Dental Microstructure Studies
Dental development in humans and great apes begins prior to birth and continues throughout adolescence. Like many biological systems, hard tissue formation is characterized by a circadian rhythm. Developmental rate and time are permanently recorded by incremental lines in enamel and dentine, which remain unchanged in these tissues for millions of years. Given that dental remains are the most common, well-preserved type of fossil evidence for extinct species of primates, examination of incremental growth processes may shed new light on the evolutionary developmental biology of early humans.
Examination of hard tissue development from a histological perspective is a relatively new field of odontological inquiry, particularly in relation to answering phylogenetic questions. Recently, there has been a dramatic increase in the number of studies on incremental dental development in hominoids. Studies on Plio-Pleistocene hominids and Neanderthals have indicated that the relatively slow developmental rate and prolonged duration of modern human crown formation may be a fairly recent and unique development.
The MPI-EVA Human Evolution Department has recently created state of the art facilities for the study of dental development in fossil hominids (Dental Hard Tissue Laboratory). Histological analysis of dental material facilitates understanding of the final functional products of the processes of development and growth, which may be understood in terms of enamel thickness (macrostructure) and enamel microstructure. Recent studies have provided information on age at death in hominids with developing dentitions, absolute and relative timing of dental development, age at M1 emergence, and differences in the developmental pathways of enamel formation. These studies have important implications for our understanding of hominid evolution and the origin of developmentally modern humans.
Cast of a hominid tooth showing growth lines (perikymata) on the surface of a canine, with one quarter of a human index finger for scale.