The number of AIDS/HIV positive patients in Japan has begun to increase and there is a greater chance for dental care workers to encounter AIDS/HIV when treating patients. Therefore dental care workers must have accurate understanding in regard to ethics and infection control. The study was conducted to investigate the attitude, behavior, and knowledge of AIDS among 165 clinical dental hygienist students in three different training schools. The survey was conducted by means of a self-administered questionnaire during classes from July 1995 to February 1996. The results were as follows : the attitude and behavior of dental hygienist students varied in each training school, although there was no obvious difference in the average correct answer rate, which was 49.0%, 51.5%, and 51.9%, respectively. The overall average correct answer rate of the three schools was 50.8%. In other words, the knowledge was about the same level, but the attitude and behavior towards AIDS were different in the three schools

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The objective of this study was to clarify the relationships between aging and the number of missing teeth. Simulation techniques are widely used to investigate real-life processes and to obtain accurate predictions with mathematical models. In this study, we used two methods of simulation, one with exponential functions and the other with polynomial functions. With the exponential functions, we could not get proper mathematical models. It required three different functions to simulate the relationships between aging and tooth loss. Then we applied the least square method in this relationships (age and the number of missing teeth). Suitable polynomial functions were found. These functions were easily differentiated, and we could calculate the rate of change in tooth loss. This rate of change in tooth loss changed according to the era and aging. The rate is an important coefficient for calculating future tooth loss. To calculate the future tooth loss en mass, it is possible to use the principles of differential equations. Our results are very useful for field workers in dentistry, and for researchers who work in the community.

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I The purpose of this survey was to determine the relationship between oral malodor and tongue coating in the elderly living in nursing homes. The main culprits of oral malodour are considered to be volatile sulfur compounds (VSC), particularly methyl mercaptan (CH_3SH) and hydrogen sulfide (H_2S). In this study CH_3SH was used as an indicator of VSC and was determined using gas chromatography. Likewise, oral and daily living conditions were studied to find the factors that relate to oral hygiene. The following results were obtained. 1. A significant correlation was found between VSC and tongue coating. This suggests that cleansing of the tongue can contribute to the decrease of VSC and consequently to the reduction of oral malodour. 2 . The elderly with increased dependency in their daily activities exhibited the same tendency in oral hygiene. Decreased chewing and swallowing functions also caused increased preference for soft food and viscous beverages, contributing to reduction in self-cleaning action. 3. Oral malodour makes the assistants unwilling to help in oral care. Thus, prevention is an important issue in the elderly needing assistance.

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The effects of Fusobacterium nucleatum lipopolysaccharide (LPS) and Escherichia coli LPS on DNA synthesis, protein synthesis, alkaline phosphatase activity, acid phosphatase activity, and morphological changes in human epithelial HeLa cells in the absence of fetal bovine serum were studied. F. nucleatum LPS inhibited ^3H-thymidine incorporation in cells up to 1 μg/ml, but inhibition by E. coli LPS was caused by adding over 50 μg/ml. Inhibition of protein synthesis by F. nucleatum LPS and E. coli LPS was observed at concentrations of 0.01μg/ml and 10μg/ml, respectively. We also examined whether LPS affects the alkaline phosphatase in HeLa cells. F. nucleatum LPS at concentrations of 0.01 to 25μg/ml inhibited alkaline phosphatase activity in a dose dependent fashion, but E. coli LPS did not inhibit it at a concentration of 25μg/ml. Acid phophatase activity also was inhibited at a concentration of 10 μg/ml of F. nucleatum LPS, but not by E. coli LPS at the same concentration. The morphological changes in HeLa cells caused by F. nucleatum LPS treatment were greater than those caused by E. coli LPS. The results suggest that the cytotoxic effect of F. nucleatum LPS may be greater than that of E. coli LPS.

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Studies show that although over 95% of Japanese adults brush their teeth at least once a day, 90% of them spend less than 3 min each time on brushing. The high prevalence of periodontal disease indicates that toothbrushing methods employed by adults do not help to prevent periodontal disease. However, there is little evidence to suggest an optimum brushing time or behavior to achieve adequate plaque control in daily life. The purpose of this study was to find the relation between daily tooth brushing behavior and plaque control levels of adults. Forty-six uninstructed dental school students were asked to brush their teeth in front of the mirror and their toothbrushing was recorded on video tapes. Plaque levels (PCR) were recorded after brushing. The tapes were viewed on a monitor, and the total brushing time, brushing pattern and the time spent brushing each of the 16 areas of the mouth were recorded. The relation between brushing methods and PCR were studied. The results obtained were as follows. 1. The mean (±S.D.) brushing time was 278.2 (±120.2) seconds. 2. Back-and-forth, up-and-down and circular brush strokes were observed by viewing the video tapes. The back-and-forth stroke was the most popular method employed. The relation between toothbrushing methods and PCR was not clear in this experiment. 3. There was a negative correlation between toothbrushing time and PCR (r=-0.301, p< 0.05). 4. The subjects who had low PCR spent more time on brushing in each of the 16 areas of the mouth compared to the high PCR group. 5 . Receiving toothbrushing instruction in schools or dental offices did not affect the PCR levels of the subjects. It was concluded that methods of proper toothbrushing instruction to make daily toothbrushing effective in preventing periodontal disease should be developed.

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In this study the trend in the caries in the deciduous teeth of kindergarten children was surveyed in Toshima Ward, Tokyo, Japan. An annual clinical dental examination of children aged 3-5 year was carried out from 1985 to 1995 with the exception of 1986 and 1990 at one kindergarten. A trend toward decrease in dental caries was seen in children aged 4 and 5 years especially in the index of df teeth rate, but not in children aged 3 years. On the other hand, in the children who had less than 2 df teeth at the age of 3 years, the number of df teeth from 3 to 5 years was gradually reduced through out the period of this survey, and it may promote a decrease in dental caries in higher aged kindergarten children. The data for each year were totaled to calculate the distribution of df teeth in each age group. By one sample Kolmogorov-Smirnov test, the distribution pattern of df teeth obtained from the survey did not fit normal, binomial, or Poisson distribution for each age. In df teeth of children aged 5 years, the distribution pattern had two major peaks. The peaks consisted of children who had 2 or 8 df teeth respectively. These two peaks showed some differences in the distribution of df surfaces and the prevalence rate of df surface per a tooth. The variety of tooth restoration changed with annual surveys. In f teeth of children aged 5 years, the rate of inlay filling increased and the rate of amalgam filling decreased gradually through the period of this survey. But the rate of crown restoration did not show any such trend. These results suggest that the prevalence of dental caries in deciduous teeth has been changed recently, so analysis like this study should be carried out in other regions. We also suggest that an administrative oral health check-up for children aged 4 and 5 years should be implemented.

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The practice of adult and elderly oral health services in each municipality in Japan was surveyed in November to December 1994, as part of an investigation to formulate more efficient systems for offering services aimed at promoting better community oral health services. The data were analyzed in relation to the type of municipality (large cities/special districts with health centers, other cities, and towns/villages), size of population, and presence/absence of dental hygienists. There were distinct variations in the percentage of oral health services offered for adults and the elderly according to the type of the municipality. Adult and elderly oral health services were most frequently provided in large cities/special districts, followed by other cities and towns/villages. Regarding oral health examination and oral health education for adults and the elderly most municipalities provided no service at all, followed by services for the elderly only, for both adults and the elderly, and for adults only. Dental hygienists tended to be stationed more frequently in municipalities with larger populations, and oral health services tended to be more frequently provided in municipalities which had dental hygienists.

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The aim of this study was to assess the cariostatic efficacy of NaF(900 ppm F) dentifrice containing 0.97% vitamin B_6. A double-blind, unsupervised, 3-year longitudinal clinical trial was conducted on 1,061 school children initially aged 6〜11 years of age. They were stratified according to school, age, gender, and initial DMFT score. They were then randomly assigned to one of the three study groups. The F+V group used the NaF dentifrice containing vitamin B_6. The F group used the NaF dentifrice without vitamin B_6. The fluoride-free and vitamin-free dentifrice was distributed to the control group. After 3 years, clinical data for 802 children were obtained for analysis. A significantly lower cumulative incidence rate and incidence rate of caries were observed in the F+V group than in the other two groups, when they started to use the assigned dentifrice at the age of 11. A significantly positive correlation was observed between the anticaries effect and the volume of dentifrice consumed in the F+V group. The mean DMFS increments were not different among the 3 groups. However, the approximal DMFS increment in the upper anterior teeth was significantly lower in the F+V group than in the control group, initially aged 11 years of age.

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In many cases, periodontal disease among the school age children is caused by bad oral hygiene and the main factor is also dental plaque as well as dental caries. Many studies have been done on the relationship between Cariostat and dental caries. However few studies have been performed on the relationship between Cariostat and periodontal disease. The purpose of this study was to estimate the relationship between Cariostat and gingivitis. We examined the relationship among caries activity test (CARIOSTAT^[○!R]), salivary occult blood test (SALIVASTER^[○!R]), gingivitis, and dental caries in 437 junior high school children. 1. The Cariostat score after 24 h incubation was correlated significantly (p<0.001) with both dental caries (D-T) and gingivitis. When the gingivitis index was divided into three groups (severe and moderate/slight/normal), the distribution of Cariostat score among the three groups showed significant difference (chi-square test plt;0.001). 2. The Cariostat score after 48 h incubation was also correlated significantly with both dental caries (D-T) and gingivitis (plt;0.05 and plt;0.001 respectively). However, the distribution of Cariostat score among the three groups did not show any difference. 3. The Salivaster test score was correlated with gingivitis (plt;0.05), but not with dental caries. The distribution of Salivaster score among the three groups did not show any significant difference. 4. The Cariostat score after 24 h incubation was not correlated with the Salivaster test score. 5. The specificity and sensitivity for gingivitis were 0.34 and 0.83, respectively, when the Cariostat score of 1.0 after 24 h incubation was used as the screening point. On the other hand, both the specificity and sensitivity were 0.55 when the Salivaster test score of (+) was used as the screening point. The Cariostat score after 24 h incubation was correlated with both gingivitis and dental caries. These results suggest that the Cariostat score could reflect the oral hygiene status and be correlated with gingivitis as well as with dental caries.

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The Dentocult^[○!R] SM strip mutans (SMT, Orion Diagnostica, Finland) has been widely used as a caries risk test by which salivary MS counts can be evaluated simply using a highly selective medium and plastic strip. The reliability and usefulness of the method has been established from mass evaluation, but its error level within an individual has not been assessed sufficiently, especially among adults. In this study, intra-individual variation was examined in adults at various time intervals. The colony formation on a strip was assessed quantitatively by the analytically digitized SMT (ADS) in CPUs/strip. Results were as follows: 1. The CPUs/strip values varied among weeks and days. 2. The variation can be categorized roughly into 2 patterns. 3. No significant correlation was detected between the ADS values and other clinical parameters (scores of RD^[○!R] test and Cariostat^[○!R] DMFT and DPS). And 4 . The ADS values correlated with CFUs of salivary MS on MSB agar plate. In conclusion, repetition of the SMT within a given interval is strongly advised for each individual to assess caries risk reliably.

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This study was done to estimate and improve the comfort of environmental conditions of the dental clinics and waiting rooms in Asahi University Dental Hospital. A questionnaire survey was carried out to gather the information from patients on hospital environmental conditions in different dental clinics and waiting rooms. At the same time, environmental conditions of waiting rooms were measured for one year in 1993. Analytical points were as follows : 1. Examination of patient's comfort factors from the questionnaire. 2. Relationship between the answers of the questionnaire and the values of environmental measurements. The following results were obtained : 1. A few patient complained of the discomfort of hospital environmental conditions. The rate of patient feeling comfortable environment with all-round evaluation was 30.4% in clinics and 25.5% in waiting rooms. A chronological change in patients' comfort ratio, from 14.6 to 38.2%, was seen according to season and hour of the day. The rate was high in the morning in March and July, and low in the afternoon from May to September. 2. The predictive value of comfort for discrimination using quantification method II was high (hospital clinics : 93.1%, waiting rooms : 91.6%). Factors affecting patients' comfort were, in order, cleanliness, lighting and noise in hospital clinics, and lighting, cleanliness and noise in waiting rooms. 3 . A higher relationship between the answers of the questionnaire and the value of environmental measurements in waiting rooms was seen regarding temperature, humidity, noise and lighting. The standard values estimated from the answers regarding patients' comfort were 21.2〜25.0℃ for temperature, 33.2〜41.5% for humidity, less than 58.9dB for noise, and 750〜937 Lx for lighting. 4. It appeared that simple monitoring of the patient's comfort in waiting rooms could be done by discriminant analysis using values of lighting and noise. From these findings, chronological changes in comfort, discrimination factors, and standard values for comfort were given and a guide for establishing comfortable environmental conditions in the dental hospital was proposed.

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The time-course changes in remineralization were examined to establish the necessary period of remineralization treatments in vitro. Enamel blocks were cut from the labial side of bovine incisors. To produce artificial caries lesions, the samples were immersed in a 0.1 M lactic acid gel at 37℃ for 3w. Subsequently, they were divided into 7 groups (n=10-12 per group). One group was not treated further after demineralization (group A). The samples in groups C-G were remineralized at 37℃ for 8 d in 20 mM HEPES buffer solutions (pH 7) containing 1.5 mM CaCl_2 and 130 mM KG with Ca/P ratios of 0.67, 1.17, 1.67, 2.17, and 2.67. The Ca/P ratios were adjusted by addition of a 0.1 M KH_2PO_4 solution. The samples in group B were exposed to a similar solution without Ca and P. To assess time-course mineral recovery, enamel surfaces were partly coated with nail varnish at days 2 and 4. Sections of about 80 μm were cut from enamel blocks and microradiographed. The lesion depth (l_d, μm) and mineral loss value (△Z, vol%・μm) were measured and the mineral uptake value (△M, vol%・μm) was calculated. The changes in the l_d, △Z, and △M values were significantly higher on days 2 and 4 (p<0.05), and lower from days 4 to 8. The △M value in each group reached 40-50% of the day 8 value by day 2 and about 85% by day 4. Regardless of the Ca/P ratios, the mineral recovery rates decreased with the remineralization period. In conclusion, it is suggested that an early period of reaction up to 4 d is optimal for examining and comparing the degree of remineralization in enamel lesions in vitro.

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The present study surveyed elderly persons retaining 20 or more teeth per individual. The number of retained teeth was determined not only from replies to a questionnaire but from clinical examination by a dentist. The subjects studied were 54 participants (37 males and 17 females). The results can be summarized follows : 1. The correlation between questionnaires and oral examination was extremely high. 2. The average number of retained teeth in the male group was 24.6 and 23.3 in the female group. A higher average score was observed in the male group than in the female group. 3. The tooth with the highest intact rate was the lower left lateral incisor (78%), and the tooth with the lowest intact rate was the upper right second molar (12%). 4 . In the male group the tooth with the highest intact rate was the lower left central incisor and in the female group it was the lower lateral incisor. In both groups the tooth with the lowest intact rate was the lower left second molar. 5. The percent of subjects having difficulty in chewing was 22%. 6. It is important for elderly persons to have a personal dentist.

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