[Human tooth development in antenatal period (a luminescent-histochemical study)]

The aim of this study was to examine the distribution and the role of biogenic amines during the differentiation and maturation of the cells of the developing tooth. The study was performed on 185 human embryos and fetuses. The material was subdivided into two groups. Group 1 included the embryos and fetuses at developmental weeks 8-18 (period of induction and differentiation of dental primordia), group 2 consisted of fetuses at developmental weeks 20-28 (period of dental hard tissues formation). Cryostat sections of the lower jaw were studied using the luminescent-histochemical methods: Falck's method for selective demonstration of catecholamines (CA) and serotonin (S), and Cross's method for identification of histamine (H). The concentrations of biogenic amines were assessed quantitatively using cytospectrofluorometry. Unna's polychromatic toluidine blue staining was also used. Serotonin index was calculated. It was found that during the period of dental hard tissues histogenesis the mast cells (MC) along with H, contain S and CA. Maximal S content in peridental MC coincided with the appearance of enameloblasts, while that one of H in peridental MC, granular luminescent cells, dental pulp MC, blood vessels and nerve fibers was concomitant with the beginning of enamel deposition. Maximal content of S in peridental MC and of H in dental pulp blood vessels coincided with the beginning of dentin deposition. The demonstrated connection between the biogenic amine content in enamel organ and in mesenchymal structures of developing tooth, as well as between biogenic amine-containing cells and nerve fibers may underlie the mechanisms of their mutual inductive influence during the process of odontogenesis.