The influence of chemically-induced modifications of root surfaces on cell migration, attachment, and orientation.

Surface demineralization of tooth root surfaces has been shown to improve re-attachment of cells and to promote tissue reconstruction following periodontal surgery. Exposure of collagen fibers has been thought to facilitate migration, attachment, and orientation of fibroblasts on the root surface. However, using an in vitro assay, we have found that both attachment and orientation of human gingival fibroblasts on demineralized dentin surfaces are further improved following digestion of the exposed collagen with bacterial collagenase. In contrast, pronase and trypsin digestion of the surface collagen had no significant effect, whereas heat denaturation had an inhibitory effect. Dissociative extraction of the demineralized dentin slices with 4 mol/L guanidine hydrochloride (GuHCl) also improved attachment and orientation, and when undemineralized dentin was subjected to dissociative extraction, cell attachment was comparable and orientation superior to that on demineralized surfaces. These studies indicate that demineralization is not a prerequisite for facilitating attachment, and that enhanced attachment and orientation of cells are not dependent upon a collagenous substratum.