Supernovae of Type II is a phenomenon that occurs at the end of the evolution of massive stars when the iron core of the star exceeds a mass limit. After the collapse of the core under gravity the shockwave alone does not succeed in expelling the mass of the star and in this sense the role of neutrinos is the most important mechanism to do so. During the emission of neutrinos flavor conversion is possible, related the phenomenon of oscillations, which however depends directly on the particular density profile of the medium. In this paper we present results of numerical simulations of neutrino flavor conversion in supernovae after bounce. The probabilities of survival for a given flavor in a complete three-flavors framework is estimated through an algorithm which conserves unitarity to a high degree of accuracy. The sensitivity of the results to the different adopted models for the supernova structure is examined in detail demonstrating how the neutrino signal could be used to check the validity of models. © 2008 The American Physical Society.