  Noncommutative geometry, as conceptualized by Nicolini, Smailagic, and
Spallucci, may be viewed as a slight modification of Einstein's theory. The
same can be said for $f(R)$ modified gravity for an appropriate choice of the
function $f(R)$. Since such an $f(R)$ could be determined from the
noncommutative-geometry background, these gravitational theories make very
similar predictions in the discussion of (a) dark matter and (b) traversable
wormholes; they can therefore be taken as equally viable models.
