We provide a computational comparison of the performance of stentless and stented aortic prostheses, in terms of aortic root displacements and internal stresses. To this aim, we consider three real patients; for each of them we draw the two prostheses configurations, which are characterized by different mechanical properties. Moreover, for each patient, we consider also the native configuration. For each scenario, we solve the fluid-structure interaction problem arising between blood and aortic root, through Finite Elements. The results show a better agreement between stentless and native displacements and stresses, with respect to the stented case.