This study examined the effect of MFP/BS combination dentifrice (MFP containing bamboo salt that has various mineral components) on fluoride uptake and acid resistance of bovine enamel. The experiment utilized bovine enamel which was treated with 5 different groups of dentifrices for 24 hours : 1) C : control dentifrice containing abrasive only, 2) F : MFP dentifrice, 3) FB : MFP/BS dentifrice, 4) FBV : MFP/BS/VE (vitamin-E) dentifrice, and 5) FSV : MFP/TS (table salt)/VE dentifrice. Fluoride uptake and acid resistance of bovine enamel treated with dentifrices were assessed by chemical analysis and morphological observation was carried out using SEM (scanning electron microscopy) , XRD (X-ray diffractometer) and XMA (X-ray micro analyzer). In order to assess fluoride uptake, each of the four dentifrices was compared with the control dentifrice as to the amount of fluoride uptake. The first layer (3〜4μm depth) of the enamel surface showed significant fluoride uptake in the experimental groups (F, FSV, FB, FBV) contained MFP comparing the control (p<0.05). In the third layer (appr. 17〜20pm depth) only the FB and FBV groups showed significant fluoride uptake compared to the control (p<0.05). In acid resistance test of the treated enamel, the F group showed inhibition of Ca dissolution for 6 hr, and the FB and FBV groups for 12 hrs (p<0.05). In SEM observations, the surface of the FB and FBV treated enamel showed innumerable adhesive particles on the enamel surface, which was analyzed by XRD and found to be hydroxyapatite and precursors of hydroxyapafite. In the FB and FBV treated enamel, K_5P_3O_<10>, KCa(PO_3)_3 and Ca_4O(PO_4)_2, products were detected. The ratio of Ca/P in the enamel surface calculated using XMA, was 1.62 for FB and 1.63 for FBV, which is close to 1.67, the value of sound enamel. It is concluded that MFP/BS and MFP/BS/VE dentifrices are more effective in fluoride uptake and an acid resistance in vitro than the conventional MFP dentifrice and MFP/TS/VE dentifrice.

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We investigated the association between the DMFT index at 12 years of age and urbanization in 39 developing countries. First, cluster analysis was performed to divide the 39 countries into subgroups based on their patterns of urbanization. These developing countries were then assigned to one of two groups (cluster I and cluster 2). These two clusters were characterized by three factors related to urbanization, namely, the percentage of the population aged between 15〜64 years, the population employed in the service sector, and the urban population. Next, the subgroups were compared with regard to the DMFT index at 12 years of age. The less urbanized countries of cluster 1 had a significantly lower DMFT index than the more highly urbanized countries of cluster 2 (p<0.001). This finding suggests that the prevalence of dental caries is increasing rapidly in the developing countries with higher urbanization such as Korea and South Africa, and therefore, a dental caries preventive program should be developed immediately in these countries.

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The purpose of this study was to evaluate the relationship between general health and oral health of elderly persons over 80 years of age. Questionnaires for participation in this program were distributed by members of the neighborhood assosiation to 1,601 residents of Kaminoyama-city in Yamagata Prefecture aged 80 years or older. A total of 605 participants (234 males and 371 females averaging 85.1 years of age) completed the program and the questionnaire. The results are as follows. 1. Overall more than 50% of subjects were three-generation households. 2. The elderly persons who expressed satisfaction with life retained more of their own teeth but those who did not express this satisfaction had lost teeth that had undergone treatment. 3. 12.1% (males : 17.6%, females : 6.5%) of the subjects retained 20 teeth per individual. 4. 81.9% of the subjects wore dentures and 44.6% of them had complete dentures. There was a fixed proportion of the subjects that needed dentures but did not have them. 5. A higher proportion of the elderly persons who did not have a personal dentist did not possess dentures or had complete dentures. There was a tendency for them to avoid treatment. 6. The data suggested that the recovery of masticatory efficiency was related to the wearing of dentures.

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To study the effects of school health activities on oral conditions in children, we investigated the incidence of caries in permanent teeth among 1st to 6th graders of primary schools in Niigata Prefecture from 1990 through 1994. The primary schools covered by our survey consisted of 263 schools which had expanded their school health program to include fluoride mouthrinsing and 299 schools whic had not. We worked out the caries prevalence rate, filled teeth rate and the average number of DMF teeth per person for comparison between the two groups of schools. In the meantime, a fact-finding survey was conducted on how school dental health programs were implemented over the 5-year period. The programs consisted of 25 items divided into 4 groups ; systematic activities health education, health supervision, and community health activities. Based on the findings, we divided the 6th graders into two groups-one with many cavities and the other with a few cavities-and looked into the relationships between the caries incidence and school dental health activities. The following conclusions were drawn : 1. Significant differences were noted in the incidence of tooth decay and the average number of DMF teeth per person between the pupils in the schools which encouraged the use of fluoride mouthrinsing and those which did not, irrespective of age. The dental caries incidence and the average number of DMF teeth in children with fluoride mouthrinsing were around 80% and 70%, respectively, as opposed to those in children who did not rinse their mouths in school. 2. A check of the implementation of school health activities revealed that the schools which told pupils to practice fluoride mouthrinsing scored more than 80% in 12 items out of the total 25 items of dental health programs, compared with 10 items in the schools which did not. The average marks for the 4 departments were higher in health supervision and community health activities in the schools that practiced fluoride mouthrinsing than in those schools that did not. 3. When the relationship between the caries incidence and school health activities was examined, the group of pupils with less caries belonged to the schools which gained high marks in more than 17 items of the dental health program. Group-wise, the schools which were low in the caries rate as well as the average number of cavities per person got high marks in health supervision. Even in the schools which did not have their students do mouthrinsing but practiced health supervision and health education, the caries rate was low and the average number of decayed teeth per person was small. Likewise, many of the children who had good scores of filled teeth were students at the schools which gave importance to health activities.

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One of the aims of this study was to make a health care plan, by investigating periodontal disease prevalence and treatment needs in pregnant women. Oral examination was done using the CPITN, indices for gingivitis, periodontitis, and calculus deposition and the VPI by inspection. Another purpose of this study was to determine the relationship between caries experience and periodontal disease prevalence. This was carried out using the DMFT. A total of 638 subjects participated, all pregnant women who received oral examinations while attending classes for new mothers at health centers from 1994 to 1997. The average age of the women was 27.6 years. The average number of weeks into pregnancy for the subjects was 19.7 weeks. Most of the pregnant women, of all CPITN age groups, were coded 2, and a small fraction were coded 3 or 4, and 94.2% of these were found to be in need of some treatment. Almost all were aged 20-29 years, and they were classified by the number of pregnancy weeks, and divided into 7 categories. We further classified them into high and low DMFT score groups, for the relationship between caries experience and periodontal disease prevalence. The results were as follows. 1. Oral hygiene was seen poor in the early stages of pregnancy and there was a tendency to improve in the later stages, but a clear relationship was not recognized between pregnancy weeks and gingivitis, periodontitis, or presence of calculus. 2. Gingivitis during pregnancy showed a statistical relationship between the state of oral hygiene and calculus. Gingivitis had more influence on the resence of calculus and condition of oral hygiene than pregnancy weeks. 3. In the law DMFT score group, oral hygiene was better, and there was more calculus, and a difference in CPITN code distribution, than the high DMFT score group. 4. Caries experience showed a statistical relationship between the CPITN code, the mean number of sextants and the presence of calculus. In conclusion, we found some relationship between gingivitis and calculus in pregnant women and caries experience. This suggested that caries prevention in the young aided prevention of gingivitis in pregnant women.

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The purpose of this study was to examine the oral health status and the environment of workers by a questionnaire. The questionnaire was based on the concept of the PRECEDE-PROCEED model. It consisted of the following questions ; QOL, subjective symptoms of periodontal disease, oral health behavior, predisposing factors, reinforcing factors and enabling factors. One hundred forty-seven of 170 office workers (128 males, 19 females) in a manufacturing industry responded to the questionaire. Subjects were 39.2±12.2 years old, ranging from 21 to 67 years. The QOL of the workers was affected by oral diseases. Most of the workers had subjective symptoms of periodontal disease. Poor oral conditions in these workers were suggested. They did not show good oral health behavior. As factors which affect oral health behavior, reinforcing and enabling factors were insufficient compared with predisposing factors. The attitude of most of the workers was positive regarding participation in the oral health program. Useful information for planning a program for Work Site Health Promotion (WHP) was provided by this questionnaire based on the concept of the PRECEDE-PROCEED model.

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In order to estimate the relationship between the chronological changes caused by airborne bacteria and dust, measurments were carried out in the oral operating room at Asahi University Dental Hospital. We measured dust grain sizes of 0.3, 0.5, 1.0, 2.0, above 5.0μm, airborne bacteria with an SY type pin hole sampler method and Koch's dropping method, and environmental factors (temperature, humidity, air flow, times the door was open and shut, and number of persons). Correlation between the airborne bacteria and the distribution of each dust grain size or each measured factor was analysed. The following results were obtained : 1. Airborne bacterial count ranged from 0.03 to 0.89 CFU/l by the SY method and from 0.33 to 4.67 CFU by Koch's method, and in operating times had the higher counts than before and after operation. The correlation between the number of airborne bacteria obtained by the SY method and by the Koch's method had a high coefficient (p<0.01). The clean standard value of dropping airborne bacterial colonies was estimated at about 2.8 CFU, and Koch's method appeared to be a useful technique for simple air pollution screening. 2. Total dust value (above 0.3μm) was high for 30 minutes after an operation started and before it ended, and indicated a different tendency from the chronological changes caused by airborne bacteria. Large grains of above 1.0μm were found at a higher rate at operating times than at other times. 3. The factor of number of persons had a high correlation to airborne bacterial and dust factor. A high correlation was found between airborne bacteria and the dust grain size of above 5.0μm. The estimated accuracy of airborne bacteria colonies by multipule regression analysis was increased by adding the dust factor to the environmental factors. Thus, the measurement of dust is useful to estimate airborne bacteria colonies in real time, and is useful for simple air pollution monitoring.

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The distribution and the extent of root surface caries were examined in 14,236 extracted teeth. Thirty-one percent of the teeth (4,394 teeth) had root lesions. The root was divided into eight surfaces. Single-surface lesion, two-surface lesions, and circumferential lesions were observed on 1.559 teeth, 996 teeth, and 179 teeth, respectively. On all examined teeth with root caries, the distal surfaces (65.1%) were the most frequently attacked surfaces, followed by mesial surfaces (51.9%). Many lesions were only small lesions. About 90% of the lesions were located on the cemento-enamel junction. The mean of the apical extent and the mean depth of the lesions were 3.5mm and 1.1mm, respectively. The height, the depth, and the number of affected surfaces were significantly correlated. These findings suggest that root caries extends three-dimensionally, i,e., toward the adjacent surface, toward the pulp, and toward the apex of the root. The mean ratio of the apical extent to the attachment level was two to five. The attachment level correlated with the apical extent of the lesions, whereas the lateral and horizontal extent of the lesions were independent of the progress of periodontal diseases.

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A periodic dental health check and odontotherapy treatment were given once a month to severely handicapped children, for 12 years from 1982 in a facility for children (adults) with severe handicaps. The evaluation regarding the effect of oral health care control by examination of the mouth was carried out in 1982 (survey I),1989 (survey II),and 1994 (survey III) The results were as follows. 1. An increase in MT and a decrease in DT were recognized in each age group between survey I and survey II by cohort observation. The decrease in DT was maintained up to survey III from survey II and the effect of oral health care control was recognized. On the other hand, PMA-I showed a decrease through survey I, survey II, and survey III in each age group. 2. When the no caries increase group and caries increase group were compared between survey I and survey II in Oshima's classification, intelligence quotient (IQ), food behavior, and also washing behavior, the number of persons was similar in both groups except for sex distinction. The same trend was seen even between survey I and survey III. 3. Between survey I and survey II the order of influence was Oshima's classification>sex distinction>IQ>behavior evaluation when the relevancy of each factor was checked by multiple regression analysis. Between survey II and survey III, and between survey I and survey III the order of influence was sex distinction>Oshima's classification>IQ>behavior evaluation between Oshima's classification>IQ>behavior evaluation>sex distinction. These results suggest that the prevention and improvement of caries and gingivitis by long-term oral health care control are effective, and the importance of detailed health care control was recognized.

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The purpose of this study was to evaluate the usefulness of the oral health check-up system in adult patients mainly by assessing the reduction of tooth loss. We have managed to control dental diseases of adults with a check-up system consisting of oral examination, tooth brushing instruction, scaling, and periodical recall at the outpatient clinic in the hospital of Niigata University School of Dentistry. 663 subjects (males, 291 ; femals, 372 ; average age, 37.6) had participated in the check-up system for 10 years or longer. Before analysis, we studied the loss of teeth over time in the subjects at the first examination. We regarded the status at the first examination as control when the subjects had not participated in the check-up system and compared the mean number of missing teeth in the same age (30〜39, 40〜49, 50〜59-year-old) group between the first and final examinations. The mean number of missing teeth at the final examination decreased in all age groups and was significantly less than at the first examination in the 40〜49 and 50〜59-year-old groups. The mean number of missing teeth per person per year during the recall period was 0.076, which was a relatively good level when compared with other surveys. The number of decayed teeth and each index for the periodontal health status were significantly lower at the final examination than at the first examination. In addition, the mean number of decayed teeth and the mean of each index for the periodontal health status of subjects who did not lose teeth during the recall period were significantly better than in those who lost teeth. These results suggest that a periodical oral health check-up in adult patients on a clinical basis is useful for maintaining periodontal health and reducing tooth loss.

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The aim of this study was to determine the buffering effect of saliva on demineralization by sugar and sugar substitutes. Modified enamel demineralization devices were fixed on the buccal surface of the mandibular first molar. Eight volunteers wore the device for 4 days without brushing to accumulate plaque on the enamel surface. After 4 days, the device was removed and a test solution or test solution+saliva were directly applied to the plaque in vitro. As test solutions, 10% sucrose, 10% coupling sugar, 10% palatinose, and 10% sorbitol were used. Thin enamel sections (100μm) were evaluated for the degree of demineralization by microradiography. The buffering effect on the degree of demineralization was remarkable. Although there was no statistical difference among the controls, the coupling sugar+saliva, the sorbitol+saliva, or the palatinose + saliva, the differences between sugar/sugar substitutes only groups and sugar/sugar substitutes+saliva groups were statistically significant (p<0.01). This study suggested that the decrease in demineralization when saliva was used was due to the buffering action of saliva.

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We examined 59 home-bound elderly persons who lived in 10 regions of Saitama Prefecture in order to assess the relationship between their life style and dental conditions. More than 55% of the chief care providers had anxiety about their own general health condition. Especially in the case of the spouses who were the chief care givers, because of their own age and the burden of supporting their spouses, these individuals were anxious about their own general health conditions. As for the relationship between life style and dental conditions, an increase in the DT and a decrease in the MT were found. In addition, as the oral hygiene conditions of the home-bound elderly were dependent on the general condition of the care provider, it is necessary for the care giver to improve his/her own general condition and consciousness of health, especially when the care is provided not at a hospital or institution but at home.

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As an approach to an integrated investigation of oral health status in Japan, adults male and female were selected from nine regions and subjects were public officers of city administration. The aim of the present study was made for statistical analysis of the cognitions of oral health and the acceptance of dental care. The regions investigated were Hokkaido. Central and Western areas of Honshu, and Kyusyu. The subjects were 865 males and 553 females (1,418 total subjects) aged 25〜64 years. The items investigated were as follows : (1)subjective evaluation of oral health status, (2) knowledges and interest for oral health, (3) attitude toward dental care, and (4) oral health behavior. The parameters of this study were (1) gender differences, (2) age specific characteristics, and (3) regional differences. The subjects with perception of subjective symptom of oral diseases ranged from 15.0% to 28.0% in all age groups. The subjects who were highly interested in newspaper columns regarding health issues were less than 10% in males and 13.9% to 33.1% in females. There were significantly differences in gender in all age groups (p<0.01). For the dental anxiety, 33.1% to 56.6% of the subjects responded positively. Especially females aged 25〜34 years and 55〜64 years showed a significantly high rate (p<0.01, p<0.05). Those who had not seen a dentist for a year ranged from 38.9% to 51.2% in males and 32.3% to 43.9% in females. The items for the regional differences and tooth brushing habits before going to bed ranged from 63.5% to 81.2% in nine regions investigated. The subjects who had a personal dentist ranged from 59.4% to 80.7%. These results might reflect the number of dentists in community and further studies are needed in this respect. Regarding promoting and hampering factors for oral health in adults aged 35〜44 years examined by multiple logistic regression analysis, the findings indicated that the decisive factor was knowledge about oral health in relation to tooth brushing before going to bed at odds ratio of 1.40 (p<0.05), and family income and dental anxiety also related to regular dental visit at odds ratio of 2.16 (p<0.05) and 0.26 (p<0.01). These results suggested that factors of gender, age, and regional differences were clearly associated with the cognitions of oral health, and that acceptance of dental care and oral health behavior were significantly associated with knowledge of oral health, accessibility to dental clinic, dental anxiety, social supports, and family income.

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