According to reports from the World Health Organization in 2014, non-communicable diseases (NCDs) are responsible for the deaths of more than 36 million people (~63% of the global total) annually, while infectious diseases are responsible for another 9.5 million (about 20% of the global total). Similar rates are seen in Japan, which has a super-aging society with increasing mortality due to cancer, ischemic heart disease, and pneumonia. Japan is also faced with national issues such as “the extension of healthy life expectancy” and “the reduction of health disparities”, which are the ultimate objectives to be realized through improvements in the lifestyle and social environment. Health care policies and approaches have therefore tended to shift in focus from society to the individual.

To date, we have investigated some novel nasal adjuvants for the improvement of mucosal vaccine that could induce a mucosal immune system in order to prevent invasion by infectious agents and environmental antigens through the mucosal surfaces. In this review, we briefly summarize our findings regarding the development and verification of novel nasal DNA adjuvants to target the activation of nasopharyngeal-associated lymphoid tissue (NALT) dendritic cells for use as nasal vaccines.

In addition, we examined whether nasal vaccines using our newly developed nasal DNA adjuvants are effective at preventing pneumococcal infection in elderly as well as young mice, and whether nasal immunization with Porphyromonas gingivalis (P. gingivalis) outer membrane protein and cholera toxin as an adjuvant prevents atherosclerosis induced by P. gingivalis infection.

We hope that the results of this study will promote the development of mucosal vaccine including nasal vaccines capable of controlling NCDs as well as infectious diseases in the near future, which will promote successful outcomes to help improve the quality of life of human beings in a super-aging society.

Studies have demonstrated that natural plant-derived components, such as crude drugs, have anti-inflammatory effects. In this study, we examined the topical application of dentifrices containing natural plant-derived components on the gingival surface in a rat periodontitis model. Wistar male rats (age: 8 weeks) were divided into three groups; natural plant-derived components group (n=6), natural plant-derived components + active ingredient group (n=4), and control group (n=6). A 3/0 silk ligature was placed in the subgingival position of the maxillary second molars to induce periodontitis for 4 weeks. After the silk ligature was removed, dentifrice containing 15 natural plant-derived components and kampo medicines, such as ninjin, toki and shakuyaku (natural plant-derived components group), or dentifrice containing 15 natural plant-derived components and 4 active ingredients, such as hinokitiol (natural plant-derived components + active ingredient group), was applied once a day for 2 weeks. The control group received no treatment. Polymorphonuclear leukocyte proliferation and expression of tumor necrosis factor-α and interleukin-1β in the natural plant-derived components group were lower than in the control group (p<0.05). These observations indicate that dentifrice containing natural plant-derived components has an anti-inflammatory effect on periodontitis in a rat model.

The purpose of this study was to calculate the number of dental hygienists (DH) required to provide sufficient preventive dental care for adults (Needed DH), to compare it with the number of dental hygienists actually employed (Employed DH), and to determine the status of preventive dental care for adults. Dental clinics in Yamanashi Prefecture, Japan were requested to complete a questionnaire that included the following queries: number of Employed DH, working hours, mean duration of preventive dental care sessions, frequency of regular dental health examinations, and dental treatment hours in the dental clinics. A formula was developed to analyze the collected data and calculate Needed DH based on them. Subsequently, the ratio of Needed DH to Employed DH was calculated. The mean durations of preventive dental care sessions in the dental clinics requiring additional DH in the shortest, most frequent, and longest sessions were 9.4, 18.1, and 32.0 minutes, respectively. While Employed DH was sufficient in the case of the shortest and most frequent sessions, it was insufficient in the case of the longest session, because the ratio of Needed DH/Employed DH in the longest session was 1.61.