The purpose of this paper was to evaluate the caries preventive effectiveness of a school-based fluoride mouth rinsing program as to whether it can decrease the number of decayed, missing and filled tooth surfaces (DMFS), considering some variables associated with the prevalence of dental caries. Subjects were junior high school children in a low fluoride district in Niigata-City, Japan. In October 1997, 3 dentists of Niigata University screened the children for dental caries in permanent teeth with artificial light, dental explorers and dental mirrors under examiner-blinded conditions. The long-term fluoride mouth rinsing group (n=32, Mean DMFS=5.56), in which the children had been participating in a schoolbased fluoride mouth rinsing program in elementary school for 6 years, had a significantly (48.3%) lower mean number of DMFS than the no fluoride mouth rinsing group (n=20, Mean DMFS=10.75), which had no experience of participating in fluoride mouth rinsing. Univariate analysis showed that children who did not like sweets had a statistically lower mean number of DMFS (n=21, Mean DMFS=4.52) than those who liked sweets (n=67, Mean DMFS=8.97). Multiple regression analysis also indicated that the interventional measure of fluoride mouth rinsing and the background factor of liking sweets were the statistically significant variables. In conclusion, it is recommended that school-based fluoride mouth rinsing programs in elementary schools in low fluoride areas should be introduced to reduce dental caries in permanent teeth, reducing mean DMFS by about half.

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Simultaneous relationships were investigated among the subjective symptoms of temporomandibular disorders (TMDs) and the possible explanatory variables. A total of 1, 137 junior and senior high school female adolescents participated in the present study. After receiving dental examination, the participants were asked to fill in a questionnaire including the frequency of TMD symptoms, presence of tooth ache and stress, oral parafunction consisting of 10 items, experience of jaw injury and orthodontic treatment, and family history of TMDs. The percentages of subjects with temporomandibular joint (TMJ) noise, TMJ tiredness, TMJ pain, and restricted mouth opening were 27.2%, 12.2%, 12.8% and 10.6%, respectively. Bivariate analysis showed the significant association of TMDs with some oral parafunctions, tooth ache, orthodontic experience, number of filled teeth (FT score), and stress. A hypothesized model was tested using structural equation modeling (SEM). The final model found a good fit to the actual data with a 0.983 of Goodness of Fit Index (GFI), 0.969 of Adjusted Goodness of Fit Index (AGFI), 0.044 of Root Square Error of Approximation (RMSEA), and 0.962 of Comparative Fit Index (CFI). Oral parafunction (p<0.01), tooth ache (p<0.01), FT score (p<0.01), stress (p<0.01) and orthodontic experience (p<0.05) affected TMDs. Stress factors also affected TMDs indirectly through the increased frequency of oral parafunction. The present study indicated that oral parafunction, occlusion-related factors, and stress influence TMDs.

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Aging can affect both oral status and oral microbial flora. The purpose of this study was to investigate the transition of oral microbial flora and to clarify the association between oral status and the oral microbial flora in 70-year-old subjects (n=43) in 1998. Twenty-five out of 43 subjects were examined over a span of 2 years (1998-2000). Oral status which included the number of remaining teeth, denture usage, salivary flow rate, buffering capacity of saliva and the level of halitosis (CH_3SH producing ability of bacteria on the tongue surface), and microbiological examinations which included the numbers of fusobacteria, staphylococci, and candida on the tongue surface and those of mutans streptococci and lactobacilli in saliva and gingival sulcus black pigmented rods (BPR) were examined. As a result, the average number of holding teeth was 18.7±8.2 and the percentage of denture wearers was 58.1%. There was a positive correlation between the level of halitosis and the number of fusobacteria (r=0.435, p<0.01). However, there was a negative correlation between the number of candida and salivary flow rate (r=-0.357, p<0.05). Using stepwise regression analysis, the pH of the tongue coating culture solution, the number of fusobacteria, the class of mutans streptococci and the buffering capacity of saliva were investigated in relation to the CH_3SH productivity on the tongue surface. As well as the buffering capacity of saliva, the number of candida was investigated in relarion to the salivary flow rate. The results obtained from 25 out of 43 subjects showed the tendency that the numbers of staphylococci, mutans streptococci, and lactobacilli decreased in contrast with the increase of the number of candida and no change was observed in the level of halitosis, the average number of holding teeth and the percentage of denture wearers. The results of this study suggested that the salivary flow rate directly influenced the microbial components of the oral cavity among the elderly and the fusobacteria in the microbial flora of the tongue surface, which may play an important role in halitosis.

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To improve occupational oral health activities, we focused on the influence of workers' stress levels on their oral health. To obtain data for our investigation, we used two kinds of check lists: one was an "oral healthiness score" check list, and the other was a "stress survey for workers" check list. The subjects were 285 males among the 459 subjects, (235 males between 20 and 49, and 50 males over 50). The results and our conclusion are as follows: 1. People who got 15 points and under by the evaluation standard of "oral healthiness score" accounted for 60% of people aged 20-49, with a similar result for people aged over 50. This result suggests that these people need to not only improve their life style but also get advice from dentists as well. This means that the employers will be expected to promote activities for improving the oral health of their employees. 2. Among the three evaluation standards of the "stress survey for workers" score, people exposed excessively to stress accounted for 30% or more of people aged 20 to 49, with a similar result for people aged over 50. Most items of stress were related to their work, as shown in the upper items of the check list. 3. A significant difference in the total "oral healthiness score" was clarified between the over stressed people and those not over srressed, based on the "stress survey for workers" score among people aged 20 to 49 (p<0.05). People aged over 50 also showed the same difference (p<0.01). Because similar results are known using some other references, we may say that stress strongly influences an employee's oral health. From the results mentioned above, we conclude that the reduction of stressors related to the employees' work will lead to better oral health as well as a reduction of diseases connected to stress. In that sense, employers should examine and improve both the quality and quantity of their employees' work.

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The purpose of this study was to investigate the effect of tablets containing the protease, actinidin, extracted from Kiwi fruit on the reduction of human tongue coating. Cross-over studies and double blind experiments were designed using 11 male adults. After taking protease tablets, the tongue coating scores evaluated visually and the amount of tongue coating evaluated by image analysis were significantly lower than those with placebo tablets. The results of this study suggested that protease tablets were effective in biochemical cleaning of the tongue.

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This study evaluated the effect of preventive oral health management by dental professionals on institutionalized severely handicapped persons. One hundred and twenty-two handicapped persons underwent examination of their oral status by a dentist every 6 months and also routinely received oral health care by full-time dental hygienists for 8 years. We assessed their oral status before and after intervention and also compared these data with those report of in the Survey of Dental Disease published by the Ministry of Health and Welfare. The main results were as follows: 1) The mean number of present teeth per person, the DT-index and the FT-index for subjects at the baseline (year 1993) and the year after intervention (2001) were fewer than those in the national survey (1993 and 1999, respectively). 2) The change in the mean number of present teeth per person, the DT-index and the FT-index after 8 year-intervention was 0.60 decrease, 0.39 decrease and 2.23 increase, respectively. 3) Especially for 30-39-and 40-49-year-olds, the decrement of the DT-index and the increment of the FT-index over 8 years were more than those of the national survey (from 1993 through 1999). 4) The gingival health evaluated by Gingival Index, the plaque and the calculus score using Oral Hygiene Index for the subjects were significantly improved during 8 years at every age group. These findings suggest that periodic preventive oral health care by professionals at an institution for severely handicapped persons effectively improves the oral health of these patients.

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Purpose: This study investigated subjective temporomandibular dysfunction (TMD) symptoms among young females in junior and senior high school by cross-sectional survey. The study also assessed the impact of school-based periodic oral health guidance on junior high school students reporting TMD symptoms, using a longitudinal study methodology. Methods: The sample for the first survey was composed of 1,447 junior and senior high students, while that of the second study consisted of 1,228 junior high school students, including 268 students who had responded to all TMD questionnaires for the full six-year junior/senior high school period (the intervention group) plus 960 students who were newly admitted at the senior high school level and responded to all the questionnaires for the 3 year-senior high school period (the control group). Questionnaires, based on the Helkimo's Ai index, focusing on 7 subjective TMD symptoms were administered to junior and senior high school students in April of every year. Junior high school students with TMD symptoms in the intervention group, received individual oral health guidance three times a year. Results: The prevalence of TMD symptoms increased with grade. While on the other hand, the mean number of the symptoms recorded per person among those students reporting symptoms, gradually decreased. Among the intervention group, the TMD symptom rate for the first year of senior high was significantly lower compared to rates recorded for the control group (p=0.010, Chi-square test). However, for the third year of senior high, we did not record any significant difference between these two groups. Conclusion: These results suggest that early intervention for junior high students with TMD symptoms is effective in reducing its prevalence and severity. Even those junior and senior high school students that do not report TMD symptoms would benefit from the provision of school-based oral health education and guidance.

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Dental caries and periodontal disease increase with age. Many junior high school and high school students have contracted these diseases in recent years in Japan. Approximately 70% of students had already contracted gingivitis by junior high school. It is reported that the appearance of periodontal disease with alveolar bone absorption of an adult type has been seen in high school students. The current state of oral health management and oral health education in junior high schools cannot be considered adequate. Therefore, it is necessary to consider preventive measures for dental caries and periodontal disease at the junior and senior high school levels. We have been investigating high school student's dental disease assessments, lifestyle, and oral health behavior since 1993. It was considered that we need to investigate not only the oral health behavior and lifestyle, but also analyze the risks for prevention of dental caries and periodontal disease at the high school level. In this study, a cross-sectional study of high school students was performed on dental caries, the periodontal disease statement, and five types of risk tests as follows; salivary flow, number of mutans streptococci, number of lactobacilli, buffer capacity of saliva, and concentration of salivary occult blood. The school year comparison of the dental disease statements and the risk tests was performed, and the relationship between them was examined. As a result, a clear difference was not observed in the risk test results and dental caries among school years although periodontal disease increased gradually at the high school level. In both male and female students, a high correlation was observed between dental caries statement and the caries risk test results, specifically in terms of number of mutans streptococci and number of lactobacilli. Furthermore in female students, there was a strong correlation between dental caries statement and the buffer capacity of saliva, and also between PMA and the concentration of salivary occult blood.

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The purpose of the present study was to investigate the frequency, distribution, and site characteristics of dental caries in the Yayoi people, the ancient agricultural group that was the first to engage in full-fledged rice cultivation in paddies in Japan. The materials used here consisted of excavated human skeletal remains of the Yayoi period (500 BC-300 AD). A total of 295 individuals with 5,544 teeth were examined. A total of 17.4% of teeth were carious, and the percentage of individuals with caries was 78.6%. Our analyses indicated that among the Yayoi people, caries was frequently found more often in the root area, and the percentage of carious tooth surfaces was highest on the approximal surface of the tooth root. When we recorded only "primary caries", which was determined with certainty as an initial carious surface located in a limited area such as a pit and fissure, crown, or root surface, primary caries was frequently found in the root area of teeth. These results suggest that caries in ancient Japanese people initiated in the root area, and that the mechanism of caries occurrence was different from that in modern Japanese, with this difference possibly being due to differences in diet.

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Due to intermittent contamination of fluoride in drinking water (Maximal fluoride concentration: 4.7mg/l) this patient developed a mottled upper right incisor tooth. This tooth was knocked out by a traffic accident when the patient was five years old. It was diagnosed as a severely mottled tooth because its labial and lingual surfaces were rough and some defects were also observed in part of the enamel. The concentration of fluoride in the enamel was 1,400 ppm on the labial and lingual surface but rapidly dropped in the interior. A rise was seen again at the dentin enamel junction. On the surface, the concentration was about 2-fold higher than that of control teeth. Fluoride concentration in drinking water was estimated to have been 2.0〜3.4mg/l by conversion of CFI in the group to which this case belonged.

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Teaching materials for assisted study to encourage oral health practices were created for seventh graders in Fukushima Prefecture. Teaching materials were predicated upon fostering the "Ability to live". Because the teeth and mouth can be examined visually, these tissues make effective study materials for students to learn aboot and think for themselves. Once students have considered health through their teeth and mouth, they will gain a health perspective in relation to their own bodies and consider total health. In addition, instruction-based study unilaterally conveys knowledge specific to prevention of diseases, but these materials involve students discussing ideas interactively and sharing information, fostering their ability to discover, learn, consider, subjectively decide, and resolve issues themselves. Based on survey results, teaching materials should be distributed from mid to late April so that they can bo used during "Dental Hygiene Week". The importance of an active approach to utilizing the mass media as well as the effects of public relations through prior distribution of the teaching materials by selecting a model school was suggested.

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