Abstract
Improved plaster models of upper and lower second deciduous molars were made from Japanese infants ranged in age from 2.5-3.5 years. A total of 152samples of upper second deciduous molars (M: 74&F: 78) and 146 counterparts in the mandible (M: 64&F 82) were examined in terms of types and frequencies appearance of accessory grooves and converging relationships of accessory grooves into grooves. The following were the results of the examination.1. Upper Second Deciduous Molar
