EMERGENCE OF THE PERMANENT TEETH IN PIMA INDIAN CHILDREN

A CRITICAL ANALYSIS OF METHOD AND AN ESTIMATE OF POPULATION PARAMETERS

¹ Zoller Memorial Dental Clinic and Department of Anthropology, University of Chicago, Chicago, Ill.

The relative merits of using the normal probability function as the basis for the analysis of tooth emergence data are discussed and arguments advanced to support its use. The advantages of cross-sectional versus longitudinal studies of dental eruption are outlined.

Estimates of the population median ages of emergence of the permanent teeth of Pima Indian children are reported and compared to those of English children in the Birmingham survey. Possible explanations for the pattern of relations between the Indian and English children are discussed. Some evidence is presented for a complex of environmental and hereditary factors responsible for the observed relatively late eruption of the Pima anterior permanent teeth and relatively early eruption of the Pima posterior teeth when compared with the English children. Lower permanent second molars precede the emergence of the lower second premolars in the majority of instances among the Pima males.