In this study we investigated the adsorption kinetics of fluoride ions on the surface of hydroxyapatite (HAP). Time dependence of adsorption was measured in both an aqueous solution and in a foam solution containing fluoride ions. The amount of fluorine ions adsorbed was determined using a F^- ion electrode in the buffer solution at pH 5.3, after HAP particles adsorbed with fluoride ions were dissolved with perchloric acid. Our results were as follows: (1) The formations of ion complexes or ion pairs could not be detected in any direct interactions between the foam making surfactants and NaF. (2) Sodium dodecylsulfate ions, which were one of foam making surfactants, were not adsorbed on the HAP surfaces. (3) The adsorption kinetics of fluoride ions on the HAP surfaces from the solution in foam was about 10 times faster than that from the bulk aqueous solution. (4) The decay rate of a slice specimen of human molar tooth, which had been treated for 3 min with the solution or the foam at the same concentration of fluoride ions, was investigated by dipping the specimen in an acetic acid solution at ambient temperature. Experimental observations by the CMR technique agreed with the results obtained in the HAP study, in that the foam treatment appeared to be more effective in preventing decay because the fluoridation rate with the foam was faster than the rate with the solution. (5) Physicochemical analysis was conducted to investigate why adsorption of the fluoride ions was faster than in the foam solution, and from the results we speculate that the electrostatic effect of hetero-electric double layers generated between the HAP surface and the adsorbed surface of SDS in foam focilitated the effect. In conclusion we suggest that this effect makes foam very useful in suppling fluoride ions onto the surface of teeth.

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In order to clarify the time of development meal taking function among systemic functions, we surveyed 89 kindergarten children from 0 to 5 years of age in Y city. Primitive reflexes, keeping proper posture, oral muscle movement function, proper eating style, systemic function, speech function, and eruption of teeth were surveyed with regard to the time of development. The following results, expressed as mean values, were obtained I 1. The frequency of chewing increased with age. 2. The sucking reflex disappeared fastest and the biting reflex was the slowest to disappear. 3. We found that 50% of the subjects could support their necks by 6.5 months and could walk alone by 12.8 months. 4. Chewing with teeth occurred about 2 months after "pushing-out" swallowing. 5. Hand to mouth eating began at about 1 year, afterward the infants began to use their spoons or cups. 6. We found that 50% of the subjects could run at 22.5 months without falling, and jump at 30.8months. 7. We found that 50% of the subjects spoke sentences containing some words at 29.2 months, and 2 months later their pronunciation became clear. By 3 years of age, they had high speech ability using compound sentences and interrogative words. 8. The subjects front teeth erupted at 9〜10 months, and their molars erupted at 13.9 months.

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Since 1979, for 20 years, we have been conducting an oral health examination in preschool children in Kikonai town, Hokkaido, consisting of oral health instruction and topical fluoride application in addition to dental examination. In this study, we analyzed the transition of child dental caries prevalence in Kikonai town between 1979 and 1999. The results obtained were as follows: 1. The caries prevalence rate in children aged 2 to 5 years old slightly decreased over the time period. 2. The caries prevalence rate of severe dental caries in deciduous molars decreased over the period in accordance with the increase of children with fillings. 3. Although the effects of oral health instruction and topical fluoride application in children during the 20 years were not significant, we suggest that, they might contribute to a decline in caries. In the future we would like to extend the program to include dental health instruction for pregnant women and the children's grandparents.

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The purpose of this study was to evaluate the clinical success of fissure sealants (SR) and preventive resin restorations (PRR) which were applied over occlusal carious lesions and to discuss the availability of these methods in a program which manages recently erupted permanent molars by means of prevention and treatment of occlusal dental caries. A preventive resin restoration is a conservative treatment that involves limited excavation to remove carious tissue, restoration of the excavated area with a composite resin, and application of a sealant over the surface of the restoration and the remaining sound, contiguous pits and fissures. Subjects were 57 children aged between 8 and 14 years, at the last examination and who had teeth treated with either SR or PRR. They had been participating in a school-based fluoride mouthrinse program from the age of 5 years, which was combined with a targeted sealant-sealant was selectively applied on the fissure detected as sticky using an explorer-in elementary school. Sixty six teeth-64 first and 2 second permanent molars-were evaluated. Carious lesions that did not exceed a width of 2 mm in a pit or fissure of these teeth were detected. Accordingly, SR or PRR were applied on them. An excavation performed with a small round bur (# 1/2) was indicated for SR, while excavation using a bigger bur was indicated for PRR. After these lesions were treated with either SR or PRR, they were assessed twice a year. The mean period of observation was 3.4 years, with a range of 1 to 7.5 years. Out of 45 teeth to which we applied SR, 9 teeth developed secondary caries. In the case of PRR 3 teeth out of 21 teeth developed secondary caries. The cumulative survival rate for subject teeth after 7.5 years was 71.9±8.0 (SE)% as detected by Kaplan-Meier survival functions; thus, the cumulative incidence of secondary caries was 28.1%. There was no significant difference between the cumulative survival rate for SR (71.0 ± 9.1%; after 7.5 years) and that for PRR (75.2 ± 14.8%; after 5.5 years) as determined by generalized Wilcoxon analysis. And stepwise multivariate logistic regression analysis indicated that the school grade at which carious lesion was detected first had a significant impact on the development of secondary caries after SR or PRR application. A cavity detected at the 1st and 2nd grade was at a larger risk (odds ratio=4.56) than that was detected at higher grades. Similar findings have been reported earlier. It is, therefore, recommended that these treatment methods, which are indicated for small and discrete pit or fissure caries, be adopted in dental clinics practicing preventive measures of dental caries, including fluoride use. It is also suggested that the condition of sealant or resin restoration be observed periodically, in order to maintain it properly.

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The aim of this study was to collect baseline data for the oral health instructions on bank office workers at the year of retirement aged 64, 65 yrs. In 1992, an oral-health examination was performed on 28 male bank employees. Including third molars, the mean number of present teeth was 20.1, sound teeth was 9.7 and treated teeth was 10.0, and 68% had more than 20 teeth. Excluding third molars, the mean numbers of present teeth was 19.0. The mean numbers of teeth with occlusal support was 8.0. Fifty percent of subjects wore removable dentures, 57% wore bridge prostheses, 2 subjects had 32 teeth and 4 subjects had 28 teeth, excluding third molars. Three subjects had upper and lower full dentures, 2 had upper or lower full dentures. In this study, 43% of subjects were classified as Eichner class A, 39% in class B and 18% in class C. These data provide a baseline for oral health status and were utilized oral hygiene instruction in office workers.

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Pit and fissure sealants have been accepted as a caries preventive strategy and have a great effect on preventing dental caries on the pit and fissure surfaces of permanent molar teeth. The retention for resin-based sealant is better than for glass ionomer sealant, but the difference in caries prevention remains equivocal. The aim of this study was to compare the caries preventive effect and retention of a glass ionomer cement (GIC) and a resin-based sealant (RBS). GIC (n=61) or RBS (n=82) was applied on the occlusal surfaces of permanent first molars with Sticky Fissure in school children (n=108), mean age=9.50±1.57 (S. D.). All sealants were applied by two operators using standard procedures and were assessed at baseline and every 6 months thereafter. Assessment criteria were based upon the inefficient status rate (Sticky Fissure or dental caries) and on the occurrence of caries. After 2 years, the ineffective status rate was 23.2% on the RBS compared to 36.1% on the GIC (p<0.05, Wilcoxon's test). For the evaluation of material for sealing, logistic multiple regression analysis was performed. As dependent variables, inefficient status (yes=1, no^O) was used. As independent variables, age, sealant material (RBS=1, GIC=2), DMFT at baseline and jaw (upper=1, lower=2) were used. The inefficient status was associated with the sealant material (Odds ratio: 1.61, p=0.04), after adjusting for age, DMFT at baseline and jaw. In addition, there were a total of eight occurrence of caries, three (4.9%) in teeth sealed with GIC and five (6.1%) in teeth sealed with RBS. The difference in the percentage of the occurrence of caries between teeth sealed with RBS or GIC was not significant. In conclusion, there was no significant difference in caries prevention using GIC compared to RBS. However, there was significantly better retention with RBS.

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In 1998, a study of people aged over 80 years old was carried out in four Prefectures, including Fukuoka Prefecture, as a project for the 8020 data bank. The purpose of this project was to evaluate the relationship between general health and oral health in people aged over 80. Of 1,282 residents in Fukuoka Prefecture, a total of 827 participants (310 males and 517 females) completed the program and the questionnaire. In the present study, we selected factors such as exercise and bone density as markers of the subject's general health condition, and analyzed the relationship between these factors and their oral health condition. The finding were as follows. 1. The mean number of teeth per individual was 7.5, and 14.1% of the subjects retained 20 teeth per individual. 2 . A significant relationship between the number of teeth and the notion that "we should take care of their own oral hygiene and oral health", one of the items on the questionnaire, was found. 3. A significant relationship between masticatory efficiency and the number of teeth (&ge; 20) was found. 4. A higher proportion of elderly people with a high exercise function possessed a higher number of teeth, could masticate a greater the number of foods, and had a higher bone density. These findings suggested that a positive attitude towards health was a common factor in subject's who retained 20 or more teeth, and that the subject's general health and the amount of exercise they took were also important factors.

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The effects of a preventive care program for gingivitis performed in Shiozawa Middle School (Shiozawa) since 1986 were evaluated in this paper. The program consisted of instruction in appropriate oral hygiene procedure to the 7th grade (12-year-old) students and recommendations to all 7th-9th grade students with a CPI (Community Periodontal Index) score over 2 to visit private dental clinics and receive oral hygiene instruction and professional care. We compared the periodontal health status and the oral health behavior of 170 (83 boys : 87 girls) 10th grade (15-year-old) students who had graduated from Shiozawa to 378 (166 boys : 212 girls) who had graduated from other middle schools (Others). When the periodontal health status was assessed utilizing the CPI, it was shown that the periodontal health of students from Shiozawa was significantly better than that from Others. It was also shown, according to the results of the questionnaire, that more students from Shiozawa had received instruction in proper brushing technique and had received professional scaling at dental clinics than those from Others, and that the students from Shiozawa were more likely to practice better daily oral hygiene. Consequently, the preventive care program, which was designed to control gingivitis in middle school students, might contribute substantially to an improvement in their overall oral health condition.

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This study investigated the influence of NH₄F solutions with different pH levels on human intact enamel. We used NH₄F solutions (900 ppmF^-, pH 2-pH 7) and freshly extracted, human premolars. We treated enamel blocks with the solutions at 37℃ for 5 minutes, and washed half of the enamel blocks with artificial saliva for 24 hours. Using chemical analysis and scanning electron microscopy, we studied fluoride uptake, acid resistance, and morphological changes in the enamel blocks following treatment with fluoride solutions or washing with artificial saliva. The enamel reacted differently depending on the pH of each NH₄F solution. After treatment with fluoride solutions, all of the NH₄F groups showed fluoride uptake into the enamel, and the acid resistance test demonstrated acquisition of acid resistance by the enamel. In the lower pH groups, in particular, fluoride uptake penetrated into the deeper layer and there was even greater acid resistance. After washing with artificial saliva, the remaining fluoride was shown in all the NH₄F groups. There was no difference among the NH₄F groups, although resistance acquisition has been reported in an acid resistance test. On scanning electron microscopy, some granular substances were seen on the enamel surface of the pH2-pH6 NH₄F groups following treatment with the fluoride solution. After washing with artificial saliva, demineralization of the enamel surface was observed in the pH2 NH₄F and pH3 NH₄F groups. After washing with artificial saliva, the granular substance remained in both the pH4 NH₄F and pH5 NH₄F groups, but it was difficult to observe following washing with artificial saliva, and in the NH₄F groups at near neutrality, pH 6 and pH 7. But the chemical analysis confirmed fluoride uptake and acid resistance acquisition, suggesting that NELF solutions at pH 6 or pH 7 are effective in preventing caries.

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This study was undertaken to clarify the effects of oral health care by dental hygienists. The subjects were 50 residents of two nursing homes. An evaluation of the effects of oral health care advice on CPI, BOP, OHI, GI, colony-forming unit of Lactobacilli, Mutans streptococci and Candida was made. Over a 3 month period the oral health care routine was performed once a month. The relationship between the frequency of the oral health care routine and the contents of the oral health care routine to the oral status was calculated. The oral health care routine was divided into four stages I tooth cleaning, tongue cleaning, advising about tooth cleaning, and advising about tongue cleaning. The results are summarized as follows: 1. The time spent on advice about tooth cleaning influenced improvement in the Gingival Index at an odds ratio of 5.94 (p<0.05). 2. The time spent on tongue cleaning influenced improvement in Candida at an odds ratio of 4.98 (p<0.05). From these findings, we concluded that over the 3 month period, a once mouthly advice session was effective for an the improvement in both the Gingival Index and in Candida.

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The diagnostic and prognostic value of Periocheck®, a chair-side kit to detect trypsin-like protease in gingival crevicular fluid, were evaluated during the maintenance phase of periodontal treatment. Seventy-two periodontal pockets of 16 patients were subjected to supportive periodontal therapy after non-surgical initial periodontal treatments. Clinical examination and Periocheck R test were performed every 3 months for a year. The sensitivity and the specificity of the kit were 40.0, 33.3, 42.9, and 25.0% and 59.7, 59.1, 60.0, and 58.8%, respectively, when the clinical attachment loss was defined as 2 mm or greater for 3, 6, 9, and 12 months. These results suggest that Periocheck® is a limited prognostic indicator in periodontal maintenance phase, but is a good indicator for current status.

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