[Observations on the dentino-enamel junction--net-like structures on decalcified dentin surface].

Abstract

As part of morphological research to investigate the development and function of the human dentino-enamel junction, structural features of net-like structures on the decalcified dentin surface of upper and lower incisors were observed by using stereoscopic microscope, and scanning and transmission electron microscopes. The results were as follows : 1) The net-like structures on the decalcified dentin surface were stained by hematoxylin, orange G phosphomolybdic acid, toluidine blue and aniline blue. 2) The majority of net-like structures were covered with a membrane-like structure. 3) An individual reticulation of net-like structures corresponds to the margin of each dentin foveolus. 4) The dentin crystals situated in the vicinity of the dentinoenamel junction were larger than the crystals of usual dentin and were more closely aligned. On the other hand, the enamel crystals in this region were smaller than those in other layers of enamel. The surface dentin in the vicinity of the dentino-enamel junction seemed to be highly calcified. 5) It was possible to clearly demonstrate the outline and distribution of dentin foveolus by using certain dyes on the decalcified specimen. 6) By observing the distribution and structural features of net-like structures in detail by applying this dye method to human and animal teeth, the formation mechanism of the dentino-enamel junction and functions of those teeth were elucidated morphologically.