Originally Posted by: Jolly McJollysonRight, and that's what I meant. If you emphasize the notes you'd emphasize with a normal C major backing, you'd be playing a C major scale no matter what you choose to label it. If C is your root note, you're not playing D dorian.

It is not what I choose to label it. It is what Music Theory calls it.
A "G major pentatonic scale" is gonna show an "F#" in the key signature in standard notation, because the parent scale is G Major not "C Major"
In the same way a "D minor pentatonic scale" is gonna show a "Bb" in the key signature, because the parent scale is D minor; not "C major".
So, if you play those scales you can`t say that you are playing a C major scale. You would be playing a G major pentatonic scale over "C" in the first case and, a D minor pentatonic over "C" in the second case.

And yes. You would say D dorian when you play the second mode of the C major scale, or C dorian when you play the second mode of the "Bb major scale".
You can read more about this in:
Guitar World
presents
Jhon Petrucci`s
Wild Stringdom.