The Initial Mineralization during Tooth Development in Sharks

Abstract

In the early stage of enameloid formation in sharks and skates, a great number of “tubular vesicles” appear in the enameloid matrix [1–6]. Initial enameloid crystallites are observed in the tubular vesicles so that the tubular vesicles are probably the sites of initial mineralization in shark enameloid [1,6]. Kemp and Park [2], Goto [3] and Kemp [4] suggested that the tubular vesicles originated from epithelial cells. To the contrary, their odontoblastic origin was proposed by Sasagawa [6] because the tubular vesicles were limited by the unit membrane which sometimes seemed to continue into the cell membrane of odontoblasts. Thus, the aim of this study was to investigate the fine structure of enameloid in the early stage of tooth development, and to reveal further details on the relationship between the tubular vesicles and the surrounding cells, and between the tubular vesicles and the initial enameloid crystallites.