This is interesting, but I've read that there is also research being done into the specific mechanism of tooth replacement (Like when you lose your baby teeth), and scientists have identified and isolated the two hormones responsible for controlling (and turning off) dental growth. They have been experimenting on mice, as usual, with favorable results. Once they are through playing with their lab rats it will be possible to go to the doctor (or dentist) and get a shot in two specific places of the mouth which will trigger the replacement of all of your teeth at once. So, in response to the statement "nevermind regrow a tooth"... It's being worked on.