Cell behavior on bovine dentin. Scanning electron microscopic images show the bovine dentin surface orientated migration of outgrown pulp sphere cells (a) and the vortical ingrowth into the dentinal tubules as well as the covering of the tubular walls by these cells (b). Multilayered cell formations with cellular emulation of three-dimensional dentin structures could be detected in the multi layered outgrowth area adjacent to a sphere (white arrows in Figure 6
c). The white arrows in figure (d) denote the fibrillar dentin tissue-like structure over numerous cell layers (black arrow).