Lower First Premolars

Abstract

The hereditary basis of the dentition long has been recognized. With the exception of a single trait, CarabeHi''s anomaly, there has been no genetic analysis of common nonpathologic morphologic dental characteristics. The addition of genes governing dental features to the small pool of human genes for common phenotypic traits already established would be of great significance for furthering our understanding of the dynamics of human evolution, of race formation, and of population genetics. Isolation, definition, and classification of morphologic dental traits that are of common occurrence are necessary preliminary steps to genetic analysis. The lower 1st premolar was selected for study because of its wide range of morphologic variability. Previous studies of this tooth have not provided data amenable to genetic analysis. Seventeen traits, and their common varieties, were isolated and defined for the lower 1st premolar, based on observations of more than 800 teeth, both on casts and extracted premolars, representing a number of ethnic groups.