I can see yellow on my white veneers, bleaching does not effect them at all. Could it be polished off by a dentist?

Using whitening products on veneers is simply not effective. Porcelain veneers are stain resistant and therefore the shade of your veneers will not change. If your porcelain veneers are thin and the underlying tooth structure is yellow, you could be seeing the yellow show through. Another possibility is that you have a build upo of tarter on your veneers. I would suggest scheduling an appointment with your dentist to have your teeth cleaned and examined. You will be able to discuss your diet and hygiene with him/her and double check the shade of your teeth. I hope this helps.  Feel free to click to save my name below, in case you have more questions in the future.

It is possible that the lab technician made the veneers look real and blended shades so they don't look fake.  Sometimes it is layers of porcelain and not stain, so it may be impossible to polish off.  Even if possible, it likely would remove the gloss and shine, maybe even texture, and the result will not be pleasant.  It is likely that the only solution is to replace, but sometimes the replacement is not better than the original.

Porcelain veneers are made out of Porcelain.  They dont change color, and they can't be bleached.  Are you sure you have porcelain veneers and not composite veneers?  Composite veneers are made out of plastic material and they do change color with time.  

Typically, veneers themselves don't pick up stain since they are not porous. One question I have is was the yellow on the veneers initially? Sometimes that yellow stain is intentionally placed on the veneer to give a more natural look to the veneer. Depending on how that stain was applied, it could be polished away. If this is something new, there are polishing devices that we use that could remove this yellow discoloration. It's important to keep the veneers nicely polished to keep plaque away from them.