  The melting of a Wigner Crystal of electrons placed into a host polar
material is examined as a function of the density and the temperature. When the
coupling to the longitudinal optical modes of the host medium is turned on, the
WC is progressively transformed into a polaronic Wigner Crystal. We estimate
the critical density for crystal melting at zero temperature using the Lindeman
criterion. We show that above a certain critical value of the Frohlich
electron-phonon coupling, the melting towards a quantum liquid of polarons is
not possible, and the insulator-to-metal transition is driven by the ionization
of the polarons (polaron dissociation). The phase diagram at finite temperature
is obtained by making use of the same Lindeman criterion. Results are also
provided in the case of an anisotropic electron band mass, showing that the
scenario of polaron dissociation can be relevant in anisotropic compounds such
as the superconducting cuprates at rather moderate e-ph couplings.
