環境別の齲蝕罹患並びに歯牙交換に関する研究

抄録

An oral examination was conducted in the year of 1959 on a total of 5053 school children and pupils consisting of 2503 males and 2550 females, residing respectively in Osaka city, Shimoichi-machi and Totsugawa-mura, the first of these communities representing the big city, the second the small town and the third the rural community in our country. The items studied included Caries Incidence Rate, Average Number of Exsisting Teeth, Number of def Teeth, Number of DMF Teeth, Age of Deciduous Teeth Shedding, Age of Permanent Teeth Eruption and Mottled Teeth Incidence. The data obtained were studied statistically and were compared with data of previous investigators. The results were summarized as follows. 1) DECIDUOUS TEETH Higher values of Caries Incidence Rate, Existing Teeth Number and def Teeth Number were observed in the inhabitants of the rural community, Totsugawa in conparison with the more populated communities. Male members exceeded female members in these respects. The age of deciduous teeth shedding was earlier also in Totsugawa inhabitants than elsewhere, and was earlier in the female than in the male in general. 2) PERMANENT TEETH Caries Incidence Rate and DMF Teeth Number the urban districts showed lower values than the rural district as alike in the case of deciduous teeth. Average number of exsisting teeth was larger increasingly with more populated communities. The femals member showed greater values for the above three items than did the male member. The age of tooth eruption was earlier in the urban communities in the order of Osaka, Shimoichi and Totsugawa, the female member being earlier in this respect than the male member through every districts. 3) COMPARISON WITH OTHER DISTRICTS Greater values were observed especially in Totsugawa district in the numbers of def and DMF teeth, with significant difference being present between the districts compared. The trend toward increasing tooth caries incidence was apparent in every districts examined, regardless of urban or rural, and it was especially noted in the permanent teeth (Fig. 44 to 47). 4) MOTTLED TEETH INCIDENCE These occurred in 9.65% in Shimoichi district, in 2.46% in Totsugawa and in the severity of the disease M_1 degree was most prevalent.