Comparative response of epithelial cells and osteoblasts to microfabricated tapered pit topographies in vitro and in vivo

Microfabricated tapered pits in vivo can stimulate connective tissue and bone attachment to percutaneous devices, secondarily preventing epithelial migration, and promoting long-term implant survival. Epithelial cells, which form a seal with a dental implant, acting as a barrier, and osteoblasts, which form bone, can come into contact with the same implant topography. To investigate whether the phenotypic characteristics of each cell type influenced cell response to micro-topography, we compared the response of the two cell types to the same dimensions of tapered pits, in vitro, and in vivo. Increased spreading, mature FAs, and restricted migration characterized individual PLE cell response to tapered pits. In contrast, osteoblasts were highly migratory, formed smaller, punctate adhesions and mineralized. Epithelial sheets formed from high-density PLE cultures demonstrated that tapered pits did not inhibit migration of the PLE sheets in vitro, similar to in vivo observations. In vitro, PLE sheet migration correlated with increases in vinculin, tyrosine phosphorylation, cytokeratin and ERK 1/2 phosphorylation. The findings of this study show that tapered pits stimulate osteoblast mineral deposition in vitro and in vivo, but do not prevent epithelial sheet migration. In vitro results suggest that epithelial sheet migration could involve altered FA mediated signal transduction.