The observations and measurements were made on the buccolingually compressed lower second premolars of a Hawaiian. The results are summarized as follows:
The buccolingually compressed lower second premolars were exceedingly large in the mesiodistal crown diameter, while in the buccolingual crown diameter they approximately showed the average size. As shown in the figure 1, bilateral second premolars were strongly compressed buccolingually in the occlusal surface itself.
It might be suggested that both the enlargement of the mesiodistal crown diameter and the compression of the buccolingual crown diameter should result from the atavism.
The mesiodistal crown diameters of the remaining premolars of this case were fairly large as compared with the average size of the Hawaiian. In this case, the central tubercle, Carabelli's cusp and sixth cusp were observed on the lower second premolars, upper molars and lower molars respectively.
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