I sent an ask about the "troll teeth grow back" fact when you posted it, but I don't think it sent, so I'll try again. Equius was only 6 sweeps/13 years old at that time. He said his teeth "usually" grow back. Assuming that trolls loose teeth like humans do, Equius could have been knocking out baby teeth that grew back as adult teeth. The ones that haven't grown back could've already been adult teeth, so they'll never grow back.
That could be.
Or trolls could have several sets of teeth
Or their teeth could just keep growing back like sharks.
~Mod T