In the discussions on the etiology of the dental caries and periodontal diseases, the relationship between the retention of foodstuffs and the tooth-brushing after meal is often regarded as an important matter.
Now, in order to determine the above mentioned relationship, the estimation of the reducing sugar by the method of Somogyi, the O₂-uptake by the manometric method of Warburg and the TTC reduction using Thumberg's tube were carried out, and following results were obtained.
The tooth-brushing after meal, immediately, removes a large amount of retaining foodstuffs, and the O₂-uptake effect decreased or the TTC activities of saliva-foodstuff mixture, which were spit out at the same time, reduced.
While, in the same procedure with the exception of the tooth-brushing, the results obtained were the contrary to the above results.

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Continuous observations were made on a total of 189 pupils, 89 boys and 100 girls, who were admitted as first grade pupils to two Grammar Schools in two villages outside of Tokyo City for a period of 9 consecutive years since 1949, having followed their physical and dental development.
Measurements of height and weight and oral examinations were conducted four times a year, -April, July, October and January-making plaster models by taking alginate compound impres sions on both jaws, which totaled 13, 608 impressions and models of 72 consecutive models per examinee.
Parallel studies were made on a total of 11, 060 girl students ranging from 1st to 3rd grades of 14 Middle Schools in Tokyo and 2 others in Chiba Prefecture.
Surveys on menoplania were made every month for a period of 30 months during 1956 through 1958. Measurements of height and oral examinations were made on those at menoplania to determine the time element of parmanent teeth eruptions and to observe the growth and development of teeth.
Having observed the time element of permanent teeth eruptions from the view point of height development and age, the frequency by the height factor demonstrated extremely narrower range than by the factor, i. e., it was learned that the height has much closer relationship with the eruptions than the age, as it had been known.
It has also come to the attention that the eruptions of the second molar have closer relations with menoplania, therefore, observations were made on 1, 458 girls on whom the meneplania and the eruptions of permanent teeth were precisely determined.
Examinee were segregated into five types; Type I with all four second molar eruptions, Type II with three, Type III with two, Type IV with single and Type V with no second molar eruptions.
The Type I amounted to 81.41% of the total examined, and it was revealed that the menoplania coincided with the eruptions of bilateral second molar on both jaws.
The average height and age of the Type I, or at the time of menoplania was 149, 5 cm and 13 years 6 months respectively.

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The authors studied on the influences of the stimulation of N. trigeminus-by dental grinding and electrical stimulation of tooth-upon the gastric movement of unanaesthetic rebbit, using so-called “balloon” method. The results were obtained as follows:
1) Each case stimulated by dental grinding and electrical stimulation, the excitatory effects were observed by the weak stimulation, and the inhibitory effects by the strong stimulation.
2) After the administration of Atropine, the excitatory effect disappeared by the weak stimulation, and the inhibitory effect was observed by the stong stimulation.
3) After the administration of Yohimbin, the inhibitory effect disappeared by the strong stimulation, and the excitatory effect was observed by the weak stimulation.
Form the above mentioned results, the authors conclude the excitatory and inhibitory effect by the stimulation of N. irigeminus take two courses: 1) N. trigeminus-Medulla-N. vagus and 2) N. trigeminus-Medulla-Diencephalon-Medulla-Spinal-splanchinic nerve.

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The authors studied the effects of the dental grinding and the electrical stimulation on N. trigeminus upon the state of the low blood pressure. The results were obtained as follows:
1) In the case of the low blood pressure state, the blood pressure descended by the weak dental grinding, and by the strong grinding, the pressure descended an first, and then ascended.
2) In the case of the electrical stimulation of tooth, the blood pressure descended by the weak stimulation, and by the strong stimulation, the pressurs descended at first, and then ascended.
3) In the case of the electrical stimulation of N. mandibularis, the blood pressure descnded by the weak stimulation, and by the strong stimulation, the pressure descended at first, and then ascended.
4) It was recognized that the descent of the blood pressure is due to the parasythic nerve superiority and the ascent of the blood pressure is due to the sympathic nerve superiority, applying Atropine and Ergotoxine.

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