Periodontal disease is a chronic infectious disease induced by bacteria residing in dental plaque. It is well-known that periodontal disease is modified by lifestyle-related factors including smoking. However, the role of nutrition in the development and progression of periodontal diseases is less well-defined. The aim of this paper was to review the available literature pertaining to the association between periodontal disease and nutrients or foods. We performed a systemic review of relevant English-language medical literature published from January 1995 to July 2010, with the critical appraisal of epidemiologic studies evaluating the association between periodontal disease and nutrition. In cross-sectional studies, it was found that there were significant associations between a decreased intake and serum level of vitamin C and increased risk of periodontal disease. A low intake and level of serum calcium were also associated with the risk of periodontal disease in cross-sectional and cohort studies. Serum levels of 25(OH) D were independently associated with inflammatory diseases such as periodontitis and gingivitis. Deficiencies of nutrients such as magnesium, folate, and antioxidants may contribute to the severity of periodontal disease. Intakes of fatty acids including ω-3 fatty acid and docosahexaenoic acid may decrease the risk of periodontitis. However, plasma triacylglycerols and low-density lipoprotein cholesterol showed a significant positive correlation with the status of periodontitis. On the other hand, there was an inverse association between the intake of foods such as whole grains, vegetables, green tea, soy, isoflavone, and dairy products and periodontal disease. Data collected from the literature suggest that nutrients including vitamin C, calcium, vitamin D, and ω-3 fatty acid may reduce the risk of periodontal disease. However, future research needs to generate conclusive evidence of the association between periodontal disease and nutrition.

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The purpose of this study was to evaluate the effectiveness of a community-based periodontal disease prevention program focused on the use of interdental brushes. The subjects consisted of community residents (15 males and 41 females, with a mean age of 48.8 years) who consented to participate in a periodontal disease prevention program performed in Nishi-ward, Hamamatsu City, Shizuoka Prefecture. They participated in every guidance and the 1-year follow-up. The program was performed 3 times (initial guidance, and that after 1 and 2 months). In each guidance and the 1-year follow-up, a questionnaire was filled out and periodontal tissue was examined. The effectiveness of the program was evaluated after 1 year. The percentage of subjects using an interdental brush every day or sometimes was 55.4% on the initial guidance, but increased to more than 90% after 1 and 2 months, and was still 87.5% after 1 year. The change in the periodontal tissue was assessed employing three indices: the CPI code, number of sextants with periodontal pockets (CPI≧3), and number of sextants with gingival bleeding. The individual CPI code improved over time, and significantly differed between the initial guidance and after 1 month, 2 months, and 1 year. The number of sextants with periodontal pockets and the number of sextants with gingival bleeding decreased over time, and further decreased after 1 year. Because 29 subjects among all subjects underwent scaling in dental clinics between the initial guidance and 1-year follow-up, three indices for the periodontal condition used to compare the subjects who had and had not undergone scaling. The 3 indices in each group improved after 1 year compared with the initial guidance. These results suggest that a community-based periodontal prevention program focused on the use of interdental brushes is effective for promoting the use of interdental brushes and improving periodontal disease.

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This study was undertaken to clarify the relationship between the level of a Sense of Coherence (SOC) and recognition of dental hygienist practice in terms of university students in their early adulthood. The analyzed subjects were 1,772 male and female students in total who, in their sophomore year at a private university, located in the suburbs of Nagoya City, responded to a health survey questionnaire (valid response rate: 90.7%). The research procedure for the recognition of dental hygienist practice was applied employing the 10 items of the dental hygienist practice questionnaire of Matsuda. For the SOC scale, the 29-item scale of the Japanese language version was used. As a result, regarding the average cognitive score for dental hygienist practice (mean±SD), it was 5.0±2.6 for male and 5.8±2.3 for female students. The average SOC score for male students was 116.8±17.7, and 117.1±16.3 for females. The female students showed a higher-level recognition of dental hygienist practice than males. More than 70% of both sexes recognized that "brushing guidance" is performed by a dental hygienist. The SOC score of male students who regard "risk evaluation" as a task of a dental hygienist was significantly higher than in male students who answered incorrectly. In the female subjects, there was no significant difference in the SOC score between the correct and incorrect respondents regarding the ten items of dental hygienist practice. In both sexes, students who effectively recognized dental hygienist practice showed a higher SOC score than those with a poor recognition. It was observed that university students with a higher SOC score also showed an excellent cognitive score for dental hygienist practice, and university students' health-related behavior in regard to teeth and the oral cavity and their recognition of dental hygienist practice were significanty correlated with the SOC. It was concluded that university students who effectively recognize dental hygienist practice show a higher SOC score than those with low-level recognition.

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The purpose of this study was to establish a method for evaluating the oral health status of school children. The subjects in this study were 1st grade elementary school children (6-7 years of age) whose permanent teeth were caries-free. Oral examinations (WHO criteria) were conducted and salivary mutans streptococci (MS) levels were assessed in 293 students. Based on the initial number of sound deciduous teeth and MS levels, their oral health status was classified into three groups: good health: 3 or 4 sound lower deciduous molars, moderate health: 0-2 sound lower deciduous molars and MS level Class 0, poor health: 0-2 sound lower deciduous molars and MS level Class 1 or more. The change in the rate of caries-free students from the 1st to 6th grades was examined based on each health level. In the good health group, 82.1% of students did not have caries in the 6th grade. However, in the poor health group, more than 10% of students developed new dental caries every year, and the proportion of caries-free students was 47.1% in the 6th grade. Moreover, in the moderate health group, the number of caries-free students decreased between the 1st and 2nd or 3rd and 5th grades, and the proportion of caries-free students was 67.6% in the 6th grade. Based on the above results, it is possible to classify the oral health status by the number of sound deciduous molars and the salivary MS level in 1st grade elementary school children.

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The purpose of this study was to explore to what extent people recognize the profession of a dental hygienist, and to clarify the relationship between the level of accuracy with which people recognize the scope of services provided by dental hygienists and people's experience of dental scaling. A total of 3,199 people in their 30s to 60s, 2,221 men and 978 women, who underwent complete medical checkups at a health care facility in Nagoya took part in this study. A total of 50.4% of the men and 74.1% of the women recognized the profession of a dental hygienist. Among several different services provided by dental hygienists, most people recognized such services as "guidance on brushing", "dental scaling", and "fluoride application." People who accurately comprehended what services dental hygienists provide recognized the profession of a dental hygienist more clearly than those who had rather vague ideas about services they provided. People who had often undergone dental scaling by a dental hygienist clearly recognized what services dental hygienists provide, compared with those who had had dental scaling less often. In conclusion, the experience of dental scaling contributed to a clear recognition of dental hygienists' profession.

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When teeth are ground, the generated dust can cause environmental pollution and expose dental staff to pathogenic microbes. Therefore, it is important to remove the dust at its origin. In this study, we examined the concentrations of scattered dust due to grinding of the mandibular bilateral central incisors. The measurements were made at the center of a clinic and at three "chair-side" locations: the respiratory orifices of the patient (phantom head), at the position of the assistant, and at the position of the dentist. We also examined the dust-reducing effect of an extra-oral vacuum aspirator. We measured the scattered dust concentrations by dust particle size using a total of four laser particle counters operating simultaneously. Our results suggested that the extra-oral vacuum aspirator was an effective method for removing approximately 75% or more of the dust at the patient's position. It removed 60% or more of the dust at the dentist's position. In this study, the extra-oral vacuum aspirator was confirmed to be effective for reducing dust in the patient's and dentist's positions. In our previous study, we ground maxillary bilateral central incisors, and performed simultaneous measurements at the same 4 locations. When these results were compared with those of the present study, the concentrations of the scattered dust from maxillary bilateral central incisors were clearly higher than those from mandibular bilateral central incisors. However, their dust concentrations decreased to almost the same level using an extra-oral vacuum aspirator. The dust removal rates tended to be lower at the patient's and dentist's positions in the present than in our previous study. In this study, we examined the concentrations of fine particle size dust from tooth grinding, and compared the concentrations with and without the extra-oral vacuum aspirator. The concentrations tended to be higher with than without the aspirator at the positions of the vacuum assistant and the center of the clinic. This finding indicated a suction leakage in the extra-oral vacuum aspirator after accounting for the rotational directions of the bur and distances from the grinding site to the measurement sites. The results confirmed the necessity of general ventilation even with the use of an extra-oral vacuum aspirator. The placement of the extra-oral vacuum aspirator needs to be examined to obtain the highest dust-reducing effect at the dentist's, vacuum assistant's, and patient's positions, and in the clinic.

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Ventilator-associated pneumonia is a major medical problem leading to high-level mortality. Prolonged endotracheal intubation frequently leads to colonization of the upper respiratory tract by opportunistic pathogens, which are commensal microorganisms inhabiting the human oral cavity. In this study, we examined the adherence of oral opportunistic bacteria to saliva-coated endotracheal tubes and cuffs, and also examined the mechanism by which a Klebsiella pneumoniae strain adheres to the saliva-coated cuff. Eight strains of oral opportunistic bacteria were examined regarding their ability to adhere to saliva-coated tubes and cuffs. An inhibition assay of the adherence of a K.pneumoniae strain and aggregation assay were performed to clarify the binding mechanism of the bacterium. Of the bacteria tested, strains of Streptococcus pyogenes and K.pneumoniae strongly adhered to saliva-coated tubes, and strains of Pseudomonas aeruginosa, K.pneumoniae, and Enterobacter cloacae adhered strongly to saliva-coated cuffs. The adherence of K.pneumoniae cells to saliva-coated cuffs was inhibited by spermidine. Both spermidine and whole saliva induced the aggregation of K.pneumoniae cells. These results suggest that oral opportunistic bacteria have the ability to adhere to saliva-coated endotracheal tubes and cuffs, and that the adherence of K.pneumoniae cells to the saliva-coated cuff is mediated by type 3 fimbriae.

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[in Japanese]

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A discrete-time mathematical model for describing the population of dentists working at medical facilities expressed in the National Survey of Physicians, Dentists, and Pharmacists in Japan (NSPDP) was developed based on the number of candidates passing the national dentist examination from 2001 to 2008 and the dynamics of the previous results of the NSPDP from 1984 to 2008. The number of dentists aged 24 to 29, which is shown in the NSPDP of the target year, was calculated based on the age-distribution of dentists newly entered in the government list, considering the effects of the number of candidates passing the national dentist examination over the previous 5 years. Ages from 25 to 84 years were divided by intervals of 5 years, excluding ages 24 and 85 or over, and parameter coefficients for the dynamics of each group were calculated from the change in the number of dentists in each group after 5 years. A mathematical model for estimating the future number of dentists practicing in medical facilities expressed in the NSPDP was constructed utilizing the above. Using the model, the future population dynamics of dentists were by simulated based on the numbers of candidates passing the national dentist examination, whereby the numbers were kept constant over time, i.e., 1,200, 2,400, and 2,700.

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