  In the paper, only Static Spherically Symmetric space-times in four
dimensions are considered within modified gravity models. The non-singular
static metrics, including black holes not admitting a de Sitter core in the
center and traversable wormholes, are reconsidered within a class of
higher-order $F(R)$, satisfying the constraints $F(0)=\frac{dF}{dR}(0)=0$.
Furthermore, by making use of the so-called effective field theory formulation
of gravity, the quantum corrections to Einstein-Hilbert's action due to
higher-derivative terms related to curvature invariants are investigated. In
particular, in the case of Einstein-Hilbert action plus cubic curvature
Goroff-Sagnotti contribution, the second-order correction in the
Goroff-Sagnotti coupling constant is computed. In general, it is shown that the
effective metrics, namely Schwarzschild expression plus small quantum
corrections, are related to black holes and not to traversable wormholes. In
this framework, within the approximation considered, the resolution of
singularity for $r=0$ is not accomplished. The related properties of these
solutions are investigated.
