Kinetic Aspects of Gingival and Periodontal Ligament Fibroblast Attachment to Surface-Conditioned Dentin

An in vitro model has been developed for measurement of initial attachment of 3H-labeled human gingival fibroblasts (HGF) and periodontal ligament cells (HPDL cells) to sieved dentin powder. Reproducible attachment was obtained and was closely related to the number of plated cells, the amount of dentin powder, the temperature, and the time (from 0 to 6 h) of incubation. HGF and HPDL cells had a high affinity for untreated dentin. Heat-denatured BSA coating of the dentin fully inhibited cell attachment, while a fibronectin coating had no significant effect. A surface conditioning of the dentin grains by 3% citric acid or by 2.5% minocycline-HCl increased the initial attachment of HPDL cells significantly (p < 0.05). Minocycline-HCl was more efficient than citric acid in that respect. In addition, HGF attachment to untreated dentin was highly significantly improved (p < 0.005) by a pre-incubation of the cells with 50 micrograms/mL of minocycline, and there was also indication (p = 0.067) of improvement by the presence of minocycline in the attachment medium, with a maximum of efficacy at 110 micrograms/mL. These results suggest that minocycline-HCl directly influenced the attachment properties of fibroblastic cells and that citric acid and minocycline-HCl could act by different mechanisms. HGF and HPDL cells originating from the same patient displayed no significant difference in their attachment to dentin in this model.