An electron microscopic study on the epithelial attachment of golden hamster molars.

Abstract

The fine structure of the junctional epithelium (JE) was studied by electron microscopy using molars of golden hamsters aged 10 days or 5 weeks. The following conclusions were obtained : 1. Primary epithelial attachment (PEA)The oral sulcular epithelium (OSE) adjoins the enamel organ at the top of the JE. Cells of the JE showed the same structure as those of the enamel organ at the pigmentation stage. Secondary epithelial attachment (SEA)In the cells directly connected with the adjoining enamel, the Golgi apparatus was located in the cytoplasm facing the enamel, and the rough endoplasmic reticulum was found in its vicinity. In other words, this cell type showed polarity, as in secretory cells. Cells located over the cells connected with the enamel contained small vacuoles with electron-dense material in the cytoplasm. Cell divisionA large number of mitotic figures were found in the basal layer and cells directly connected with the enamel of the JE, and these were very numerous in the infected JE. This finding was considered to indicate that there is a relationship between the deepening of pockets and bacterial infection.Polymorphonuclear leukocytes (PMN) were found mostly in the intercellular spaces between ameloblasts of the PEA, and in the papillary layer of the PEA. In the SEA, PMN were found mainly in the intercellular spaces between cells connected with the enamel and those of cells containing small vacuoles, as well as in the OSE. Very occasionally, PMN infiltrated the JE through the basal lamina at its apical end.