Is it possible to whiten fillings andteeth the same degree?

Not quite.: Whitening gel are not effective on dental filling material.

Not really: White fillings are colored by the manufacturer. And though they can discolor over time, especially with the tannins in sodas, coffee/tea and red wine- you can't change the intrinsic color of the filling. Tooth bleaching removes some of the natural yellow of teeth- so in some cases, bleaching your teeth may make your filling look more yellow.