Abstract
Age distribution studies have been conducted by Nohara for Osaka city (♂1588♀1342), by Ogata for Kumamoto city (♂2217♀1739) and by Urata for Kitakyushu city (♂1481♀1263) with reference to the deciduous teeth eruption in the younger populaiton of respective city. Based on the data obtained by these authors, geographical difference in the time of eruption of individual deciduous teeth was presented here by a special diagram for the purpose of clearer understanding. In the preparation of the diagram all the cases of eruption ages from the earliest to the most retarded ones were plotted by percentage values for the individual teeth. Any difference existing between tooth groups on both sides of the jaws was discarded from the diagram because of its insignificance found. The horizontal elongation of areas occupied by the individual teeth and the tilting of individual areas in this diagram represented the geographical difference of eruption age as well as the extent to which individual teeth divergently came into eruption.
