant and non-pregnant women, and analyze these factors to improve the oral environment of pregnant women.

 Three thousand three hundred and fifty-nine subjects who enrolled in the Dental Health Survey for Pregnant Women during 2016-2019 in Kochi Prefecture were included in the pregnant group, while 316 women of the same age in the 2020 Kochi Prefecture Dental and Oral Health Promotion Survey were included in the control group. Items regarding oral hygiene conditions and oral health behavior of both groups were compared in each age group. Furthermore, a binomial logistic regression analysis of the pregnant group was performed using the periodontal condition regarding “periodontal pocket” or “gingival bleeding” as the dependent variable.

 From the comparison of the questionnaire items, the rate of “swelling of the gums” in the pregnant group was significantly higher than that in the control group. From the comparison of the examination items, the rate of subjects with periodontal pockets in the pregnant group was higher than that in the control group. The proportion of pregnant women aged 16 to 24 years with “periodontal pocket” and “gingival bleeding” was larger than in the control group. There was no significant difference in current smoker rates between the two groups. In the pregnant group using the presence or absence of “periodontal pocket” or “gingival bleeding” as the dependent variable, “presence of a family dentist”, “use of adjunctive oral hygiene device”, and “malocclusion” showed significant correlations.

 These results suggest that an adverse periodontal condition may arise during pregnancy. It may be necessary to visit a family dentist and receive oral health guidance regarding the use of appropriate adjunctive oral hygiene devices in order to maintain a good oral condition during pregnancy.

 The aim of this study was to analyze factors influencing dental caries in 3-year-old children. In addition, we investigated the effect of prenatal oral health examination on oral health behavior related to dental caries by a retrospective cohort study.

 The subjects enrolled in this study were 647 children and their mothers who received oral health examinations from 2015 to 2020 at both the 18-month and 3-year-old health check-ups, which were conducted by Naruto City, Tokushima Prefecture, Japan. The relationship between dental caries in 3-year-old children and items related to oral health behavior were analyzed by binomial logistic regression analysis using the results of the questionnaire for the 18-month-old or 3-year-old child health check-ups. Furthermore, 480 subjects who had not received a dental check-up during pregnancy were divided into two groups: a prenatal examination group, who received prenatal oral health examination conducted by the municipality, and a non-examination group. Then, differences in oral health behavior after childbirth were analyzed between the two groups.

 The prevalence rate of dental caries in 3-year-old children was 14.5%. It showed that dental caries was significantly correlated with the frequency or regularity of eating between meals, regular dental check-ups, mothers’ knowledge of periodontal disease, and smoking habits of mothers or family members. In addition, the rate of mothers/children who acquired the behavior of regular dental check-ups after childbirth significantly increased, and the rate of regular dental check-ups of the mother at the 18-month-old child checkup was higher in the prenatal examination group when compared with the non-examination group.

 These results indicate that factors related to dental caries in 3-year-old children were eating between meals, regular dental check-ups, knowledge of periodontal disease, and smoking habits. Furthermore, prenatal oral health examinations may promote mothers’ acquisition of good health behavior for themselves or their child, such as understanding the necessity of having regular dental check-ups after childbirth.

 We performed a cross-sectional study to examine the association between Kasanetabe, defined as consuming ≥2 different types of staple foods as sources of carbohydrate at the same time, and periodontal disease among male workers. We analyzed data from 539 men who participated in annual health check-ups conducted at a company in Fukuoka Prefecture, Japan, along with dental examination, dietary survey, and questionnaire survey data. The periodontal pocket depths (PPDs) of 10 index teeth were measured during the dental examination. Dietary carbohydrate (g/day) was estimated with the dietary survey, and the top 20th percentile was defined as high intake. The outcome variable included the number of teeth with a 4-mm PPD. The exposure variable included the frequency of Kasanetabe (≥1 time per day or <1 time per day). A negative binomial regression model was used to assess the association between the above two variables. Furthermore, we constructed a model on the basis of the hypothesis that a high frequency of Kasanetabe is associated with high carbohydrate intake, which in turn might mediate the relationship between Kasanetabe and periodontal disease. We employed a generalized structural equation model (GSEM) to examine relationships and predictions among Kasanetabe, carbohydrate intake, and periodontal disease. A total of 14.8% of the study population engaged in Kasanetabe ≥1 time per day. Compared with those who engaged in Kasanetabe <1 time per day, those that engaged ≥1 time per day had significantly more teeth with a 4-mm PPD (incidence rate ratio=1.47, 95% confidence interval=1.10–1.96). GSEM revealed that a high frequency of Kasanetabe was associated with high carbohydrate intake. Moreover, GSEM revealed that a high frequency of Kasanetabe was significantly indirectly associated with periodontal disease and that high carbohydrate intake mediated this association.

 The aim of this cohort study was to investigate the association of calcaneus stiffness with the risk of tooth loss among older females in the Okhotsk area of Hokkaido, Japan. One hundred and sixty-two older females participated in this baseline survey in 2000. About five years after the baseline survey, 70 older females participated in follow–up survey. Written informed consent was obtained from the 70 participants. At the baseline survey, public health nurses interviewed the participants with a structured questionnaire. The survey items were age, history of systematic disease, habit of smoking, habit of alcohol drinking, frequency of eating foods such as milk, cheese or yogurt, small fish, soybeans product, seaweed, and processed foods, frequency of tooth brushing, frequency of seeing a home dental doctor, and number of deliveries. Dental examination was conducted by a trained dentist under sufficient artificial light, with a dental mirror, and explorers. The contents of the dental examination were diagnoses of dental caries (filling teeth, decayed teeth, and missing teeth). Anthropometric and calcaneus stiffness measurements were done by a clinical technologist. The body mass index (BMI) was obtained by dividing the weight in kilograms by the height in meters squared. Ultrasonographic heel measurements (A–1000 Express from Lunar, U.S.A.) were used for the calcaneus stiffness. Interview items at the follow–up survey in 2005 were almost the same as in the baseline survey. Dental examinations were conducted by the same dentists as in the baseline survey. Anthropometric and calcaneus stiffness measurements were also performed by a clinical technologist in the follow–up survey using the same devices. Risk factors for tooth loss were evaluated using simple and multivariate stepwise logistic regression. The results of multivariate analysis showed that the number of deliveries, frequency of eating green or yellow vegetables (≦five days a week), and frequency of tooth brushing (≦once a day) were significantly correlated with the risk of tooth loss. Stiffness was non-significantly associated with tooth loss. This study suggests that the number of deliveries and dietary habits are correlated with tooth loss.