  We study the consequences of including parity preserving matter for the
effective dual theory corresponding to compact QED_3; in particular we focus on
the effect of that contribution on the confinement-deconfinement properties of
the system. To that end, we compare two recent proposals when massless fermions
are included, both based on an effective anomalous dual model, but having
global and local Z_2 symmetries, respectively.
  We present a detailed analysis to show that while for large mass fermions the
global Z_2 symmetry is preferred, in the massless fermion case the local Z_2
scenario turns out to be the proper one.
  We present a detailed discussion about how the inclusion of massless fermions
in compact QED_3 leads to deconfinement, and discuss the stability of the
deconfined phase by introducing a description based on an instanton dipole
liquid picture.
