Ultrastructural study on the regeneration of the junctional epithelium following gingivectomy (author's transl)

Abstract

The present experiment was undertaken to study about early stages in the regeneration of the junctional epithelium following gingivectomy in rats. Gingivectomy was carried out on the lingual side of the maxillary molar teeth. At intervals of 0 hour to 28 days post-operatively, the maxillary molar teeth were extracted with the surrounding gingiva and coronal portion of the alveolar crest in situ. The sections were examined in light and electron microscope. The results were followed.1) After 2 days, the epithelial cells were put in contact with the enamel. New junctional epithelium was consisted of the oral epithelium. The junctional epithelium was attached to the enamel surface by means of the basal-lamina-like structure and halfdesmosomes.2) After 3 to 5 days, the junctional epithelium was consisted of the same epithelial cells both the apical and the coronal parts. These newly formed epithelial cells of the apical part provided with welldeveloped Golgi complexes, elements of rough endoplasmic reticulum, but the epithelial cells of the coronal part possessed few organelles. From these results, it was postulated that the epithelial cells had migrated from the apical toward the coronal part. In the junctional epithelium, the epithelial cells seemed to be always supplied and renewed from the oral epithelium. The sulcular epithelium was consisted of keratinized epithelium.3) Formation of the new junctional epithelium following gingivectomy was completed in 28 days. The cells of new junctional epithelium were provided with the Golgi complexes, elements of endoplasmic reticulum. The junctional epithelial cells showed appearances of numerous intracytoplasmic vacuoles. The cells constituting the coronal part of the oral sulcular epithelium showed keratinization.It seems, therefore, that the gingival sulcus following gingivectomy in rats had been reformed by the newly formed junctional epithelium and the keratinized oral sulcular epithelium.