Maybe that advice has corollaries. “Just exercise the body parts you want to stay healthy.” “Just change the oil in the car you want to keep.” Those pearlies in your mouth have no other place to go for care and no other place to serve as masticators. Your teeth will be your teeth and no one else’s teeth. So, here’s another corollary: “Just care for the people on your planet. You’ll lessen the chance that any of them go bad.”