Explants of bovine gingival mucosa were cultured for four days on scaled
and citric acid-conditioned root surfaces. Demineralization of the hard
tissue with citric acid exposed the collagenous matrix of the root.
Undemineralized islands were frequently seen among the collagen fibers
of the treated roots. When cultured on scaled, control root surfaces,
the epithelium migrated inwards between the connective tissue of the
explant and the root surface. On citric acid-treated roots, epithelial
migration in this direction was rare although it was possible. Citric
acid treatment of the substratum directed the epithelium to migrate
outwards from the explant. Only a few of the controls showed epithelial
migration to the outward direction. The findings indicate that
demineralization of the root surface has an influence on the direction
in which the epithelium initially starts to migrate. An induced delay of
epithelial migration between the gingival connective tissue and the
hard tissue may be favorable for connective tissue attachment to the
root surface