抄録
It is often observed that tooth contact point develops through physiological ear a surface form rather than a small dot. Hence, it may be as well called tooth contact surface. In its full development, the contact surface extends as wide as approximately 4 square m. m., so that the types of contour which it assumes can afford to be classified simply by naked eyes. 306 out of 686 teeth were chosen on the basis of easy identification of individual tooth and clearness of the contact surface, and these were classified into seven types, i. e. first cocoon, 2nd round, 3rd oval, 4th dean, 5th heart, 6th double, 7th triangle. In the present study the occurrence of these 7 types were examined for each tooth kind. For all kinds of tooth, the contact surface of the 3rd oval type was most frequently observed, followe dy 2nd round type and 4th bean type. The bean type was rarely met in anterior teeth. The 7th triangle type was rare in molar teeth, The Ist cocoon type, 5th heart type and 6th double type were met occasionally in molar teeth, but least in anterior teeth.
