My sister discovered that she had a couple of genetical conditions related to her teeth. Amelogenesis imperfecta, and another one. A specialist noticed this when she was doing some other tests, which required that her teeth be dry.

In any case, said dentist that discovered this told her that she should urge any siblings to also get tested. I've bee absolutely meticulous about my teeth, but I've always had problems with them - they simply seem to break and crack far too often, among other things.

I've gone to three different dentists since that, and they've all been completely uninterested finding out more. All told me "I recommend that you go to the dentist that diagnosed your sister".

It should be said that where I live, Norway, you get heavily subsidized treatment for damage related to such conditions - so we're potentially talking about quite a lot of money.

Other than that, I've been quite happy with my experience (with dentists).