This is an attempt to make a survey of the particular conditions under which dentists are forced to work in a standing posture almost all day long, from the two viewpoints namely of their energy consumption and fatigue.
In the first place, concerning the former point the author has figured out how much energy is usually dissipated on a day's work by knowing their day-schedule according to Time Study on one hand, and Relative Metabolic Rate (R.M.R.) on the other measured from unit operation in their dental consultation.
Secondly, the examination as to the latter point has been made over 108 dentists that it might be known how much difference of fatigue they are conscious of before and after a day's consultation work, and besides, such tests as Flicker Test, P.S.R, near point Method were applied to 8 to 10 practioners continually from Monday to Saturday in a week for calculating their fatigued condition.
In conclusion, two things have been apparent, -they have very little free time, while their fatigue increases and accummulates remarkably day by day though its condition has something in common with that of other mental workers.

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Five typical paterns were at first selected regarding to the conditions of eruption of six-year molar teeth. This was applied to and investigated on 5647 males and 5722 females of from 3 to 17 years of age youngsters of from nurseries and kindergartens to high schools. Research was made on change of types of eruption by age.
1. At the age of 4, years eruption of six-year molars can not still be seen, but it starts at around 4.5 years old and by 5-6 years about half of them have at least 1 six-year molar.
2. Complete eruption (4 full six-year molas) reaches at the age of 6.5-7.0.
3. It is well to be supposed that eruption of six-year molars is generally earlier in females than in males.
4. Generally speaking, no difference is noted among children of nurseries and kindergartens.
With regard to the caries of six-year molars, because of the period between the first eruption of six-year molarand the completion of the eruption is short, decaying is seldom seen. Incidence percent of caries of 4 erupted teeth increases along with the advance of age.
An observation was made on accumlative curve which shows break-downs of decaying types by change of ages.
Following results were obtained
1. Trend of decaying of six-year molars ups in straight line from 4 to about 11 years of age.
2. With regard to one decayed tooth' no difference is noted between both sexes; but frequencies of 2, 3 and 4 decayed teeth seem to be higher in females by each age than in males.
3. To obtain general percentage of patients of decayed teeth straight line system was taken for from 4 to 11 years of age. This straight line is presumed that it is generally well fitted to the actual conditions.

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The program for a week drawn up by the Dental Hygiene Section of the Tokyo Chuo Health Center and 12 Months' Reports, from January to December of 1956, about the people who came to Mass Medical Clinics directed by the Health Center, and about the conditions of dental treatments belonging to the extent of the Health Center Dental Section, all things above-mentioned and the transition aspects from the 1951 to the 1956 (for 6 years in all) were statistically arranged, at the same time, Mass Medical Treatments from the “Welfare Monthly Reports” of the 1956 and the results of Health Center of the whole country reported by the Welfare Department in the 1955 and 1956. From this, the average value obtained was classified and compared with that of the Chuo Health Center. About the results in the 1956 of the Chuo Health Center, the authors we considered the very clinical limit from the view point of the required time in the presence of treatments.
1) The program of the week was planned in order to answer the content of Dental Sanitary Service required by the Chief of Public Health Bureau, and the Chief of Preventive Bureau of Welfare Department, considering morning and afternoon each (half a day) as a unit, the authors roughly arranged them as follows:
Sanitary education: one unit: Mass Medical Examination and Directions: 2 units; Pregnant women and Maternity Directions: 2 units; Preventive treatment, Early Cure and General Directions: 4 units; Investigation, connection of in and out: 2 units.
2) The cases of Medical Examination of children in the 1956 were 1,959 and children Mass Medical Examination by the “Law of Children Welfare” were more than 2 times a year and others were done in Dental Sanitary Weeks and in co-operation with the plans of Mother-Child Section, while adults were examined in the Dental Weeks and Safety Labour Weeks, but these cases were rather a few. The total cases of the Health Center were numerous compared with those of one Health Center in, any other prefecture and cities at large. Monthly changes also proved so. There has been a tendency of increase in childern and decrease in adults during the 6 years with transition in view.
3) The number of children and school-children who came to Clinics were 834 cases in younger children, while 310 cases in school-children in 1956. The children came to Clinics on the occasion of Mass Examination, while school-children mainly came to the clinic in winter and summer vacation. The cases of children who visited the Health Center was numerous compared with those who came from one Health Center of the country, but with Monthly Observation in view, in March, June and December visitors were rather a few. The transitions during the 6 years shown a tendency to increase.
4) Of the numbers of adults and pregnant women, there 1,524 cases of adults and 916 cases of pregnant women in the total of the 1956. Adults were liable to avail themselves of the time when Children Mass Examination was held, but pregnant women visited the clinic mainly in October regardless of the time availble. The cases of women of the Health Center were numerous comparing with those of any Health Center of the country. It was, also, the cases with the Monthly Observation.
5) The total number coming to Clinic in one day, on the parts of children, school-children and adults; The average was 17.1 and was larger in number comparing with that of the National Hospitals and when calculated in unit, the rate would be higher. It was considered mainly to be ascribed to the elaborite activities of the Dental Sanitary Personnel. A unit of pregnant women was 8.7 and they can be directed well by the hands of our operators concerned.

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“Miss Dental Contest in Tokyo” in the 1957 was held under the auspices of the Tokyo Dental Association and the Sankei Shimbun, and through -certain bodies' co-operation. 33 candiates of “Miss Dental” of wards and districts recommended by each Dental Association were examined to-gether on May 30th at the Tokyo Chub-Health Center. The individual examination table of the candidates who gathered on this occasion were statistically arranged and compared with the data of those of the 1956 which were able to be compared with.
(I) The ages of candidates were from 19 to 25, and the average was 20.8 years old. In ages, 19 were numerous, and in profession, they were mostly business girls and clerks, age width being similar to that of the 1956.
(II) The examination results of the candidates, gained through each examiner concerned:
1) The 1st results examined by the hands of 10 examiners:
(i) In general, the state of teeth, 100 got full marks and the extent of the marks gained was 60-100. All the average marks were 82.8 -worse that of the 1956.
(ii) As for the state of dental caries, 200 won full marks, and the extent of marks was 130-200, and all the average marks were 189.3 -worse than that of the 1956.
(iii) In general, of the state of the oral conditions examined, 100 took marks, and all the average marks were 84.8-worse than that of the 1956.
2) The 2nd results examined through 8 dentists and 2 doctors:
(i) In culture, speech, movement and sanitary common-sense, 100 won full marks, and the extent of marks was 50-100, and all the average marks were 85.3-better than that of the 1956.
(ii) In the present condition of the disease of the subjects, 100 won full marks, the extent of marks was 70-100, all the average marks being 85.0.
(iii) As to growth, granted that 50 was full marks, the extent of marks 25-50, all the average marks 46.8-better than that of the 1956.
(iv) In nourishment, 50 got full marks, the extent of marks was 35-40, all the average marks were 46.3.
3) The results of the special examination which were done in 13 candidates who had given better marks in the 1st and 2nd examinations: they were examined by the 10 representives of the auspices of certain bodies. Granted that 100 was full marks, the extent of marks was 50-100, the average were 83.2-similar to that of the 1956.
4) The examination results of those who were tried in the 1st examination, were almost equal to that of the 1956.
(III) As above-mentioned, in the 1st examination, the result was rather inferior to that of the 1956, and in the 2nd one, it was better than that of the 1956 and in the special examination, it was equal to that of the same.
Now, the difference between the 1956 and the 1957, and that between the 1st and 2nd examinations, were both due to the differnce of the candidates and, to a partial change of the examiners. It would be an interesting subject to attribute the cause of this difference to the qualities of the candidates who joined the examinations and, to the way of marking a standard of them. And the special examination results of the 13 excellent candidates and the 1st examination results of the candidates, who were qualified to take in the special examination, were both the same ones in 1957, and though all the candidates were examined by the hands of diffrent examiners, but as it was only a partial change then, the very cause of the results in the 1st and 2nd examintions, should necessarily be attributed to the side of the candidates on this occcasion.

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“Miss Dental Contest in Tokyo City” in the year of 1958 was held under the auspices of the Tokyo Dental Association with the co-operation of the connected groups at the Dental Association Hall, and among 31 candidates, one “Miss Dental” and five “Semi-Miss Dentals” were elected. The examination table obtained on this occasion was statistically, arranged and the following results were acquired:
I) An average age of the candidates was 19.7 years old and in the classification of the occupations, the business girls and the office girls were most in number.
II) Each candidates was examined and given marks by 10 examiners in the 1st, 2nd and special examinations in addition, the following were the results they have got:
(1) The results of 31 candiates of the three examinations: in general, the condition of teeth, 100 marks was full: a perfetscore and the average marks were 91.9±1.00.
In the condition of caries teeth, 200 was full marks, average being 187.8±2.03.
In oral general conditions, 100 full and a width of giving marks was 70-100, average being 95.2±0.60.
The total marks of the 1st examination were 400 marks in full and 374.3±2.38 were in the average of them.
(2) The results of 31 candidates of the 2nd examination:
In culture, speech, behaviour, both figures and looks, hygiene common sence, 100 marks was full, an average being 82.9±0.86.
In the present conditions, 100 was full an average being 97.7±0.21.
In growing condition, 50 was full, an average being 43.1±0.49.
In nourishing conditions, 50 was full while an average was 43.3±0.46.
The total marks of the 2nd examination were 300 in full and 266.6±1.78 were in an average.
(3) In the results of the special examination the results of which, 12 candidates were excellent in total marks of the 1st and 2nd examination, 100 was full and a width of giving marks was 40-100, an average being 81.4±2.14.
III) The whole total marks.
As to the relation of the total marks and each item mark in each examination, the coefficient of cor-relation 4 to 12 persons of special examination was obtained, which resulted in the following:
(1) On the total marks in each examination and in each item mark in all the course of examinations, the total marks the 1st examination to the caries candition was highly significant, those to the general condition of teeth were significant and those to the general oral conditions, were not significant. The total marks of the 2nd examina tion to each item was of highly significance.
(2) In the whole total marks and the total marks in all the examinations, the whole total marks to the 1st examination was significant, and further proved highly significant to the 3rd examination.
IV) Through the above results mentioned, the acquired marks of all the candidates which were the standard marks of selecting “Miss Dental” had the most essential relation to the caries conditions in the 1st examination, but from general point of view, the special examination marks affected most, the 2nd examination affected next and the 1st examination did very little.

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The calcium concentrations in saliva have been investigated by large number of workers since the first report about it was presented by Rose (1908).
These reports, however, do not necessarilly show the same results because of their different experimental methods, but also considerablly a wide range of variations observed among the values obtained.
Therefore it is necessary to seek and clarify the cause for it.
Adding to this, other papers dealing with the mechanism of salivary secretion, especially the study in regard to inorganic constituents of saliva and blood serum, or the rate of salivary flow and constituents of salivary secretion were available too.
The author studied ccmparative calcium concentrations in mixed saliva and parotid saliva, relating to blood serum calcium, urinary calcium, age, daily fluctuations, water supplies and caries activity.
The results obtained are as follows:
1) The average value of calcium concentration in mixed saliva, taken from healthy male adults (from 20 to 27 years of age) was 5.81 mg/dl±1.16.
2) A slight significantcalcium correlation between calcium concentrations in mixed saliva and that in blood serum was observed.
3) No evidence that the presence of caries, dental calculation to the calcium concentrations was detected.
4) The marked variations in calcium concentrations in mixed saliva occured under some conditions, espeially dietry condition.
The average value of calcium concentrations was lower in parotid saliva (3.32 mg/dl) than in mixed saliva (15.8 mg/dl±1.16).
Any remarkable daily variations in calcium concentration could not be found in each individual.
6) With an increasing secretion of parotid saliva (during one fixed time) per time, calcium concentration was raised, and if the amount of saliva secreted was over 7-8 ml/10 min., it reached maximum.
7) Calcium concentration in parotid saliva was higher in children in adults.
8) The presence of caries, DMF rate and calcium concentration in parotid saliva, taken from under a specific condition, that is, a restricted water intake, none of those had any significant correlationship to the calcium concentration.
9) No significant correlation was observed between calcium concentrations in mixed saliva and blood serum.
However, if under the condition of restricted water intake, a significant correlation (r=0.42±0.016) was present between two of them, whereas the relation to urinary calcium was diminshed.
This indicates the occurence of the variations in salivary calcium concentration results from a very similar metabolic behaviour to that of urinary calcium, even though calcium itself was distributed from blood serum.

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In October of 1957, a Dental Mass Medical Examination of 191 factories and active plants in Tokyo was undergone by members of the Tokyo Dental Association, and 15,104 individual cards obtained on that occasion, among which those perfectly filled up in description were the very objects of this study whatever. The factories and active plants to which the laborers belonged were arranged according to Japan Standard Industry Classification and the observation, according to the distinctions of their professions, was devoted at the same time, in which the authors endeavoured to have the numbers of the works classified and observed dividing them into eight groups (a) 1-50, (b) 51-100, (c) 101-200, (d) 201-300, (e) 301-400, (f) 401-500, (g) 501-1000, and (h) 1001-2000, laborers.
The calculation of statistical value obtained concerning teeth according their professions and the numbers of laborers, on D.M.F., missings, dummies, treated teeth invaluing false-teeth, both. common decayed teeth and decayedteeth, furthermore, on subdivisions according to the conditions of caries as (A) Surface caries, (B) Deep seated caries and (C) Root stump caries was minutely made. As for each of them, the rate of laborers with caries was calculated, moreover, if necessary, the cor-relation coefficient (r) and its significance decided by decimal instance, which came finally to the following results:
I) Observation on each profession.
(1) The rates of laborers with caries and an average number of teeth per person were in D.M.F. in missing company showed especially low degrees, and transport communication industry and electric, gas, water industry ones showed rather high value. In missings of teeth, wholesale, ratil sale service ones showed the lowest, while transport and communication industry laborers, the highest. Intreated cases, mining lower and transport and communication industry, higher. In decayed teeth, whole sale, ratail sale showed lower, while degrees electric, gas, water industry ones higher.
(2) The value of surface caries and deep seated caries of each profession showed cor-relation.
II) Observations on each member of laborers.
(1) The rates showed in each statistical value and an average number of teeth per person were both not so remarkable in tendency in D.M.F., but in missings, surface caries and root stump caries, there was a tendency of decrease, according as the numbers of laborers increased, while treated teeth, common decayed and deep seated caries, the class of 100-300 (c), (d) showed the lowest value.
(2) The value of surface caries and deep seated caries of each classified number showed rather converse cor-relation.
(3) From those examined, in the factories and active plants especially the ones small in number less than 50 members, it, generally, could observed in D.M.F. and its subdivision (decayed, missing and filled permanent teeth), remarkably higher tendency. Therefore, the possitive necessity for the dental hygiene supervision in detail should anyway be recognized.

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Vol. 9 (1959) No. 1 p. 74-75

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