Occlusal Surface Indices of the Japanese Deciduous Molars

Deciduous molars were examined in reference to the occlusal surface indices, which are contrived to represent the size of teeth on the theory morphological changes accompanied with teeth reduction are brought forth in varying degree for different types of teeth. First the occlusal surface indices of the deciduous molars were calculated, and then compared to those of the molars which have much in common genetically and morphologically. By these comparison, we have obtained the following results.The occlusal surface indices of the upper and lower second deciduous molars, both with male and female, fall between those of the first molars and those of the second molars. Excepting the indices of the lower second deciduous molars, those of the second molars and those of the third molars with female, the rest of the occlusal surface indices all show statistically significant differences with one another.In short, centering the occlusal surface indices of the first molars, the indices decrease both toward anteriorly (the second deciduous molars) and posteriorly (the second and the third molars), with the posteriors being less than the anteriors.