Abstract
For the purpose of studying the mottled teeth in Kyushu, 4254 children from 6 to 15 years old resing in Kumamoto city, and Tagawa and Yame region of Fukuoka prefecture, Aso region and Kitamorogata region of Miyazaki prefecture were investigated. The result were as follows, 1. The percentages of individuals infeced with mottled teeth were 52% in Aso region, 44% in Kitamorogata region, 23% in Yame region, 17% in Kumamoto city, 10% in Tagawa region. 2. Caries rates, averages of caries number, caries index, D.H.C. of first molar were found to be inverse to the percentage of mottled tooth infection, tooth health herefore being best in Aso region and worse in the order of in Kitamorogata, Yame, Kumamoto, Tagawa region. 3. The intensity of infection by mottled tooth was most clearly observed in Aso, diminishing in the order of in Yame, Kumamoto, Tagawa. 4. As the rate of mottled tooth infection between each tooth the upper front teeth were the most predominant and the upper teeth were generally more frequently attacked by the disease than the lower teeth. 5. Mottled tooth manifested itself in the most case on the whole tooth crown, then in the order of at the cusp, at the centre part of the crown, and at the neek, 6. Fluoride contents of drinking water 2.7 P.P.M. in Aso, 0.7 P.P.M. in Kitamorogata, 0.4 P.P.M. in Yame, 0.02 P.P.M. in Tagawa respectively.
