Characteristics of infant deciduous teeth of the Yangshao culture at the Yuhuazhai site in Xi'an, China

Abstract In this paper, we observed and measured 168 infant deciduous tooth crowns from the early Yangshao culture (4500 ± BCE) excavated from the Yuhuazhai site in Xi'an, China, in an attempt to reveal the phenotypic characteristics of this population, as well as to complement the morphological characteristics and dimensions of the crowns of prehistoric Chinese deciduous teeth. Additionally, the Yangshao cultural population's formation factors of hereditary traits and their relationship with other groups were investigated using the deciduous teeth. The research methods we used were mainly the buccolingual diameters (BL) and mesiodistal diameters (MD) of the crowns of deciduous teeth with varied dental locations that were measured in addition to the obsevation and statistical analysis of the 11 most representative unmeasured features. Our results indicated the tooth crown shape of the Yuhuazhai infant's deciduous teeth is similar to that of the Northeast Asian population's "Sinodonty," and it also has a small percentage of the Southeast Asian population's "Sundadonty" traits. Additionally, compared to other Chinese groups, this group showed no change in the crown of deciduous teeth in varied dental locations, with the exception of the mandibular second deciduous molar crown, which was somewhat smaller than that of Homo erectus in China. Overall, the morphological traits of infant deciduous teeth in the group are essentially compatible with the genetic characteristics reflected in the skulls of other Yangshao culture populations. Furthermore, the similarity of deciduous tooth size in different Chinese populations may be connected to the continuity of human evolution in China.