An electron microscopic study of the regeneration of gingival epithelium following gingivectomy in the dog

Abstract

Regeneration of dog gingival epithelium following gingivectomy was studied electron microscopically. The wounds were sampled at 24 hour intervals until 14 days following the operation. From a relatively undifferentiated migrating epithelium the process of differentiation resulted in the following sequence of events. In areas where the cells made contact with the fibrin of the blood clot, a basal lamina and hemidesmosomes appeared, the number of cytofilaments increased as did the number of desmosomes and free ribosomes. Further differentiation in the masticatory epithelium was related to keratinization. The cytofilaments in the cells of the upper layers became grouped into bundles, membrane‐coating granules and keratohyalin granules appeared, the intercellular spaces in the superficial layers became narrowed and finally a stratum corneum was formed by the seventh day. In the epithelium lining the crevice a stratum corneum was not formed, the intercellular spaces in all the layers remained wide and the cells in the upper layers developed a relatively prominent Golgi apparatus and numerous membrane‐bound granules throughout their cytoplasm.The result of the differentiation in the regenerated gingiva was the formation of masticatory and crevicular epithelium which were ultrastructurally similar to the two epithelia originally present.