Veneers help!?

if you can see the tooth underneath it has nothing to do with the lab. sound like the dentist didn't prep the teeth down enough for the lab to put any bulk on the veneer. and after he re-did them he should have taken what is called a stump shade. that is the shade of the actual stumps (teeth after they are prepped) he bonded the veneers to. if the lab had a stump shade they would have put a layer of opaque porcelain which would block out any shade that would show through underneath the veneer. if you are not happy after 3 attempts the dentist should at least refund half the cost and you should find a better dentist! one with a clue