[Migratory ability of cells derived from periodontal tissues and their attachment to root surfaces]

The migratory ability of cells from the periodontal ligament (PDL), alveolar bone and gingiva of monkeys was compared in vitro using a three-dimensional collagen gel model. In addition, the cell attachment to cementum and dentin was examined ultrastructurally. Cultured cells were obtained from monkey periodontal tissues using an explant method. Type I collagen solution was pipetted into the wells of 24 multi-well plates and polymerized. And the cell invasion assay was performed by seeding test cells onto the gel, and subsequent culture for 1, 3 and 7 days. The specimens were fixed and embedded in epoxy resin. Semi-thin sections of 1 micron thickness were obtained and subjected to visual assay under a light microscope. Parameter was two fold; numbers of cells migrating into the gel and the maximum distance from the gel surface to the leading front of migrated cells. Secondly, two kinds of root surface conditioning were performed on extracted monkey teeth, in which included scaling only surface cementum and root planing. Each root fragment was placed into the wells and collagen solution was subsequently pipetted into the well. And the collagen solution was polymerized to prepare the 100 microns-wide gel layers on the root fragments. Test cells were seeded onto the gel and cultured for 2 and 3 weeks. The interaction between the cells and the root surfaces was examined under a transmission electron microscope. The migratory ability of PDL cells was less than that of cells from bone and gingiva. Although the migrated bone and gingival cells produced fibrillar materials on the cementum, the PDL cells could not establish an ideal attachment to either cementum or dentin.