I've looked, but haven't found one that seems worthwhile.
Some cover routine visits, like cleanings, for about what it would cost anyway. They just spread the cost over the whole year.
Others that have "real" insurance provisions for unexpected work, seem to have very low max payouts, which wouldn't cover the procedures you're most likely to need.
Then there are the "discount" plans where you pay an annual fee to get a discounted rate from the dentist, or network of dentists. But the discount doesn't seem like much, and if you shop around you can probably get the same procedure for about the same price anyway.
I haven't found one that acts like a medical plan, where I pay for all or part of routine care, and the policy will pay for unexpected dental bills.
My guess is that almost everyone needs expensive dental care at some point, so it's not the kind of risk you can pool. You just have to basically self-insure.