Abstract: From measurement and analysis of the crown base area and relative cusp base area of M1and M1 of 532 teeth from northern China ranging from Neolithic to the Iron Age, we gain an understanding of northern Chinese dental traits. There are obvious differences in amphiprotic crown base area of M1and M1 with males larger than females. Relative cusp base area shows no sex differences. The male M1and M1 shrank 1.16% and 4.96% respectively, the female 5.68% and 6.11% form the Neolithic to the Bronze Age with no obvious variation from Bronze to Iron Age. When the crown base area shrank, the prongs evolved in a way that the occlusal surface can be enlarged to make the best use of the occlusal surface, and thus the relative cusp base area formed. Throughout the world, the size order of modern prongs is nearly the same. We conclude the order of the area of the prongs in M1 is protocone > paracone > metacone > mypocone. In M1 the area of the protoconid is the largest while the hypoconulid is the smallest. Areas of the other prongs are almost the same.

Key words: Molar; Crown basal area; Relative basal cusp area; Holocene