I've had cavities disappear, and teeth recover. I've had before and after x-rays side by side taken by shocked dentists. It's not to hard to believe, children teeth grow.
I study oral history and you’d be surprised what mundane information amazes people 50 years after the fact. Regrowing teeth would definitely fall into such a category, even if the evidence is unintelligible to present day dentists or you want aspects embargoed.