  Based on the weak coupling expansion of gravity, we calculate the
gravitational contributions to yukawa coupling, scalar quartic coupling as well
as gauge couplings with general Landau-DeWitt gauge-fixing choice and a gauge
preserving (of SM gauge group) cut off regularization scheme. We find that the
results depend on the Landau-DeWitt gauge-fixing parameter. Based on the two
loop RGE of SM couplings with one loop full gravitational contributions in
harmonic gauge, we study the constraints on the higgs and top quark mass from
the requirement of existing the other degenerate vacua at the Planck-dominated
region. Our numerical calculations show that nature will not develop the other
degenerate vacua at the Planck-dominated region with current higgs and top
quark masses. On the other hand, requiring the existence of the other
degenerate vacua at the Planck-dominated region will constrain the higgs and
top mass to lie at approximately 130 and 174 GeV, respectively.
