In plants manufacturing lead batteries the potential of workers being enveloped in high density leaded air is great and requires a special compulsory medical examination.
In the factory tested a special medical examination was made and saliva samples were taken in order to measure lead levels. Besides this, due consideration of the relationship between these levels and the level of lead particles in the air was made.
The average level of lead in the saliva of 136 workers tested was 47.58 μg/dl. There appeared to be no particular relationship between this level and that of lead levels in the air. But when the air lead levels were divided into 3 levels, namely, less than 0.05 mg/m³, 0.05-0.10mg/m³, and more than 0.10mg/m³, it was found that to a certain extent estimates of lead levels in the air could be made from measurements of lead levels in saliva.
It became evident that scientifically testing the saliva and separating the leadparticles made it possible to evaluate the outside influence of lead particles in the air.
Judging from the above experiments, a relationship does exist between lead levels in the air and those in saliva and individual levels can be appraised.

抄録全体を表示

In vivo dissolution rates of enamel in acid in school children were determined to confirm wheather or not the technique could be used to distinguish each individual. In vivo dissolution rates of enamel in acid on the upper left central incisor and the lower left first molar were determined by using 2μl of sodium acetate-hydrochloric acid buffer as described by Nakagaki (1979).
The following results were obtained:
1) No clear relationship was observed between the dissolution rate of enamel in acid and the age of the subject.
2) The dissolution rate of enamel in acid in the upper left central incisor was related to that in the lower left first molar within the same individual.
3) The dissolution rate of enamel in acid of an individual was roughly consistent throughout the survey.
4) In general, the results of the dissolution rate of enamel in acid in the lower first molar presented here show distinguishing characteristics for each subject.

抄録全体を表示

The present study was undertaken to determine the relationship between the in vivo acid dissolution rate and the Relative Increment of Decay Index (R.I.D. Index) in school children. The dissolution rates on the upper left central incisor and the lower left first molar were determined in vivo in 1981 and in 1983. Then dental caries was examined by the same examiner every six months from the ages of 7 (1981) to 11 (1985).
The R.I.D. Indices of the upper central incisors and the upper and lower first molars were calculated by comparing each examination with the base lines at 7 or 9 years of age. The results were analysed using the sum of sensitivity and specificity.
The results obtained were as follows:
1) The value of the mean-1/2SD was the most effective threshold for the dissolution rate of enamel.
2) In general, the rate of the central incisor was insignificant, but the rate of the lower first molar was meaningful.
3) The increment of dental caries is an important factor when it comes to evaluate a method such as that used to determine the dissolution rate of enamel in acid.

抄録全体を表示

The present study was undertaken to compare the in vivo dissolution rate of enamel in acid with four other tests in school children as caries activity tests. Cariostat®, buffer capacity of saliva, plaque scores, and snack intake (in addition to the dissolution rates which were reported previously) were examined in 30 school children when they were 7 and 9 years old. The dental caries was examined by the same examiner every six months from the ages of 7 (1981) to 11 (1985).
The R.I.D. Indices of the upper central incisors and the upper and lower first molars were calculated by comparing each examination with the base lines at 7 and 9 years of age. The results were analysed using the sum of sensitivity and specificity.
The following results were obtained:
1) At 7 years of age snack intake was the most useful of the five tests for prediction of the R.I.D. Index of the lower first molars, but after the age of 9 years it was only useful for prediction of the R.I.D. Index of the upper first molars.
2) In vivo dissolution rate of the lower left first molar and the plaque score of the upper left central incisor at 7 years of age were useful for prediction of the R.I.D. Index of the lower first molars.
3) Cariostat® and the buffer capacity of saliva tended to relate to the R.I.D. Index of all the teeth surveyed.
4) in vivo dissolution rate of the upper left incisor and the plaque score of the lower left first molar were meaningless in predicting the R.I.D. Index.
5) In conclusion, in vivo dissolution rate of enamel in acid of the lower left first molar was the most useful when we predicted the R.I.D. Index of the lower first molars from a relatively low age.

抄録全体を表示

Determining trace amounts of total fluorine (F) in biological samples requires tedious and time-consuming pretreatment and measurement. Recently, a new analytical method has been developed by Tsunoda et al. for the determination of subnanogram fluoride based on aluminum monofluoride molecular absorption spectrometry (AlF method). However, this method requires a fairly high level of skill for generating the aluminum monofluoride (AlF) vapor in an electrothermal graphite furnace with two separate injections, one of the Al matrix solution and the other of the sample solution.
In this study, we investigated the operating conditions of the atomic absorption spectrophotometer and the procedures for the determination of F in blood serum by the AlF method. In order to examine the practicability of the AlF method for determining low level F in various samples, we applied both the AlF method and the ashing method (low temperature plasma ashing followed by gas chromatography) to determine the total F in the blood plasma of rats which had been given drinking water containing fluoride; the results obtained by both methods were then compared.
The results were as follows:
1. To increase the sensitivity and reproducibility of AlF analysis, it is important to find the original (optimum) working conditions for the apparatus used since we obtained results which were different from experimental data published in other research.
2. For the sample injection procedure, the two-injection procedure with intervening drying and ashing steps proved unsatisfactory under the conditions we employed. The best results were obtained from one injection of the sample diluted with the Al matrix solution in a ratio of one to one.
3. The composition of the Al matrix solution (amounts of Al and matrix modifier) and the Triton concentrations which were added to the samples seriously effected the intensity of the AlF absorption and its reproducibility.
4. The total F values in the rat plasma determined by the AlF method and those determined by the ashing method showed excellent agreement, even though the values obtained from the AlF method were slightly higher than those from the ashing method in most samples.
5. In conclusion, it was found that the AlF method is a useful means for determining the total F in serum and plasma, although there is the possibility of a serious error when the F content is determined without proper knowledge of the AlF analysis.

抄録全体を表示

At present, it is important for the dental health service to understand the relation of demand and supply for services in each district, considering the movement of population, the social security, and patients' behavior visiting dentists. A new method for investigation and analysis was employed to study the geographical distribution of dentists, and the following results were obtained.
1. Immediately after being licensed, over half of all dentists engaged in business in the prefecture where they attended dental school. After that, the number gradually decreased. About eighty percent had their practices in their native prefectures.
2. The ratio of practitioners in their native prefectures (the settlement ratio) varied from 43% in Nara Prefecture to 90% in Aichi Prefecture. The average was 78%. The settlement ratio by city size varied from 42% in rural areas to 80% in cities of over 300, 000 population. The average was 64%.
3. The ratio of dentists who moved from their native prefecture to another prefecture (the movein ratio) varied from 0% in Toyama Prefecture and three other prefectures to 55% in Chiba Prefecture. The ratio in prefectures including metropolitan areas was found to be high. The movein ratio by city size varied from 21% in rural areas to 44% in cities of 200, 000-300, 000 population.
4. The ratio by number of practitioners in the prefecture to the number of dentists coming from the same prefecture (the practice ratio) varied from 0.52 in Yamagata Prefecture to 1.56 in Chiba Prefecture. The ratios in ten prefectures including metropolitan areas was found to be over 1.00. The practice ratio by city size varied from 0.53 in rural areas to 1.44 in cities of over 300, 000 population. Also, practitioners tend to concentrate in urban areas of their native prefecture (J-turn phenomenon).
5. As to reasons for selection of practice location, “Financial reasons at the time of starting practice”, “Business conditions after opening” and “Enviromental conditions for daily life” were each slightly less than 20%. Significant correlations were found between the practice ratio vs social life indicators and the move-in ratio vs social life indicators which include the rate of population increase, the average income per person in a prefecture and the Japan potentials indicator in each prefecture.
6. The geographical distribution of dentists in the future was forecast from the ratios mentioned above and analysis of reasons for selection of practice location. In prefectures including metropolitan areas such as Tokyo or Osaka, the rate of increase will be lower. In the prefectures close to metropolitan areas such as Saitama, Ibaragi or Nara, the number of dentists will increase markedly. Accordingly, the difference in number of dentists per 100, 000 population is expected to decrease. However, no increase is expected in Aomori, Fukui, Tottori, and other rural areas.

抄録全体を表示

From the view point of health maintenance for adults, it is very important to control periodontal disease. However, scientific, effective and simple screening tests for evaluating periodontal disease are very few, so that many high-risk adults can not be discoverd.
For these reasons, I have studied the screening tests of periodontal disease using salivary occult bleeding test strips named “Salivaster-Bld. ®” (S-Bld., Showa yakuhin kako. LTD, ).
These test strips were developed by Nakao et al, and I compared these test strips with the urinary occult bleeding test strips named “Hemastix-III®” (H-III, Sankyo CO., LTD.) which had been used for screening tests of periodontal disease for clarifying the differences between both strips. The subjects of this study were 42 adults (Average age: 34.5 years old) and 36 young adults (Average age: 18.9 years old). Two kinds of saliva were used here. One was collected after one minute chewing of sugarless gum (stimulated saliva) and another was collected without chewing (resting saliva). Resting saliva was collected first and stimulated saliva next, and then they were each tested with both strips. Oral examinations were also carried out for taking indices which showed the oral condition. The DMFT index, the OHI, the PMA index, the Russell's PI, the pocket depth, and the gingival crevicular fluid (GCF) measured by Periotron® (Harco electronics LTD.) were used.
From the results of S-Bld., the increase of each index value was recognized according to the increase of occult bleeding in stimulated saliva and resting saliva in both adults and young adults. In the index value of the PMA index, the PI, the GCF, and the pocket depth in resting saliva of the adult group, statistical significance was found to be between (-) and (+++).
Also, the periodontal disease showed up more clearly in resting saliva rather than in stimulated saliva. On the other hand, stimulated saliva was more suitable in young adults.
The reason for this was the difference in the number of missing teeth, which might have an effect on the stimulation from chewing. However, the consistency between each index value and judgement by H-III was not as clear as was expected. Since these test strips were developed for the measurement of occult blood in urine, sensitivity for occult blood was so high that it could detect hemoglobin of 0.015-0.045 mg/dl. This might cause the inconsistency. About 74% of all subjects who were judged negative with S-Bld. were judged positive with H-III. From these results, and from the validity of the screening tests of periodontal disease, the comparison of S-Bld. with H-III was carried out using the value of the PI and the GCF as markers. S-Bid. showed a superior property in the screening test from the standpoint of the balance between sensitivity and specificity, although sensitivity was a little low. H-III showed that only sensitivity was high, but specificity was quite low, that is, there was imbalance between sensitivity and specificity. Moreover, the false-positive rate of H-III was 70-90%.
From these findings, S-Bld. is recommended as a screening test for periodontal disease.

抄録全体を表示

This study was carried out to investigate whether _D-phenylalanine (which inhibits the activity of carboxypeptidase A, a decomposing enzyme of β-endorphin) might inhibit the caries development of mice in vivo. 21-day-old male Balb/cAJcl mice were used They were fed on a cariogenic diet, Diet #2000, which prepared as original prescription except sucrose concentration down to 30%.
The results were as follows :
1) Compared with the control group, dental caries was significantly decreased in the group which was administered _D-phenylalanine for 10 days from the 21st day after birth. But dental caries was not decreased in the group which was administered _D-phenylalanine after the 31st day after birth.
2) Compared with the control group, the number of bacteria attached on the tooth surfaces was significantly decreased in the group which was administered _D-phenylalanine for 30 days from the 21-st day after birth.
3) Compared with the control group, humoral and cellular immunity were significantly enhanced in the group which was administered _D-phenylalanine for 10 days from the 21st day after birth. In the _D-phenylalanine group, the globulin content in the serum was higher and the A/G ratio in the serum was lower than in the control group.
4) In the control group, β-endorphin concentration in the blood of the mice was high in the morning and low in the evening, but in the _D-phenylalanine group, β-endorphin concentration in the blood was always high from morning till evening.
5) Dental caries was increased in the mice which were administered carboxypeptidase A, naloxone, or anti-β-endorphin serum 5 times every other day from the 22nd day after birth. But dental caries was decreased in the mice which were administered _D-phenylalanine or β-endorphin 5 times every other day from the 22nd day after birth.
6) The cariostatic effect on the mice depended on the administered amount of _D-phenylalanine. _L-Phenylalanine also showed a cariostatic effect, but this effect was lower than that of _D-phenylalanine.
7) _D-Phenylalanine, _DL-phenylalanine, and _L-phenylalanine demonstrated very little bacteriostasis against cariogenic bacteria.
From these findings, I suggest that _D-phenylalanine has the effect of keeping the concentration of β-endorphin in the blood high, and consequently it enhances the immuno-system of the mice and decreases the bacteria on the tooth surfaces. As a result, I conclude that administration of _D-phenylalanine to mice effectively inhibits caries development.

抄録全体を表示

We have been studying medical ethics and this time we have comparatively investiatged the consciousness of dental students and pharmaceutical students.
2022 dental students and 704 pharmaceutical students cooperated in the investigation.
We have noticed a great difference in consciousness between dental students and pharmaceutical students. As to the professions of dental students' parents, 42.1% were physicians and dentists and 35.4% of the pharmaceutical studients' parents were office workers.
Dental students' future hopes and expectations that pharmaceutical students had for dental students showed a similar trend.
The question asking if they had ever read any book concering medical ethics was answered “No” by 83.2% of the pharmaceutical students and 49.5% of the dental students, and we noticed a great difference in consciousness between pharmaceutical students and dental students.
As to the word “benevolent” in “medicine is a benevolent art”, both types of students showed similar understanding.

抄録全体を表示

In 1970 a weekly fluoride mouthrinsing program using 0.2% neutral NaF solution was initiated in the elementary schools of Yahiko District, Niigata Prefecture, Japan (F<0.1ppm in drinking water). The same program was started at the juniour high school in 1973 and a daily fluoride mouthrinsing program was started in 1978 at all four nurseries in the district. Therefore at present, such programs start at the nursery school level and continue to the 3rd grade in the junior high school within an individual school system.
We investigated the benefits to the permanent teeth from this 17-year school-based fluoride mouthrinsing program. This report presents the effects of ongoing supervised fluoride mouth rinsing program on caries prevalence of permanent teeth according to the age of starting the fluoride mouthrinsing program.
A baseline examination for schoolchildren in 1st-6th grades was conducted in 1970, before the mouthrinsing program began. An examination conducted in 1978 presents the data of children who participated in the program since their entrance into the elementary school, that is, at the age of 6. An examination conducted in 1987 presents the data of children who participated in the program since the age of 4 in the nursery schools.
The DMF person rate in all grades decreased from 72.8% in 1970 to 41.6% in 1978 and 27.6% in 1987.
The DMFT-index in all grades decreased from 2.27 in 1970 to 1.39 in 1978 and to 0.48 in 1987. The differences in caries prevalence were 38.8% and 78.9%, respectively, and were statistically significant (p<0.001).
The school-based fluoride mouthrinsing program produced high caries-preventive effects. Especially, the program started from the nursery level provided higher caries prevention when the 1st molar teeth erupted.
The younger the children were when they entered the program, the longer that they rinsed, the greater were the accumulated benefits.

抄録全体を表示

This program for dental caries prevention was started in Hisayama-cho, a suburb town of Fukuoka city in April, 1984. Younger inhabitants ranging from 1.5 to 15 years of age were subjected to the program. The dental health program consisted of dental hygiene instruction and fluoride application. The 1.5 to 3 year age group were recalled every 3 months after the initial dental examination and received dental health instruction, dental examination, and topical fluoride application with APF gel. Kindergarteners and primary school children received fluoride mouth rinsing with 0.2% NaF once a week, dental health instruction and dental examination twice a year. Junior high school students received dental health instruction and dental examination once a year.
Comparing the improvement of dental health status between 1984 and 1986, it was found that dental caries prevalence decreased in all age groups of subjects, particularly in the lower grade children in primary school. The DMFT index and DMFS index in 1986 decreased to approximately one half compared with those of 1984. And the dft index of age group of 3 decreased from 4.17 to 2.40, and the DMFT index of age group of 12 decreased from 5.13 to 4.36.
Presumptive calculation of cost for caries treatment was estimated from the chart of dental examination in primary school. Thus, the cost for caries treatment was calculated by using the standard that was made from the table of numerical rating of the health insurance issued on April, 1986. It was estimated from the survey that an amount of 4, 500 yen per child in primary school was saved in this dental health service for 2 years.
In conclusion, the caries reducing effect during 2 years by this program was evaluated, and further effects will be attained by the continuation of this program in future.

抄録全体を表示

The type-specific antigens of the serotype i and g Streptococcus milleri were extracted with trichloroacetic acid from purified cell wall preparation of the strains K39K and K1K, respectively, and then purified by DEAE-Sephadex A-25 column followed by Sephadex G-100 column. The serotype i-specific antigen was composed of rhamnose, galactose, and glucose in a molar ratio of 1.6: 6.8: 1.0, and the serotype g-specific antigen consisted of rhamnose, galactose, glucose, and galactosamine in a molar ratio of 1.3: 3.8: 1.0: 2.5. The quantitative precipitin inhibition test with various haptenic sugars showed that galactose and its related carbohydrates were the effective inhibitors of the reaction between type i antigen and anti-i serum, and galactosamine was the most effective inhibitor of the reaction between type-g antigen and anti-g serum. The purified serotype i specific antigen contained a significant amount of phosphorus, and the serotype g specific antigen contained a trace of peptides. The Rantz-Randall extracts from all the 15 strains tested belonging to serotype i contained galactose, and those from the 6 serotype g strains had galactosamine. The results suggest that galactose and galactosamine are involved in the major immunodeterminants of the serotype i-specific antigen and serotype g antigen of oral S. milleri, respectively.

抄録全体を表示