Comparison of the Crown Dimensions between the Maxillary Fourth Deciduous Premolar and the First Molar in Tupaia glis

抄録

The crown dimensions were compared between dp4 and M1 on the maxilla in Tupaia glis. Although the dp4 resembled the MI in pattern, the structure of the dp4 was more primitive than that of the Ml. The dp4 was 86.707% of the Ml in the module. The mean values of the crown dimensions were larger in the MI than in the dp4 and these differences were significant statistically except for the distal buccolingual diameter (DBL). The DBL was slightly larger in the dp4 than in the Ml, but the difference was not significant. More pronounced differences between these two teeth were found in the lingual mesiodistal diameter (LMD) and the mesial buccolingual diameter (MBL). This result could be explained by the differences in the development of the hypocone and the mesiobuccal stylar shelf.