I cannot tell a lie. But this book can.
The book almost seems like it's trying to set the record straight about Washington never actually having wooden teeth, but it fails at this because it's not accurate about what actually did happen, even according to its own timeline! At least it's not marketed as a non-fiction book, but kids aren't going to know that, and most parents probably won't even notice. But I guess ultimately the book isn't really about what the teeth are made out of, it's about dealing with problems.
Message
Washington had problems with his teeth that were completely fixed by hippopotamus ivory dentures.