The patient has no real recourse against a dentist in the US short of a lawsuit. And that is going to cost $5-10 thousand up front.
Filing a complaint with the state medical board has all the impact of filing a BBB complaint against a car manufacturer. If the dentist is interested in his/ her patients, they will try to make it right. If they have your money and don't care the state board has no power to require/ enforce action by the dentist.
Dentures, like crowns, inlays and composite filings can be any color the patient desires. Monarch Dental is infamous in the Dallas area for their lab not matching existing tooth color, so a crown stands out as obviously not a natural tooth.
One advantage of dentures is that the teeth are all the same color. While I was working with the doctor for mine, which I choose as one shade lighter than my few existing teeth, he had a lady patient who wanted hers pure white.
I overheard her complaining they were not white enough, so he redid them. They were so white already they looked like a new car, not teeth.
Yes, dentures look a bit unnatural because very, very few people have perfect teeth. Especially at our age. We aren't fooling anyone that we have great natural teeth.
We just have no pain, comfort when eating. And will almost certainly never, ever need a dental anesthesia shot again for the rest of my life.