Yes, but it would have "broken the plot" if the idea was to teach children about not worrying when they loose baby teeth. Unless Ruby told him that he would get a new tooth and he could just abandon the old one. It doesn't make real-life sense, I know.
Of course, predators like Chomper often lost and regrew teeth throughout their lives, so not only do they not need to worry much about cavities, but losing teeth would not likely have been a big deal.