ω3 fatty acid metabolite, 12-hydroxyeicosapentaenoic acid, alleviates contact hypersensitivity by downregulation of CXCL1 and CXCL2 gene expression in keratinocytes via retinoid X receptor α.

ω3 fatty acids show potent bioactivities via conversion into lipid mediators; therefore, metabolism of dietary lipids is a critical determinant in the properties of ω3 fatty acids in the control of allergic inflammatory diseases. However, metabolic progression of ω3 fatty acids in the skin and their roles in the regulation of skin inflammation remains to be clarified. In this study, we found that 12-hydroxyeicosapentaenoic acid (12-HEPE), which is a 12-lipoxygenase metabolite of eicosapentaenoic acid, was the prominent metabolite accumulated in the skin of mice fed ω3 fatty acid-rich linseed oil. Consistently, the gene expression levels of Alox12 and Alox12b, which encode proteins involved in the generation of 12-HEPE, were much higher in the skin than in the other tissues (eg, gut). We also found that the topical application of 12-HEPE inhibited the inflammation associated with contact hypersensitivity by inhibiting neutrophil infiltration into the skin. In human keratinocytes in vitro, 12-HEPE inhibited the expression of two genes encoding neutrophil chemoattractants, CXCL1 and CXCL2, via retinoid X receptor α. Together, the present results demonstrate that the metabolic progression of dietary ω3 fatty acids differs in different organs, and identify 12-HEPE as the dominant ω3 fatty acid metabolite in the skin.

Survey on Availability of Domiciliary Dental Care under 16-km Rule.

In Japan, domiciliary care fees are only covered by the public health insurance system if the clinic concerned is located within 16 km of the patient's residence. This nationwide rule does not take local conditions into account and therefore may not be appropriate. The goal of the present study was to assess the current state of domiciliary dental care nationwide in view of this restriction to clarify the current situation and any inherent problems. Six dental institutions providing domiciliary dental care were selected by location (urban or mountainous area) and size. Travel time from clinics to the 16 km points and the longest time required for the journey from clinics were investigated. Two of the dental clinics were located in depopulated areas with few dental institutions. These clinics had to provide domiciliary dental care not only in the 16-km area around the clinic, but also in areas over 16 km away. Travel time to the 16-km points was between 52 and 90 min. On the other hand, the longest time for actual visiting was between 30 and 60 min. In some areas, no domiciliary dental care was available within the 16 km limit. This indicates that the 16-km area is too wide to be covered by one dental institution alone and that it poses a problem in areas with few dental institutions. This suggests that it would be preferable to consider time required to visit rather than geographical distance in forming policy. The 16-km limit often spans multiple residential areas, indicating that greater coordination is needed between the Community-based Integrated Care System and dental offices.

Maternal ω3 docosapentaenoic acid inhibits infant allergic dermatitis through TRAIL-expressing plasmacytoid dendritic cells in mice.

BACKGROUND: Maternal dietary exposures are considered to influence the development of infant allergies through changes in the composition of breast milk. Cohort studies have shown that ω3 polyunsaturated fatty acids (PUFAs) in breast milk may have a beneficial effect on the preventing of allergies in infants; however, the underlying mechanisms remain to be investigated. We investigated how the maternal intake of dietary ω3 PUFAs affects fatty acid profiles in the breast milk and their pups and reduced the incidence of allergic diseases in the pups. METHODS: Contact hypersensitivity (CHS) induced by 2,4-dinitrofluorobenzene (DNFB) and fluorescein isothiocyanate was applied to the skin in pups reared by mother maintained with diets mainly containing ω3 or ω6 PUFAs. Skin inflammation, immune cell populations, and expression levels of immunomodulatory molecules in pups and/or human cell line were investigated by using flow cytometric, immunohistologic, and quantitative RT-PCR analyses. ω3 PUFA metabolites in breast milk and infant's serum were evaluated by lipidomics analysis using LC-MS/MS. RESULTS: We show that maternal intake of linseed oil, containing abundant ω3 α-linolenic acid, resulted in the increased levels of ω3 docosapentaenoic acid (DPA) and its 14-lipoxygenation products in the breast milk of mouse dams; these metabolites increased the expression of TNF-related apoptosis-inducing ligand (TRAIL) on plasmacytoid dendritic cells (pDCs) in their pups and thus inhibited infant CHS. Indeed, the administration of DPA-derived 14-lipoxygenation products to mouse pups ameliorated their DNFB CHS. CONCLUSION: These findings suggest that an inhibitory mechanism in infant skin allergy is induced through maternal metabolism of dietary ω3 PUFAs in mice.

Development of a bivalent food poisoning vaccine: augmented antigenicity of the C-terminus of Clostridium perfringens enterotoxin by fusion with the B subunit of Escherichia coli Shiga toxin 2.

Food poisonings caused by Clostridium perfringens and Shiga toxin (Stx)-producing Escherichia coli (STEC) occur frequently worldwide; however, no vaccine is currently available. Therefore, we aimed to develop a bivalent vaccine against C. perfringens and STEC infections. Although it has been considered that the C-terminal region of C. perfringens enterotoxin (C-CPE) could be a good vaccine antigen to block the binding to its receptor, it was insufficient for induction of a protective immune response because of the low antigenicity. However, the fusion of C-CPE with Stx2 B subunit (Stx2B) augmented the antigenicity of C-CPE without affecting the antigenicity of Stx2B. Indeed, high levels of C-CPE-specific neutralizing IgG were found in the serum of mice immunized with the fusion protein Stx2B-C-CPE. Additionally, comparable and substantial levels of Stx2B-specific neutralizing IgG were induced in mice receiving Stx2B-C-CPE or Stx2B alone. These antibody responses against C-CPE and Stx2B lasted for at least 48 weeks, which were sufficient for protective immunity in vitro and in vivo, indicating that Stx2B-C-CPE could induce long-term protective immunity. As an underlying mechanism, ex vivo stimulation with Stx2B, but not with C-CPE, induced cytokine production from splenic T cells collected from mice immunized with Stx2B-C-CPE, suggesting that Stx2B-specific, but not C-CPE-specific, T cells were induced by the immunization with Stx2B-C-CPE and plausibly promoted immunoglobulin class switching of both Stx2B- and C-CPE-specific B cells from IgM to IgG. These findings collectively indicate that Stx2B-C-CPE is a T-cell-antigen-supplement-type bivalent vaccine, which could be an efficient against C. perfringens and STEC infections.

How to Increase Number of Present Teeth in Elderly: Consideration of Percentile Curves for Present Teeth in Tokyo.

Maintaining dental and oral health and increasing healthy life expectancy are important issues for Japan as it deals with the rapid aging of its population. The purpose of this study was to determine effective dental health measures aimed at increasing the number of present teeth in the elderly. Change in the number of present teeth was determined based on data obtained from the 2009 and 2014 "Good Teeth Tokyo (Ii-ha Tokyo)" surveys carried out by the Tokyo Metropolitan Government. The number of present teeth and percentile curves were compared between these two time points. The number only showed a significant increase in individuals aged 60 years in 2014 (p<0.05). This may have been due to the establishment of a national public insurance system. The number of present teeth showed an increase in 2014 in the 25th, 50th, and 75th percentile curves. In the 75th and 90th percentile curves, tooth loss accelerated when the number of present teeth was fewer than 25. This finding is consistent with studies reporting that tooth loss itself is a risk for tooth loss. Tooth loss showed a slight acceleration between the ages of approximately 20 and 45 years in the 90th percentile curve. These results indicate that dental check-ups at universities and companies, periodontal disease check-ups performed by local governments, and health instruction at these check-ups are necessary to increase the number of present teeth in the elderly. They further suggest that implementing measures to promote periodic visits to dental clinics and providing incentives to undergo treatment for tooth defects are necessary in high-risk individuals. In conclusion, dental check-ups, health instruction, and strategies for high-risk individuals in their 20s and 40s are necessary to increase the number of present teeth in the elderly.

Dietary coconut oil ameliorates skin contact hypersensitivity through mead acid production in mice.

Coconut oil is used as a dietary oil worldwide, and its healthy effects are recognized by the fact that coconut oil is easy to digest, helps in weight management, increases healthy cholesterol, and provides instant energy. Although topical application of coconut oil is known to reduce skin infection and inflammation, whether dietary coconut oil has any role in decreasing skin inflammation is unknown. In this study, we showed the impact of dietary coconut oil in allergic skin inflammation by using a mouse model of contact hypersensitivity (CHS). Mice maintained on coconut oil showed amelioration of skin inflammation and increased levels of cis-5, 8, 11-eicosatrienoic acid (mead acid) in serum. Intraperitoneal injection of mead acid inhibited CHS and reduced the number of neutrophils infiltrating to the skin. Detailed mechanistic studies unveiled that mead acid inhibited the directional migration of neutrophils by inhibiting the filamentous actin polymerization and leukotriene B4 production required for secondary recruitment of neutrophils. Our findings provide valuable insights into the preventive roles of coconut oil and mead acid against skin inflammation, thereby offering attractive therapeutic possibilities.

Immunological association of inducible bronchus-associated lymphoid tissue organogenesis in Ag85B-rHPIV2 vaccine-induced anti-tuberculosis mucosal immune responses in mice.

We previously reported that Ag85B-expressing human parainfluenza type 2 virus (Ag85B-rHPIV2) was effective as a nasal vaccine against tuberculosis in mice; however, the mechanism by which it induces an immune response remains to be investigated. In the present study, we found that organogenesis of inducible bronchus-associated lymphoid tissue (iBALT) played a role in the induction of antigen-specific T cells and IgA antibody responses in the lung of mice intra-nasally administered Ag85B-rHPIV2. We found that expression of Ag85B was dispensable for the development of iBALT, suggesting that HPIV2 acted as an iBALT-inducing vector. When iBALT organogenesis was disrupted in Ag85B-rHPIV2-immunized mice, either by neutralization of the lymphotoxin pathway or depletion of CD11b+ cells, Ag85B-specific immune responses (i.e. IFN γ-producing T cells and IgA antibody) were diminished in the lung. Furthermore, we found that immunization with Ag85B-rHPIV2 induced neutrophil and eosinophil infiltration temporally after the immunization in the lung. Thus, our results show that iBALT organogenesis contributes to the induction of antigen-specific immune responses by Ag85B-rHPIV2 and that Ag85B-rHPIV2 provokes its immune responses without inducing long-lasting inflammation.

The 17,18-epoxyeicosatetraenoic acid-G protein-coupled receptor 40 axis ameliorates contact hypersensitivity by inhibiting neutrophil mobility in mice and cynomolgus macaques.

BACKGROUND: Metabolites of eicosapentaenoic acid exert various physiologic actions. 17,18-Epoxyeicosatetraenoic acid (17,18-EpETE) is a recently identified new class of antiallergic and anti-inflammatory lipid metabolite of eicosapentaenoic acid, but its effects on skin inflammation and the underlying mechanisms remain to be investigated. OBJECTIVE: We evaluated the effectiveness of 17,18-EpETE for control of contact hypersensitivity in mice and cynomolgus macaques. We further sought to reveal underlying mechanisms by identifying the responsible receptor and cellular target of 17,18-EpETE. METHODS: Contact hypersensitivity was induced by topical application of 2,4-dinitrofluorobenzene. Skin inflammation and immune cell populations were analyzed by using flow cytometric, immunohistologic, and quantitative RT-PCR analyses. Neutrophil mobility was examined by means of imaging analysis in vivo and neutrophil culture in vitro. The receptor for 17,18-EpETE was identified by using the TGF-α shedding assay, and the receptor's involvement in the anti-inflammatory effects of 17,18-EpETE was examined by using KO mice and specific inhibitor treatment. RESULTS: We found that preventive or therapeutic treatment with 17,18-EpETE ameliorated contact hypersensitivity by inhibiting neutrophil mobility in mice and cynomolgus macaques. 17,18-EpETE was recognized by G protein-coupled receptor (GPR) 40 (also known as free fatty acid receptor 1) and inhibited chemoattractant-induced Rac activation and pseudopod formation in neutrophils. Indeed, the antiallergic inflammatory effect of 17,18-EpETE was abolished in the absence or inhibition of GPR40. CONCLUSION: 17,18-EpETE inhibits neutrophil mobility through GPR40 activation, which is a potential therapeutic target to control allergic inflammatory diseases.

Effectiveness of Communication Studies Program at Tokyo Dental College Based on Comments from Members of Public in Educational Organization.

The purpose of this study was to investigate the effectiveness of the Communication Studies Program at Tokyo Dental College as a tool in behavioral education. The number of Patient Community members who had participated in multiple sets of the program for third-year students in the same year within the 3-year period spanning 2016 to 2018 (152, 148, and 129 students in 2016, 2017, and 2018 respectively), and the period during which they had participated in multiple sets were investigated. Comments on student behavior, including on hairstyle, clothes, and attitude, were also analyzed. The total number of members who had participated in multiple sets (1 set comprised 1 lecture and 2 training sessions) was 5; and their comments were more favorable during the second (sets 3 and 4) than the first half of the 1-month program (sets 1 and 2). During the first half, the students were criticized for speaking softly, having bad posture, not concentrating, and having an attitude inappropriate for a medical worker; but in the second half, they were praised for beginning to adopt the proper attitude for a medical worker, speaking louder, having better posture, and a very serious attitude. These findings suggest that the Communication Studies Program is effective in improving student behavior.

Gut microbiome, metabolome, and allergic diseases.

The number of patients with allergic and inflammatory disorders has been increasing during the past several decades. Accumulating evidence has refined our understanding of the relationship between allergic diseases and the gut microbiome. In addition, the gut microbiome is now known to produce both useful and harmful metabolites from dietary materials. These metabolites and bacterial components help to regulate host immune responses and potentially affect the development of allergic diseases. Here, we describe recent findings regarding the immunologic crosstalk between commensal bacteria and dietary components in the regulation of host immunity and the influence of this relationship on the development of allergic diseases.

Intentions and Factors Regarding Selection of Workplace by Postgraduate Dental Trainees after Clinical Training.

The purpose of the present study was to investigate the reasons governing selection of geographical location of workplace by postgraduate dental trainees. We believe that such data would aid in the development of measures aimed at reducing regional disparities in the number of dentists. A total of 10 dental colleges and faculties in Japan were invited to participate in the study. Anonymous, self-completed questionnaire surveys were given to 739 dentists at 13 clinical training facilities following training in 2012 and 2013; 713 responses were analyzed. The items surveyed included the local population in the area in which they wished to work and whether they wanted to work in rural areas or remote islands. The most common response to the question regarding population was "medium-size cities" with a population of 100,000 to 300,000 people (67.3%). The largest number of respondents stated that they hoped to work in their hometown or a neighboring area (49.9%). A large percentage wished to work in medium-size cities, which may reflect the population of their hometowns. The current system allows dentists a free choice in becoming practitioners or hospital dentists on completion of training. This may explain why so many expressed a preference to work in their hometown or a neighboring area here. These results suggest that policies relying on increasing the supply of dentists as the sole solution to rural shortages are flawed.

Longitudinal Evaluation of Community Support Project to Improve Oral Function in Japanese Elderly.

Change in oral function was evaluated longitudinally in elderly persons participating in an Exercises for Healthy Oral Function program implemented as part of the Long-Term Care Prevention Project. The participants comprised high-risk and healthy persons aged 65 yr or over. A questionnaire was used to classify them into two groups ('every day or sometimes' or 'rarely') at the end of the study for a comparison of change in repetitive saliva swallowing test (RSST) scores and oral diadochokinesis between 3 time points: at before, at immediately after, and at 1 yr after completion of the program. The average RSST score showed a decrease at 1 yr after intervention, but the difference was not statistically significant. Oral diadochokinesis showed a significant increase for all syllables upon completion of the program compared with at the beginning. This was followed by a significant decrease at 1 yr later compared with at the time of completion in the 'rarely' group for all syllables, but not in the 'every day or sometimes' group. In addition, the number of repetitions was significantly lower in the 'rarely' group than in the 'every day or sometimes' group for all syllables at 1 yr after completion. The results of the present study suggest that Long-Term Care Prevention Projects are necessary to maintain and improve oral function.

Participation of Patient Community Members in Communication Classes for Dental Students at Tokyo Dental College.

In 2009, the Ministry of Education, Culture, Sports, Science and Technology launched its "Program for Promoting University Education and Student Support, Theme A: Program for Promoting University Education Reform". The ministry's stated aims were to 1) enhance student training centered on the needs of the individual patient; 2) improve their ability to make comprehensive diagnosis and treatment plans; and 3) instill high ethical standards and good communication skills. One of the main pillars of this project was to establish an educational organization aimed at encouraging public participation, the "Patient Community". The aim was to have members of this community roleplay patients in the Communication Studies component of the 1st-4th years of dental school. It was hoped that they would be able to respond to the students in a more realistic manner than simulated patients. Here, the number of Patient Community members and number who attended Communication Studies classes in 2010, 2011, 2012, and 2014 were investigated. The results showed that the number registered in the Patient Community increased annually, as did the number participating in Communication Studies classes, which rose in accordance with the number of classes held. No difference was observed in the number of attendees per Communication Studies class by grade (years 1-4). The number of members never attending Community Studies classes increased annually, although some members repeatedly attended. These findings suggest that the members who regularly participate tend to remain the same.

Treatment Capabilities of Postgraduate Dental Trainees at Tokyo Dental College Suidobashi Hospital Based on Dental Services Income.

As of fiscal year 2006, it became compulsory for all newly licensed dentists in Japan to undergo a year of practical training at one of the designated training facilities found throughout the country as part of their postgraduate programs. The goal of this training is for the trainees to acquire diagnostic and therapeutic skills. While officially trainees, they are nonetheless regarded as members of staff. Clinical training emphasizes improving both technical skills and theoretical knowledge. However, taking on such trainees is sometimes considered unprofitable, as work productivity is claimed to be low. The purpose of this study was to compare work outcomes and income generated between trainees and part-time dentists working at the Tokyo Dental College Suidobashi Hospital. The part-time dentists comprised clinical instructors and dentists responsible for outpatients. Postgraduate dental trainees also generally conduct dental treatment for outpatients. Therefore, part-time dentists were considered the most suitable for a control group. No significant difference was observed in the total number of patients seen by either group by the final term of clinical training. Furthermore, no significant difference was observed in insurance-based dental treatment unit income (insured care unit income) per patient between the two groups from the mid-term period of training onwards. These results suggest that, although the trainees were less efficient in terms of time taken to provide a diagnosis and treatment, their performance was almost equal when viewed from the viewpoint of insured care provided. Taken together, this suggests that time-related care efficiency must be increased and specific training policies and strategies developed to improve the work productivity of dental trainees.

Monitoring caries risks before the window of infection and later caries increment: a caries prediction study on rapid detection of Streptococcus mutans using monoclonal antibodies.

A new semi-quantitative enumeration system has been developed for the detection of Streptococcus mutans in saliva. Using two kinds of species-specific monoclonal antibodies, this system can quickly detect salivary S. mutans within 30 min and classify the results into three levels. The aim of this study was to evaluate the potential of this test kit in determining risk for the development of caries. Saliva samples collected during a compulsory dental examination from 56 children aged 18-months were tested. The children were classified into 3 groups according to the level of salivary S. mutans determined. After 18 months, 36 of the children underwent a second examination to investigate whether there was a correlation between salivary S. mutans level at the first examination and subsequent increment in caries. The results showed a good correlation between the two. This indicates that salivary S. mutans level before the window of infection is an indicator of caries risk and can be quickly detected using this test kit. This rapid test should be particularly useful in assessing risk of future caries in very young children.

Career paths and aspirations among postgraduate dental trainees on completion of clinical residency program at Tokyo Dental College.

Career paths and aspirations were investigated among postgraduate dental trainees on completion of clinical training at Tokyo Dental College between 2006, when clinical residency became mandatory, and 2011. Overall, those finding employment with independent general dental practitioners accounted for the majority (34%), followed by those entering postgraduate courses at the Chiba Hospital (20%), those embarking on a postgraduate clinical specialty course at the Chiba Hospital (16%), and those going on to other universities (7%). At the Chiba Hospital, the number selecting postgraduate courses, residency training (including further residency training or a postgraduate clinical specialty course), or employment with a general dental practitioner was almost the same; however, the number selecting postgraduate courses at the Suidobashi Hospital was low, showing a strong tendency toward becoming a general or clinical practitioner. At the Ichikawa General Hospital, most of the trainees decided to remain at the same school or hospital as postgraduate students or residents, showing an aspiration toward further specialization. The results of the Fisher's exact test showed a significant difference in career paths between the Chiba, Suidobashi, and Ichikawa General Hospitals. Trends among postgraduate dental trainees from this and other schools completing the clinical residency program here and subsequently entering postgraduate courses, further residency training, or a postgraduate clinical specialty course at this school were investigated. No major difference was observed in the percentage of trainees remaining at the same school or entering postgraduate courses between those from this and those from other schools; however, more trainees from other schools selected further residency training, while fewer selected a postgraduate clinical specialty course.

Accidental ingestion or aspiration of foreign objects at Tokyo Dental College Chiba Hospital over last 4 years.

The aim of this study was to investigate cases of accidental ingestion or aspiration occurring at Tokyo Dental College Chiba Hospital over the last 4 years in order to determine how the incidence of such events could be reduced. Forty cases of accidents occurring at our hospital over a 4-year period commencing in 2008 (representing 27% of the total number of accidents) included accidental ingestion in 39 patients and aspiration in one. Most of these accidents occurred during the removal or placement of restorations or prosthetics, and the ingested objects were mostly crowns and inlays. Accidental ingestion or aspiration occurred more frequently in the right molar region and when procedures were conducted by practitioners with less than 1 to 7 years of experience, and especially 1 to 3 years only. A higher rate of such accidents was observed in male patients in their 50s to 70s. The conventional safety procedures developed by the Medical Risk Management Team should be adhered to wherever possible. Furthermore, we propose the following measures based on the present results: accident prevention training for students and clinical trainees; improvement of the in-hospital manual; personal coaching for those breaching the guidelines of the safety manual; and raising awareness of the need for greater care in preventing incidents of accidental ingestion or aspiration at the Tokyo Dental College Chiba Hospital.

Can the Ordered Multi-Stepping Over Hoop test be useful for predicting fallers among older people? A preliminary 1 year cohort study.

BACKGROUND AND AIMS: To prevent falls among older people, we developed a new fall-risk assessment, the "Ordered Multi-Stepping Over Hoop (OMO)" test. The aims of this study were preliminary: to investigate the association of the OMO with cognitive and physical function and to investigate whether the OMO could predict incidents of falling. METHODS: Fifty-nine community-dwelling older people (mean age = 88.0 ± 0.87, female = 49) were recruited. We assessed cognitive and physical function including the OMO test at baseline and monitored the falls of participants during a 12-month follow-up period from the baseline. We investigated whether the OMO was associated with cognitive function, physical function, and incidents of falling. To investigate whether the OMO could predict incidents of falling, a receiver operating characteristic analysis was conducted. RESULTS: The OMO time in fallers was significantly slower than for non-fallers. There were significant correlations between slower OMO times and lower physical functions and executive function. The area under the ROC curve in the OMO was 0.71 (p < 0.05). Times above 21.9 s for the OMO identified those more likely to fall. CONCLUSIONS: The OMO time was correlated with cognitive function, physical function, and incidents of falling. Our preliminary study indicates that the OMO may help to make a distinction between fallers and non-fallers among older people as effectively as other tests.

The harmonic ratio of trunk acceleration predicts falling among older people: results of a 1-year prospective study.

BACKGROUND: Gait variables derived from trunk accelerometry may predict the risk of falls; however, their associations with falls are not fully understood. The purpose of the study was to determine which gait variables derived from upper and lower trunk accelerometry are associated with the incidence of falls, and to compare the discriminative ability of gait variables and physical performance. METHODS: This study was a 1-year prospective study. Older people (n = 73) walked normally while wearing accelerometers attached to the upper and lower trunk. Participants were classified as fallers (n = 16) or non-fallers (n = 57) based on the incidence of falls over 1 year. The harmonic ratio (HR) of the upper and lower trunk was measured. Physical performance was measured in five chair stands and in the timed up and go test. RESULTS: The HR of the upper and lower trunk were consistently lower in fallers than non-fallers (P < 0.05). Upper trunk HR, was independently associated with the incidence of falls (P < 0.05) after adjusting for confounding factors including physical performances. Consequently, upper trunk HR showed high discrimination for the risk of falls (AUC = 0.81). CONCLUSIONS: HR derived from upper trunk accelerometry may predict the risk of falls, independently of physical performance. The discriminative ability of HR for the risk of falls may have some validity, and further studies are needed to confirm the clinical relevance of trunk HR.

Factor analysis on implementation of domiciliary dental care in Metropolitan Tokyo.

The need for domiciliary dental care has increased with the aging of Japanese society. The Tokyo Metropolitan Government and Tokyo Dental Association conducted a survey of dental institutions within Tokyo in order to clarify which factors influenced implementation of domiciliary dental care by dental institutions. The proportion was significantly higher in (1) dentists in their 50s or older, (2) those working in cooperation with primary care physicians, (3) those providing dysphagia rehabilitation, (4) those who give information on prevention of aspiration pneumonia, (5) those who attended training on medical or domiciliary dental care for the elderly in need of nursing care, and (6) those who attended training workshops and seminars provided by the Tokyo Dental Association in 2010. In the logistic regression analysis, a significant odds ratio was obtained for the same items, excluding age. Attendance at training on medical or domiciliary dental care for the elderly in need of nursing care had the highest odds ratio. Those who attended any kind of training course implemented domiciliary dental care significantly more often. Training conducted by the Tokyo Metropolitan Center for Oral Health of Persons with Disabilities, Tokyo Dental Association, and local dental associations showed a significant odds ratio, with the highest by the Tokyo Dental Association. Traditionally, education on domiciliary dental care in the elderly is not provided at the college level. The present results indicate the importance of educating students with regard to the unique challenges such work poses. Attending seminars hosted by the Tokyo Dental Association also significantly influenced implementation of domiciliary dental care. This seems to be an important result, suggesting the effectiveness of training provided by dental associations with regard to the promotion of domiciliary dental care. This indicates the need for dental associations to provide such training throughout Japan.