Dental implants vary markedly in the topography of the surfaces that contact cells. Four principles of cell behavior first observed in cell culture explain to some extent the interactions of cells and implants. (1) Contact guidance aligns cells and collagen fibers with fine grooves, such as those produced by machining. (2) Rugophilia describes the tendency of macrophages to prefer rough surfaces. (3) The two-center effect can explain the orientation of soft connective tissue cells and fibers attached to porous surfaces. (4) Haptotaxis may be involved in the formation of capsules around implants with low-energy surfaces. Keywords: cell behavior, dental implants, percutaneous devices, surface topography