Histological reconstruction of dental development in four individuals from a medieval site in Picardie, France.

The majority of dental development studies in modern humans are based on radiographic analysis. In comparison, very few full histological studies have been carried out. In the present study, the onset of enamel formation and crown formation time have been established by histological analysis of the complete dentition in a medieval French individual. Crown formation times were established for the dentition of three further individuals. The number of cross-striations between adjacent striae of Retzius was measured and accentuated striae were used to construct a chart of the chronology of tooth development. Results on crown formation times in individual teeth when compared with previous histologic studies are slightly greater than values in a modern African male and near to or less than values in (M1) and (I) respectively in a modern population from Spitalfields, London. Histologically derived crown initiation times are earlier than those reported for radiographic studies. Values for crown formation times derived in general from radiographic studies are less than those of our study. Attention has recently been focused on the overlap of molar development as a key character for distinguishing between humans and great apes. In this study, there is an overlap in crown formation between M1 and M2 of 0.27 years and a temporal delay of 1.7 years between M2 crown completion and the initiation of the M3.