The biomaterials used in the oro-maxillo-facial region, in particular the oral cavity, center of the region, require unique biocompatibility characteristics compared to those for other parts of the body. Cell-to-material interaction is a key approach in elucidating such aspects as biological, mechanical, and chemical compatibility of biomaterials in vitro. The results obtained by the in vitro tests under dynamic conditions mimicking the functions of this region are considered to better reflect the material's behavior in vivo than those obtained by the conventional, static testing methods. We have obtained data different from those obtained by the conventional methods. A simulation approach appears to be necessary to elucidate biocompatibility. Also, the measurement of the adhesive strength of cells on biomaterials is important in elucidating the cell-to-biomaterial interaction. Further refinement of methods is essential for standardization.