Human population variability in relative dental development.

Using dental X-rays, the calcification of various teeth was compared between samples of black southern Africans, white French-Canadians, and prehistoric Native Americans sharing the same stage of calcification of a specified "reference tooth." The French-Canadians have markedly delayed relative development of the M3 compared to the Africans. They also appear delayed in their M2 development compared to both the Africans and Amerindians. While no difference in relative mandibular canine development is found between the African and French-Canadian males, French-Canadian females are advanced over the African females. Prehistoric Native Americans may be delayed in mandibular central incisor development compared to French-Canadians. These results are in general accord with other studies of variability in dental development between Africans/African Americans, Europeans/European Americans, and Native Americans, and demonstrate that population differences in ages of eruption are attributable in part to differences in relative dental development. Two potentially falsifiable hypotheses concerning the significance of population variability in relative dental development are discussed: 1) the variability (at least for molars) is associated with the amount of space in the jaws for developing teeth, 2) the variability is due to population differences in the timing of dental and skeletal development.