乳歯脱落の研究
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概要
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A study was conducted on the pupils and children in Saga district, consisting of 2837 males and 2706 females 6 to 14 years of age, in an aim to know the possible relation existing between the ages, sexes, occupations, Tuberculin reaction, Vervaeck-Wellish's physical nutrition index, the number of existing deciduous teeth and the shedding ages of deciduous teeth. The results obtained were summarized as follows. 1. The average number of existing deciduous teeth in the male exceeded that in the female. 2. The order in the magnitude of the average number of existing deciduous teeth for all the regional groups of subjects examined is expressed in the following simplified formula. Male……Kokura city>Saga district〓Tokuyama city Female………Saga district>Tokuyama city>Kokura city 3. The rate at which the average number of existing deciduous teeth decreases with increasing age of the subjects is expressed in the following formulae. In terms of individual teeth of the dentiton the formula is as follows. Deciduous central incisor>lateral incisor>canine>first molar>second molar In terms of the teeth in upper and lower jaws the formula is as follows : the teeth in lower jaw>the teeth in upper jaw In terms of the teeth in both sides of the jaw it is as follows : the teeth in the left〓in the right In terms of the sexes of the sudjects it is as follows : the teeth in the female>in the male 4. The relation between the occupation of the subject's family and the average number of existing deciduous teeth is expressed in the following formulae. Male………Agriculture〓Trade〓Salaried<Pitman Female………Agriculture<Trade〓Salaried<Pitman 5. There was hardly noticed any relation present between Tuberculin reaction and the average number of existing deciduous teeth. 6. The average numbers of both existing deciduous and permanent teeth show strong inverse relation with values ranging from (-0.12) to (-0.961). 7. As to the average age for the deciduous tooth shedding, that for the contral incisors in lower jaw is the earliest with 6.2 years in the male, 6 years in the female, followed by those for the upper central incisors, the lower lateral incisors, upper lateral incisors, lower canines, lower first molars, upper canines, lower second molars, and that for the upper second molars is the latest with 10.7 years in the male, 10.6 years in the female. Thus the average age of deciduous teeth shedding for the female is earlier than that for the male by 3.8 months on the average. 8. The average age for the shedding of deciduous teeth in lower jaw is earlier than that in upper jaw, and the difference in this respect between the right and left halves of the dentition is not present in the male. In the female, however, the age of shedding is earlier in the right half than in the left half of the dentition. 9. The average age for the shedding of deciduous teeth in the subjects of Saga district is earlier than that in the subjects of Kokura city. 10. Correlation coefficient between Vervaeck-Wellisch's physical & nutritional indices and the average number of existing deciduous teeth ranges from-0.01 to -0.10.
- 九州歯科学会の論文