Can I get teeth whitening on a build up tooth?

I see no reason to wait for a crown, as long as there aren't any issues with the Root canal. I would go ahead with it.

Hello,
I’m not sure why you were told to wait six months.  Typically, I have patients wait a week or so to make sure that they do not have any discomfort after the root canal and then we can restore the tooth. I find that internal bleaching does not guarantee that the tooth will whiten to the degree of the other teeth.  Restoring the tooth with a crown is much more predictable because we can match the shade of the crown to the other existing teeth. Best of luck to you. Best,
Dr Mancuso

Excellent question. 
If there's natural tooth around the build up you can whiten that, but not the build up material, sorry. 
An in-person exam is the best way to go, please see a dentist with experience in the cosmetic field. 
Best of luck!
Dr. Laurence Rifkin 
#beverlyhillsdentist
#celebritydentist

Hello,
There are different types of teeth whitening for different situations. Normally teeth whitening works on vital natural teeth. Composites and porcelain veneers and crowns can not be whiten. As far as teeth tht have received root canal treatment, they can be whiten through internal bleaching. Ask your dentist if he offers internal bleaching. It's typically done for the front teeth when the root has darkened, not as much for the back teeth which is what it sounds you may have. But it never hurts to ask. Best of luck.