"Why are the orcas teeth so bad if the have dental care?"

Killer whales, like all toothed whales and dolphins, develop worn teeth. It's important to note that wild killer whales wear their teeth as well. And just like our killer whales, it's a result of exploring and manipulating things in their environment. Remember that killer whales, bottlenose dolphins, both species of toothed whales and dolphins, don't have hands. They use their mouths to manipulate their environment. Looking at photos of stranded killer whales, you actually see that a lot of them have the exact same tooth profile as our killer whales. If they are exploring things in their environment or they're brushing against a more abrasive surface, like a wall, there may be some tooth wear as a result. The important difference is, of course, that we have a team of veterinarians there to intervene. If that were to develop into a problem and on the rare occasion that it does, we can step in and provide the comprehensive care that’s needed. Interestingly, tooth wear is actually part of the latin species name of the bottlenose dolphin, tursiops truncatus. “Truncatus” is a reference to worn teeth. There is even fossil evidence of worn teeth in pre-historic cetaceans.* * “Handbook of Marine Mammals, Volume 6”, ISBN 0-12-588506-7