  An approximate model of a spacetime foam is presented. It is supposed that in
the spacetime foam each quantum handle is like to an electric dipole and
therefore the spacetime foam is similar to a dielectric. If we neglect of
linear sizes of the quantum handle then it can be described with an operator
containing a Grassman number and either a scalar or a spinor field. For both
fields the Lagrangian is presented. For the scalar field it is the dilaton
gravity + electrodynamics and the dilaton field is a dielectric permeability.
The spherically symmetric solution in this case give us the screening of a bare
electric charge surrounded by a polarized spacetime foam and the energy of the
electric field becomes finite one. In the case of the spinor field the
spherically symmetric solution give us a ball of the polarized spacetime foam
filled with the confined electric field. It is shown that the full energy of
the electric field in the ball can be very big.
