Organization of an oriented fiber system in vitro by human gingival fibroblasts attached to dental tissue: Relationship between cells and mineralized and demineralized tissue

The purpose of this study was to examine the effect of partial demineralization of cementum on the morphology of the interface between gingival fibroblasts (HGF) and tooth in an in vitro oriented cell‐fiber system. Thirty‐two pairs of transversally‐cut root slices, 150 μm thick, were obtained from porcine premolars. Each pair of root slices was attached to the floor of a 35 mm culture dish, leaving an interdental space (IDS) of 500 μm between their peripheral surface. The root slices in half of the dishes were partially demineralized in a solution of 12% EDTA. Cocultures of root slices and HGF were examined using light and electron microscopy after 20 and 30 d. HGF were found to be oriented approximately perpendicular to the partially‐demineralized tooth surface. The cells exhibited cell processes that were attached to, and embraced, the exposed collagen. Similarly oriented fibrillar material, possibly collagen, was present between the cells and adjacent to exposed organic matrix of the tooth, sometimes appearing to be continuous with the collagen fibrils of the organic matrix. The HGF were oriented parallel to the non‐demineralized cementum. They were attached to it and formed a continuous capsule‐like covering. Fibrillar material, apparently newly synthesized, was oriented parallel to the tooth surface and was separated from it by the continuous cell layer. These observations suggest that the nature of the tooth surface that provides a substrate for the HGF may influence the morphology that they express in vitro.