Oral health promotion has involved an "8020" goal, with the objective of achieving an ideal of reaching 80 years of age with 20 teeth. Dental examinations for office workers are not sufficient compared with those of preschool-age children, which are provided for in the statute of The Maternal and Child Health Law, and those of school-age children, which are provided in the statute of The School Health Law. The self-administered questionnaire method was developed for persons who feel difficulty in having professional checkups I subjects can get a diagnosis sheet from a computer program after answering the questionnaire concerning such factors as the condition of dental diseases and toothbrushing habits (Okuchinokenkou-Advice system<0. A. system>). This study was conducted to compare the diagnosis by the O. A. system with the results of a conventional checkup of office workers. The results obtained from this study were as follows: 1. The percentage of correct answers was 61.1% in the category of caries. 2. The percentage of correct answers was 63.3% in the category of periodontal disease. 3. The percentage of correct answers was 73.3% in the category of hypersensitive teeth. These results indicate that the O. A. system is useful for self-checking of oral diseases.

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The purpose of this study was to examine the effects of NH₄F solution (100 ppmF^- and 900 ppmF^-, pH 5.0) on human enamel. The action time was 5 min. and the temperature was 37℃. We measured fluoride uptake, Ca/P molar ratio and acid resistance by chemical analysis with powdered enamel. Morphological observation was done by SEM, element analysis (distribution of fluoride, calcium and phosphorus in the enamel surfaces) and state analysis (identification of the reaction products) by EPMA with intact enamel. We performed similar experiment with NaF solution for purposes of comparison. In the 100 ppmF^- treated NH₄F group, fluorapatite and CaF₂ were generated similarly of that in the NaF group. Fluoride uptake of NH₄F was lower than in the NaF group, but that of the acid resistance was as high as or higher. In the 900 ppmF^- treated NH₄F group, fluorapatite and CaF₂ were generated, and the quantity of CaF₂ was greater than that in the NaF group. Fluoride uptake and acid resistance of the NH₄Fgroup was higher than that in the NaF group. These findings showed that acid resistance was influenced by the quantity of CaF₂. Therefore, an NH₄F solution is expected to have a cariostatic effect, in the 100 ppmF^- as well as, in the 900 ppmF^- higher than NaF solution, if action time is for 5 min. We suggest that NH₄F solution be used for mouth rinses and dentifrices.

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The purpose of this study was to evaluate sampling bias caused by present teeth or general health condition in an oral health survey of elderly subjects. A mailed questionnaire survey was carried out for residents of Niigata City who were 70 or 80 years old, investigating the number of present teeth, general health condition and intention to participate in an oral examination. Follow-up mailings were sent once to non-respondents. The response rate was increased from 60.4% to 79.5% by the follow-up mailing. A telephone survey was carried out for subjects who didn't answer the questionnaire. The invitation to an examination was targeted toward subjects who answered that they would participate in an examination in the questionnaire, and 763 elderly participated in the examination. We compared the number of present teeth, general health status and other items whether the subjects answered the questionnaire or not and whether subjects participated in an examination or not. We also estimated the number of present teeth in the population. Results showed that the number of present teeth of participants in the examinations was higher than the estimated value in the population (difference: 2.6-3.9 in 70-year-old, 0.8-1.8 in 80-year-old). The general health condition of early responders to the questionnaire was better than that of the later responders, but the degree of difference was smaller than that of the number of present teeth. Therefore, bias caused by the number of present teeth was larger than that caused by general health condition under which the dental examination was carried out for subjects, according to their wishes to participate in an examination.

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The purpose of this present study was to evaluate the construct validity of a questionnaire. To diagnose periodontal disease comprehensively at a worksite, a questionnaire (FSPD-34) was developed based on the PRECEDE-PROCEED model. The questionnaire consisted of multi-factorial sub-scales that were mutually related to each other. Subjects of this study were 324 factory workers aged from those in their 20 s to those in their 60 s who completed the questionnaire. The data were analyzed using covariance structure analysis. Covariance structure analysis used the linear structural relationship system (LISREL), using the method of maximum likelihood analysis. As a result of LISREL, Goodness of Fit Index was 0.824, and causal coefficients showed remarkably that latent variables as constructs were mutually related to each other. The results of this study suggest that a construct of FSPD-34 was suitable for the PRECEDE-PROCEED model and reliable for diagnosis of peridontal disease at a worksite.

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Male Wistar strain rats were fed a zinc (Zn) deficient diet for 4 weeks and the tongue microvasculature and mechanical characteristics of the femur bone studied in order to determine the biological effects of Zn. The following results were obtained. 1. Rats fed the Zn-deficient diet consumed less feed than the control group, and body weight gain was suppressed. 2. Macroscopic findings that are characteristic of Zn deficiency, such as skin symptoms and piloerection, were observed in the Zn-deficiency group from about 3 weeks after starting the experiment. 3. Serum Zn concentrations and serum ALP activity were significantly lower in the Zn-deficiency group compared to the control group. 4. Tongue Zn concentrations were significantly lower in the Zn-deficiency group than in the control group. 5. Femur length and bone density, as well as the maximum asymmetry and maximum bending stress were significantly less in the Zn-deficient group compared to the control group. 6. Leakage from the tongue microvasculature was observed in the Zn-deficient group from an electron microscopic image of the tongue microvasculature. The results of the present study suggest that taste abnormalities due to Zn deficiency are related to impairment of the tongue microvasculature, which is the nutrient supply route for the taste buds, and that impaired growth and decreased bone strength in the femur are caused by Zn deficiency.

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Dental examination and investigation of oral microbial flora in elderly people in two different institutions were performed and compared to each other in this study. Special attention was paid to the following : A) the number of Candida on the tongue and its correlation to denture wearing, and B) a comparison of Candida on the tongue of elderly people in both institutions versus that of elderly people living in their own homes* (*This study was a part of a project for the Ministry of Welfare investigating oral Candida in patients 70 and 80 years old). Subjects had been institutionalized in a nursing home in Kanagawa (n=50) and in a hospital for elderly people in Tokyo (n=29) and their mean age was 80.9 years old. Salivary flow rate, buffering capacity, the numbers of lactobacilli and mutans streptococci in saliva, and the numbers of Candida and staphylococci on the tongue were investigated after dental examinations were performed. When comparing the all results obtained from the nursing home and the hospital for elderly people, there were no differences. However, when comparing elderly people divided into denture-wearing and non-denture-wearing groups, the numbers of Candida and staphylococci on the tongues of those in the denture-wearing group were significantly higher than those of the non-denture-wearing group. The number of subjects who were classified in Grade IV (the number of Candida on the tongue was more than 101 CPU) was higher in the institutionalized elderly people than in the elderly people living in their own homes. These results suggested that the institutionalized elderly people had a higher number of Candida on the tongue, and denture wearing increased the number of Candida in the oral cavity because it acted as a reservoir for oral Candida.

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The purpose of the present clinical crossover trial was to compare the feeling, plaque removal and bacterial counts after mouth cleaning by toothbrushing with or without dentifrices when using dentifrices containing foaming agents or not. The examiner was blind to the subjects' treatment; 64 subjects in two groups (one consisted of 38 workers at an enterprise and another consisted of 26 first-year students at a junior college for education of dental hygienists) completed the study. Influences of four types of mouth cleaning methods (A〜D) were assessed: A was toothbrushing with a foaming agent-containing dentifrice; B was with dentifrice not containing any foaming agents; C was with water alone; and D was with a dentifrice routinely used by each subject. Comparison of pre- and post-brushing (with water alone) feeling scores showed a statistically significant increase when brushing with dentifrice ; increase in scores of feeling and plaque removal effectiveness and decreased oral bacterial counts in saliva collected immediately after mouth cleaning were more evident in brushing with foaming agent-containing dentifrices than that with dentifrices in the absence of a foaming agent. The scores (feeling, plaque removal effectiveness and bacterial counts) tested were maintained even if a small amount of dentifrice with foaming agents was used. The plaque re-growth inhibition was dependent on the amount of dentifrice measured (from 0.23 g up to 1.66 g); the foaming agents enhanced the observed effect. It can be concluded that under the conditions of this study, brushing with foaming agent-containing dentifrices is effective for mouth cleaning.

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In a technical report of the WHO, it is described that fluoride mouth-rinsing is contraindicated or not recommended for children below the age of 6 years, as it might contribute to the risk of dental fluorosis. However, no epidemiologic evidence has shown that the fluoride mouth-rinsing is a risk factor for increasing dental fluorosis in children in communities where fluoride was in short supply such as Japan. To determine the prevalence of dental fluorosis, an epidemiologic investigation was conducted in a part of the regular school dental health examination in the spring of 1997, among Japanese 5 th and 6 th grade elementary schoolchildren in three communities of different experience of fluoride. The children: (1) participated in a fluoride mouth-rinsing program since 4 years of age (5 times/week rinsing with 0.05% sodium fluoride solution, in preschool and weekly rinsing with 0.2% sodium fluoride solution in elementary school) in fluoride-deficient communities (FMR group); (2) resided in an area with naturally fluoridated water (about 0.8 mg F/l) for their entire life without a fluoride mouth-rinsing program (Nat. F group); and (3) had no exposure to fluoride (Control group). The Fluorosis Risk Index proposed by Pendrys was modified and applied to detect individual enamel opacity on 7 numbers in all of the developmental age-related enamel surface zones, which were formed between the second and sixth birthday, designated as classification II in three restricted teeth, the upper right first premolar and central incisor and lower right first premolar. If either more than two questionable findings or any number of positive findings in classification II were found in a child, then he/she was classified as having dental fluorosis (fluorosed enamel opacity). If a child had any enamel opacity that was not induced by fluoride, then he/she was classified as having non-fluorosed enamel opacity. One dentist screened enamel opacity in 268 children. Cohen's Kappa value of reproducibility in diagnosis of enamel opacity was 0.84. If any of the restricted teeth of the child were unerupted or he/she had disturbance of diagnosis, for example, orthodontic therapy, he/she was excluded from analysis. Ultimately, 222 children were included in the present analysis. The prevalence of fluorosed enamel opacity in Classification II of the FMR group was less than that of the Control group (Odds ratio; 0.358, 95%CI; 0.127-1.008), which was not statistically significant. The prevalence of fluorosed enamel opacity in Classification II of the Nat. F. group was significantly larger than that of the Control group (Odds ratio; 3.112, 95%CI; 1.515-6.395). The prevalence of non-fluorosed opacity in both the FMR group and the Nat. F. group was lower than that in the Control group, but it was not statistically significant. From the results of this study, a fluoride mouth-rinsing program from preschool (4 years of age) was not indicated to be a risk factor of dental fluorosis in fluoride-deficient communities.

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To determine the influence of strontium ions (Sr^<2+>) on dental pulp tissues, we used cultured dental pulp cells derived from rat incisor pulp and an osteoblastic cell line (MC 3 T 3-E 1), and estimated the effects of Sr^<2+> on the activities of alkaline phosphatase (ALP) and protein kinase C (PKC) in both cells. 1. Although Sr^<2+> increased the level of ALP activity in the pulp cells at concentrations less than 10^<-4> M, it did not directly activate ALP extracted from the cells at all. 2. Sr^<2+> gradually decreased the level of ^3H-thymidine uptake into DNA in the pulp cells according to its concentrations, but significantly increased the level of ^<14>C-leucine uptake into proteins in the cells. These results suggest the possibility that the increase in the level of ALP activity in the pulp cells by the addition of Sr^<2+> is correlated with the increment of protein synthesis by the ions. 3. Sr^<2+> did not affect the level of calcium in the pulp cell layers. However, Sr^<2+> markedly increased the accumulation of calcium in MC 3 T 3-E 1 cell layers according to its concentrations. 4. Sr^<2+> (10^<-3> M) increased the level of PKC activity in both these cells and also activated PKC extracted from the cells as well as calcium ions (Ca^<2+>). 5. Sr^<2+> below than 10^<-3> M activated authentic PKC from rat brain, but this activation of PKC was less potent than that induced by Ca^<2+>. The PKC activation induced by Ca^<2+> was reduced in the presence of Sr^<2+>. 6. The binding affinity between PKC and Ca^<2+> was about 2-fold higher than that between the enzyme and Sr^<2+>. These results suggest that Sr^<2+> below than 10^<-3> M increases the level of ALP and PKC activities of the cultured hard-tissue-peripheral cells, and induces the mineralization of bone and teeth.

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This study aimed to investigate the relationship between mothers' knowledge, attitudes and behavior towards application of fluoride and caries experience of their 3-year-old children. The subjects were all 437 pairs of mothers and their children who participated in the 3-year-old check-up at a community health center in Hiroshima from 1993 (Nov.) to 1994 (March). At the 3-year-old check-up, the mothers answered a questionnaire on their knowledge, attitudes and behavior toward application of fluoride, and the caries experience of their children was recorded by dft based on WHO caries diagnostic criteria. The results were as follows: I. Sixty-nine percent of the mothers reported brushing to be the most effective method in preventing tooth decay, but only 1 percent of them cited the application of fluoride as the most effective method. 2. Twenty-four percent of the mothers used toothpaste with fluoride for their child. Eighty-one percent of the children had some experience of topical application of fluoride 3. Neither the use of toothpaste with fluoride nor the topical application of fluoride had an influence on the dental condition of the children. These results suggested that most of the mothers didn't regard fluoride as a means of preventing dental caries, and mothers' better behavior toward application of fluoride didn't lead to better dental conditions of their children. Therefore, specialists in dental health should give information about fluoride to mothers.

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