I found this great web site that I feel really answers your question I took a monet to copy some of the information they had for your review and then listed the web site address below
Ask almost any dentist or orthodontist and they’ll tell you there is no such thing as a “best” whitening toothpaste for kids or adults with braces. Actually, whitening toothpastes are products you should altogether avoid until you’re free of all your brackets and wires. You’ll have plenty of time to work on the color of your teeth after you’ve perfected your smile. For now, just focus on the straightening of your incisors, canines and bicuspids.
If you use a whitening toothpaste while belted in braces, you run the potential risk of having the area underneath the bracket a lesser shade of white than the rest of your tooth. It works much like coffee, cola, tea, red wine and tobacco, simply with the opposite effect. Instead of discoloring or yellowing your teeth like these items could, a whitening toothpaste will lighten the areas exposed, while never touching or altering the section of the tooth protected by the braces. And just because you drink dark cola or smoke, don’t think that the whitening agents in those toothpastes will counteract what you’re putting your teeth through. Stop using them all.
So in short I think you should just get the toothpaste brand you like without the whiting.