DENTAL DEVELOPMENT IN PLIOPLEISTOCENE HOMINIDS - ENAMEL EXTENSION RATE IN FOSSIL HOMINIDS

The speed of advance of the the matrix-forming front (extension rate) was estimated from the slope of the stries of Retzius with the enamel- dentine junction (EDJ) and measured by the distance between adjacent s triae along the EDJ. The comparison of the results shows that the vari ation in both characteristics is similar in Plio-Pleistocene hominids and thus, the angles stria-EDJ can be used as an estimation of the ext ension rate of enamel in Plio-Pleistocene hominids. Some Plio-Pleistoc ene hominids show a reactivation of the extension rate in the last thi rd of crown formation; it is probably an adaptation to prevent a long crown formation time.