Cells and Materials


An explant culture of human gingival epithelium has been set up in order to provide a valuable test for evaluating the cytocompatibility of dental material s. In an attempt to supply a bank of gingiva ex plants, frozen and freshly excised specimens were cultured in parallel. Optical and scanning electron microscopy showed an early release of cuboidal cells forming a dense layer around the explants. Afterwards, cultures evolved differently . Spread cells grew and migrated more rap idly in fresh than in frozen explant cultures but their adhesion to substratum increased earlier in frozen ones. Epithelial phenotype of cells had been immunologically characterized by using a battery of monoclonal antibouies to cytokeratins (CKs). We found a time increasing expression of CKs 5, 6, 13 , 14115 , 16 and 17, whereas amounts of CKs 1, 2, 10 and 11 , specific for terminal differentiation , remained constant. The freezing procedure decreased the yield of CKs but did not modify the electrophoretic pattern . These results suggested that the differentiation of epithelial cells might proceed as in vivo. As an application, the cytocompatibility of precious (Au, Pd, Ag) and non-precious (Ni-Cr) alloys was assessed, the reference metals being Ti, which was chosen for its cytocompatibility and Cu, which was chosen for its cytotoxicity. Alloys differed by their ability to modulate cell proliferation and migration . Pd and Au exhibited a high migration potential, whereas Au-Pd and Ti allowed efficient cell proliferation but restricted migration . Reduced migration and proliferation attested the low cytocompatibility of Ag. The toxicity of Cu and Ni-Cr prevented cell migration. These result s showed the availability of this method for selecting biomaterials.