[Ultrastructure of the connective corium in hereditary gingival hyperplasia].

The ultrastructural study of the gingival lamina propria of 4 patients from the same family with hereditary gingival hyperplasia showed a density increase of the collagen fibres, a decrease in their mean diameter and the dissociation in sub-units of certain fibres whereas their periodicity was not altered. This study showed also the presence of elastic and oxytalan fibres in greater amounts than in normal gingiva, whereas the number of fibroblasts did not seem to increase. However these fibroblasts seemed to undergo modifications in relation to age and to secrete a large quantity of amyloid substance in the extracellular spaces. The glycoproteins and the glycosaminoglycans more abundant than in normal gingiva were not influenced by the age of the tissue.