Recent epidemiological studies have demonstrated that deficiency of various nutrients is associated with periodontal disease. Based on this evidence, it can be hypothesized that various functional foods, which include active components that have a health-promoting or disease-preventing property, may benefit periodontal health. This article systematically reviews the currently available literature on the effects of functional foods on periodontal health. We performed a systematic review of relevant English- and Japanese-language medical literature published from January 1995 to October 2010, with critical appraisal of epidemiological studies evaluating the effects of functional foods on periodontal health. On randomized controlled trials, supplements containing vitamins C and E were found to significantly improve the clinical parameters and biomarkers of periodontal disease. Furthermore, dietary supplementation with calcium and soy isoflavone was shown to maintain the alveolar bone level in periodontal maintenance. In randomized clinical trials, oral administration of Lactobacillus spp. as probiotics reduced periodontal pathogens, improved the status of periodontal disease and could contribute to beneficial effects on periodontal health. As antibacterial agents including chemicals and substances isolated from plants, chewing gum that contains chlorhexidine or eucalyptus extract showed a meaningful effect on plaque and gingival inflammation in human clinical trials. Other nutritional supplementation such as fatty acids and vitamins also showed beneficial effects on periodontal inflammation. However, additional studies will be necessary to more fully assess the potential of functional foods to favorably affect periodontal health.

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Granitoids contain higher levels of fluoride than other rocks. This may affect the fluoride level in drinking water. A previous study showed that fluoride levels of more than 0.3mg/L in drinking water may contribute to caries prevention. From the viewpoint of caries prevention, we selected water plants providing public water with a fluoride level of more than 0.3mg/L (group A) and investigated the geographical distribution. The number of water plants in group A was 94, equivalent to 1.7% of the total water plants in Japan. Many of the plants are situated in the western part of Japan, similarly to the granite distribution: Ehime, Hyogo, and Hiroshima Prefectures. Then, for a comparison with group A, we randomly selected 100 water plants providing public water with a fluoride level below 0.3mg/L (group B) in 25 prefectures within which group A plants were situated. We plotted the positions of group A and B plants on the Japanese granitoid distribution map, and investigated the geographic relationship between these water plants and the granitoid distribution. About 96% of group A situated within granitoid distribution sites, with the percentage of group A plants being significantly higer in such areas. These results suggest that water plants providing public water with a fluoride level above 0.3mg/L are unevenly distributed in the western part of Japan similarly to the granitoid distribution, and the high levels of fluoride in granitoids may effect the fluoride level in drinking water.

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Humans absorb fluoride which is naturally present in soil, water, air, and foods. Although Japanese drinking water also naturally contains fluoride, no study has examined the caries-preventive effect of drinking water on a nationwide scale. The aim of this study was to determine the association between fluoride concentrations in Japanese drinking water and the caries prevalence in 3-year-old children. This was an ecological study employing data on fluoride concentrations and caries prevalence among 3-year-olds in each municipality. Data from 1,861 of the 3,252 municipalities in Japan were used which contain water fluoride concentrations (57.2%). We applied multiple regression analysis to determine the association between the empirical Bayes estimator of dental caries prevalence and water fluoride concentrations, with the adjustment of covariates including dental health indices. The mean caries prevalence in the municipalities with 0.000-0.049 and 0.400mg/L or higher fluoride concentrations in drinking water was 43.6% (SD=11.1) and 35.9% (SD=7.6), respectively. After being adjusted for covariates in the multiple regression model, compared to municipalities with 0.000-0.049mg/L fluoride concentrations, those with 0.300-0.399 and 0.400mg/L or higher concentrations showed a 7.2% (p=0.005) and 7.3% (p=0.001) lower caries prevalence. The results suggest that fluoride in drinking water exerted a beneficial effect on caries prevention, even though there is no artificial water fluoridation in Japan.

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Attaching marked importance to continuous dental health guidance based on caries risk assessment, a certain district of Akita Prefecture has begun accumulating the records of infant dental health examinations and initiated Dentocult®-SM tests. In this study, we analyzed caries risk factors using those accumulated data, and considered what is important when we provide dental health guidance. The subjects were 245 children who underwent all recommended dental health examinations at the age of one year and six months, two years, and three years. Comparisons were made between the findings of the questionnaire survey involving their guardians by interview, the change in the number of dft, and Dentocult®-SM scores. As a result, it was found that 142 infants (58.0%) were caries-free throughout the period under review, 43 (17.6%) had caries at age 2, and 60 (24.5%) at age 3. The rate of those infants with Dentocult®-SM scores of 2 or 3 was 12.7% at the age of 18 months. The rate increased to 25.7% at age 2 and over. A significant difference between the two was recognized (p<0.01). When the numbers of dft and Dentocult®-SM scores registered in each examination were examined in comparison with the findings of the questionnaire survey, we found that there were significant differences in the rate of respondents who checked off "toothbrushing by caretakers" and "need to teach" in the queries about eating between meals and beverage drinking (p<0.01, p<0.05) for 2-year-olds. Logistic regression analysis was performed with the number of dft at age 3 as a dependent variable. The results showed that the odds ratio of Dentocult®-SM scores (6.524, p<0.01) to "kind of sweet beverage" (2.582, p<0.05) was significant. All these findings suggested that helping small children form good eating habits and toothbrushing by caretakers play important roles in the prevention of caries while they are under the age of 2, as colonization by Str. mutans is marked during this period.

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Reports indicate that tooth loss can be prevented through regular mechanical tooth cleaning and guidance on oral hygiene. In response to this, in the present study, factor analysis was conducted on the discontinuation of regular dental check-ups using data-mining. Questionnaires were administered to 106 patients receiving regular dental check-ups through the outpatient preventive dental services of a university hospital. The content of the questions was related to feelings, requests, and satisfaction regarding regular dental check-ups, as well as the oral health-related quality of life (QOL). The General Oral Health Assessment Index (GOHAI) was used to assess the oral health-related QOL. Additionally, the sex, age, and residence of the patients were obtained through medical records. Patients were grouped into two: respondents who had continued to receive dental check-ups after one year (continuation group: n=75), and those who had discontinued check-ups after more than six months (discontinuation group: n=31). A comparison of these groups showed that the discontinuation group scored significantly lower on the GOHAI than the continuation group (P<0.01). Furthermore, a decision tree analysis of the groups revealed that, among those who scored ≦40 points on the GOHAI (n=11), 82% (n=9) of such respondents had discontinued check-ups. Respondents who scored ≧41 points on the GOHAI were more likely to have undergone continued check-ups. However, most of those who did not describe check-ups as "safe" and "comfortable" had discontinued treatment. The results indicate that those with a low oral health-related QOL tend to discontinue regular dental check-ups, and those who feel "safe" and "comfortable" about regular dental check-ups appear more likely to continue attending such check-ups.

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The purpose of this clinical study was to investigate the correlation between visual examination as a subjective method and examination using a quantitative light-induced fluorescence (QLF) image as an objective method for evaluating the oral health condition of the deciduous dentition. The subjects of this study were 119 nursery school children (4 or 5 years of age) in Osaka, Japan. The occlusal and buccal surfaces of the 2nd deciduous molar and buccal surface of the deciduous incisor were examined visually and tactilely with a dental mirror and CPI probe. The tooth surfaces were classified into: sound, filled (including a sealant), decayed caries, or early caries lesion. Examination using a QLF image was performed for the same tooth surfaces with the same criteria as for visual examination. Thirty-five tooth surfaces with early caries lesions were detected by visual inspection, whereas 332 surfaces were detected by QLF. There was nearly a 10-fold difference between visual and QLF examinations in the detection of early caries lesions. Moreover, 134 filled surfaces were observed by QLF examination. On visual inspection of these 134 surfaces, 63 surfaces were identified as filled surfaces, and 61 as sound surfaces. These results suggest the importance of introducing a new examination system which consists of subjective and objective methods into dental management in the future.

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[in Japanese]

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The purpose of this study was to evaluate the relationship between the items of a specific health checkup and periodontal examination in a community-dwelling population. In Osaki Town, Kagoshima Prefecture, Japan, inhabitants (114 males, 149 females, average age: 65.1±9.4 years old, range: 40-89 years old) participated in the specific health checkup, called Tokuteikenkoushinsa, and periodontal disease examination carried out together in 2008-2010. Information on the general condition and lifestyle was obtained based on the health checkup information sheet. The periodontal condition was examined using the community periodontal index (CPI). In addition, oral moisture, oral malodor, and the accumulation of dental plaque and tongue coating were examined. Using mouth rinse solution that was collected after rinsing with 3mL of distilled water for 10sec, the optical density at 660nm, ammonia concentration, and viscosity were measured. Lifestyle items regarding changes in the body weight, dietary habits, sleep, and willingness to receive health instruction showed an association with the oral cleanliness. Subsequently, the subjects were divided into 2 groups (high and low) based on the median of each value of the specific health checkup items, and oral condition items were evaluated. In the group showing a favorable hepatic function, the oral cleanliness, oral hygiene, periodontal status, saliva viscosity, and oral moisture were also favorable. In the group showing a low blood glucose level, the oral cleanliness, oral hygiene, and oral malodor were again favorable. These results indicate that the items of periodontal examination are related to those of a specific health checkup.

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