Not a dentist, but I've lost a couple of teeth to bruxism - they were cracked all the way down to the roots. The endodontist told me there was nothing that could be done to fix them. Got one of them replaced with an implant. I wear a mouth guard now when I sleep so that things don't get worse. Since I suspect there are maybe a couple other teeth that could be have the same problem I'd very much like it if there were some way to regrow teeth.